Eilias

Hello again all,

I have a 1993 auto that stalls when given gas. If you lightly press the pedal it'll take off smoothly with no issues. If you press it a little harder, about 1/4th, it will stumble for a second before catching itself (most of the time) and going like nothing happened. If you give it around 1/2 or more it just stalls unless you release the pedal.
After it gets to 1500 RPM you can floor it and it'll happily go all the way to redline.

Recent things done to it are:
EGR. fixed a previous stumbling issue.
Intake gaskets/ RTV changed last week. It had the same issue before changing these plus an oil leak out of the intake, which hasn't returned
Injectors were changed with Bosch 3s from FIC for a 1993 Corvette.

Fuel pressure is around 40 PSI when primed and 38 when idling, and goes up to 44 under WOT or when it stalls. With the vacuum hose off the regulator it stays at 44 when idling or at WOT.
Pressure drops to 35 PSI after 30 minutes.

FSM is currently in storage, and I can't get to it until later tomorrow, so until then I was wondering if anybody had any ideas or other tests I could run? I'd rather not throw parts at it, that gets expensive quick.

Thank you,
James

EDIT:

Don't want to bump this, but in case anybody has the same issue there was a hose under the ASR that I left unplugged that solved the stalling.
Also had wires 3 and 7 swapped that solved the rough idle and low power. Miscommunication between my dad and I on which cylinder was which.

CVG323

is the gas low?
my 92 stumbles when im at 1/4 tank. add more gas and check if that works.

Eilias

It was filled before I changed the intake gasket, and hasn't been driven much since. I used stabilizer to make sure the gas stayed fresh.

Kevova

Fuel filter or egr you could block vacuum hose see what happens.

Eilias

Unplugged the EGR and blocked the end, same symptoms. Fuel filter is recent on it (about 4k miles ago, and what a bear to change!)

Will probably spend the weekend doing plugs and wires because I don't know the condition of them. Will report back if that helps or not.

Thank you!

Eilias

A week late changing the plugs, and I still have the coil plug to change. It broke off by the optispark, so I took it as a sign to take a break and start again tomorrow when its cooler.

I found 2 plugs that were "spliced" together like the one in the picture, the #5 and #7 plug. Hopefully that solves my issue. Every other wire was a MSD wire execpt for those two, where were a hybrid.

If I ever have to change the plugs again, I might just pay to have someone else deal with the #8 plug, that thing is a nightmare.

I will update later when I change the coil wire and start it.

pcolt94

If you plug wires don't fix your problem, consider these two items.
The speed density unit and the TPS. Either one could cause an affect like this.

Eilias

Good evening all,

Again a little late with updates. Plugs and wires are changed, I believe I have one spark plug loose contributing to a rough idle and air escaping. The car however doesn't stall anymore when you give the car more than 1/4 throttle from a stop. After that minor issue is solved it should be time to work on suspension!

Originally I connected a vacuum line to the wrong place and had the car barely idling, and when the AIR pump turned on it made an awful sound that had my dogs howling. That's corrected, but something worth mentioning.

Thank you pcolt94, I have checked the systems you mentioned. The TPS smoothly changes voltage as indicated by a Tech 1 scanner, and the MAP sensor seems to work properly, and the IAT reads within a degree of the cars outside thermostat upon start up.

pcolt94

At idle I get about 9.1 g/s in open loop and in closed loop about 6.5 g/s.

Eilias

MAP sensor is functioning correctly.

One problem solved, another uncovered. Plug #6 wasn't torqued down all the way, now it is.

Now the left BLM is maxed out at 160 at idle, with the IAC at 130 steps at idle. I assume this points to an issue on the drivers side, maybe a crossed wire could do this? I'll try to get the car on jack stands and get a helper to figure out if the wires are at the right position and plugged in properly.

It has an odd exhaust tone with it, almost sounding like a v twin bike exhaust currently. It sounds cool, but doesn't sound right.

Any ideas are always appreciated, thank you.