hi guys. car is running rough and has little power. when i hit the gas it blows black smoke like a honda and exhaust burns eyes. any ideas

 

un hook the o2 sensor and see if the car runs better,if it does the o2 is bad.
also check the map and tps sensors
if not u could have an leaking injector(s)

 

Since fuel control is computer driven, the first step is to determine
if your system is functioning. Most computer failures give us what is
called "limp home mode". That is rich with fixed advance according to
default tables. Fixed advance gives no Pep.

Second, Injectors and fuel regulators do not last forever. A check of
fuel pressure and then a fuel injector balance test would seem to follow.

The best way to zero in would be a scan tool...

Let us know,

sixgun (jjr)

 

My wife's 3.1 runs exactly that way- still has power, but at idle it runs very rough and puffs out the pipe.

No codes at all though.

I borrowed my bud's auto x-ray, and scanned realtime data.

I didn't know what it all meant, but some others did- my BLM's were 160, which is as rich as it can go. 128 is "ideal", lower than that figure is lean, over that is rich. Between my high BLM figures and what they called out of range O2 sensor voltage, they determined the O2 sensor is bad, telling the ECM "I'm lean! Must have more fuel!"

Not that I have CHANGED the o2 sensor yet, I don't drive it much, and insist on a genuine GM Delco sensor. Just have not gotten by the dealer to pick one up yet.

 

91 v6,

I thought some more about your description of problems.

And frankly we'd need more info to help.

Sometimes I forget that others don't fiddle with this stuff
as much as I ; or have a scan tool/shop manual to look at.

There is a simple way to read out the codes, with a paper clip
even... but that in itself may not be the answer. It's just a starting
place.

To date I've repaired both of my third gens and it wasn't obvious.

My '86 had two bad injectors and doesn't like the Bosch auto parts
store O2 sensors. The Bosch goes lazy and stays midrange (~450mv)
after less than a year. That'll drive ya crazy! As mentioned before, get the Delco!

My '90 3.1 had a bad ECM, it was funny, no codes until I shut it down
then it filled a page - including ECM and Memcal failures. This car also
had clogged/failing injectors.

drop us a line with what you find or questions Sir...

sixgun (jjr)

 

OK OK OK I know it was a bad thing to do,especially being a rider myself.But them boys was askin 4 it!!Had a couplea sports bike stunt riders drag racin on the interstate tonight,climbed right up my butt with highbeams.So's I got on the gass....I mean floored it...WHAT a cloud of raw barely burnt gas!!!!Them boys dropped baaaaacccckkkkkkkkkkkkkkkk and behaved till i could get out their way.Maybe burnin rich ain such a bad thing.Just wish i had spark plugs in the exhaust!!!

 

Did you ever find your problem? This probably isn't your problem from what you have described... but a crack or leak in your exhaust pipe can cause the engine to run somewhat rich, depending on where it is in relation to the O2 sensor. Unless you have a really loud exhaust, you should be able to hear a leak, though. My car was running somewhat rich and getting sluggish, until I found and fixed a leak in my exhaust right near the O2.

 

Hey 91?? What did it turn out ta be?As i commented same issue goin on here with my 90 3.1 how ever mine has some pep it's just slo almost like she's draggin brakes or the tranny and rear end are from an 8cyl set up matched to my 6.she gets there just slowly some times and with enuff fumes and smoke to kill every mosquito in the florida and georgia everglades.
I've been told everything from the exhaust leak and bad o2 sensors to intake leaks and worn injectors/lazy relays+bad brain connection(car not me i have no connection).
So basicaly I've decided to start building up a stash to rebuild the fule system from gas cap to ehaust tip.(LOL)And at 80+ per injector guess I've got a while to go b4 the bugs feel safe in my neighbor hood.