L695speed

I ditched my AIR system because the smog pump seized making it worthless. But because I plugged up the vac lines that were part of the system it was not an issue. e

naf

iTrader: (7)

If the CTS for the ECM has failed and is reading 'cold', the ECM won't go into Closed Loop. While Closed the ECM will command the last known good dwell for that block of TPS/VAC reading. You'll be able to tell it's not in Closed Loop with the dwell meter because the needle won't be wavering as the ECM re-writes the blocks based on O2 readings-it will have a steady reading. The dwell may still change with throttle change but it won't adjust back and forth and won't respond to choking the air horn.

An easy check of the CTS is to short the leads, although if the wiring is crap the pigtail may need to be replaced.

RocketyMan

Mk...so if I put a rag over the air horn to try and simulate a "rich" condition, the %duty should decrease or increase? I'm guessing decrease. And then if i open up a vacuum leak it should be the transverse opposite where the %duty will increase.

And these are both granted the system is in closed loop...right?

naf

iTrader: (7)

Close. The ECM will respond to a forced rich condition by trying to lean the mixture, dwell will increase as the rods spend more time in the jets-restricting fuel. You're letting less air in so the carb needs less fuel to mix with it.

A vac leak will cause the ECM to try to add MORE fuel to the mixture, dwell decreases, rods down less, more fuel.

ZedorZee?

Hey l695speed, I also am looking for a remanufactured CCrochester at a reasonable price . I've found a company called Allstate carbs the web site is allcarbs.com they have them for under 500.00$. Hope this helps.

RocketyMan

Ok yeah-yeah. That makes sense. Duh. So if dwell is related to the amount of time the plunger goes up and down, how can you relate %duty to that. Is that semantically the same thing? Or is it like I.E. 40% of the time its on and all the way down/lean while the remaining 60% its up/rich?

Yeah $500 sounds about right for a remanned rochester. At that much, I'd rather buy a TPI from the junkyard with ecm, wiring harness, tpi, dash, etc..

L695speed

Thanks, but I already rebuilt mine, just as I suspected mine was a total mess to say the least. What I found in there left me shocked that it even ran, let alone having power in reserve in 5th gear. I didn't have a problem with rebuilding the carb. So far all is good, I'm just waiting to hear that my mom doesn't need any money so I can go get the CTS and O2 sensor and CTS connector along with some heat shrink wrap. No sense in trying to tune the car without those two critical sensors.

Also for those who know their dwell meters. I know its been mentioned that I should be looking for 30 Degrees on a 6 cylinder scale. What should I be looking for on a 8 cylinder scale. I can change it from 4-8 but I would rather work with what is appropriate for this motor, and being a V8 I would rather work with the 8 cylinder scale. I'm hoping to get the go ahead from mom before the weeks end.

RocketyMan

Well basically to my knowledge, the engineers used the 6 cylinder scale. But I'm pretty sure there are conversions figures out there.

naf

iTrader: (7)

The MCS cycles up and down 60 times a second, which is defined as the duty cycle. The Dwell is the amount of time it spends DOWN during each cycle, hence it is expressed as a percent. It can't spend 100% of the cycle in the down position (because it must cycle back up) so you'll see it maxed out around 78-80%.

The dwell meter was designed to measure the dwell of points style ignition systems, which were replaced by HEI in GM cars in the 70's. The points would open and close each time a cylinder fired and had to be routinely adjusted for gap and DWELL - and they often had to be replaced as they wore themselves down. The 4-6-8 on the meter was intended for the points adjustment on a 4, 6 or 8 cylinder DISTRIBUTOR. Nothing to do with measuring dwell on your carburetor. Use the six cylinder scale because it corresponds to the duty cycle that the ccc-qjet uses.

L695speed

Oh I see. (another thing they didn't touch on in school, perhaps because it was too "new", I was a restoration major in school for older cars) Anyway, if thats the case I will use the 6 cylinder scale and look for 30% when I get that far which might be as late as next month.

naf

iTrader: (7)

Look for 50%. 30 DEGREES would correspond to 50% dwell time for a points contactor in a six cylinder distributor. 360 Degrees / 6 cylinders = 60 Degrees per cylinder: max dwell time if the points were closed for the entire period of that cylinder would be 100% or 60 Degrees. (Which won't happen unless it's broke).

You'll see on the dwell meter that the scale for six cylinder should be shown in "%" and "Degrees" and 30 Degrees would correspond directly to 50%. Hooked up to the ccc-qjet system look for either 50% or 30 degrees, although since it's not a rotating assembly, like a distributor, speaking of degrees for the MCS cycle is mis-leading.

