Hello there fellow thirdgen lovers I was wondering if u guys can help me out pass my emissions hopefully. I was wondering if any of u guys know where the screw to lean out a 4bbl rochester carb is or if there's even such a thing I need to go do my emissions by monday the latest I would really appreciate it if anybody helps me out with this thanks.

 

No such screw exists. It is accomplished electronicaly based on information from various inputs. The most important input, the one that typically goes "wrong", is the O2 sensor.

After that, a good ignition tune (plugs, cap, rotor, wires), and basic carb adjustments (IAB primarily).

 

well I did change all of the plugs, wires, rotor, cap and the ignition coil the only thing that I haven't replaced is the o2 sensor I went in for my test and the carb is too rich is giving too much gas on the results it showed a lot of unburned fuel. also what is (IAB) oh and how do I do carb adjustemnts I don't really know much about them but I always wanted to have one and now it seems a never ending battle to adjust it. one more thing my engine does not have a timing mark and the bottom to adjust the timing I don't remember the name of the little mark how do I adjust that too will that have anything to do with emissions too?
thanks for the help I appreciate it.

 

10GunMan,
The IAB is the "Idle Air Bleed". If should not be adjusted without a dwell meter. If you start turning screws without the proper tools and knowledge your gonna end up with a car that runs like CRAP. I am by no means an expert..... but I have a fairly thorough knowledge of the Rochester and what makes it work (and not work) it has taken several months of questions & answers on TGO, a good bit of reading, and a few special tools to feel comforatable making adjustments to the carb. IMPO- The only thing you could accomplish between now and Monday is to make the car run MUCH MUCH worse!

I suggest that you follow Five7Kid's instructions and replace the O2 sensor. Assuming the carb was not "ADJUSTED", and nothing has become faulty WITHIN the carb, it is quite possible the 02 sensor is bad.

The O2 sensor "TELLS THE CARB WHAT TO DO" (basically) if the sensor believes the mixture is LEAN... It tells the MCS (Mixture Control Solenoid - inside the carb) to provide more fuel. Likewise, if it thinks the exhaust is too RICH it tells the MCS to backoff a bit.

The O2 Sensor is probably about $30. It might be OK and that would be a wasted $30. But if you have such a tight deadline it might be worth a try.....

Just my
Kurt

P.S. I purchased the book (photo below) at AutoZone for about $15. If you want to get some good info and a great start on tuning your Rochester it's the best $15 you'll ever spend!!!

 

kboehringer listen I went and changed the o2 sensor yesterday it did looked pretty crappy but then again I don't know how it was supposed to look it was pitch black with carbon so I went ahead and did what five7kid told me to do I also bought that book but still haven't opened it will do that tonight while at work. so you are telling me that I can't do nothing about the running rich condition how much does that tool cost and where can I get it also does the idle control screw have anything to do with this? let me know and thanks for the help.

 

kboehringer one more thing can the tps be wrong too how can I check to see if it's working properly let me know thanks.

 

The book goes through that very well. I forget exactly what the section is called (don't have the book in front of me), but it's dedicated to the electronic feedback carb.

 

will changing the fuel filter in the carb help any and is that hard to do? I have been reading the book but I still don't know a lot of stuff on how to lean out the mixture I'm going to go buy a dwell meter now and do some more searching and reading on it. I was planning to buy an old carb (used) and practice on that post some pics and go from there see what the internals look like and have a better understanding of how the carb works I'll keep u guys posted thanks for all the help. :thubsup:

 

10gunman,
The proper tools for adjusting your carb are a little hard to find in local retail stores (i.e. Autozone, Advance Auto). My local NAPA had the MIXTURE screw adjustor (special tip on a flexible shaft). However they did not have the proper tools for adjusting the MCS, Lean Stop & Rich Stop. I was able to find them online.



You will need the following (see photo):
Multi-Meter - for Adjusting MCS
Dwell Meter - for Adjusting IAB & Mixture Screws.
2MM Female Specialty - MCS Adjustment
10mm Double-D - Lean Stop & Rich Stop
Small Ruler/Scale - Comes with a rebuild kit for Float & MCS
Paper Clips - I push them into the back of the TPS Connector to check voltage.

Hope this helps, it'll take a little trial & error to get the hang of it (and I am by NO MEANS an EXPERT) there are a few around TGO that will help out.

The Fuel filter is an easy change. It's located in the cavity behind where the fuel supply line attaches. However, I don't think that's gonna have any effect on the Rich condition. Can't hurt to change it on regular basis or during a rebuild!

Sincerely,
Kurt

 

so that's how you would check the tps! I was wondering how I could get the conectors all the way in the tps holes cause the tips of the voltmeter weren't long enough so u use paper clips that's a great idea thanks for the tip. so far this is what I have...

multimeter
dwell/tach/volts meter

need the napa mixture screw adjustor and the part # 711 I also got coming a carb rebuild kit oh and the mini ruler hope I can do this I will post back if I don't know how to use any of the tools thanks.

