Firebird355

I have a 85 camaro with the 2.8 and I have oil coming up through the throttle body? anyone know what is causing this, it also isnt running very well right now..

Engine wont stay at same speed, sounds like it has a great big cam in it....kinda, it just fades in and out.. any idea on that?


Thanks alot,

Joel

Quick_Trans_Am

iTrader: (2)

Oil in your TB huh? That's different. Not sure I can help you there. Has your check engine light been coming on at all? If so do you know what trouble codes have been set? You say your engine won't stay at the same speed, and I'm assuming that means at idle and not with you applying any throttle. Sounds to me like your IAC may be on its way out, or you may have a vacuum leak as well.

Firebird355

well This is the second 2.8 i have owned that had out coming out of the throttle body but the other one ran great besides it burned oil, somone had rebuilt it and did something wrong to make it burn oil.

I looked around for a vaccum leak i havent seen anything, i know i cleaned the plenum and everything out with carb cleaner and there was ALOT of oil in there. Before i did that it like to stall. I cleaned that and it doesnt stall anymore just wont idle right, Ill check into the IAC.

Thanks

Lee7

i dont see how oil could possibly get into the TB... there are no oil lines going to it.

Quick_Trans_Am

iTrader: (2)

that's what I thought as well. How about carbon, was there a lot of carbon built up in the throttle body too? I'd definitely say your IAC is in need of a disassembly and cleaning, or total replacement if it's bad.

Doward

Yeah, are you sure it's oil? black, liquid oil?

I mean, I had oil in the TB... but it was caused by too small of a return line from the turbo, causing oil to force past the seals, and into the intake

camaro_junkie

I took my IAC out not too long ago, and I noticed something similar. It was black-oily crud on the IAC (pintle?). I just assumed that it was junk coming from the EGR or PCV vavles. Where does the PVC go back to the intake (I forget)? And I thought you weren't supposed to use CARB cleaner in FI intakes?

FAST RS

The oil in your TB is from the metel tube that goes from the passanger valve cover into your air intake hose the big rubber thing. Just clean it with some Throttle Body Cleaner and just do it every year or so. All it is is oil being sucked in from the valve cover.

Nixon1

If that tube is feeding oil into your throttle body, you need a new filter element in there. The filter keeps oil from feeding through so that just the air goes through. Who knows the kinda crap that thing could be drawing in through the intake.

Check your engine vacuum, see what it reads. A vacuum leak will cause that loping idle...and if it's a leak at the intake manifold gasket between the upper plenum and lower intake, that will cause an oil leak there and possible explain oil getting into your plenum.

camaro junkie....you're not supposed to use carb cleaner on EFI engines, BUT it's ok to use on a hard cleaning job as long as you let whatever you cleaned dry out thoroughly and let the cleaner evaporate before you install the part back into the engine and run it. Otherwise, use throttle body cleaner. Only real difference, as far as cleaning goes, is TB cleaner is EFI-safe but it's not quite as powerful.

camaro_junkie

Nixon1: that filter element you are referring to, is that the rubber 90° grommet on the valve cover? Also I thought I remembered TomP say something about CARB cleaner destroying a coating on the internals of the plenum... maybe I'm thinking of something else.

edit: see this post https://www.thirdgen.org/techbb2/sho...leaner+coating

Nixon1

Yes, you're right about the carb cleaner. That's why I say to let any parts you use the cleaner on DRY before you install them again. I'm not saying to go shooting it all in the engine...I'm just saying use it on the IAC valve if ya need it.

Now, as far as the filter goes, I'm not sure where it's located exactly, but I assume it's either in that elbow or right below it.

camaro_junkie

That's cool. I'm not questioning your expertise or anything, I just remembered seeing that, so I thought I'd bring it up. We don't want anyone to go out to the garage and ruin their intake or something.

edit - Firebird355: did your question get answered here? Messages sometimes get a little off topic. Let us know how it turns out.

