I just smoked a cat and dont want to burn out the new catco that I just put on there. What are some of the things that make you car run rich. I dont have the AFPR on there yet do you guys think that if I put it on and turned it down would that help? Also I do not have a chip and there are new Accel 8.8 race wires on there. What elso should I look at? Thanks for the help.
Evan

 

DH,

The AFPR idea is on the right track - or at least your thinking is in the right direction. Unfortunately, most AFPR kits will not allow adjustment much below the factory setting, if at all. Most are designed to increase pressure above the factory units. Besides, the ECM should be able to control fuel injector pulse width to correctly set the flow leaner at any reasonable pressure. The problem is usually just the opposite of yours - trying to get the system to deliver more fuel to compliment intake enhancements.

In other words, the higher pressure shouldn't prevent the ECM from reducing fuel, within reason. If your pressure is way above 55 PSIG, it might be an issue, but I'll guess your stock regulator is closer to 45-48 PSIG.

The final check in the system is the oxygen sensor, so you need to make sure it is functioning properly. If you don't have access to a data scanner, you might want to replace the sensor just for argument's sake. Bosch (the O.E.M. supplier to GM) recommends a sensor change every 30,000 miles as a preventive measure. While that may be a little extreme, if your sensor is aging, it might be a good idea.

Another item to check is the PCV system. Since the PCV is a "programmed vacuum leak" the ECM expects to adjust fuel based on the higher intake manifold absolute pressure. If the PCV is plugged the mixture will tend to be rich.

You mentioned that you do not have a chip. I presume that you mean you don't have a performance PROM, but are still using the factory PROM. If you think you are running rich, you should be able to use the SES lamp to give an indication of the ECM's efforts to adjust mixtuire once it's in closed-loop.

The directions are somewhere in the Tech Articles, I believe. If you can't find them, post back and I'll try to dig up the procedure.

Later,
Vader

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"Some Body...Someone"

 

Just a quick post the O2 sensor was changed only 3000 miles at most ago and I will now go check the articles.

 

Ok I searched for the articles I must be blind or something. Could you help me out yet again Vader? Try and find them if you cant it is ok I am sure I can figure something out.

 

Vader's talking about jumping the ALDL connectors and monitoring the flashes, not sure if I've seen it in the Tech section or not.

O2 readers that plug into the ALDL are about 20 bucks if I recall.

Your car TPI or TBI? Assume it's an '89?

 

if you jump it while the car is running, you are performing a different function whereas you jump it with the key in the on position. if you jump it while the engine is running you should get real fast flashng on your ses light in your dash. this means the ecm is in closed loop. if it flashesslow then it is in open loop. now if the car is at operating temp and the light flashes slow, then the o2 sensor is nt giving the ecm the proper info and thus will prevent proper air fuel mixtures.

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I have experience...unfortunatly.its from bad judgement.
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Reasons for running rich:

Bad O2 sensor
Faulty TPS or its connection
Faulty MAP or its connection
Exhaust 'leak' near O2 could cause rich run
Intermitant+small vacuum leak (fools MAP)
Faulty injectors (leaking?)
Too much fuel pressure (bad Reg?)
Bad PROM or ECM (probably not, though)
Clogged fuel return line (raises FPressure)
Sucking gas through misrouted canister system
Spark control not working properly
PCV malfunctioning/incorrect P/N
Misfiring cylinder(s) (unburnt fuel/O2 traveling down pipe trick O2 snsr into thinking engine is lean)

Tired now, need sleepy...

 

Also, you want to avoid driving your car or revving your engine at high speeds while it is still cold. Your cat doesn't actually start doing its job until it reaches about 600 degrees internally. Running them cold can trap carbon deposits causing them to clog. Let it warm up a little before driving it or revving the engine. I let mine warm up until the needle on the temp guage starts to move. My engine usually heats up pretty fast after that.

 

8Mike9 I do have a TPI. I have checked the operation of the car and it is in closed loop from what I have seen. Could that change over time? I have a 160* stat in there but am afraid that it wont go into closed loop could that have anything to do with it? Also it seems like all of you keep mentioning that the O2 sensor has a lot to do with it should I just go out and get a new one or do the ALDL thing to see if it is in open loop?