Zwrench

I wouldn't use that thin gasket over the thicker one. My advice is to go to the parts store and just get a new one. You shouldn't have to buy a whole other kit, just the base gasket.

As for the air horn gasket, as long as you don't have fuel leaking to the outside of the carb or into the bores, you should be o.k. Since that gasket is in contact with fuel it makes sense that it would absorb a bit of gas. Just be sure you tighten all the air horn screws evenly.

Also, it's hard to tell from your pictures but, it looks like you only have sealer on the middle of those plugs. Or maybe you scraped it off before the pics. I always coat the whole plug and a little past the edges onto the carb body itself. You have to be careful not to get it too thick, though, or it can interfere with the throttle body on reassembly.

L695speed

I went to the local Napa with the carb number and they said they would have it for me tomorrow. Also I ordered an all metal float. Unfortunetly due to the massive snow storm I'll probably not get it til Thursday. I'll do my best to help you compare notes and etc.

I am waiting to pull it out of the car til I have the kit. When I have all that stuff in hand I'll get it out and get to work. As for your problem with the carb base to Intake manifold gasket. I initally thought that gasket was my problem as it was falling apart on me. I went to the local parts store and they had it in stock and I walked away with a new one (nice and thick). It didn't solve the problem but the point is the gasket is available. I might take my project one step further and ensure the intake gaskets are ok. I also have new weatherstripping coming in soon too. So I will have plenty to do and hopefully have it up and running strong come spring.

RocketyMan

Alrighty. So I got the JBWeld all on there nice and dry. Yeah I covered the whole plug so that there would be no way that the fuel could leak out. I also put some epoxy on the other little plugs just for fun I guess. haha.

Anyway...with all that, I'm gonna bolt her on soon and see what happens.

I'll let you guys know.


(It might be hard to tell from the pictures, but the epoxy is covering all of it.)

L695speed

Hey Rockety, nice work. Just got a question so I'm not running back and forth to the stores. What tools have you needed to use for this project? I don't know if I have them all. I saw something about needing a 6 or 8 Torx and stuff like that. I already have the double D for the mixture screws. But I think there are other tools that I might need for the project that I don't have. So if you list what you've used I can go through it and see what I have or don't have. Thanks

RocketyMan

Well if you already got the torx and idle adjustment tool, then awesome! I actually used an allen wrench and..umm...yeah. Luckily I didn't strip anything.

The rectangular adjustment tool is very handy. I did a thing like the allen wrenches and just used a deep socket. It like BARELY fit over the idle mixture screws when I adjusted mine. :X

Anyways, another tool would be to measure the M/C Solenoid plunger depth when rich (all the way up) and then when its lean (all the way down). I actually just made that tool and marked on it the correct travel. (I'll tell you more about this later if you cant find one slim enough)


Needless to say, I still managed with my limited 'specialty' tools. But if you want to make life easier, you'll need basically this:

1. The torx (you already have)
2. The idle adjustment tool (you already have...I really need to get one of these)
3. A modified plunger gauge (its like a very slim ruler made out of steel thats very accurate)
4. Then if you get the carb rebuild kit, you should get a paper "L" shaped ruler
5. JBWeld (if needed)
6. Carb cleaner/acetone
7. A nice scraper

naf

iTrader: (7)

You can do without the lean stop guage if you count number of turns to seat then re-install at the same height.

RocketyMan

Weellll...I dunno about that because when I was tearing down my carb, I counted exactly 3 and 1/2 turns out (which is what is called for) before I took the rest of it out. But when I actually measured the lean stop of about 1.304" (really just 1.3"), I could only obtain that with doing 2 and 1/2 turns. I think the default is just 3 and 1/2 turns out which might lead to it being too rich. So ultimately it would be more accurate measured.

naf

iTrader: (7)

Yes there's certainly no guarantee if someone else has been in there before you-and there's probably some factory tolerance on some as well.

Shouldn't lead to a too rich condition though unless it's so far off that the MC dwell is unable to adjust the mixture.

