Black smoke under boost...

[John84GN]

Hey guys...

This is an ongoing problem...but it's kinda weird...it doesn't happen ALL the time. Usually, it does happen when I drive the car for the first time that day...now it doesn't happen right off the bat, but if I get into it about 3-4 miles down the road...I see black smoke so thick, that I can't even SEE the car behind me, and the car just SHAKES like it wants to go, but it can't. Now...the boost goes up (about 14-15 psi), and the knock guage only goes up to the last green, or first yellow. I have turbolink, but don't know what the hell "all those numbers" mean...

For what it's worth, I recently went to a GSCA club meeting this past Sunday, and after talking to a few fellow boost heads, they said that it's probably the cam sensor being out of adjustment...

I did some homework on this, and also checked some previous posts via the search menu, and also gnttype.org, and I have to say that I am pretty handy when it comes to cars, but adjusting that damn thing looks like GREEK!!! I can read the directions, but
I have NO CLUE what the heck they mean!!!

Any info from those of you who have had this problem would be GREATLY appreciated, and any of you who have and idea of your own...shoot!

Like I said...it doesn't happen all the time...but lately, it's been happening more times than not!

Thanks...

 

[JayLashua]

List your mods !!

Is your coil good?

HAve you replaced injectors/fuel pump/FP regulator?

whats your fuel pressure at idle with the vac. line off

Did you replace the ECM with a '87 ecm?

Do you run a 84 maf with the 87 ecm if so?

Black smoke is a result of running rich. Sounds like your mixture needs to be leaned out.

If your FP is right on (38 PSI static for a stocker) tghen check your spark plugs/wires/coil - weak spark can also do that I beleive.

Does it pop at all?

 

[John84GN]

Check Sig. for mods...

only thing off an 87 is the coil pack (previous owner converted the coil pack to an 87...everything else is 84 I believe) He said that he changed the coil pack, wires, plugs, and cam sensor. Fuel press static is 38 ish.

explain "pop"

I know that this is a fuel problem...kinda makes me feel better about it all, but it's recently becoming a real pain in the A$$...

 

[John84GN]

TTT

 

[WFO]

if it's intermittant i'd look towards the maf taking a dump.

 

[JayLashua]

hmm. tap the maf and see if the idle changes, gets rough?

 

[John84GN]

MAF checks out ok...nothing when I tap it, and if I unplug it...the car then starts to stumble?!?

anything else?!?

 

[6 to go]

I am having the same problem. Only mine is worse. My 85 has the 87 ECM and chip for the 85 MAF. I changed spark plugs, wires, checked the coil, changed the MAF. and still there! I am going to change the O2 sensor and FPR and see if that helps. Lets keep this thread going intil we find the problem, please.

 

[John84GN]

ok by me!!!!

I'd REALLY like to fix this...especially when some punk wants to play, and you don't want to get embarrassed b/c of all the BLACK smoke that comes pouring out of your "fast car"...

anything else fellas?!?

 

[DR BOOST]

i had the same problem on my 85. black smoke screen and stuttering..

it the o2 sensor..replace it they dont always set off codes
hth

surej

 

[6 to go]

I'm going to replace the O2 sensor tomorrow and check the FPR.
I'll let you know hwat happens next!

 

[gsbuick65]

im way ahead of yall, already did all this to my 84, 1st converted over to 87 ecm and maf, added mat sensor, put in adjustable fpr, nothing changed, so finally changed my injectors and that fixed it, at least untill today went out to the car, turned on the key and before i turned the key my o2 gauge was all the way rich, so im thinking something is telling the computer to add fuel but what? maybe IAC? I took pos cable off to reset comp and it brought the gauge back to normal. had to clean plugs off so it would start.

 

[John84GN]

car has new o2 sensor as of about 1500 miles ago...would it crap out THAT fast!?!?!? The injectors are stock...so...just letting ya know...

So...who's got new idea's?!?

 

[gsbuick65]

i didnt mean that the o2 sensor was bad, what im thinking is maybe the injectors or letting to much fuel go by, u know there 18 years old. after i took mine out i check them with a ohmeter they all checked out the same, i changed mine from stock OEM, just put in some tomco green stripes and man did it make the car run so much better. and the O2 sensor gauge showed the car running smoother too. idled steady too

 

[WFO]

Originally posted by gsbuick65
turned on the key and before i turned the key my o2 gauge was all the way rich, so im thinking something is telling the computer to add fuel but what?

fwiw,i've seen the coolant temp sensor do this before.if it's gone bad and it's telling the computer the wrong temp(t-link said it was -40* )the computer will add a sh!tload of fuel(like a choke on a carb).


later,sean

 

[6 to go]

Well, guys, I changed the O2 and FPR today and started on putting in a new module and coil pack AND i found one of the wiring harnesses under the coil pack was disconnected!
I am going to go ahead and put the new coil and module on and see what happens then. The injectors can be checked with a fuel pressure gauge. They should hold pressure for some minutes after the ignition is shut off. If they were clogged, I would think they would leak down, too???? The ones on my 84 did. And they were junk when I pulled them out!

 

[John84GN]

TTT

 

[JayLashua]

Make srue the EGR valve isnt stuck?

 

[John84GN]

checked EGR...works fine...been there, done that.

Anything else?!?

 

[gsbuick65]

well im gonna get a scan tool and see what my coolant sensor is saying, sounds logical. mine starting running rich yesterday had to pull the plugs out and clean then, then it ran right, but it does run better with the new injectors, so im thinking more than one problem.