 

10gunman,

The Napa Tool has the following ID stamped on it:
K-D 2776

I think that the link above is to the correct tool#. NAPA MAY have all the tools you need. My local "NAPA guy" said he could get the tools from a NAPA in Florida if I wanted to wait about a week. According to the "NAPA Guy" they are no longer stocking any carb tools and I was lucky to get the one he had. Don't know how much knowledge the "NAPA Guy" really had.

Sincerely,
Kurt

 

kboehringer listen I have been only asking about the carburetor about maybe it may be dumping too much gas but I forgot to mention one very vital thing to ask and I probably need to address this first before I continue with the carb tuning I'm missing a bunch of emissins stuff wich that is one more reason that I did not pass I will post some pics and if u can do the same so I can get some of the hoses to where they go I'm also missing my air pump let me know if u have some pics of your lg4 emissions stuff by the way is there a tool to check vacumm? let me know thanks a lot for your help I relly appreciate it.

 

ok I tried using the dwell meter but I could not get any readings I hooked up the green little clamp to the tach with the provided wire and the black clamp to a ground but it the meter would not move it stayed at 0 no action noted I'm I doing something wrong?

 

10gunman,
You could have the dwell/tach hooked up wrong OR that could be the actual reading..... You can try the paper clip deal directly to the MCS.

I am at work.... Hopefully someone else will chime in and lend some info. Otherwise, I'll send a response late this evening.

Kurt

 

ok I'll wait that way you can tell me how to use the paper clip on the MCS and TPS thanks.

 

pics of carb

 

http://pg.photos.yahoo.com/ph/pimpkike/album?.dir=/a96a
I wanted to post some pics of my car so I could ask questions about it but I couldn't get pics large enough like kebouhringer but here is a link to my phots thanks.

 

10Gunman,
Here's the paper clip deal I use. I think someone at TGO told me about this so it's not my idea. I can't remember who deserves the credit but it is a great idea.

You can do exactly the same thing with the MCS. I'd have to double-check the book but I BELIEVE you need to use the wire attached to the "B" terminal on the MCS. I use to do it this way until I found the Green connector which works fine on my son's ride.

Kurt

 

10Gunman,
You really do have some problems... OUCH! The emissions stuff is normally not TOO hard to find in the J.Yard. I have installed ALMOST everything into my son's Z-28. However, we do NOT have the Air Pump. We have a non-air Cat (courtesy of the previous owner) and although that may be a non-compliance issue for your area, in Georgia they do NOT inspect ANYTHING except for what comes out of the Tailpipe. I am very confident that my son's Z-28 will PASS an emissions test.

If they INSPECT the engine compartment you're gonna need a little more help than I can provide. Attached is an LG4 hose routing diagram (compliments of a good TGO buddy or ours "SELLMANB")

Kurt

 

10Gunman,
My son and I completed the swap you are doing a few months ago. We had one of the longest treads the Engine Swap Forum ever saw. It's at the top of the Engine Swap Forum threads.

Take the time to look it over (especially page 7&8) as several TGO guys helped us sort out all the hoses etc. In addition, some of the MOST knowledgeable folks you'll ever find on TGO have a variety of comments about the function of the Cat & Carb Set-up on Page #8.

Here's a link.....
LINK TO ENGINE SWAP FORUM - Father & Son Project Page#8

Kurt

 

hey this helps a lot thanks now how do I know what kind of cat I have? I did go to the jyard and found an exact car with an lg4 engine and took most of the emissions hoses now I just need to install them and the air pump. I have heard that if your cat is and air cat and you don't use the air pump it may fry is that true? will getting a new cat help after I put everything back together also on the tps wich two little holes do I use for the paper clips the pic is kinda blurry thanks for all the help and I'm going to check the thread of father and son I probably will learn something good there too thanks again oh by the way thanks for the diagram of the hose routing for emissions I was looking for one of those in months.

 

kboehringer I was looking today at my carburetor and I found the little letters from the diagram good thing I read your other thread because you say that there is a "K" and mine is capped off is it supposed to be that way also my map sensor is missing a hose I don't know wich or where that hose goes. the other thing is that I can't find the letter "L" or "N" let me know if you know where they are I can't find my air pump I must of missedplaced it but I'll just buy a new one. I did the test on my tps and I don't know if I did it right but here is what I got .27 at normal throttle and .36 at wot also was I supposed to be doing the test while the car is on or off? more questions to come now that's all I can think off. hey kboehringer that was a real good thing you did there with your son how is the car running now?

 

on the emissions routing diagram what's the efe stand for and where is it located? can u help

 

10Gunman,

It's a valve in the exhaust manifold. Off the top of my head I don't actually remember what "EFE" stands for. I'll try to find a photo of one for you.