L695speed

I thought I would post an update on where I am at. I started taking the carb apart, got the airhorn off the bowl. And I found a few things that might point to how long it was since it was rebuilt, sitting on a shelf and why it was stalling out at idle. I discovered the gasket between the airhorn and the bowl was torn in five places. Including one tear that was through one of the barrels and half the width of the gasket. Also the springs for the plunger were so covered in grime, old gas, dirt etc., that it was sticking. The screw that held the mixture control solenoid was all corroded. Finally carbon was present throughout and everything seemed sticky.

Now I've no doubt seen worse than this, but most of the things here point to just sitting around, age and etc. Despite the common sense mantra that me and my dad followed, (if it ain't broke, don't fix it) this is one case where we should have just ignored the fact that it worked fine 7 years prior. I'll get some photos, and keep working on it tomorrow. Everything could also use a good cleaning. For all I know I might have this thing up and running again tomorrow night. Now about that tool you made that looks like a ruler Rockety....how about it? LOL. I think my airhorn is actually not showing any signs of warping.

naf

iTrader: (7)

A gallon can of carb dip does a lot better job than the stuff that comes in the aerosol can. Pick it up at most any parts store.

L695speed

I saw it but I wanted to see how it cleaned up with the carb cleaner before I dropped 22 bucks on a gallon of stuff that will only be used once sofar.

L695speed

Ok, I'm gonna have to get carb dip. I also left several things on the carb body (choke weight assembly and etc, but I took the element out). Because I didn't see the point of trying to take it apart and risk stripping the one torx bolt trying to break it loose. However I've got everything except for the mixture screws out. And maybe some compressed air. The final thing is when I flipped the carb over a metal tube and spring fell out, I guess I missed it when I thought I got everything out. So I might need to ask where it goes when I get there. First I'm gonna go ahead and get everything cleaned up then I'll start gradually putting it back together starting with plugging the wells. We shall see how it goes.

Rockety, I might need your help with the plunger gauge, thats the only thing I don't have.

naf

iTrader: (7)

Post your Q's, no problem.

Zwrench

I agree that the stuff in the gallon can works better but, I don't think the carb body will fit in the can. You might need to find an old cake pan or something similar and pour the cleaner in that.

Try to get the choke housing off. Someone will correct me if I'm wrong but I think there is a seal on the shaft that operates the choke. That could be damaged or softened by the carb cleaner and cause the shaft to bind.

L695speed

I'm using an old oil change pan (we don't use it for oil changes so its clean) and also my understanding is with the electric choke you don't need to do that seal as it doesn't have one. The biggest challenge with rebuilding a carb is the fact that the diagram is not applicable in some cases. I've got an older diagram from an old rebuild kit (I think Dad did this before) and it says that with electric chokes you don't use that seal. I'll try to get it off but only if some one confirms that you need to replace a seal in there. Right now I've got the bottom of the carb soaking in the pan. along with a bunch of parts. Smells nasty but after 5 min you could see serious progress in getting everything off.

L695speed

Ok I just saw there is indeed a seal, I also managed to get the choke housing off without damaging anything. Everything is soaking (as much as I can put in the pan) and I left the mixture screws in for now. Naf, I'm pretty much following your rebuild plan that you posted. I'm probably unknowingly following your build up. I'll use that as a guide as much as I can so I'm not jumping on here with a billion questions. But here is one that you didn't cover, how the hell do you get the choke seal out? Everything is in reasonable shape, but I noticed one of my metering rods spring is broken. A small piece of the spring broke off one end. I haven't taken the kit apart yet because I want to get the three main pieces clean first so I can clear off the dip and start with a clean surface.

I remembered I had the 87 LG4 carb, I might take that one apart and salvage some parts out of it to use on the L69 carb. The metering rod springs for instance, and perhaps the TPS and MCS. I know that the guy who owned the donor car (caprice) had the motor rebuilt so no doubt all the sensors and etc are in good shape.

RocketyMan

Sorry about taking a little while to respond. I've been working on my '83 and well yeah...while she may run, she makes me worried about the piston rings and valve guides. I don't know why sometimes it burns oil..and sometimes not. On the dipstick its full all the way to the top!

Anyways...the gauge I made was to measure the plunger solenoid from the top of the air horn (final measurement needs to included the space from the gasket installed) where it goes inside. That's for once you make final adjustments and what not. All it consists of is just a straight metal wire that's relatively rigid. But we don't need to worry about that just yet since you're still cleaning it.

