Well heres the deal in the last week or so my engine has been acting up. The main problem is everytime it slows to an idle it dies and it also takes a million times to get it to start and it won't start at all unless you give it loads of gas. I had a problem w/ the idle a year or so ago that just went away but this is a lot worse than that ever was. I've had an almost constant code 13 for lean O2 sensor for a while too. Plus she leaks oil pretty badly now days too. Seems like it'll only hold oil for a few days to a week Could the thing just plain be ready to die on me?

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Red 1986 SC, 2.8L, rebuilt 700R4, 3.42, t-tops, 167K miles and counting, K&N air filters w/ removed air baffles, hopefully more to come!
RIP #3

 

Pull out your IAC, I bet it's in pieces, that is what happen to mind, what the IAC does is alows air in when the "butterfly" closes, so the engine can run things like A/C. Just buy a new IAC. By the way when the IAC fails it never really sets a code, don't know why. Also since your high in miles you should look at your MAF and/or MAP sensors and I would just change the o2 sensor if you haven't already.

 

Also if you just want to move up, talk to KED85 about swaping in the 3.4L v6 out of a 1994 and 1995 4th Gen Camaro, the reason I say this is he knows all about it. Bolts right in, you use your transmission and intake and front stuff.

 

Sounds like the IAC to me too. Idle air control Valve. MAKE SURE WHEN YOU GET A REPLACEMENT THAT IS THE RIGHT ONE. THERE ARE LIKE 4 OF THEM THAT WERE MADE. I know from experiance because mine was acting up a few years ago. Took a LONG(900) plus mile trip at around 90MPH and it went away.

 

I know I'm gonna feel like an idiot but where exactly is the IAC? I popped the hood this morning and there is a lot of stuff around the TB. Also one other thing I noticed was that the valve on the valve cover beside the oil fill cap was not in place. I put 3 quarts of oil in last Friday and I have never been able to get the oil fill cap off so I always put it in through there. I put it back in place and it did start better but it would still die. I took it for a spin and it ran better w/ that valve (sorry but I can't remember its name for the life of me right now) in place. Also could it cause any damage running the car w/o it in place? It was only off for around 300 miles or so.

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Red 1986 SC, 2.8L, rebuilt 700R4, 3.42, t-tops, 167K miles and counting, K&N air filters w/ removed air baffles, hopefully more to come!
RIP #3

 

The PCV valve? yeah, that sucks excess crankcase fumes out of the engine; running for a few hundred miles wouldn't hurt too much, but if you ran a while without it, you'd start gunking up the engine. The PCV system helps keep the motor clean. It runs off engine vacuum; maybe without it in, the car had a vacuum leak?

That lean O2 sensor code; it's not your fuel pump, is it? My car smelled "fine" exhaust-wise before my fuel pump died; now it smells rich.

You could try cleaning your IAC before replacing it. W/engine off, remove the IAC motor from the passenger side of the throttle body. Use a large open-ended adjustable wrench; the thing screws into the TB like a spark plug (later model V6's are different). Clean the pintle (motor tip) and IAC passageway (inside the TB, runs from the IAC hole to the front inside of the TB, pull off your intake hose to see it) with a can of "throttle body/intake cleaner for Fuel Injected engines". The carbon will probably pour out of the IAC passageway (inside front of TB, on passenger side, see it by removing your air intake hose). Screw the IAC back in approximately as tight as it came out- remember; IAC motor = steel, TB = aluminum, don't strip the hole out! Re-connect the 4-wire plug, and go for a drive.

Do NOT turn the car on while doing this procedure. If you have the IAC removed from the TB, and the IAC's still plugged into the engine harness, and you turn the engine on, the IAC pintle will extend outward- and you won't be able to seat the IAC motor back into the TB. If you do this, it's fixable, but it's very easily avoided.

Your TPS might also be mis-adjusted thru the years. That has a hand in the air/fuel mix. There's a tech article on thirdgen.org about it, even though it deals with a V8 TPI system, the same stuff applies. (Later model v6's do not have an adjustable TPS.) It's titled something like "TPS & IAC settings"- aw heck here's the link: https://www.thirdgen.org/newdesign/tech/tpimod2.shtml We have a slightly different TPS spec than the TPI's, though- our spec is 0.55v, +/- 0.05v.

[edit] Oh, one more thing to check re: code 13- make sure your oxy sensor wire isn't burnt and shorting against your exhaust.

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-Tom P (Hot rodded 1986 Firebird 2.8l)

[This message has been edited by TomP (edited October 09, 2001).]