Ozz1967

iTrader: (4)

Jet Performance also sells them in the $500.00 neighborhood. I'd recommend them above just about anyone else for a Qjet.

kbhughes87

Wher can i get a rebuild for my quadrajet? summit? jegs? this is my first car and it is running really rich and the service engine soon flashes for like a second and the car stops accelerating then it picks back up then when i come to a stop the car wants to like die.

naf

iTrader: (7)

Welcome to TGO. Check your service engine codes, start here:

https://www.thirdgen.org/service-eng...ht-error-codes

RocketyMan

.wysiwyg { FONT: 10pt verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif; BACKGROUND: #f5f5f5; COLOR: #000000 } P { MARGIN: 0px } .inlineimg { VERTICAL-ALIGN: middle } Just out of curiosity, so would vacuum be irrelevant since the ECM could compinsate in a way? Like I checked earlier today, and when my car was warm and probably in closed loop, my vacuum was running around 20-21 in. Hg.

L695speed

I got my carb back on the car today, got all the vac lines, fuel line, and wires hooked back up. I checked one thing before I called it a day because I didn't want to start it without the CTS hooked up (still waiting for the pigtail), anyway, I checked the choke by throwing the weight forward, covered up the hole to create a vacuum on the port that goes to the air cleaner, then blipped the throttle. In theory it should hold the choke wide open then when blipped it should snap shut. My problem was the choke was not being held wide open. I had to manually hold it open. The thing that perplexed me was the fact that I did that squence when it was on the bench and it worked. So what changed or what did I screw up? Or is there nothing wrong? BTW I finally found the vac leak that I was looking for near the TPS. Time to plug that up.

L695speed

Forget that choke issue, I just checked it with the throttle spring attached and it worked like it should. But I am trying to find out where the hood solenoid vac line goes on the 84 TA.

L695speed

Ok guys I've got small caps for the vac ports that were open, put the O2 sensor back in (not 100% tight but tighter than it was before as I found it half out). I also got "Hair clip" retainers for my throttle cables to make it easier next time I do service on the carb. Only one problem. The temp sensor pigtail they gave me was the one for the sensor on the block. Not the one for the CTS on top of the thermostat. Does anyone know where I can find that connector/pigtail? I can start it up without it as it was totally broken before when it ran but I am going to need that pigtail to fix it right. Also if someone can point me to a double port (stacked) vac outlet that goes in the back of the intake then that would be awesome too as I've been striking out trying to find those. I stupidly somehow broke mine years ago. Anyway, I'm gonna put the retainers on the throttle cables and give this thing a shot. Wish me luck. I know that without the CTS hooked up its going to run like crap but I'm right at the point where I can start it so no point in not trying.

L695speed

Ok I got a chance to fire it up. It took a few attempts to get gas back to the carb, but once I did it fired right up, but was short lived, ran for 10 seconds at high idle then stumbled and stalled out. Part of it could have been because I had parts on the floor where my feet were and screwed up the pedals (car could have been in gear...DOH). But all the attempts quickly wore our the battery so I couldn't keep trying. But like I said, the car will run, but it could be a matter of it being out of adjustment or the CTS not being hooked up.


EDIT, Its not the carb, I just went down and checked, when I turn the key I've got no power to anything. Nothing, not even the lights on the dash. So I've got an electrical issue here, and its not the battery. (#)%$&)(#%i%$_#)#(@%*$)(W&W_)($

Maybe I should just rebuild the whole car from the ground up.

RocketyMan

Hmm...electrical... yikes. Wwweelll..I know this might be redundant, but check for vacuum leaks. Like I forgot to hook up my brake booster and I didn't know for the longest time. Then also, check your fuses.

L695speed

Ok guys. Found it. It was shorting on the ground battery cable. Fixed it it lives again. Now, it runs at 1800 for about 20 seconds, then dies. Any suggestions? I'm probably going to have to mess with the adjustments for a while before its right.

RocketyMan

What are your idle screws and idle air bleed adjusted at?

L695speed

the idle screws are at where they were before, but the air bleed is at what it says in the factory manual. Could be that due to the fact that it was messed with before that they conflict with each other?

RocketyMan

Is your idle air bleed 4 full screw-turns from lightly seated?

L695speed

I set it according to the measurement from the service manual. So I don't know where it is. I'll play with some of the adjustments today or tomorrow.

L695speed

Ok all of us may have different meanings of some terms. But what do you guys mean by lightly seated, you mean when it starts getting tight? Tight, or can't go any further without using force or what? I'm going by finger tight as lightly seated, but I don't want to screw anything up if I'm wrong.

