So far, I have replaced the cold start injector, plugs (AC/Delco Rapidfires), cap, rotor, ignition module & pole piece (both GM),replaced the 195 degree thermostat, installed an MSD replacement coil, and pressure tested the injectors on the car. They held over 40 psi for more than 40 minutes, and kept constant pressure with the engine running. I have checked and set timing to factory specs, cleaned the throttle body and serviced the K&N Filter, Only my plug wire are original red Packards. I have not found and exact fit wires in red. Any leads on this? The engine runs great, does not miss or stumble, but smells rich and soots up the exhaust tips after about a month. The ECM only flashes code 12, so I assume the sensors are ok. What am I missing? People behind me at a long light tend to pass out.

Thanks for any help on this,

Rick

What about the O2 sensor? That tells the ECM what the air/fuel ratio is.
How old is the catalytic converter? Partially clogged can reduce power and make the car run richer.

You can buy an Air/Fuel ratio meter and actually measure what is coming out the exhaust. If it is running richer, then start troubleshooting.

I replaced the O2 sensor with a new Bosch unit. No change. The exhaust smelled rich with the cat so I thought it was bad. I removed it and just have a stainless baloney resonator in its place. No change on the exhaust smell. I have pulled the plugs and they are evenly colored and not overly dark. Has anyone else had this problem with an 88 2.8?

Someone mentioned a sensor in the air cleaner that might be the culprit. Would it throw a code if it is bad?
How about the emissions canister? Also, how much is an air fuel meter and who sells them?

[This message has been edited by Rick 88 (edited 04-18-2006).]

If you haven't you may need to replace the ecm coolant sensor, it is located by the thermast housing.

Well you have covered a lot. So all I can add is a list of what can cause rich running and you can eliminate what you have done.

O2
High fuel pressure. (I know you checked the pressure and bleed down. Did you check it driving or higher rpm)
Timing.
Bad coolant sensor.
Small chance air temp sensor.
Map sensor.
Injectors
Cold start inj.
Worn timing chain.
Ingnition misses. Misc parts.
Bad ecm.
Minds gone blank.

Anyway some ideas of other things to look at.

I have an 88 GT 2.8 that does the exact same thing. New O2, rapidfires, and exhaust that would choke a horse. Exhaust tips with thick black soot I wish I knew what was up. no codes either.

quote Originally posted by Rick 88: I replaced the O2 sensor with a new Bosch unit. No change. The exhaust smelled rich with the cat so I thought it was bad. I removed it and just have a stainless baloney resonator in its place. No change on the exhaust smell. I have pulled the plugs and they are evenly colored and not overly dark. Has anyone else had this problem with an 88 2.8? Someone mentioned a sensor in the air cleaner that might be the culprit. Would it throw a code if it is bad? How about the emissions canister? Also, how much is an air fuel meter and who sells them?

Rick, How many miles do you have on it, I don't remember.

Just wonder about the timing chain. The 85 I just tore down has about 128K on it. the timing chain has enought wear on it to be off 13-15 degrees. I know it's hard to get to but grab the crank pulley and rock it back and forth. On mine I would get a really good knock from the chain that I first thought was a rod bearing until I found that it would do it in any positions of the crank.

I know you replaced the CS inj. Have you tried leaving the plug off the inj. for the fun of it..

[This message has been edited by Dodgerunner (edited 04-18-2006).]

I think it's always gonna smell rich now that you've removed the cat.

------------------

'88 Fiero GT - 3.4L GM Crate engine
http://www.cardomain.com/ride/707857
'91 GMC Syclone - #449
http://www.cardomain.com/ride/2067330
'02 Yamaha V-Max - it go fast

Same symptoms here. Warm start flooding too. I haven't tried unplugging the cold start injector yet or replacing the coolant sensor, but everything else has been tried.

My vote goes to the coolant temp sensor that feeds teh ECM. It's telling the ECM you have a cold engine so it enriches the fuel/air mix. It doesn't set a code because it's still within a spec, for example maybe it's telling the ECM your engine is ice cold. Also ther eis a different sensor that feeds teh temp gauge so it may look to your eyes like the engine is normal operating temp but the ECM is being told it's ice cold.

The sensor screws in horizontally underneath the thermostat housing. Easy to replace but you'e going to lose some coolant in teh process. I suppose if you were clever with a wet vac you could replace the sensor without losing any coolant but that's just idle speculation from a twisted mind. Sensor costs about $25 new.

Best of luck.
Jim C.

Hi, If you really want to nail it down with out throwing parts at it try winaldl. Takes the guess work out of it. Its better than running lean though..lol...

quote Originally posted by Zewerr: I think it's always gonna smell rich now that you've removed the cat.

With the Cat Removed the ECM thinks the car is running lean and dumps more fuel. Check the archives I think there is a way to add a resistor to the O2 sensor input to the ECM.

------------------

quote Originally posted by bonzo: With the Cat Removed the ECM thinks the car is running lean and dumps more fuel. Check the archives I think there is a way to add a resistor to the O2 sensor input to the ECM.

