Picked up a 350 tbi camaro, but runs real rough. Trying to get it to run well.
When I turn it on it struggles then it finally catches and idles rough. If i accelerate in park it sounds good and strong but when it comes down to idle it sounds rough and sometimes stalls. Driving it also doesn't wanna go. If i accelerate slowly it goes, got it up to 70 mph on freeway was running good but if I floor it it bogs and doesn't wanna go and stalls if i don't stay on the gas. I had three codes. Code 33 for map sensor. I had a spare map and it did the same thing. Code 35 for Iacv. Iacv is brand new. And code 54 for fuel pump/egr valve. Egr valve is not stuck and is pretty clean. What could be my problem? Fuel Filter? Also its seeping some juice from the front intake manifold but not much. Car does not smoke and oil looks good just a little dark. needs tlc. No vaccum leaks. What could be the culprit?

 

Sounds like the ecm could be faulty. Have you tried to follow trouble tree for any of the codes?

 

Whats trouble tree?

 

You might want to look at 33 first. This is for tpi but the principal is the same ecm pinout doesn’t show the 746 ecm.
http://www.chevythunder.com/map_code_33.htm

 

Map signal on c11

 

You should be able to use this for the code 35
http://chevythunder.com/code_35%20%2...0detected..htm

 

Well I went ahead and bought some intake manifold gaskets to redo them since I knew for sure they were leaking. I took off the tbi and it looked fine all passages looked good, they weren't clogged gaskets were good. Then I went ahead and removed the intake manifold itself and I noticed the egr passages/ports had a wall of carbon caked on real hard. At first I thought someone j b welded it shut as to remove/block off the egr. But the pcm needs the egr to idle and run good correct? Then I took a screwdriver and punctured the wall of carbon and was real solid, had to hammer away at it and sure enough it was carbon, cleaned up the passages and they are good now. besides that another port was also clogged with carbon on the head. Hopefully this fixes my problem. Lmk what you guys think.

 

After checking the old intake manifold gaskets that are on the motor, It seems that the gaskets have no openings for egr.....Is this correct?? And the new ones don't either, Btw Its a 5.7 TBI off of a 95 tahoe if thats makes a difference.

 

This v8 stuff is new to me. Were does the egr get the exhaust gasses from?

 

FIFY

The exhaust crossover in the middle of the intake manifold gasket. The passage in the head has to be open all the way to the exhaust valve port. The EGR pulls exhaust from that passage, and routes it to the plenums via more cast passages. They all have to be clear/open for the system to work.

https://www.summitracing.com/parts/fel-ms93317

^^^ rectangular hole in the middle of the gaskets, bolt holes on either side.
This gasket set may not be correct for your Camaro. It's listed for my TBI K1500

Take the EGR valve off, blow compressed air through the two passages and see where it comes out.

EGR is not used at idle, so fixing this won't change the rough idle unless some exhaust was leaking past the carbon build-up and the EGR valve into the plenum(s)

"I" would check the following, clear the codes, see what comes back.
What is your fuel pressure?
What is the short- and long-term fuel trim numbers?
Does the coolant temp sensor report correct information to the computer?
How old is the cap and rotor, plug wires, plugs?

 

Well I finished changing the intake manifold gaskets and cleaning up the egr passages. But like you said it wasn"t gonna fix my idle issue... Can tell It idles a lot better though, feels a lot better but still has the weird idle. Im gonna set the timing tommorow to 0 degrees. Can having the timing a bit off cause the bad idle? Also looks like someone messed with the idle screw. I don"t wanna keep throwing parts at it I wanna narrow down the problem.. My bro has a scan tool, im gonna try to scan it tommorow. It didn"t throw any codes this time.

 

I was comparing my engine to other peoples engines and mine has like a 2 or three inch spacer between manifold and tbi. Would this effect idle as well? Im gonna try to remove the spacer and see if ot solves the issue. Maybe fuel is not getting to the cylinders fast enough. I compared it to pictures of other peoples 350s and nobody has the spacer.

 

A throttle body spacer will not cause the engine to run erratic. You might have a aftermarket cam causing the issues. Or computer tune

 

I think im gonna remove the spacer just to return things back to stock.

 

I checked the fuel pressure and it was a measly 5 psi.

 

That would definitely effect running .

 

Well I changed out the fuel pump , and now I can actually drive it. It still hesitates a bit from takeoff but it drives now, BUT it still idles like crap and dies when coming to a stop. For a min while I was driving and came to a stop It idled perfectly fine. Then came back. Still getting code 33 and 54. Havent tested the maf yet.

 

Tbi is map not maf, great news on the fuel pump solving some of the drivability issues.