I will send you photos of all the hoses on my son's LG4. The Map's line goes to the port on the rear of the carb. It must be hooked up to work. The Baro sensor does not have a hose.

I HAD always done it with the car off. However, another guy had told me to do it with the engine running. The last time I adjusted the TPS I did it with the engine running (low idle) and the car actually ran much much better. I'll try to find the guys name. He apparently rebuilds carbs as part of his job (or it sounded that way). He seems to have been correct.

Kurt

 

of course, if you want to pass emissions without any tuneups at all, you could move to florida. there's no emissions testing, new or old. something about a year-round breeze blowing away smog. of course, some of those "breezes" reach upwards of 100 MPH and pull he shingles off your roof, but i guess thats the price you pay.

 

"Early Fuel Evaporation".

I'm not that smart, someone on the Board told me that a couple of years ago.

Well, maybe 4 years ago. About the time mine came off and never went back on...

 

kboehringer thanks for the help I'll be waiting for the pics from your son's motor and I'll try the test with the car running now see what I get thanks. I hooked up the egr valve and the car seems to be running just berly whilel on idle it's like 400rpm I almos have to keep my foot on the gas to keep it from turning off but I think I'll leave it like that until I get everything hooke up and then do the tunning what do you think?


SaintedCorrupt I think I'll stay in Illinois instead of having to pay that price just for emissions you know what I mean? here in Illinois there are some counties that still don't requiere emissions but I luckilly live in one that does thanks for the info.



five7kid thanks I'll look for that then and see if I can find it thanks.

 

10gunman: Did a quick read and may have missed something, but for an update: Have you retested your TPS? The readings don't look good. Have you got the MAP sensor vaccuum line run to the back of the carb? (MAP driver's side/baro pass side) The MAP sensor unplugged should throw codes unless the TPS is bad. Have you checked for trouble codes?

kboehringer is a good egg and will provide some good, detailed help. Five7kid knows his stuff but doles his information out in small doses.

 

10Gunman,
My son is taking the air cleaner off of his car as we speak and we are going to take some really good photos for you. I will spend some time with PhotoShop and try to make them really really easy to understand. It may take a couple hours.

As far our Father & Son project is concerned we've been doing little stupid stuff for several weeks. Getting locks fixed for the trunk and rear glove, repairing the headliner, replacing some interior plastic, we installed a GM hatch/trunk popper (That is a GREAT uprgade) all kinds of little tiny restoration type stuff that is beginning to make the car seem more complete and attractive. Now we're getting some help from other TGO guys in the restoration section as we are going to do some painting for X-Mas. The car runs FANTASTIC and is a heck of a lot of fun.... I'm now searching e-bay for a project car of my own!

Please make sure you spend some time READING the book you purchased...... Photos will be ready later this evening!

Sincerely,
Kurt

 

10Gunman,
I have made use of the EFE TVS for a unorthodox purpose. You should not plumb yours identical to mine. The colored lines are correct. Take the line indicated directly to the Air Cleaner Thermac. You'll need to use the EFE TVS in the fashion indicated on the hose routing diagram to control the EFE below the manifold. I hope some of the Labeling helps a little.

Kurt

 

hey kboehringer thanks for that photo and do some more plumbing and go from there thanks again I will work on it and let u know the next thing

 

naf I have checked the map sensor and there is a hose missing I will try to address that today while insalling the air pump and some emission hoses. the check engine light is on but I can't get a peper clip to read what the code is I will uninstall the battery and see if it clears if not I will keep trying the paper clip until I get a reading I guess.

kboehringer I did some looking around in my engine compartment and you are right some of your stuff do look different than mine but I got an idea now on how things go thanks I will keep you guys posted on what happens today.

 

10gunman,

You do not have to remove the battery cable to reset the ECM. Somewhere close to your battery there should be a quick connector. It is located in-line on an orange wire. My son's is located right next to the battery yours may not be quite so close but should be within a foot or so of the Battery. Just unplug it and plug it back in an the codes will be gone. However, they will probably just come right back if the problem is still there.

Kurt

 

10Gunman,
The paper clip might be a little small for the code slots. It's probably a little tough to keep a connection. I had been using a small loop of wire for that purpose but you still have to keep it firmly pressed into the slots. I purchased one of these stupid little code retreiver tools from AutoZone. It's nothing more than a piece of metal with spurs the proper spacing. It does stay in place with holding onto it and it was less than $2.

Fortunately, we haven't had a check engine code for a few weeks (since I finally got the TPS adjusted properly).

Kurt

 

kboehringer thanks for that info I will do that. so I installed my air pump and my bigger hoses today but still smells like gas but I still have a couple of hoses that still need to be hooked up maybe that should do it hopefully...