Blind Driver

What are you guys calling "air bleed".
I have never heard of that term before.

L695speed

Ok I reset the air bleed at four turns out. Fired it up. It ran through the warmup stage at its high idle, then when it kicked down, it idled, but it idled like crap and occasionally you needed to feather the gas to keep it running. So, I have it idling but it is fairly erratic at 350-800 rpms. But if you don't watch it it will stall on you. Its progress. Again I don't have my CTS installed, and my O2 sensor I don't think is 100% tight. I'll say its the best its been though. I'm thinking of resetting my mixture screws at three turns out and seeing if that does anything. I know I'm pretty damn close. I have some faint smoke from near the water pump but I think my belt is slipping a lil there so that is an easy fix. The battery is charging according to my voltmeter in the car. Somewhere in the 14.5 range

naf

iTrader: (7)

MCS clicking with key in 'run'?

Do you know the timing is set correctly?

If it's idling too rough to maintain a steady idle verify the timing at idle speed is 'around' twenty degrees. There won't be any marks at twenty but you can estimate it.

Make sure no plug wires are disconnected or crossed. Check condition of cap and rotor.

If the ignition is right try giving it more fuel first. It's more likely to run better rich than lean. That means out a little on the idle mixture screws or in on the IAB.

If a little adjustment doesn't help look for vacuum leaks and re-check your ignition.

L695speed

When I let the car quit I heard something clicking near the top of the motor. Because I could hear it I knew it wasn't the starter solenoid. I went back and the car was on and when I shut it off the clicking stopped. So no doubt the MCS is clicking. Wires crossed is doubtful but I'll check. Timing at 20 degrees won't run. The LG4 likes it at TDC and the L69 ignition specs say 6 degrees. Cap and Rotor were changed for a new one and have less than 100 miles and running in the garage time. It could be that all my adjustments are conflicting one another. I've set the bench adjustments according to the factory manual, and some of them I set as they were when I took it apart. I reset the IAB according to Rockety's four turns out and it ran. Maybe I'll reset the mixture screws at 3 turns out and start there. The other thing as I said the O2 sensor is probably in need of replacing, and the CTS is not hooked up. All those things combined could be causing a rough idle. I'll try the mixture screws tomorrow. As for the timing that was one of the things I had the mechanic check and set for me, and I haven't messed with it since. So its probably ok.

L695speed

I have the IAB set at four turns out, I reset the mixture screws at 3 turns out. It is running rich. Not so rich that there is black smoke pouring out but enough that you can see the tailpipes smoking when you kill it. Because I stupidly forgot to reattach the TPS it stalled out while warming up. However, there might be a problem in the accessories as you can hear a chugging or chuffing sound that speeds up, slows down with the RPMS. I'm willing to bet I've got a bearing going bad in either the power steering pump, the AC or the water pump. or all three. I know that the power steering and the AC sat out in the elements with the car as we didn't remove them completely from the car when we did the swap. The AC was seized or stuck til we unstuck it. I'm willing to ditch the belt that runs the AC because I've got T-tops and am willing to take em off. However, the power steering and the water pump are another story. Fortunately, neither one of them costs that much.

naf

iTrader: (7)

Easy enough to pull the belts off each one to figure which it is.

Your BASE timing with ESC disconnected will be in the 0 to 6 range. Reconnect the ESC and you should see 20+ degrees of timing at idle.

RocketyMan

On a Rochester, the idle air bleed is the top most adjustment that has this valve open and close based off the MCS position.

https://www.thirdgen.org/tech/images/e4me003.jpg

RocketyMan

Speed,

You can test your O2 by disconnecting the sensor and probing it when your engine is running and the exhaust manifold is hot. When the sensor is around 1 volt its lean, and then when its around 0-ish volts its rich. But be careful to not ground out the wire!! Oh..and the O2 sensor really just needs to be tight enough to not leak exhaust.

http://www.ls1tech.com/forums/attach...2_afr_temp.gif

When your engine is still surging, it makes me think there might be a vacuum leak or running lean (again, can be like a vacuum leak). Did you put on a vacuum gauge and check? Mine runs around 20 in Hg when idling warm at ~550 rpms.

And then just to make sure about the adjustments, the "until lightly seated" is kinda when you screw it in and it stops all of a sudden. Careful not to strip it. And then when you do ONE full turn out is 360 degrees or 2*pi radians. Same thing on the idle mixture screws.

