I am completely flustered

This is a continuence to the arrrrrgh thread. My car is still bellowing black smoke and surging. it doesnt do it all the time, just once In a while when I get a little hefty on the throttle. I had injection service done, then got diagnostics done "only tossed o2 error" which I put a new one in, still smoked. was told map sensor, cleaned the old one out and put back in, still does it but not as frequent. so i put a new map sensor in, still does it, again not as frequent. what else could be causing this? pressure tests were done by pep boys as well as my usual mechanic and everything checks out good. block test, head gasket, manifold gaskets, everything checks out good. has new plugs and wires which were tested as well. oil level hasnt changed thru all of this either. I for once am out of ideas, my mechanics are all baffled. btw, new tps, iac, pcv, vacuum hoses, the list goes on. what else could cause black smoke when getting into the throttle??? ideas please? Im so flustered, if i wasnt bald, i'd pull my hair out!!!
oh, it doesnt toss any codes now either...

btw, the name DnaProRacing is from my old online racing days. I ran a team of drivers against other teams. In no way does it mean I am a mechanic. Im learning as I go. This is a new found love "working on my cars". and you guys have taught me a lot...

Leaking injector, high fuel pressure, bad fuel pressure regulator, there must be some pending or live codes as a result of this, also a full scan should be done. BTW, I'd suggest posting year and engine here.

1992 Chevy Lumina Z34 3.4L 6cyl fwd dohc LQ1

Have your catalytic converter checked. Mine is out, and it caused it to surge quite a bit.

magnaflow converter less than 6 months old. they checked all the exhaust. flowmaster 40 muffs too...

Definitely excess fuel or retarded spark.

Hows the timing chain. Jumped teeth and excess slop could cause these symtoms. They don't last forever you know. I have replaced them on cars with less than 100,000 before. Teeth worn off and chain stretched usually.

I was quoted $432 for the timing job. not exactly chump change. Im going to have my usual mechanic check the fuel pressure first. if that checks out, i'll bite the bullet and get the timing done. Its due now anyway. bought the car with 172k, now at 208k. and the guy that owned it before me did absolutely nothing to it "maintainance wise". in fact, he changed the front 3 spark plugs, but he couldnt get to the back 3, so he left it as is. the car didnt even run when I bought it. the oil looked like black water. the air filter was NEVER changed. some people have no brain. they say these lums have to have the timing done every 50k. but i'll have to wait a week for the $$$. I've got about 5k dumped into this car, its not even worth that much. lol. in fact, the blue book is $3100
thanks for all the help guys. hopefully its the fuel pressure. I'll keep ya posted.
update: after i put the new map sensor in, it did it only once a short time after test driving it. hasnt done it since, and I've been driving it pretty hard...

Sometimes when you replace sensors, the DTC's need to be erased before the computer will come out of compensation mode. Other wise you have to go through about ten cycles of starting and driveing the car to get out of that loop.

Scratch that. It did it again today, quite a lot. whatever it is, its getting worse...

I was quoted $432 for the timing job. not exactly chump change. Im going to have my usual mechanic check the fuel pressure first. if that checks out, i'll bite the bullet and get the timing done. Its due now anyway. bought the car with 172k, now at 208k. and the guy that owned it before me did absolutely nothing to it "maintainance wise". in fact, he changed the front 3 spark plugs, but he couldnt get to the back 3, so he left it as is. the car didnt even run when I bought it. the oil looked like black water. the air filter was NEVER changed. some people have no brain. they say these lums have to have the timing done every 50k. but i'll have to wait a week for the $$$. I've got about 5k dumped into this car, its not even worth that much. lol. in fact, the blue book is $3100
thanks for all the help guys. hopefully its the fuel pressure. I'll keep ya posted.
update: after i put the new map sensor in, it did it only once a short time after test driving it. hasnt done it since, and I've been driving it pretty hard...






I would think injector hanging ever so often. As for the money in it, I assume it is paid for, so who cares what it is worth if you like it. Better to spend on a used PAID FOR CAR than buy a new one, or even another one.
I got too much in my 97 Blazer 4x4 but it is paid for & we like the truck I will just pay to keep it running.

Just when you think you can wait a little longer, problems remind you they are still there. Funny that we seem to think they fix themselves somtimes.

have to wait a week for the cash anyway. but im hoping its just the injector. its the cheapest of the few things left that it "could" be. but it ran so bad today, im wondering if its going to last a week.