 

kboehringer listen I can't find those code retreivers if u happen to go to the autozone by you and find a couple more can u let me know or buy them and I'll send u the money for them cause the engine light is still on and I can't get the paper clip to read and I'm starting to think is the ecm I did some searching around and the ecm is not that expensive so if I can't clear it I'm just going to have to buy a new one or what can you sugest I do let me know thanks.

 

If the ECM is throwing codes there is a problem with something besides the ECM. Have you connected your MAP sensor? It will throw a code if disconnected.

Go by Autozone, Parts America, NAPA or one of the others. They'll all have the code retriever tool. Just ask at the counter. Most of them will retreive the codes for you if you're able to drive the car there.

 

yes everything is connected now that I see anyways this code wasn't there before all of the plumbing well it was there but it would go away after I started driving now it's there even when I'm driving and it stays on all the time.

 

10Gunman,
Were you finally able to get the codes? What are they?

I agree with NAF, if the ECM is throwing codes it's probably trying to do it's job. I'd be concerned about the status of the ECM if you were to disconnect something and DIDN'T get a code. My local AutoZone could not help with the codes on the Z-28 as our connector is NOT an OBDII but is rather a ALDL. I don't know if your AutoZone is better equipped to help, ours wasn't.

Let us know what the codes are and maybe someone can lend a hand. The description of the codes (in Chilton's Anyway) is not always a complete listing of the items that can cause the code(s).

Sincerely,
Kurt

 

well my autozone is not able to help me either for the same reason they told me that they only do code checks for obd ll like cars from 96 and newer do I'm out of luck I need a gm decoder key like the one you have I have been looking all over the place overhere but have not found one yet and the paper clip is just not connecting so I can't retreive the codes to check the problem and I heard that they won't test my car if there is a check engine light so even dough I kinda fixed my car now they won't even test it to tell me if I improved or not any more ideas thanks. I was thinking I shorted out on the ecm that is why it was always on could these be possible?

 

I'm sure your ecm is fine. I've got to pick up some parts today and will look for a key. I'll let you know if I can get one this evening.

 

10Gunman....

Got a fork??? Cut two of the prongs off of it and I bet it will work fine. You're trying to cross A&B right? Try a fork!!!

Hopefully, your wife, mom, or significant other won't get too pissed but I think it'll be worth it!!!

Kurt

 

kboehringer cool I'll try the fork thing thanks.

naf thanks let me know if u find one thanks I'll leave the ecm alone then and just try to get it to read some how thanks.

 

10GunMan,

Make sure you review your Chilton's etc. in the code reading section.

It's pretty simple but if you are not paying attention you can get confused (don't ask). Basically, it'll repeat each code three(3) times and then move on to the next one. You're probably going to have a couple codes (if not more).

Example
Flash..Flash.........PAUSE.........Flash
Flash..Flash.........PAUSE.........Flash
Flash..Flash.........PAUSE.........Flash (that's a code 21).
Flash..Flash.........PAUSE.........Flash..Flash
Flash..Flash.........PAUSE.........Flash..Flash
Flash..Flash.........PAUSE.........Flash..Flash (that's a code 22).

Make sure you have paper and a pencil ready.
If you get lost or confused....Remove the "FORK" and start over.

Sincerely,
Kurt

 

10GunMan,
I'm pretty sure my AutoZone has more..... If NAF can't find one, I'll probably drive near AutoZone on the weekend. The Code Reader "FORK" could easily be placed in a regular envelope and mailed.

Kurt

 

10Gunman,
That's a problem easily solved. Get a torx driver.... remove the black face plate over your guages. Use a set of needle nose pliers to REMOVE THE BULB. DUH! The inspector will never know the difference (on an OBDII he would know...not on a ALDL because they use the sniffer instead of the computer interface).

However, You're probably gonna end up wasting an inspection fee. The ECM is probably trying to tell you what is wrong. if something is wrong enough to set-off the ECM it's not likely to pass an inspection!!!! IMPO - Don't waste the inspection fee to find out you're gonna fail.

Sincerely,
Kurt

 

cool thanks kboehringer I'll try the fork but it used to work I got a 23 code last week with a paper clip and then these week I tried the paper clip again and now it doesn't work. if u find a code reader let me know thanks I appreciate it guys.

 

Autozone here no longer carries the real fork, at least round these parts. You have to buy the $30 scanner now.

 

naf yeah that'a what I have been told here too thanks for checking. I tried the fork that kboehringer told me but no luck there either no reading I don't know what's going on if it used to read before and now it doesn't very weird

 

10Gunman,
Try to disconnect the power for the ECM at the Quick Connector. Do this with the CAR OFF. MAYBE it will reset....

You haven't accidentally crossed the wrong poles or anything? You are crossing the proper poles???

You should NOT start the engine with the diagnostic test pole grounded. On carb models, you can attach the test "FORK" after the engine is running but NOT before!!!

Kurt