I pulled out my plugs from running 3-1/2 turns out on the idle mixture screws and 4 turns out on the idle air bleed. After puttin' around with it, my spark plugs were all black. So then I adjusted my idle mixture screws to 2-1/2 turns out and idle air bleed to 3 turns out to compensate. It helped clean up the spark plugs a bit...but I'm thinking somewhere between 2-1/2 to 3-1/2 turns out is the sweet spot...so probably 3 turns out-ish. It was hard to run at 2-1/2 turns out because my car would also surge too.

L695speed

I see I assumed correctly about the lightly seated part. So thats good. Now as you might see I'm running 4 turns out at the IAB and 3 out at the mixture screws...obviously its not right still as I have said. You have it at 3 turns out for the IAB and the screws are somewhere around 3 turns out? How is it running when you do that? I know I am close despite not having the sensors right. Just need to get that last bit. An idle that is erratic so far has been better than not idling after the warm up. I will rummage around as I know I have a vac gauge somewhere, and I will look for 20inches of Hg. Also I know I have an issue in the accessories with a bearing, so maybe I'll drop the AC (that was already stuck so the bearing might be bad anyway) and see if some of the whine and chugging go away, while I'm at it. I will try at 3 and 3 and see how it runs because it sounds like you found the sweet spot there.


EDIT*****I took off the belts, water pump seems in good shape, that was in the garage while I built the motor. AC as I suspected due to issues we had before....is not in good shape at all. Once I got the belt off I spun it, barely spun too far before it got stuck. Then I hand turned it for a couple revolutions. I'm amazed it didn't destroy the belt yet. Got stuck, then loose then stuck then loose maybe 3 or 4 times per revolution on the AC. That might explain the extra noise I hear in the engine bay. Back to work, I'll set my IAB and screws at 3 turns and see how it goes when I fire it up.

EDIT PART II******Fired it up at 3 turns each at the IAB and mixture. Ran then died while warming up. But took the belt off the AC and just about all the noise in the engine bay went away...So one thing fixed for now, but still can't quite nail down the carb tuning.....

EDIT PART III******Fired it up again after fiddling with the carb. I have it idling at approx 550. Not the smoothest idle but far from what it was before. I had it running at 550 for about 5-10 min and it surged a lil at the beginning after it kicked down, and threatened to stall once but then smoothed out and idled. Killed it with the key and now I'm scared to screw with it anymore. But I have it so damn close. Its on the rich side but rich is better than lean. Nowhere near as rich as it was earlier.

L695speed

Well I tracked down the part number for the CTS pigtail. Hoping they have the part in stock when I go. If they do I should have all the sensors hooked up and working right the next time I fire this thing up. I'm wondering if the idle at 550 might be the car in limp mode due to no CTS and bad O2 sensor readings. I know these computers are stupid but they are not that stupid. I will make the adjustments accordingly. At least we know one thing. I did this rebuild right and it will work.

naf

iTrader: (7)

You should be able to get the CTS pigtail at AZ or any of the chain parts stores. It's usually in the electrical parts aisle, listed as a GM Coolant Temp Connector.

You'll really need the dwell meter (or scanner) to set this thing correctly once your sensors are good. Any other method relies primarily on luck.

RocketyMan

Hey speed,

Does your car at least run smoother when it's off the idle circuit? Like can you just hold a steady 1000 to 1500 rpms with your foot? I'm also wondering if your throttle shafts might be worn...I don't remember you saying anything about checking that. But to test it just like take off the spring on the throttle linkage and see how much it wiggles (kind of a crude test). Mine wiggles a very tiny bit, but not that much.

On my carb, adjusting the idle air bleed really isn't that sensitive, but does make some difference (mine could be funky..??). 3 turns out on the idle mixture screws should be a really good guess of a setting. naf is right about getting a dwell to be most accurate...but for our purposes of just getting it to run relatively right, default settings should be nominal.

L695speed

I've got a new O2, and the pigtail for the CTS. Working on it here. I've got a dwell meter, but I'll wait til I got the sensors all in before I try again. It runs fairly smooth at 550, I started it last night and the car settled at the same idle it did earlier in the day....only one thing...coolant was starting to boil in the over flow bottle again after about 10-15 min, my last glance at the temp gauge indicated it was somewhere in the 150 range or so. I'm wondering if the CTS not being hooked up has anything to do with that. My thermostat was replaced when I put this thing together.

naf

iTrader: (7)

A motor that is out of tune-too rich, too lean or timing off-will run hotter than a well tuned motor. It's burning more fuel to maintain the same power, even at idle. All of the fuel 'burn' is not contributing to pushing the piston down.