Hope springs eternal. Keep us informed.

Day 1: no smoke. ran fine all 100 miles. 6 to go. lol

Could be something broke loose or flushed away!!!

Try some injector cleaner like "Techron" Also a few ozs of ACETONE cleans also. I run it regular in my trucks & cars.
Just a thought.

Injectors tested out fine. my usual mechanic looked at it pretty closely today and put yet another map sensor in. ran perfect all the way home. weird thing is even the brakes work better now. ?????
we'll see if its fixed now. give it a day or two. I have the worst luck as it pertains to getting faulty "new" sensors. btw, he said the fuel pressure was exactly what its supposed to be. hmmmm, good news, thats odd...
4x4, i had injection service done about 2 weeks ago. when it started to get real bad...

Funny thing about electronic stuff, they either work or they don't!!!

day two with new map sensor. seems to be ok. ran great both ways...
can I finally start on cosmetic???????? please????

guess not. day 3: it did it once on the way home. guess i'll have to have the timing checked. $432 quoted. this money pit has no bottom...
think i'll get a 2nd opinion on the injectors before I commit to timing tho. will I ever get to start cosmetics???

Before you go anywhere into expense try popping your hood, and opening the fuse box on the left hand side if your facing the front of the car. Pull the 15 or 20 amp fuse labelled ECM Batt, hold the fuse out for over 20-30 seconds, then replace the fuse, go get into the cockpit of your car, make sure you have the AC, Radio, even dome lights off with door closed. Now without touching the gas, hit the starter and let the car idle for about three minutes. If no missing, then keep your foot on the brake, and put it into gear and let it idle, if it still does not miss, then you've found your problem. If this fixed the problem then your computer needed to relearn how to keep idle.

By the way... Your Hi-Flow Air Filter may be confusing your computer. If your car blows black smoke only at certain times, then that may be caused by the computer trying to match the Air to Fuel Mixture ratio by dumping to much fuel into the cyinders at times of unneed, and thus causing your Lumina to blow the excess fuel out her tail pipes, or stutter, or fall on her face.

If you added the Hi-Flow Air Filter after the Car had many thousands of miles on her engine, then her manifold could have already been clogged with many thousands of miles worth of Carbon, thus the Carbon causing the air pockets in the manifold to be smaller, thus causing the Air flow to move much quicker through the manifold, and so the computer may be dumping fuel, in order to equalize the Air/ Fuel mixture.

I would try the I posted earlier, See if you can trick your computer.

If not, Have you replaced thr EGR, and PCV Valves?

If none of that works I would try one last thing and go back to the old stock Air Cleaner set-up, before you spend alot of money on the Timing Chain.

Don't give up! Your Lumina is very nice! It sounds like you are narrowing down the problem. If I had that Car I would never give up.

Good Luck...
Craig

upper intake cleaning done when i first bought the car and I keep it clean with regular blasts of carbon cleaner thru the upper manifold. i also ran seafoam in the gas and oil for quite a while, as well as the vac lines. as far as being clean, i would eat of it. lol. and yeah i also relearn everytime i fix/change something. the timing needs to be done anyway. the guy that owned it before me did nothing for it, and i've put almost 40k on it. its in need. and ill never give up on it, ill post a list of things i've had done to it when i get home from work tonight. there is no way im ever giving up...

yet another opinion from yet another mechanic, the egr valve is clustered with carbon. sure enough it was. like mud. put new gaskets on and test drove it, ran fine. but like before, gotta give it a few days before I celebrate. gonna do the cosmetic anyway. bahhh
sooooo, new o2, iac, tps, map, and a clean egr. think I got it? oh yeah, when I pulled the hose for the pcv valve, it broke in half. put a silicon hose on in place of it. been meaning to do that anyway, since all the others are silicon now...
if this doesnt cure it. im gonna kick it. then love up to it saying "im sorry baby"... then look for something else to fix...

hate to bring this thread back to life, but wanted to give everyone an update. after all those replacements, the issue got worse than ever before, i couldnt go faster than 70mph without it bellowing black smoke. knowing black smoke = fuel. the entire fuel sytem was replace and the problem was still there. i finaly got a new computer put in cuz my mechanic said it was holding the injectors open longer than they should. well guess what? its fixed. wanna thank everyone for all your patience and help with this. it was a long run but finally kicked the problem... can i start on cosmetic now? pleeeeeease??? hmmm, heard that before...