Since the cat is AFTER the O2 sensor it is this is not true. What it does do is reduce the amount of backpressure for the engine. Removing the cat will NOT cause your car to run rich, I have been driving mine for about 6 months no without it.

quote Originally posted by wanobi: Since the cat is AFTER the O2 sensor it is this is not true. What it does do is reduce the amount of backpressure for the engine. Removing the cat will NOT cause your car to run rich, I have been driving mine for about 6 months no without it.

I agree with this. Removing the cat will not make the car run rich. It will make it smell like it's running rich.
With my cat removed, the fumes would run me out of the garage in short order, with my eyes watering. When I reinstalled it, the gas odor was reduced tremendously.

You said that you removed your cat and didn't notice a difference in the smell?
You should have noticed a drastic difference. Your cat was probably shot.

Ok, lots to check. My car has 85k miles and runs very well. I did try running with the cold start injector unplugged and it did not make a difference. I replaced the temperature sending unit in the cylinder head but I am waiting on a replacement connector as my original fell apart when I disconnected it to replace the unit. The coolant temp sensor has not been replaced. I just got a win aldl connector and software, but I have not used it. It there a thread on how to use it and figure out what it is telling me?

Thanks,
Rick

Again, the cat will make no noticable diffrence in how the engine functions. If you are running rich you want to check your CTS and IAT, Both of which can put out wrong readings, but as long as they are within range, the ECM will not throw a code. IF the engine thinks its colder than it really is, it will put in extra fuel. Also make sure you are attaining operating tempature, low temp thermostats or fan switches will keep the engine out of its optimal operating range and cause richness.

Please not the CTS is on the front of the engine, above the waterpump, and has nothing to do with the tempature guage.

Ok the CTS is coolant temp sensor. IAT??? whazzat? I plant to replace the cat but would like to install a quality stainless unit. Any recommendations on brand and size? I did not want to do this till I figured out the rich problem. I thought it might damage the new cat. I own a 72 455-HO Trans Am with the factory long duration cam and 800 CFM Quadrajet, and my 2.8 smells more rich than the T/A at idle. The T/A idles with a noticable lope. Just to add to the confusion, my Fiero passed a emissions sniffer inspection with no problem. Aaagh!!!

Rick have added a link on using Winaldl that should get you started. For other question just post back.

I would get the engine into close loop and then look at your INT value. That is the short term reading of where the ecm thinks your AF is running at. 128 is the normal reading that an ecm is set for. IE an engine running should keep the INT right around 128. Above 128 is lean, below is rich. So if your truely running rich you will see your INT running below 128. A few counts less is not a concern but if you stay 10 or more below 128 then thinks are not right. The BLM is another value to is looked at after driving. This is a longer term adjustment that the ecm makes to try to get the INT back to 128. IE if your INT is running rich you should see the BLM go below 128 most of the time and stay there. That is the ecm adjusting the injector pulse widths to reduce the amount of fuel . As the INT and BLM values go below 128 it is trying to remove fuel because it thinks your lean. Above 128 it is adding fuel to get richer. The starting point for the fuel is of course the fuel tables built into the prom.

This is a very simple explaination and someone will want to flame me saying it's not right but it's a VERY simple way of looking at it to understand what is going on.

Another recomandation is don't even bother with the Raw data. Go right to Sensor data since it will make more since to you.

https://www.fiero.nl/forum/Archives/Archive-000002/HTML/20030819-1-026777.html

Oh and IAT is intake air temp. What the incoming air is at.

[This message has been edited by Dodgerunner (edited 04-19-2006).]

Sorry but I can't let this pass by - Smells rich because you poured a bunch of money into it.

Oh Buffy shall we go to the club...

does it have rich Corinthian leather?

[This message has been edited by Erik (edited 04-19-2006).]

quote Originally posted by Phil: Sorry but I can't let this pass by - Smells rich because you poured a bunch of money into it.

I really think my car likes all the attention. Unfortunately, my wallet is complaining! Hope wifey doesn't find out......

[This message has been edited by Rick 88 (edited 04-19-2006).]

quote .....and serviced the K&N Filter......

Is that an OEM style filter, or a "cold" air intake kit ? If it's an aftermarket CAI kit, did you install the intake air temp sensor in it ? could be the IAT is always reading cooler (outside) air than the exhaust-warmed air the engine's breathing...

[This message has been edited by D B Cooper (edited 04-19-2006).]

The intake is factory stock. Only a K&N filter installed. All the hoses and connectors are attached.

I have a similiar problem on my 85 GT. When I get into the throttle on the interstate you can see a cloud behind me.It soots up my tips and bumper.Everything replaced,but still running rich. Maybe I'll put in smaller injectors.
Robert

I really think the coolant temp sensor is the culprit. I'll post the results. Anyone with a lead on exact fit red ignition wires? Or, does anyone have a good set of red Packards?

A notorious problem on all GM's with the crappy thin metal exhaust manifolds is cracks allowing in unburned air driving the O2 crazy. The O2 then sees the extra air as a lean mixture and tries to continually enrichen it.

