ok,i just got this 85 firebird (2.8 TPI,automatic.) im trying to bring back to life,but theres a few problems,wondering if some of you might have an idea of what a problem could be...the idle is choppy and lopey and uneven also seems to idle low,exhaust smells sweet and leaves a bit of white smoke...i expected something was up with the exhaust,which led me to the cat,so i drilled some holes in the pipe before the cat and its better on acceleration now,but the idle is still about the same...

any ideas?..

 

White smoke and a sweet smell is likely antifreeze...in other words, blown or leaking head gasket, or worse, a cracked head. Idling problems could be anything from a vaccum leak (likely, esp if the hoses haven't been changed), dirty throttle body, or a dirty or non-functioning IAC.

 

could be an EGR stuck open. are you sure that the smoke is white? cause white smoke means water/coolant in the exhaust which is typically caused by a blown headgasket. also, the sweet smell in the exhaust is probably antifreeze.

just FYI, TPI refers to the V8s. the v6s are MPFI which is multi-port fuel injection. the actually differences in the two systems are minimal but knowing that could make life a little easier at times.

edit: LT1guy beat me to it... lol

 

agree with head gasket, or intake gasket. And bad vac lines.

 

i'll do a search for IAC test and cleaning

i'll should do a teardown and rebuild with a top end gasket set and do some cleaning while i'm in there...

anything i should look out for or get done while i'm under there?

 

head gasket leak, you wont have to really tear it down for looking. I belive a compression test, along with sparkplug inspection would be a good start. Anyone correct me if I'm wrong.

IAC cleaning is quite easy, but read about it carefully first! Spin that tip a hair and your screwed.

Vac leak is easy check with a gauge and some wd40.

 

Thanks alot, I'm going to clean that IAC and do a thorough check for vacuum leaks to the best of my ability... i have a vac gauge, about how many inches should this motor be pulling at the vacuum lines? i'll get right on it as soon as I hear back from someone on that...

I don't know of the wd40 method... Spray a little here and there and if the idle jumps then you found a leak? thats all i can think of... (or maybe it would stall??)

i just cleaned the intake with some carb cleaner up really good, both while the car was on and off, and it cleaned up the idle ALOT. The thing stopped jumping all over the place and it seems to hold a stable idle now, I just had it running for about 10 minutes and it never acted like it wanted to die like it did before either.

Seems to have a little more power and throttle response also.

but...

NEW PROBLEM

the reason the intake plate and inside the TB was getting so dirty is because the vent hose coming from the passenger side valve cover is spewing some pretty nasty black smoke, not severe, but definitely excessive and noticable.

it is also putting OIL into the TB and the boot that comes from the air box to the intake on the TB...

That vent hose is controlled by the EGR, correct?

Is there anything we can do to remedy this? what would cause this smoke?

Time for new EGR?

also hope to get a dist cap & rotor, plugs & wires, and a fuel filter in before I start driving it... Maybe ignition problems could leave unburned fuel which would cause this?

If not ignition problems, then hopefully changing all that will get rid of some of the "putt-putt" feel and sound of the car. It seems to pull strong at high RPM, but is really lacking down low.

 

amount of inches will depend on wear and mods. That really doesnt mater that I know of. Its how steady is it. (will move a bit with rpms up n down) but if its twitchy like a crack head waiting on a fix, you got issues. Very correct on wd40 method. Spray the hoses, any place thats not overly hot and may run a vacume.

Sounds like you have ALOT of interal blowback, which is a good sign of a head gasket problem, or worn piston rings.

PVC controls internal vent back into the engine, which is one of 2 places the oil is getting into your intake.

The EGR puts burnt "gases" back into your manifold intake. This has nothing to do with your problem.

Wait on any tune up part untill you can do a compression check. Otherwise your waisting parts n cash.

