I've been having a TON of problems with my LE2 350 as of recently. I got a new PCM tune maybe a week ago. Car ran great, idled perfect, no smoking, etc. Now maybe after 15 miles of driving, I go to take it for a ride today and all of a sudden it fouls plugs, has gas in the oil, and smokes like a chimney (so, it's running REALLY rich). I honestly have no clue where to start, I know it's not the tune because it did this before the tune also, and I was hoping the tune would fix it. I have Accel 30# injectors so I know it's no overkill. What could be causing this? I have brand new AC Delco O2 Sensors, so it's not that. I'm this ---> <---- close to completely giving up on this motor, it's been giving me nothing but problems since day one. Any help at this point is good help, thanks guys!

 

Verify that the coolant sensor in the waterpump (provides signal to PCM) is working correctly and that your MAF is properly functioning as well.

 

Brand new MAF so it should be good (stock GM), and the coolant sensor in the w/p has always worked, so I see no reason it wouldn't be, but I guess I could look into it, I'm getting desperate.

How would that effect the AFR anyway? Just curious, thanks for the help!

 

Make sure that coolent sensor is connected good. I some how knocked mine loose one time and it ran super rich. It would at least be worth checking.

 

Have you tried resetting the PCM? If it drives better right after doing so that would indicate a PE idle with the BLMs locked might be a help.

 

You can't just assume everything is good, you have to prove that it is. Otherwise, you won't ever find your problem.

 

This is true, but the MAF is BRAND NEW, there is absolutely nothing I can do but buy a different one. And how do I "test" the w/p sensor, as it's always worked fine in the past, and after I throw a new set of heads on the car, it doesn't work all of a sudden?

And maybe I will try resetting the PCM. I bought a brand new PCM from the dealership and had Bryan just flash it along with my car's info. How do I reset it? Just unhook the battery for 5 minutes or so?


Thanks guys!

 

New means nothing. Did you ever buy something new that did not work? You can verify MAF and sensor operation with a scanner. There is also temp sensor testing info on my Tech Page.
Resetting the PCM only takes removal of the PCM BAT fuse for about 30 seconds.

You also said you had problems before you did the modifications.

 

Well the MAF was working fine, but piece of the plastic for hte clip broke, so I got a new one. And I shoulda reworded my sentence before, it did this before on the OLD tune (the madz28 tune), so I got a PCM4Less tune hoping to fix it.

 

I suggest use a laptop w/ freescan, run some datalogging and have someone look at it

 

Got datamasters tonight and i'm gonna borrow pete's akm cable. I should have some more info for you plus a video by monday.

 

Just went out and checked it a little bit ago, everything looks good visually.

 

Tried resetting the PCM and that did nothing. I'm sure my plugs are beyond fouled though, so maybe even if it would do something, it's still not gonna run right because the plugs are already fouled. Time for set #3 of plugs....

 

Bump, any other suggestions?

 

If you have a scanner to look at data real time, you should look and see what the fuel trims and the O2's are reading. The 2 together can give you a wealth of knowledge.

You can test the MAF easily with a volt meter that reads frequency.

On another note. Over the years I have seen complaint after complaint regarding Accel injectors. I would be highly suspicious of them first.

Obviously you have to correct the problems you know of like fouled plugs and an oil change before you go on from there. After you do that, look for any dead cylinders. Wouldn't be the first time a spark issue caused an engine to run too rich.

Does it have a problem from cold start or only after it warms up?