Heller everyone,
Been tinkering with my 92 5.0/5spd camaro(tpi) and haven't been able to get it to idle.
It's been parked without running for probably 18 mos. Was a DD before with a full tune up, rebuilt heads and odds and ends, all stock.

Now that I'm getting ready to clean it up I want to figure this issue out. I may end up dropping in a 350 but anyway. I can get it to run after it skips along and finally fires up. It's usually hard to start. I tried resetting the IAC but that's as much as I've done. I've burned through 1/2 tank including the old 1/4 that was is in. I added half bottle of berrymans but that was on the shelf for a while so it may have lost its potency. Running at high RPM I know it has fuel pressure and blipping it to 4K it responds fine.
I'd think the FPR might be shot but would it rev up if so?
Injectors clogged but only create an issue at low rpm?
IAC is faulty? I think I replaced it before and cleaned the passage.

I know this is a common issue and I've read plenty. Not sure if this symptom would lead to a specific part. I'm thinking fuel related considering the hard starts.

Thx.

 

You know it has fuel pressure? How much?

 

Sorry, didn't see your post until I clicked in. That's my problem, my fuel pressure gage is missing some fittings so I can't get a reading. Just need to break down and get a good one, just haven't yet.

The assumption was since it's revving fine at higher rpms it should have enough fuel for low? As soon as I get close to 1500 it'll incrementally dies out until I save it with a blip of the throttle.

Thx.

 

From your original description of what's been done, I'd check the timing first. Since the engine is basically still stock, set the timing to the recommended setting. Also check to make sure all the plug wires are in the correct order. 18436572 clockwise rotation. It's really easy to get 5 and 7 mixed up.

As for fuel pressure, high rpm with no load isn't a good test. The engine needs a load on it at higher rpms to determine if fuel pressure or volume is good enough to feed the engine. At an idle, very little pressure is required to keep the engine running.

 

Good stuff Alky. Will check the fuel first. I doubt wire crossing b/c I never messed with those since I daily'd it. Will be hard to check timing at that rev. Isn't it 8* btdc at idle and brown wire unplugged?

Thx

 

Oops. I misread the original post. I thought you already dropped in a rebuilt 350.

One other thing to check. See if the EGR valve is stuck open.

 

The clue here is the amount of fuel that's been consumed. I would guess that the rubber diaphragm in the fuel pressure regulator is torn. What this means is fuel is just pouring into the cylinders unregulated. Eventually, when things get even worse, the fuel pump will push through so much fuel your engine will hydro-lock. It's a cheap part but it's not too easy to get to, at least it wasn't on my 86 IROC with TPI. Took about 3 hrs.

 

Wow. I remember reading about the FPR and has been suspect since I started troubleshooting. I have a used one that I could swap out, still cheaper to check the pressure first then move on. I guess more pressure at the injectors isn't always good. Always thought about them as regulators but they are more just open/close nozzles.

Thx for the tip.

 

More pressure to the injectors is good but too much pressure and they can lock out. Injectors can only flow so much fuel through them. How much fuel is required depends on the HP created by the engine. A basically stock engine does not need 30 pound injectors and a high performance engine wouldn't run very well with 18 pound injectors.

TBI is only worse. All the fuel the engine needs can only be flowed through 2 injectors and they start to act up around 15 PSI. They normally run in the 9-12 range.

With a TPI system, the injectors don't need to be as big since 1 injector feeds 1 cylinder and bumping up the power requirements which needs larger injectors is much easier. There does come a power level when even 8 large injectors isn't enough and a second bank is required. This would be on a very high HP race engine but it is possible.

 

Good info. I think Nelson racing engines runs a 2nd bank on his high HP monsters.

I'm finally going to be able to tinker with it today. Will post back results.
Thx.