If you post a pic of the spring that fell out or whatever, I'm pretty sure I can identify that fairly quick. You can also try looking at this diagram.

http://dyeager535.topcities.com/CCCqjetdiagram.html

Oh!..as far as your mixture screws, did you drill out the plugs that cover them already? I noticed that when I adjusted mine (3-1/2 turns out), the tip of the needle is JUST about flush with the ventri tube on the primary. You might not need to mess with them...BUT I did notice when I took mine out, a lot of debris followed it!!! So I think it's a good idea. Just make sure to record how many screw turns in they were set at. That way you can know a good idea what to expect when re-installing them.

L695speed

I decided to leave the mixture screws in for now. They are in the base so I will leave that til I get most of the small pieces in the inner guts of the carb put back together. I have the needle seat assembly installed, and the check ball and screw installed, I'm looking at setting the float now. I discovered I had a bad vacuum break and also a spring on the metering rod is broken. I will see if I can get you the photo of the spring to you. It might be the TPS sensor spring. I've got an LG4 carb that I'm salvaging some parts from so I might find some of my answers from that.

As for your smoking, my L69 blew up (block is under the bench). But when I tore down the motor I discovered broken piston rings on numbers 3, 5 and 6. Also the cause of my blow up was the rocker twisted off the spring, jammed and snapped a push rod. Eventually the lifter got thrown into the space between the intake manifold and the block. Since it was pouring smoke out the back it was no doubt the intake side that snapped. I am not sure how it started or what the cause of the rocker twisting off was but I'd suspect the lash got out of adjustment. While your rings could be shot, I'd take the valve covers off and check the lash on the valves. It was too late to do anything about mine but maybe we can prevent another one from blowing. Ofcourse it could be something far simpler.

RocketyMan

I just got done taking mine out for a spin. And I rode on it a little hard. I hear no valve lash or anything. Like it's pretty silent. At any rate, it didn't smoke or anything when I took it out. So I'm still a little unsure why sometimes it smokes randomly.

But yeah..a broken metering rod spring is pretty serious! Hopefully you can use one from that other carb or something. But yeah...my vacuum break is completely shot on mine too. :/ So starting her up I have to hold the choke flaps open until she warms up.

L695speed

Well it was just a thought as far as the oil smoke went. Hopefully you resolve that. I've been making progress on putting the carb back together. The good news is, I've got the float in and set, the MCS in and set at four turns out from lightly finger tight. (due to my realization that I never counted it when I took it out which resulted in some choice words) I was also able to salvage one metering spring from the LG4 carb, as well as the TPS and the vacuum break (mine worked but it was on its way out so it was bad). I also figured out where the spring that fell out went. Now the bad news, I discovered an O ring was missing on the IAB, and what I thought was only one broken metering spring was in reality two because when I got the good one out it revealed that the other one was broken too. Also upon looking at pictures and the LG4 I discovered that in fact one of the bigger tubes on the airhorn that go into the bowl was missing, but I can salvage them from the LG4 so no biggie there.

I'm wondering how the hell this car ran so smooth with so many things wrong with the freaking carb? Also is it possible to get the metering springs from a parts store? I know old carbs is one source but they've got to be available elsewhere.

EDIT****More progress, choke rod and choke assembly installed, base installed, mixture screws installed, fuel inlet and filter and spring installed and I got a tube from the LG4 carb to put in the airhorn. Going nice and smooth, everything is clicking into place so to speak. I've also got the booster spring and retainer installed on the new booster, and the all that remains is the retainers for the seals on the airhorn, and the rods and the rest of the airhorn assembly and the gasket, as well as the TPS. now if only I could find primary metering rod springs I'm golden to finish this sucker and reinstall on the motor and see if it'll run, and more importantly idle.

L695speed

I got to work today on the MCS plunger, because I forgot to count the turns when I took it out. Using Naf's method on his guide I finally got to 1/8 of an inch. The only thing is the choke rod fell out of the link to the shaft. I'll have to get it back in. Other than that I believe all I've got left to do is install the airhorn and related parts then put it back in the car.