 

nah, this is all stuff i want to change anyways because the car was only bought the night before last (two days ago) and I always do a full tuneup on every car I buy before I start driving it.

i'll do that wd40 trick though, and see what kind of vacuum problems i'm looking at.

I jumped the aldl and I got a code 34

I can't seem to use the search engine very well on this site... What the hell is a code 34? Seems like I remember it being an o2 or MAF code right?

 

and also, the PVC is on the drivers side valve cover, and goes around to the back of the motor... I already replaced that, and I don't see how it can put oil into my intake

The Passenger side valve cover vent is the side that is hooked up to my intake through the air boot right before the boot meets the butterfly valve, I just went out and took a look and there is no valve in there whatsoever.

It is just a plain rubber boot going to a metal line that runs into my intake.

THAT is where I'm getting oil from. I'd like to know any suggestions or ideas as to what is causing this.

 

34. Low voltage (high vacuum) at mass air flow sensor (or MAP sensor)


https://www.thirdgen.org/newdesign/faq/thirdgen.shtml (very bottom of page)


That tube is how air goes in for the pvc to suck it out. Still means you have ALOT of blowby if ****s coming back out of it. STill check compression before you install new plugs, otherwise your just going to toast a new set of plugs.

 

MAF seems to work, it idles a bit better with it connected. But it kind of seemed a little better at higher RPM's

I'll clear the ECM and drive it around a bit, if it still throws a code 34, we'll replace the damn thing anyways I guess, I suppose it could be getting an incorrect signal due to old age? The thing DOES look pretty damn old...

Another thing came to mind earlier, the previous owner (or the one before that) hotwired the fan to an ignition source, so everytime you hit the key the damn thing turns on.

It never really gets above 160 or so it seems, you think that could be part of the problem? I read somewhere that certain systems (namely the o2 sensor and EGR) aren't effective until the motor reaches a certain temperature (around 160)

I thought maybe that because the car never reads above a certain temperature that the o2 would remain in closed loop, dumping more fuel than nessecary... ??? Just a thought.

Tommorow I'll clean the IAC, adjust the minimum air, and adjust the TPS, and see if that helps.

We're just trying to get his damn car running reliably and to the best of it's ability really... We aren't looking to do any major motor work, but if a couple hundred bucks of small stuff all around can get him another 10K miles out of the motor then that's what we're shooting for.

As of now he is more concerned with bodywork and getting his suspension setup for a motor swap later.

Sorry about the confusion, I've been posting on his name for awhile, Eighty5 is my brother.

We ARE a bit concerned though, the damn thing seems pretty sluggish compared to my 3.1...

Any suggestions would be taken with an open mind.

Thanks for everything so far you guys, especially Dale for periodically checking back.

 

Ok, so is it a map or maf system? The mafs are famous for going bad. So its very likely that is a problem, and I'm unsure of what all havic it does when its out. Someone with a maf system will have to answer that.

I would still do a compression check, and vac check.

If you just have to replace head gaskets, thats not overly expensive, just time consuming. Now if it cracked a head, or needs head work, then your talking a bit of cash.

The 160 thing seems to be more directed to the ODB2 systems. But having the fan on all the time would need to be fixed. Are you sure its hard wired, and not the sensor stuck on? I belive on a 2.8 system, that sensor is in the right rear head.

 

it's an MAF system,im not sure about that fan sensor though,ill have to check in on it.

anymore suggestions would be appreciated,just trying to get the motor in good running order while i fix the body & suspension.

 

No, the fan sensor is bypassed and the fan is hotwired to an ignition source.

We should probably wire a relay and temp sensor back into the harness, I don't think it would be that hard at all.

I think I have a compression gauge laying around in the garage, I'll have to check, but I don't know if I have a spark plug fitting for it even if I do.

I have a vac gauge though, and as soon as we can grab some WD40 we'll get on that because we saw that alot of vacuum hose seemed to be deteriorated.

5/16 right? I always see KED85 screaming about 5/16" hose........ lol