awcforever

Hey guys,

Just bought a 94' Z28 LT1, 130k miles with 4spd auto

When I bought the car all seemed fine, drove it home 75miles

I was on my way to work the other day and decided to floor it....just becuase and at 70mph the RPMs dropped out and the car cut off. I threw it in neutral and started it back up and it sputtered, cut off, and finally I got it started.

Got off the exit and it cut off as I left the ramp, got it started and them it cut out again and stayed down for about 30min. Last effort finally cranked up and drove 40miles home with not so much as a hiccup.

Today, I took it out close to home and ran the **** out of it trying to get it to act up again when I was close to home where my tools are and nothing. Replaced the fuel filter and still ran great. SO I drove it to work again.......bad idea.

Made it to work with no problems. 7am. Left at 4:30pm and took about 10min to get it started, then it died about 100ft later, after trying everything I sat there for an hour it cranked right up. Got about a mile down the road......died again, sat there for maybe 30min and some folks helped me push it out of the road and as I was rolling down the hill from the stop sign.....boom, cranked right up.....stuttered once on the highway, but never cut off again.

Sorry for the book.....but I put it in the shop today after taking it for a drive with no issues, got it on stands and it starts, runs for 15 seconds, dies. Cranks right back up, runs 15 seconds, dies again. About 6 of those and it finally stayed idling.

I am just at a complete loss. I was thinking trash in the tank, but after the hell I put it through yesterday that should have shown up.

PLEASE HELP> I am mechanically capable, but intermittent issues like this kill me as you can never get it to do what it needs to do when you need it to do it.

THanks a lot and again sorry for the book.....

moparman

Have you checked the fuel pressure?

timnfxr

Welcome to the site... A good place to start would be to run two tests...

1 - With a fuel pressure gauge, measure the fuel pressure at the Schrader valve (located just behind the intake manifold). Key on, engine off it should measure 41-47 psi. And it should hold that pressure (within a lb or so).

2 - Check for error codes with an OBD1 scanner.

Good luck.

Injuneer

Better yet, measure pressure at idle and under full load.

At idle - With the vacuum compensation line off the fuel pressure regulator, you want 43.5 psi, with GM spec accepting 41-47 psi. Attach the vacuum line to the FPR and pressure should drop proportional to intake manifold vacuum, or about 8 psi with a stock cam, less drop with a more aggressive cam.

Under load - Then take it out on the road (if you can keep it running), and measure the pressure under max engine load - WOT, over 5,000 rpm. Pressure should not drop below 40 psi.

There is a link on the "Computer Diagostics....." forum to a free download of OBD-1 data logging software specifically written for the 94/95 LT1:

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

Also describes the cable requirements, with a cable you can build for $20.

awcforever

I will have to see if I can find a scanner, no lights on dash or anything.
I do need to get a fuel pressure gauge, I got my new trans mount in today, and pulled it out of the shop, and strangely enough, hopefully this is related somehow, but the car is really hard to turn over. It has a brand new Interstate battery in it, only about 2 months old, and I measured between 14.1 and 14.3 across the battery while the alternator was charging, but it litterally is starting like I left the lights on all night.

Coil? maybe starter?

I am so close to just re-selling this thing. I was trying to find a beater that ran good to get me to work, this thing is now seeming like its going to be a money pit. When it runs it runs GREAT! But thats the problem.....WHEN it runs.

I've driven it for about the last 4 hours with no issues, starting, stopping, launches, and no issues other than a very weak starter....VERY weak.

awcforever

Cool man! I'll definitely have to look at that. Gotta get my ducks in a row before hand. Tomorrow when I get some free time I going to replace the coil and check the fuel pump and strainer out. I'm sure everything is factory, and albeit coincidental,.....when I had the car running today I hit the coil lightly with my breaker bar and the car cut off. Figured why not throw a $20 part on it.....probably needs it anyway.

Injuneer

Check the harness connectors.... they are getting old and brittle.

bw_hunter

Me too....

Injuneer

LOL..... that makes two of us.

awcforever

Well, now it will not act up. I guess I'm going to drive it to work and hope for the best. I drove it all day yesterday without any problems.

Still weary though. I just know when I get to work its going to crap out.......we'll see! I replaced the coil for shts & giggles, and pulled the front end apart to test the opti and everything seems fine there so I at least re-seated the plug wires and flushed coolant as I had to drain the radiator anyway.

Didn't pull fuel pump yet, but I may jump into that today and check the strainer out....but if it was junk in the tank I'm fairly sure the way I was driving yesterday would've shown it.

Injuneer

Scanning is one way to check. The Opti cam position sensor and the ignition control module intermittent problems can shut down the engine, the code will set, and they DO NOT turn on the SES light.

awcforever

Hmm! Maybe I'll get it scanned.....I just listed it on Craigslist, maybe I'll get some bites and go find something different. I just don't feel like working on anything right now. It ticked me off and now I just have this sour taste for the old LT......we'll see.

Injuneer

Problem is finding someone who can scan it. Auto parts stores generally only do OBD-2. Some of the newer combination OBD-1/OBD-2 scanners will not work with the 94/95 PCM because there is no 12V pin in the ALDL connector. The cheap ($30) Actron codes scanner only works on 93, because all they do is short the ALDL pins to flash the codes on the SES light.

The Scan9495 software is the best bet, free download, but requires a cable.

Zee man

hi, I just signed up here to throw an answer at this problem. my 94 was doing the exact same thing, drove me batty. Turned out that the rotor screw had fallen out. would run great one minute then die like someone turned the key off. I have a picture of it somewhere.....

Pull the water pump and then the cap, its worth a quick look for the price of a water pump gasket.

Zee man

Here's what was left of the cap, the white dust is from the rotor grinding away when it was off center from centrifugal force.


no pic of the rotor though darn it