RocketyMan

On the lean mixture screw on the MCS, four turns seams a little rich for the lean mixture. Like I said, the default is 3-1/2 turns out. One thing I like to do is to push down on the platform (the springs can be pretty stiff) but make sure its all the way down. That way I can be the most accurate. But I would seriously measure the 1.304 inches. It seams hard to imagine 4 full turns out being correct for 1.304 inches.

I'm not really sure about getting real specific pieces like the metering rods spring. That would seem hard to come by. I would seriously just pick up a CCC quadrajet at a junkyard for 30 bucks.

The 1/8 inch is the travel for the plunger. When the plunger is resting, this is considered the rich mixture. Then when the plunger is all the way down its the lean. Now you measured the rich mixture stop, right? Otherwise the 1/8 measurement will only be the correct travel, but not the correct place.

L695speed

I haven't messed with the rich mixture stop yet. In fact I just decided to leave it alone because it wasn't worth it to try getting it out and wrecking stuff. I put the idle screws back in exactly the way they came out. I fixed the four turns out, I'm definitely closer than four turns out. Maybe closer to 2 1/2 or 3 now. So in theory the rich mixture stop should be the same as it was before I did this. The airhorn isn't screwed on yet so I can still pull it off to check the 1.304 measurement. I just am not sure if its worth messing with because I didn't mess with the rich stop. I am definitely closer than four full turns out. Looking at the service manual its not clear where you put whatever it is you are using to measure on the bottom. I am also going by what Naf did on his build up because I had it come apart at exactly the way he had it. Left some things in, most things came out.

Finally, as for the springs, I talked to a couple of guys at the shop I worked at. They looked at them and agreed they were broken, but they pointed out a good point. The rods only travel so far. He said to see how much travel is in the springs and go by that. I thought about the junkyard idea, but since the LG4 carb also had a badly broken spring (worse than the L69's) the chances of me scoring a Q jet in the junkyard is already remote, let alone good springs. So I went by the restoration shop's advice. And checked how much travel is on it, and determined that I could get away with it as it was only the extreme ends of both that was broken off.

L695speed

Just to confirm, I never touched the rich stop. Also I measured 1.304 to the base of the plunger from the jet, as shown in the service manual. The only problem I had was I'm using needle nose pliers to turn the screw now and I still have a lil further to go before I reach the right spot. The metering rod springs I am going to be ok with. I'll just keep them in mind the next time I go inside the carb.

EDIT*****Ok I have the lean stop set at 1.304. Now the rich stop is definitely off because when I checked the plunger travel it was more than 1/8 of an inch. So now I am gonna have to find something that I can use to adjust the rich stop. Now that I think about it it smell like it was running rich when it was running before I took it apart. So maybe I was on the right track with the carb being part of the problem when it wouldn't idle.

RocketyMan

2-1/2 to 3-1/2 sounds about right. Somewhere in there. But yeah, generally if you didn't mess with the rich stop and the total travel of the plunger is very close to 1/8" then that's good!

I really don't know what to think about the metering rod's spring because I don't know how badly it looks damaged...and then how it would get damaged.

I would try to get 1/8" travel as best as I can. Make sure you're doing this with the gasket on (you don't need the acc. pump or tps...just the space difference when measuring). As far as running rich, I really got a good idea of this because of my spark plugs. Before I took my carb off, my plugs were BLACK as hell with ALOT of soot. But the reason for that was because of my rich stop screw was screwed all the way out.

Don't you have that tool to adjust the rich stop?

L695speed

Well the springs likely have over 100K miles on them. It was only the extreme top and bottom of both springs that was broken off. There was plenty of travel in the spring still that I could get away with it for now. If it was broken in half then I would have been in trouble. I'll figure something out to get at the rich stop. I have a bunch of tools but not the highly specialized ones that were specifically for this. I got 1.304 using a micrometer that had a depth gauge on it. The travel is maybe around 6 or 7 thirty seconds. So it shouldn't be too bad to get the rest of the travel right. Like I said earlier, I know the car was running rich not due to smoke but I could smell the gas in the exhaust. The rich stop might be out of place. I would give you the same advice you gave me. Get that 1.304 then measure it to 1/8 inch travel using the rich stop. In fact I think the factory Service manual also said to get the travel using the rich stop. I'll let you know how I make out. If I figure something out to get at the rich stop screw I'll let you know how I did it.

