Hey guys, Sunday I was driving my car with no issues... Monday the car would not start on it's own.
Here's what I've done.
Checked coil
Replaced CTS
Check TPS
FUEL pressure does not drop
Checked for spark
Burned a chip that I know worked.
Checked my chip/buffer addressing on coated burn 1

So it.wouldnt start..then I floored the throttle and it fired.
Yesterday before I replaced the cts I cleaned the old.one and it almost fired but still needed my foot on the throttle to run.
Then I changed the CTS and the same thing happened.
When I got.org running with help from.the throttle being depressed I held it at 1k..the fuel pressure gauge was spiking from 34-60 psi..I have a GlowShift unit so it may just be crap as it's just a cheap one...the car does not smell like it is rich..

Anyone have Any idea?
Thanks

 

Does it idle once it's running? I suspect you have an idle air control fault. If the engine does run on its own once started, try turning on the AC and see if the idle flairs in response to the AC load. If so, the IAC is working. If not, it isn't.

 

No it will not run on it's own...I also don't have AC anymore..I deleted it...I will check my IAC and MAF tonight...

 

might sound silly, but change your fuel filter under the car. see if the old one is plugged up. might even be able to blow it out with compressed air?

 

I will eventually...that filter is only 2 years old and has honestly 2500 km on it...the fuel pump is priming strong...like.I said, I drove it Sunday, excellent throttle response...it's a bit rich in PE mode as im still tuning...I bet it's something stupid like a ground wire that needs a wiggle... Keep the ideas coming..if I figure out what it is I'll post it for future searching.

 

The toggling fuel pressure gauge is normal on this car. Batch fire injection fires all 8 injectors at once every rotation of the crankshaft. The pressure will drop each time they fire, then bounce back. For a more viewable fuel pressure reading, use a viscous(filled with fluid) gauge.

 

If you have no AC, you can just watch the tach as you shift in and out of gear. As you shift into drive from neutral, the RPM should raise slightly then level off as the ECM commands the IAC in response to increased load. When you shift back into neutral, the RPM should stay high for just a moment before the ECM brings the engine back to normal idle.

What system are you using to tune? Are you burning PROMs or is your ECM programmable. If you have a programmable ECM with Tuner pro or some other tuning software, you should be able to control the IAC through the software and check its operation in this way. Later GMs had idle speed in the functional tests.

 

Ya im using tunerpro and burning PROMS...im gonna link the aldl up in a bit and see what's all going on.. Anything specific I should be looming for? The tune I was using worked great. It's just one day I came out and she won't fire.. Dead close to during though....

 

Hey guys, got it figured out... IAC was m
agged out.. Stuck closed... To the track tomorrow... Thanks for everybody input