95 z28 wont start
06-20-2014, 03:42 PM
#17
Registered User
Thread Starter
Join Date: Jun 2013
Posts: 16
06-22-2014, 11:27 AM
#19
Administrator
Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,648
Re: 95 z28 wont start
When it won't start. MAF reading it zero and injector pulse width is zero. Explains no start. When it does start, MAF and injector pulse width are normal. It keeps running until something happens to the PCM and the data log readings are totally messed up.
When you finally get it running, you have DTC 18 for an injector circuit fault code - either you do not have 12 V at the pink wire at one or more of the injectors, an injector resistance is outside the range of 12-16 ohms, or the PCM is not sending a ground to one or more of the injectors to fire it.
Your MAP is higher than it's supposed to be. Possibly due to misfires/injector problem. Do you have the stock cam, or a slightly more aggressive aftermarket cam?
Because it has not run for 206 second consecutively, it hasn't gone into closed loop. And, even though it has run for 141 seconds, both O2 sensors show "not ready" and neither appears to be working at all. The AIR pump relay is active (do you still have an AIR pump?) which should have the O2 sensors reading under 0.100V,but the left one is stuck near 0.45V and the right near 0.50V.
There are numerous instances of PCM faulty data, possibly due to the system voltage dropping very low while you are cranking it. But as much as as hesitate to ever say "faulty PCM".... you may have one.
When you finally get it running, you have DTC 18 for an injector circuit fault code - either you do not have 12 V at the pink wire at one or more of the injectors, an injector resistance is outside the range of 12-16 ohms, or the PCM is not sending a ground to one or more of the injectors to fire it.
Your MAP is higher than it's supposed to be. Possibly due to misfires/injector problem. Do you have the stock cam, or a slightly more aggressive aftermarket cam?
Because it has not run for 206 second consecutively, it hasn't gone into closed loop. And, even though it has run for 141 seconds, both O2 sensors show "not ready" and neither appears to be working at all. The AIR pump relay is active (do you still have an AIR pump?) which should have the O2 sensors reading under 0.100V,but the left one is stuck near 0.45V and the right near 0.50V.
There are numerous instances of PCM faulty data, possibly due to the system voltage dropping very low while you are cranking it. But as much as as hesitate to ever say "faulty PCM".... you may have one.
06-22-2014, 03:12 PM
#20
Registered User
Thread Starter
Join Date: Jun 2013
Posts: 16
Re: 95 z28 wont start
As far as i know the cam is stock but it does sound like it has a cam when it is running. It doesn't have a CAI or headers, doesn't have Tb bypass or airfoil so i assumed it has a stock cam because none of the free or cheap mods have been done. It does still has the AIR pump. I have another 95 z28 that has been wrecked, so i have a complete donor car full wiring harness, pcm, motor, trans, everything. It ran great until it was wrecked.
06-23-2014, 05:35 PM
#21
Registered User
Thread Starter
Join Date: Jun 2013
Posts: 16
Re: 95 z28 wont start
What would you recommend i do. Am i at risk of screwing up my other pcm if i swap it in. Should i continue to check the wiring harness and injectors. Should i run another scan and allow it to go into closed loop. I'm not trying to be a bother, i just miss driving my car and i didn't realize this one had as many problems as it does, at $1100 I guess you get what you pay for. Thank you for helping me out so far.
Thread
Thread Starter
Forum
Replies
Last Post
dbusch22
Forced Induction
6
10-31-2016 11:09 AM
chevroletfreak
LT1 Based Engine Tech
202
07-04-2005 05:00 PM