RocketyMan

Well I got the rich stop screw from the other side and just adjusted it by my fingers. Then I checked my travel by putting the plunger in and gasket on and putting it together. It took several tries, but I eventually got 1/8"

But if you got your lean to be 1.304" using a micrometer, then I'm impressed. I just used the "L" shaped ruler that came with my kit. It's pretty much set for 1.3" but in reality, it's probably set a little less than 1.304".

naf

iTrader: (7)

Those primary springs are often broken in carbs I dig into-of the 1/2 dozen bodies I've got stuffed in a wooden ammo crate, I don't have one spare spring. New ones can be ordered from Carbs Unlimited: http://www.carburetion.com/quadrajet.asp at around $10 plus shipping. You may be fine with what you've got unless the 'skinny' end broke off-I've seen them ride up the rod when this happened.

The exact settings for rich and lean stop aren't as important as establishing 1/8" of travel. I've pulled several apart and found that the factory setting for the lean stop was NOT 1.304-that's why I always set back to original height. I don't think it would make much difference either way the error is so slight. I've always dialed them in with the dwell meter to verify proper feedback, which is the important part.

If you change the factory settings you'll definitely need to readjust the IAB (and possibly the idle mixture screws) with a meter after re-installing. It's recommended either way though, but going with original settings may not require any adjustment provided Closed Loop operation is verified.

If you can get the lean stop set to correct height-great, but don't skimp on establishing the correct travel distance. You can use a needle nose on the underside of the rich stop screw and turn it from underneath if you don't have the tool.

L695speed

The springs are not riding up so they should be good to go. Well the problem I have is I don't have a dwell meter that I know of. Would you recommend, since I didn't mess with the rich stop yet (didn't take it out or move it), that I set it to 1/8 travel according to where the rich stop is now? I don't want to be burned because it wasn't 1.304 from the factory.

Also I did find the idle mixture screw specs in the service manual for those who are interested. According to those specs the mixture screws are supposed to be 3 3/8 turns out from lightly seated. However, I put them back in the way they came out . I'm guessing that some things in the service manual are not said because they no doubt adjusted them with meters at the dealerships back in the day.

This carb has been messed with before because all the plugs are not in it.

naf

iTrader: (7)

Since it's been into before you're likely going to need to set the dwell with a meter once it's back running. You can try to set everything exactly as it was-get 1/8" of travel from the rich stop and might get by. You'll have to let it run then confirm that it's going into Closed Loop at the ALDL (IF the LG4 will let you do that-I've never tried, never had to).

A dwell meter, if you can't borrow one (or a scanner), will run around $30 and it's a good tool for troubleshooting as well.

L695speed

ALDL? And its an LG4 from an 87 caprice, with the carb, accessories, exhaust etc from the original L69 and no smog pump as that seized up on me. I don't know if that changes anything. As for the dwell meter I suppose I could see if I could get one via "rent a tool loan/return programs. However, I guess I could set everything back the way it was and it should run. After all, before I pulled it apart, it would run at warmup high idle, then kick down and run for 3 sec or so at 750 then die. I then would fire it back up but keep the rpms at about 1000 with the accelerator and it would run. So because of that I'm tempted to go back and set the travel to 1/8 using the rich stop, and have a friend come over and help with the fine tuning by feel and ear.

I know that the rich stop is already out since I could smell gas in the exhaust. And since I already have the lean stop set at "factory" (at least according the the service manual) spec give or take a couple thousandths (it ever so lightly comes into contact the gauge I used to measure that out), I'll turn the rich stop so I have it at 1/8 travel. The travel adjustment is done by the rich stop according to the manual anyway. Then I'll set the IAB at 1.725 or whatever it is in the manual. I was discussing the adjustments with a collegue of mine from school who graduated a year or two before me and he said he would just go to the "factory" spec in the manual, and make the adjustments as you go. Drive it and adjust it til its to my liking. I might just do that as I'm already half way done with that.

naf

iTrader: (7)

Assembly Line Data Link is the scanner connector under the driver hush panel, right side.

