I just became a member of this forum,so be gentle.
I've reviewed a few threads that involved this topic and confused
myself. I have an 89 305tpi iroc. I've owned her for 7-1/2 years now. The car did'nt give me any grief until a few months ago,so I behaved myself and left my tinkeritus to other things. Anyway,
the car started smoking (black) and I could not idle at stops. I took the car to the shop told them the problem and they plugged in the scanner and everything was within the parameters. They agreed something was wrong because I let them drive it. I gave them the car for three days so they could "throw parts at it". It's
still not fixed. Now I don't even get 200 miles to the tank, the car
huffs black smoke at idle and you can't see through the cloud when I bump it to wot. Since then I've put cap-rotor-plugs-wires
k&n filters. No change so is it being narrowed down to the injectors? I've only used amoco ultimate fuel to "avoid" an injector related problem. I'm unskilled in this area, but if I'm having injector problems from them not working properly I would
experience a "lean"problem not a "rich" problem.
I don't mind buying parts- if it fixes the problem. I've noticed that the torx screws holding the tps are scared so it has been adjusted or replaced before I bought it. I don't know how to adjust it, is it done using the scanner? I checked for vacume leaks and found the brake booster hose was flared at the intake so I clamped it. I've heard a ticking around the plenum but can't localize to an injector. I'm going to stop rambeling,but I just want my "cool ride" back. thanks!

 

Yo d,

Welcome the thirdgen.org.

I'd start with looking at the main page and scanning the ECM yourself for codes...see if the ECM also thinks the engine is rich...if no codes and you're indeeed blowing fuel out the ***-end, I'd be thinking the o2 sensor isn't working correctly.

Not that the O2 sensor is the "tell-all" but it should be able to indicate rich/lean conditions.

Start with the ECM scans, there's several things that can cause a rich condition.

 

Well, check your fuel pressure, ohm out the injectors, put a scanner on your ECM.

Those combined efforts will provide you a yes or no answer with no question on whether you have bad injectors. Stock injectors are crap, they fail in every single car at some point.

 

Thanks for replying guys;
how many ohms should they read? one of the guys at the shop checked them and the #'s were between 13-16, but i don't remember if he meant 13 or .13 ohms. The computer has been replaced but they used the old prom. I read the thread on how to adjust the tps but where do the jumpers go? I tried checking voltage with my dmm using the center pin as common,the other lead on the bottom pin and got .33 vdc and the top pin read 4.5 vdc. It did'nt mean anything to me because it was'nt plugged into the tps. Would all the injectors go bad at once? I pulled the plugs after a few weeks and they are all covered in soot not just one or two.

 

Ohmimg the injector only tells you about it's electrical properties, not mechanical (i/e stuck open/closed or not opening/closing properly).

But it seems they are a bit on the low side, but should be electrically okay. IIRC my stock injectors were all about 18 ohms, but it's been so long, I don't truly remember.

You'll have to head back to the main page and look at the "How to" for the TPS, I use a scanner when I check mine.

 

doesnt that much black smoke mean oil/ rings??

 

It could be the rings but I thought that was a bluish/white smoke so I have'nt given it much consideration. I guess that could be my excuse to get a 383 started.

 

try the coolent temp sensor, i had it fail in my rs and no codes. motor thought it was -400 degrees and made up with extra feul.. if not you only wasted about 12 bucks and you get a new sensor.. well worth the try before tearing motor down..

 

I've had that replaced,but that does'nt mean the new one was good. thanks. I talked to my neighbor yesterday who's an old school hotrodder, he said he had a similar problem in his sisters truck. He talked to the parts & service dept. about it and they told him to buy a new dist.?,so he did and it solved the problem. Apparently the top bearing on the shaft was bad and the ecm was constantly changing the timing to compensate for the bad bearing. New one on me but he is going to get back with me this week on it.