TechSmurf

Your PCV system has malfunctioned or you've got *serious* engine blowby that the PCV system cannot handle. The oil is coming in from the passenger valve cover, as said earlier. Check this by removing the PCV valve from the driver's side valve cover while the engine is idling. There should be hella vacuum being pulled through the valve. If it's just a PCV malfunction, that means one or more of the following:

1: Your PCV valve is toast.. you should be replacing this every 3000 miles anyway. They cost about 3 bucks at major parts stores.
2: You have a vacuum leak which is affecting the vacuum reaching the PCV valve. Primary suspect on this would be a broken hose leading to the PCV valve from the TB, however any vacuum leak *could* degrade the amount of vacuum being pulled through the valve.
3: Your PCV system is clogged with dried oil sludge. This scenario sucks. TB cleaner alone won't dislodge this crap once it's built up to the point of a clog... actually it'll rarely dislodge it anyway. Remove the PCV to TB hose (driver's side and passenger's side) and make sure they're both relatively 90%+ clean inside. Remove the PCV valve and make sure it works. Replace passenger's side hose and start engine. Make sure the PCV vacuum port on the TB is pulling good steady vacuum at idle. If not, it's clogged. Grab can of TB cleaner with a straw on it and start cleaning it out. If the engine stumbles, good, it's getting through. If it backwashes, you're in for a trip. Either remove the TB and give it a THOROUGH cleaning, make sure those vacuum passages shine and flow perfectly, or just use something as a pipe snake and force the sludge to go ahead and go through the motor (the stuff is obnoxious, but it's not likely to damage your engine)

And to Nixon: There is no breather filter on the V6 cars. They're supposed to be drawing in air from the main intake stream (post-MAF, none the less).. much like your mustang EFI's pcv system is routed.

Nixon1

Right...I know they're drawing in fresh air....but isn't it only the driver's side valve which draws in air, and the passenger side tube recirculates the outgoing air back into the intake stream? This is the way I've always seen it pictured anyways.

And I just thought the V6's have a PCV filter because my Mustang does...I assumed they all do.

Firebird355

yes this has answered my question mostly, ill have to go out tomorrow and try a few things on it,

I replaced the PCV, and cleaned the EGR, i will go check the hoses to see if they are clogged, and remove the Throttle Body and IAC to clean them out really good. I have new gaskets for the plenum laying around so maybe ill take that off and clean it out.

I get back with the results

Thanks

Firebird355

i forgot to say, I checked for engine blow by and there is no signs

TechSmurf

No, Nixon, it draws air from the intake stream and *into* the crankcase throuth the passenger's side.. vacuum is supplied to the crankcase via the PCV valve on the driver's side, sucking air through the crankcase and into the throttle body, giving blowby gasses a second chance to burn off (and keeping them out of your crankcase in the process).

As I said, 355, pull the tube between the TB and PCV valve, clean out the tube, fire up the motor with the tube off and make sure that vac port is pulling.. my v8 had a solid plug of crap over an inch long blocking off that port internally.. I had to ream out with the handle of an ignition file.. and I'm still sure there's more crud on the inside that I can't reach without pulling my TB. If you go to ream it out, don't fret over pushing too hard. The TB will withstand it. That crud can feel like you're hitting metal if it's been in there a while, but it'll give eventually.. or just pull the TB like you're thinking, but beyond the IAC, make sure every vac port is immaculately clean inside.

Firebird355

I just checked the pcv tube and it was filled up, i could barely get air through it with the air compressor. I cleaned it all out but havent had a chance to install it yet, I will put it back together later on today and get back with you.

Thanks

TechSmurf

That means the port on the throttle body is probably in the same condition, and the PCV valve is probably toast.

TechSmurf

My first real double-post.. whee! Only took 3 years to finally pull it off

Nixon1

Lol..thanks for the input, Tech. I had the idea right but the sequence backwards.

Is there any sort of filtration setup in the PCV valve itself now? Or does it just keep any sort of oil and crap out just by its design alone?

TechSmurf

No filtration at all.. it'll keep large particles out by its design, but any particle big enough to count will do just as much damage in the crankcase anyway..

TomP

Yeah PCV just sucks out fumes, which should be the only "air" in the valve cover that's high enough to reach the PCV valve. If oil gets up that high, well, hell, PCV ain't your only problem so a filter is kinda pointless.