You can't tune the ccc-qjets by feel or ear. The IAB is adjusted so that the carb is operating in feedback mode (O2 sensor sending readings that the ECM understands-narrow band) and that the dwell is nearest 50% at idle-gives the most leeway for adjustment each way: rich/lean.

It is highly unlikely your rich stop setting was actually causing the carb to run rich. There are so many other variables that are more suspect causes. Remember that the rich stop setting just limits upward travel of the primary rods. The dwell, commanded by the ECM, determines how much time the rods are down in the jets, restricting fuel flow. How far up (or down) isn't near as important as how much TIME the rods spend restricting fuel.


See above.

L695speed

So in short Naf, the engine swap itself could have thrown things off without the scanner to adjust the settings on the carb? I suspect I have a bad O2 sensor as the check engine light came on after a certain amount of time at speed. The time it took the light to come on and conditions matched the 02 sensor on the check engine light chart, in the diagnostics section of the service manual.

I guess my best bet is just put the damn thing together and see if I can get my hands on a scanner and set everything by that, and get a new O2 sensor. I don't know if this changes anything but the AIR pump and etc has also been removed due to the smog pump being taken off. I have a OBD II scanner that sounds like it can be used to check cars like the TA with early OBD capabilities. So all I may have to do is get the connector to keep going. If that is the case. Regardless of what I do I guess I'm gonna need that scanner.

So, I guess in order to get this thing running right. Put the carb together with 1/8 travel, and the IAB set at factory spec, along with everything else. Then replace the O2 sensor, and get my hands on the scanner and adjust everything with that. If that is what I am going to have to do I'll get it all back together and when I get a scanner I'll get back to you. Funny how everything you learn about carbs and adjustments goes out the window with these ccc Q jets.......

naf

iTrader: (7)

Exactly. If your scanner can read the older ALDL with the appropriate cable, you're gravy.

First job is to set the timing and verify that it's advancing correctly.

Then set the TPS voltage to near 0.40 volts at idle (engine does not need to be running). Scanner helps with this.

Then set the IAB until the ECM goes Closed Loop and the dwell hovers around 50%. With a different motor under the carb, this may require adjustment of the idle mixture screws AND the IAB.

L695speed

I was hopeful that my scanner would read OBD I cars too. Unfortunately it does not as it is the model that is the level below the one that reads both OBD I and II cars. I know that you can get trouble codes with a paper clip. Is there a way to do something similar to get all the settings right? But anyway, I'll get the carb put back together with all the settings according to the service manual, if the car will idle then I will see if I can get my hands on a scanner to do further tuning on it. Just how does the scanner make all those adjustments is my question. It doesn't quite make sense how a code reader can also make adjustments to things like the TPS.

Zwrench

The scanner doesn't actually make the changes. You make the changes and read the results from the scanner. I'm no expert on using a scanner that way, however. I've always relied on the ol' dwell meter and multimeter.

L695speed

I know I could use search, but is there a writeup detailing how to do everything and what everything should read? Using the dwell and multimeter?

Zwrench

You've no doubt seen this sticky:

https://www.thirdgen.org/forums/carb...e-rebuild.html

In it, it explains how to adjust the TPS. When I was a tech, I made a 'jumper' to adjust the TPS. All it was, was a TPS connector with pigtails. I would plug my jumper into the TPS and the pigtails into the factory harness plug. I would then clip my multimeter to the exposed terminals that were pushed into the factory plug, turn on the ignition, read the voltage and adjust accordingly.

Like I said earlier in the thread, my memory is getting fuzzy on certain details so I'll rely on others to fill in the blanks.

One wire is a 5V reference voltage. Another is ground. The other is what the ECM sees. That is the one you read with a voltmeter to determine your setting.

I had access to Weather-Pac terminals when I made my jumper. I don't know if they're still available but, with a little imagination, I'm sure you could easily make yourself an in-line jumper. Or, you can back-probe the connector.

To be safe, you should use a high impedance meter. 10 meg-ohm is recommended.

