mudflap1989

iTrader: (4)

I have a stock 98 Z28 that has 60psi of fuel pressure at the rails, but it will not start up, it will turn over with the starter, but it will not even try to run. I gave it a small shot of starting fluid and it ran for a second, so I am pretty sure that it is a fuel problem. About 2 weeks ago it wouldn't crank on about 5 different occasions, but after trying it a few times I could get it to crank. For the last week I have been cranking it at various times and it has not fired up at all. I am thinking that it has to be a computer or sensor problem.

I have HP tuners, but I really have no idea how to use it, but I have logged everything with the injectors that I can find and they seem to be firing according to HP Tuners. I have logged the below things....

INJ B1 (msec) (I believe that this is the pulsewidth)
INJ B2 (msec) (I believe that this is the pulsewidth)
INJ duty cycle

The INJ B1 & B2 reads 9.7msec when I'm not trying to crank the car, then when I first try to crank it, it spikes up to about 14msec and then it settles right back down to 9.7msec while I am cranking. The duty cycle goes to 1% when I am trying to crank it.

So this tells me that my injectors should be firing, right???

Should my cam or crank sensor be broke causing the injectors to fire at the wrong time???

mudflap1989

iTrader: (4)

Update...I got it to crank and it ran for about 3 minutes and then it died and wouldn't crank back up.

If it was something mechanical I could figure it out, but I'm pretty sure that it is a computer or sensor problem and therefore I am lost. Can someone please help?

Todd157k

iTrader: (5)

There are tons of things that "can" be wrong... cam sensor, crank sensor, etc.
but before going wild, explain what happened (or what you did) before it stopped running.
It's usually more simple, but need to know what happened.

mudflap1989

iTrader: (4)

I'm not sure what you are asking??? I didn't do anything, it just won't crank up sometimes...sometimes it will. Yesterday I got it to crank for the first time in a week and it died after about 3 minutes of idling. That is the first time that it has died while running. That is all that has happened, I have 60psi in the rails and it will try to run on ether so it must not be getting fuel.

Todd157k

iTrader: (5)

any mods to the engine?

If the car was running a little funny before it started all this, I would guess cam sensor or the bolts on the cam came loose. That usually only happens when you swap cams and don't locktite the bolts. You would have noticed it getting harder and harder to start before it finally got bad.

post up your log file(s)

mudflap1989

iTrader: (4)

When it runs, it runs fine. Only mods are air lid. I loosened the fuel rail and popped the injectors out of the manifold and tried to crank the car and the injectors are not firing at all. I believe that the sensor at the back passenger side of the intake is the cam sensor right? I reached back there and it is real loose feeling like it is broke, so I think that it might my problem. I think that I have a spare one off of my 03 Z06 that I am going to swap in there and see if that fixes it.

I attached the log. On this log the car wouldn't crank the first few times I tried, then it cranked, then it ran for a couple of minutes, then it died and wouldn't crank back up. I'm sure that I was not logging all of the things that I should have, like I said I am just learning HP Tuners.

carfreak07

iTrader: (10)

Well I'm not an expert but I did have a similar experience.....first off, see what happens when you disable your VATS. My SS has been giving me fits for a long time......you might turn the key 3 times and it crank and run or you might turn it 300 times before it cranks and runs....drove me nuts!!! I replaced switches, troubleshot wiring time after time.....someone said my VATS had went bad even though it was disabled and wouldnt let it start....I was still in disagreement....finally tore into the steering column and removed the ignition switch and the little wires that read the key resistance were broken apart.......how it ever started I have no idea but id did, never failed, sometimes i would be there for 20 min before it would crank.....sometimes it wouldnt even do it and others it would just drive me nuts....I sure hope this is the same problem for you.....since you have no mods, I am thinking that all your sensors and such should still be going strong.....please let me know if this cures your problem! Instead of taking your steering wheel and all that off, take the panel by your feet on the driver side out.....there will be a yellow plug with two small wires in I believe a yellow protector sleeve.....unplug that and mimic the resistance that is in your key chip with a resistor from radio shack and stick it in the plug going into the dash....bcm....make it kinda look like a jumper wire! If it starts flawlessly then you know you have found your problem and you can then take everything apart and repair your wires! I hope all that made sense.....if not shoot me a pm with your questions. GOOD LUCK

Todd157k

iTrader: (5)

well, looking at the file... it looks like you are getting fuel. The o2 sensors are picking up a reading of 451mv. You're also getting pulses on your injectors. I'd be leaning towards the electrical side.. like stated above.

mudflap1989

iTrader: (4)

Thanks for the input guys, but I have already disabled my VATS system wth HP Tuners and I have already tore my steering column apart and checked my VATS system and it is working just fine (this was before I had HP Tuners). Also I think that if the VATS system is bad, the engine will not even turn over at all, please correct me if I am wrong??? My engine turns over fine, it just won't fire up.

I'm 99% positive that it is a fuel problem and not a spark problem. Like I said, I popped my injectors out of the manifold, but left everything plugged in and they did not spray at all. And if I squirt a little bit of starting fluid in the intake the car will try to run.....so it should definitely be a fuel problem, not a spark problem, I will pull a plug wire and see if have any spark jumping just to triple check.

Thanks again, any other input?

mudflap1989

iTrader: (4)

That's what I can't figure out, based on my limited knowledge of tuning and HP Tuners it seems to me that my injectors should be firing by looking at my log file.....but they are not.

mudflap1989

iTrader: (4)

Does anybody else have any ideas??? Could it be a cam or crank sensor problem? Computer problem?

Thanks