94z28cam

I have a 94 Z28 lt1 camaro 151k miles recently it shut while driving. I was getting off work that morning needed gas. Stopped got gas and it shut off bout a mile up the road. I pulled over tried to start again til i ran the battery dead. I called my roadside service got a jump it took a little while but it started again. I drove home and a few blocks from my house it shut off again but started right back up. I then turned a corner and it shut off again but ran my battery dead again trying to crank it up. So i got it towed home. I jumped it off with my other car and it started right up. I left it running to see if it would shut off but it didnt. I stopped driving for a week then had a guy look at it. He told me it could be my fuel pump or my catalytic converter or my ignition coil. I then got my catalytic cut off. I drove to the shop and home no problems. Then i tried to drive it to work 1 night and it cut off again. I again called roadside got a jump a it started up. So i drove it home and caught a ride to work. I then stop driving again for a week. But tried again 1 night. Drove to work and home no problem. So i had a guy check my fuel pressure. He said it was kinda low like 30% i think. I have a new fuel filter a new maf sensor new plugs new wires new opti. I even got a new battery and got the alternator checked its good. I need help i need answers. I think it's the fuel pump but i also dont think thats it i think its something else.

Injuneer

Has it only shut off after your current tank of gas?

At any point have you scanned it for codes? There are codes that shut down the engine, but don't turn on the SES light.

A knowledgeable mechanic would not reference fuel pressure as a “%”. You need to measure the pressure at idle, with and without the vacuum compensation line attached. No vacuum should be close to 43.5 PSI (41-47 PSI is OK). Vacuum line connected, the pressure should drop about 8 PSI below the "no vacuum" pressure. Then take it out on the road and check pressure at WOT, ~5,000 RPM. Should not drop below 40 PSI.

94z28cam

Ok sorry i referred to at 30 % instead of psi. But i havent had it scanned yet. But check engine light does come on. And yes it has shut off again. I ran that gas out re fueled drove good that day. Went to the barbershop then home then later to the store. Turned off crunk up then to another store cut it off then wouldnt start again

Injuneer

You can pull codes, monitor sensors and PCM parameters, and run a PCM data log with this free Scan9495 software. Just need a cable:

https://www.camaroz28.com/forums/com...95-lt1-874306/

Also reads airbag and ABS codes.

I can help with interpreting the data.

andrewparker

Fuel pressure sensor/regulator perhaps?
That is just my assumption though, of course codes will tell you way more...

Injuneer

There is no "fuel pressure sensor"..... only a regulator.

Caroline Doolin

my 94 Camaro z28 is doing the exact thing. I had it 2 4 different mahcanic and they cant figure out what's wrong. I really need someone to tell me what's wrong. Please

Injuneer

Have you (or the “mechanics”) scanned the PCM for codes? Have you checked the fuel pressure?

Is the engine modified in any way? Have you had any parts tested (e.g. - ICM) or replaced? How many miles on the engine? When it’s cranking but won’t start, have you checked for spark at the coil wire? ..... at several spark plugs?

Caroline Doolin

It has been modified to a 383 . I took it to a garage that only works on high performance engines. He checked the fuel pressure and it is good. I had a fuel pressure sensor on (I think this is what it's called it goes on inside the oil pan.) But it is not the correct one. Could this be causing it. I just ordered the correct one and hoping it takes care of the problem . If not the garage that works on high performance engines wants $400 to figure out what the problem is.

Injuneer

You need to provide more info than that on an engine that has been highly modified. Particularly info on the ignition system. Have they tested the ICM? Have they checked the signals from the optical cam position sensor in the Optispark distributor? Have they checked for spark at the coil wire and at a few plugs? Have they examined the ignition switch for burned or loose contacts - common problem when these cars reach 20+ years old.

There is no fuel pressure sensor on a 1994 LT1 engine. And even if there was, a fuel pressure sensor wouldn't be “inside the oil pan”. There is an oil level switch located on the side of the oil pan, but that has no effect of any kind on how the engine runs. You ordered this part.... but you don't know what it's called ? ? ?

If the “garage that works on high performance engines” is feeding you all this BS, they are serious scammers. Did they provide any info on the fuel pressure, like the pressure at idle, with and without the vacuum line connected, and the pressure with the engine under full load (WOT ar 5,000+ RPM? Or is “good” the best they can do?

What about checking the PCM for diagnostic codes..... surely they would have done that too?