As far as the dwell meter, well, I think you could get one pretty cheap at a parts store. It will likely be a volt-ohm meter as well. My advice is to buy a good multimeter and a cheap dwell meter but don't use them interchangeably. In other words, use the multimeter for checking voltages and resistance in ECM controlled circuits and just use the dwell meter for checking closed-loop operation of your M/C solenoid.

If you ever want to tune a car that still has points, the dwell meter will come in handy for that as well!

You check the dwell of your M/C solenoid by clipping one lead of your dwell meter to the green connector in the carburetor harness and the other to ground. You do that after the car has gone into closed loop.

Yeah, I know this is really long but, I suck at explaining things!

naf

iTrader: (7)

Copied from an earlier post of mine:

Check your timing with the four wire EST connector to the distributor disconnected. The car may not want to idle well with it disconnected and you may have to temporarily bump up the idle speed while you set timing. Do it with the engine warm. Try setting it to four degrees advanced (first big notch on the timing tab after zero). Reconnect everything and re-adjust idle to about 600 rpm. With everything disconnected verify that the timing advances to around 25+ at idle and advances more with throttle. The exact amount isn't as important so long as it is advancing.

Check your TPS voltage by backprobing the three wire connector at the top and middle pins. The connector must be attached to get a reading. The ECM sends 5volt to the TPS on the third lead, one is a ground and the last is the TPS signal lead to the ECM (in case I got the top and middle pins wrong--it's been a while). The TPS should be adjusted so that it reads near 0.40 volts at idle, close is OK. Ensure it reads near 4.0 volts with throttle all the way open. Engine does not need to be running for this test, ignition on/engine off is fine. You may have to drill out the tamper proof plug-be careful. A properly sized roll pin can be lightly tapped over the TPS adjustment screw to turn it.

With timing and TPS set correctly, connect your Dwell meter to the green single wire connector that comes out of the ECM harness near the blower motor. It should be right near the fender where the harness passes through. Other (black) wire to ground. With the engine running and fully warmed up you should see the dwell meter (six cylinder scale) reading near 50% (or 30 degrees) and wavering slightly +/- about 5 or so degrees. The needle will waver as the O2 sensor readings re-write the vac sensor/TPS blocks based on O2. Choking the air horn with a rag should cause the dwell to increase (less fuel) in response to choking the carb.

If the meter is wavering correctly, adjust the IAB screw to get dwell nearest 50% at idle. Turn out to lean the mixture (get dwell to decrease) in to richen mixture (get dwell to increase). Remember the IAB meters the amount of air that mixes into the air/fuel mixture. Out = more air = leaner. Higher dwell means the metering rods are in the jets more which is a response to a rich mixture (higher dwell = less fuel).

If the dwell reading is steady and unresponsive then the O2 readings are likely out of the narrow range that the sensor can work with (assuming the motor is warmed up and everything else is working correctly). If your readings are steady try shorting out the leads to the Coolant Temp Sensor (CTS). This will trick the ECM into thinking the engine is fully warm and rule out a bad CTS.

Next try setting your idle mixture screws at 2-1/2 turns out each. Run your IAB screw from 2 turns out to 7 turns out, pausing for about a minute each half turn to see if the dwell responds. If nothing go another 1/2 turn on each of the idle mixture screws and repeat. Don't go past 7 turns out on either. The goal is to be near 3-4 turns out on each with dwell near 50% and properly reacting to changes in O2 readings (like choking the air horn).

RocketyMan

Zwrench, naf

I think if I can do the final tune with both of your descriptions, anyone can!

Zwrench

Thank you! Does that mean you have her running like she should?

L695speed

Ok guys, I've been busy, but I have made a lil progress. I found a few things that might explain why the car was running like crap despite having power and running smooth. Other than the carb being a disaster zone, I found my O2 sensor was fried based on the fact that it was located where all the oil smoke was pouring out when the original L69 blew up the number three cylinder 8 years ago, and a check engine light that corresponded to the O2 sensor. Along with that I found my temp sensor was broken and not doing a damn thing. 25 year old plastic and a connector that is long since gone (plastic connector) is to blame. Finally, I think I finally found that vac leak that no one could seem to chase down. It was the port under the TPS, so it was well hidden, now to plug that one up, as well as one other one. Most of the vac lines are hooked up right.