Injectors blubbering or spraying crappy patterns can cause this. If you haven't had the injectors cleaned (out of the car) and tested within the last ten years, then get cracking.

I gotta say, everytime I see the "Smell Rich" I keep thinking maybe you bought your car from MTA and its burning dimes

for those w/o a clue to this:
https://www.fiero.nl/forum/Archives/Archive-000002/HTML/20060206-1-054478.html

I couldnt resist, hope I didnt hijack your thread

I have checked the entire exhaust system for damage , found none and only replaced one manifold bolt that would keep backing out. I don't hear any exhaust leaks/ticking at all. I recently had my injectors pressure cleaned on the car. Is it necessary to remove them for proper cleaning?

I actually purchased my car from the original owner who is getting up in years. He reluctantly sold it after an operation on his leg made it too painful to depres the clutch. He also had a nice automatic that he kept. That is how I became the lucky owner of a very clean, original paint yellow 88 GT.

quote Originally posted by Rick 88: ........... I recently had my injectors pressure cleaned on the car. Is it necessary to remove them for proper cleaning? I

In chasing down the fuel smell, I decided to check my emission cannister, When I removed the lines one smelled/sounded like it had fuel in it. After removing the canister the round filter at the bottom just fell apart. The canister has a fuel smell but does not seem to have fuel inside if I shake it. Do I have another problem?

Also, I wanted to recheck my timing after removing the distributor to replace the cold start injector. Darn V6 timing marks are a bear to see. Which mark "VVVVV" is 10 degrees? Maybe it's time for bifocals.

This help Rick

Replaced the coolant temp sensor today, along with the thermostat (good PM if I'm messing with coolant anyway, I'd think).

Initial testing seems positive. The car has no cat, so I expect increased smell anyway, but prior to messing with it, it was terrible. The car runs VERY smooth now (wasn't bad before, but would seem to miss or cough at idle every so often). The couple of warm starts I tried resulted in it cranking for 1-2 seconds before starting, and when it did, it didn't sputter - it just started right up.

I didn't get to drive it much today, but it seemed to smell less, and it definitely ran better. The old sensor was the original (112k+ mi), and the portion that contacted the coolant was black and somewhat crusted.

Thanks Dodgerunner! My timing is now set correctly.

White Formula. How much coolant did you loose changing the sensor?

[This message has been edited by Rick 88 (edited 04-24-2006).]

Didn't lose much coolant. I did add coolant after I replaced the sensor and thermostat however.

I've got an old cookie sheet as a drip pan under the car (to catch the occasional oil drip from the seeping pan gasket), and it didn't even fill that. I was surprised it didn't get everywhere. I have it next to the passenger's rear tire, running lengthwise, right under the cradle rail.

The real issue is cleaning off all of the surfaces that it ran down to get to the ground. Mostly collected in the valleys of the water pump, etc and the cradle rail. I was able to clean it up pretty well without even taking the wheel off the car. I'll really get in there this weekend when I tighten the alt belt (again).

The car definitely runs better. Idle is rock solid, low and nice. Still smells a bit on cold start, but I expect that. Just backed it into the garage and I didn't gag, so it looks like it was worth it. And I found out that the fan switch still works too, so all in all, a very good evening.

White Formula,

I don't gag quite as much backing in after all I have done and checked. But, a new coolant sensor is going to be my next day off project. Glad you fixed the problem! I'll post how mine does after I install the new sensor.

Interesting post script to this story...

Since I installed the new coolant sensor, cold starting has become problematic. Where before the engine would fire instantly after almost no cranking, it now takes quite a bit and even a kick of the throttle before it sputters to life.

In the interest of full disclosure, just prior to replacing the sensor I added a bottle of Techron fuel injector cleaner (as I've done in the past). I suppose it's possible that contributed to the problem, but it never has before. I'm withholding judgment until I run this tank of gas out, but it's certainly odd.

But if you old temp sensor was actually bad and since you where running rich that would indicate that the sensor was telling the ecm your engine was very cold. Hence your engine would start better when cold.

Now with a good sensor the ecm is setting the fuel correctly for the temp it is reading.

Is it possible the bad sensor was covering up a cold start problem? Or is your cold start injector still functioning? Was is it disconnected?

[This message has been edited by Dodgerunner (edited 04-25-2006).]

Well, if the old coolant temp sensor was telling the ECM that the engine was cold all the time, that would make me think that cold starts would be normal (since the data would technically be correct at that point). When the engine was actually warm, it should run rich. The new sensor should also tell the ECM that the engine's cold, but only when it actually is.

Not sure why the new sensor would create a cold start problem.

I replaced the intake air temp sensor (the one in the air filter housing) years ago, but it didn't make any difference. I'm going to replace the O2 sensor for good measure ($22 at Napa), but that shouldn't affect starting.

Stepping back a bit, the things that could cause the engine to flood at start (that I haven't replaced) would be:

injectors

cold star injector

TPS (?)

The real burn here is that once started, it runs very nicely. Smooth, stable idle, lots of power, no hesitation, no backfire. I guess I could just never shut it off...