Sparking it too early causes some of the combustion pressure to fight the piston on it's travel up. Lighting it too late doesn't allow it to burn completely before the exhaust valve opens. A rich mixture won't completely burn in the chamber some is burned in the exhaust. Lean mixture will cause a hot, inefficient burn.

88gta3508

if you are going to replace the E4me carb..
replace it with a 1979 - 85 P.U. truck and eliminate the TPS
and swap your distributor to a normal HEI..
this is all your ECU is controlling on the engine

RocketyMan

Speed,

Maybe your rad-cap is messed up causing it to release pressure when its not up to 13 lbs? but idling for 10-15 minutes is quite a while. Did your coolant fan come on?

I'm thinking if you can idle at 550 rpms for 10-15 mins, then you're doing alright.

Naf does have a point about the timing being correct. I need to check mine cuz it's been a real long time since it was ever checked probably. But it seems to run fine.

L695speed

Its possible the rad cap is messed up. Not sure though. my overflow bottle is broken, though I doubt that is a problem as we have a bronco with a broken overflow as well. I've changed the O2 sensor, the CTS is soldered in place, just need a heat gun (I'm gonna borrow one from someone) and the heatshrink is done. Then hook it up and all my sensors are in place. I'm thinking maybe I'll start it up after that and see if it makes a difference.

Naf-I'll check the timing after I'm done with all this. You said it needs to be at 20 degrees with the distributor? I see your point about the car running hotter than usual when its rich. I'm suspecting due to the fact I'm on the rich side you might have answered my question there. It could indeed be running hotter than usual thus the boiling coolant in the bottle.

Someone I know brought up a good question, and said are you sure that all the air bubbles are out of the motor? Since I did the heater core last summer, it is possible that he is on to something.

At least I'm getting ever closer to getting this thing more road worthy than last summer.

L695speed

Ok, everything is hooked up and set, now here is the stupid question....should I try firing it up now with the adjustments where they were when I had it idling at 550? Or should I go back to wherever they were when I first started 4 for the IAB and 3 for the mixture and start over?

naf

iTrader: (7)

Try it where you're at first then go back to 2 1/2 turns out on the idle mixture screws like I outlined above if it doesn't get happy. Just be sure to give it about a minute at each adjustment to see if the ECM catches up. You'll know you're near when the dwell meter needle starts wavering and responds to choking the airhorn.

five7kid

iTrader: (14)

Without going back to see exactly what he said; no, that isn't what he said. You set the timing with the EST disconnected. 6 degrees is a typical setting (zero is factory for LG4, 6 for L69).

After you reconnect the EST, you'll probably see the timing at around 20 or more at idle if you check it again with the timing light, but that only verifies the ECM is doing its job advancing the timing. You don't "set" the timing in that configuration, you just let it do what it wants to do.

And, you need to properly set the timing and reconnect the EST before you go setting the rest of the stuff, not after.

L695speed

Oh I see what he means now, Thanks Five7. He was referring to what I would see after the EST is connected. I'll see if I can keep it running long enough to check it before I do everything else. That boiling coolant might not be of much help in that regard. If it indeed still does boil

L695speed

So for this engine guys, what do I use for the timing? I've got the L69 ignition and distributor and the motor is an LG4. Do I use 0 or 6? Also can I set the base timing while it is doing the warm up cycle? Everywhere they say to wait til it warms up. I don't know if I can keep it running after the warm up cycle to get the timing set. I can adjust the carb to keep it running to do the timing but that is doing everything backwards.

naf

iTrader: (7)

Exactly. Nothing worse than setting the timing, thinking everything's hooked back up and working correctly then it runs like crap because the connector's hanging loose, a wire's broke, your ICM is toast, your 305 KS is pulling all the timing back out on your 350, etc. I ALWAYS turn the light back on the tabs after reconnecting everything for that final check.

L695speed

Ok guys, I was talking to a friend of mine from the shop I used to work at and he did one of these carbs himself. He said that its possible that because some things I left alone, and some things I re did, its possible that everything that I adjusted according to the factory manual and the sheet wihle right, doesnt' do much because I didn't adjust the choke plate and etc when I rebuilt it. So hes sending me all the tools (special ones) to do this job and told me to take at least the air horn off and make sure all my adjustments are right. I can't adjust the timing if it won't idle and allow me to set it at the 700 RPMs that is specified at the rad support. So I'm going to make sure that these bench adjustments are all right and start again. The TPS is still plugged so should I drill it out and re adjust it or leave it alone. Also if I am going to go that far is there anything I can do about the throttle shaft seals? I didn't see any throttle shaft seals in the kit.