Sinister_Z28

Ok so for the past couple months i have been doing alot of work on my 98 Z28 and its new 408. So for about a month i have had it on open headers while i save more money for a UMI torque arm and relocation bracket, and i will start it up and let it idle for a couple minutes then shut it off. I do this like once a week. So yesterday i had it running and i heard a little belt type squeal so i gave it a little gas and brought the rpms up from idle to about 2000rpms. About 10-20 seconds after it reached 2000rpms and i started to hold it there it just shut off. It didn't sputter or struggle to keep running, it just died. It has 3/4 full tank of gas and i can hear the fuel pump prime. I scanned it for codes and came up with a A/C Clutch High Voltage code# P1539. So i put some more fresh gas in it today and went to start it. I cranked it and it tried to start and it just sputtered a little then nothing. It just keeps cranking when i try to start it. The oil pressure goes up to normal pressure if i keep cranking it for a bit. So im out of things to check before i have to start throwing money at it like a new fuel filter. I also checked and i have fuel pressure in the fuel rails. I dont know how much exactly but it sprays out with quite a bit of force. What are ur guys ideas?

Sinister_Z28

Anybody

Sinister_Z28

Today i switched the fan 2 fuse with the ignition fuse and same thing it just cranked. It did however almost start randomly. It idles at 1000 rpms and it started for like 3 seconds and it only got to 500work rpms. Im out of ideas. Now if it wouldnt crank or none of the lights came on i would think its vats but since it cranks and all the light and radios work im totally comfused. Any feed back or ideas are welcomed.

MTN_Z

iTrader: (7)

Try the fuel pump relay. My car had intermittent no-start issues and it was the fuel pump relay. It would also be hard to start and it would stumble sometimes I guess because the pump wasn't running consistently. $10 part. Also, just because there is pressure in the rails doesn't mean your fuel pump isn't on the way out. After you replace the relay, put a gauge on the rail. It should be right around 55 psi. If not, change the fuel filter. If you still have issues, it may be the pump.

LS6427

iTrader: (2)

Crankshaft Position Sensor could be taking a ****.......and you don't always get codes or SES lights until its totally dead.

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Sinister_Z28

The crankshaft position sensor is 8 months old and has less than a 100 miles on it. Im planning on getting a fuel pressure gauge on the rails to see what my pressure looks like. Also can u swap the fuel pump relay to see if it truly is bad with another relay?

MTN_Z

iTrader: (7)

You can, but don't swap one you also need. For example, don't take the ignition relay and swap it with the fuel pump and vice versa. It could actually be either one of those two relays causing the problem. I also stated incorrectly that it was the fuel pump relay for me. It was actually the ignition relay now that I think about it. Either way, both of them should be checked out.

dailydriver

I'm having these same exact problems, and have already replaced A LOT of the 'usual suspects', the car has been down the OVER a month (it's my ONLY car), and I am at my wits end with it at this point.

Short of rewiring/replacing the WHOLE engine harness, replacing; the PCM, fuel pump, battery, all coils, and pulling the heads to check for dropped valves and blown head gaskets, I do NOT know what to do either. (I've replaced everything else it could be.)

Sinister_Z28

That sucks to hear that ur car is doing the same thing. I am fortunate that my parents have a extra car that they loaned me while i build my car. And if the engine is cranking over but not running can u hear the coil packs firing or the plugs sparking. I did a real fast spark check with a buddy but didnt pull a plug but i could hear a faint rythmatic click like plugs sparking. Is this possible or just me hearing things?

BRUTL

iTrader: (27)

Why not zero in on what you don't have. Motor needs four things to run, the classic fuel, fire, air, as well as being properly timed. People waste more money guessing at things when simply narrowing down what's missing drastically reduces the possible problems, take a wire off a plug, grab an old plug, and plug it in the wire and lay it on a suitable ground, then have some one crank, see if its sparking. Or get a $15 fuel pressure gauge from harbor freight to see if you have fuel pressure. Start with those two VERY easy steps, stop guessing.