Rummaging through my garage yielded among other things a Dwell meter combined with a tach. Now if I get those sensors, and get everything hooked back up I have everything exactly the way the specs listed or specified in the service manual it should fire up and hopefully at least idle after warm up. Final tuning will take place after I'm confident that I can keep the car running long enough at idle to allow me to do the tuning. A friend said he would send me the special tool to make the adjustments too. Looks like I'm in good shape sofar, the carb went right back together is is mocked up on the intake, just gotta hook everything up.

RocketyMan

Well...I'm not really sure. Ok...so I hooked up my meter to the green wire and then grounded the other. When I started the car and what not, the percent duty cycle was around 30% or so. Then if I stuck a screw driver down the sides of the air bleeder to stop the solenoid plunger moving, my percent duty would go all the way up to like 90%. Once I removed the screw driver and the solenoid starts moving again, the duty goes back down to around 30%.

I tried adjusting the IAB, but it doesn't seem to change the % that much. But should I be aiming for 50% duty?


My temp sensor is broke too! You can look at the picture and see the wires are bare there and I think they grounded out or something at one point because my dash temp gauge is pegged! I don't know if it's broken or not, but I'm pretty sure this will have an effect on the computer controlling the mixture, right?

Do you have any idea how you're gonna fix yours, l69?

Zwrench

Sounds like you did a good job! 30% is what you want.

L695speed

I was going to replace the sensor as the sensor is physically broken, as for your wires.......if you think that was bad, you should see mine. Ok, mine are bare for a good 4-6 inches, and the connector is nonexistent. Just wires jammed into the sensor and silicone sealant was used to keep it in place/insulate it. Mine worked til the plastic failed and snapped. You can get both the connector and the sensor from the local parts store. Which was what I was going to do and play electrician. lol. I was going to clip the bad wiring to a point, lash the two wires to the new connector, solder and heat shrink wrap the connection. I've done this before but I'm going to have to put a plank of wood on the car to use as a bench while I perform this surgery.

L695speed

Oh and another thing, is your ignition key cylinder, switch etc combo sticking after you start it. Mine does, I just have to make sure it is in the run position and I'm good. The reason I'm asking is because if I don't make sure it is back at run and its on start or halfway between the two some of the gauges don't work right. Most of the time it was the temp gauge not working right. It would be pegged unless I ensured it was in the on/run position after I started it up. Once in run or on position it worked as it should. Just something I thought I'd bring up.

naf

iTrader: (7)

You're looking for 30 DEGREES or 50 PERCENT on the dwell meter (when set to the six cylinder scale.

The temp sensor for the ECM is separate for the one that sends to the guage. The ECM CTS is the two-wire sensor on the water neck. It doesn't hold up there very well with the AIR tubes crossing over it. The guage sender is on the driver's side cylinder head, single wire connector.

Shoot for 50% duty-follow the outline above starting at 2 and 1/2 turns out on the idle mixture screws. Take your time and make sure the motor's fully warmed up when you dot it.

L695speed

whoops I forgot about that temp sensor. Thanks for clearing that up Naf. So there could be nothing wrong with your ECM one, rather there could be a problem with the one on your block Rockety. Either that or that quirk with the key cylinder I described on mine. Hopefully (if mom doesn't need any money) I can get the parts by the end of the week and I'm hopeful by this time next week it will be a running car again. Ofcourse if mom needs the money, its gonna have to wait til next month.

Zwrench

A 'whoops' for me, too!

Degrees.

RocketyMan

Yeah I understand what you're trying to say about the ignition..but the temp gauge never moves. I'm thinking I have to take apart the dash and try to unstick the needle or something. But funny thing about my ignition is that when the ignition is set to "on," it doesn't lock the key in there. So I can take out the key when it's running. :X

Yeah the stupid AIR system is just in the way of everything and makes under the hood look all a mess. Speaking of which, its the temp sensor that's right next to the thermostat that the cooling fans will come on through the ECM, right?

50% makes more sense on the duty-cycle rather than 30%. But won't the ECM not go to the correct %duty if it doesn't sense the car to the correct temp?