MiROC_89

Here's the skinny...
First i replaced fuel pump, f.p. relay as they were bad. Car would start but had an erratic idle and would not stay running without giving it some amount of throttle. Less than a minute after trying to idle it would stall out an die.
Had a spare (but new) TPS sitting in the garage so I put it on to see if it'd help.
Car started and had a lot better idle even though I still had to feather the throttle a bit. Shut it off to further investigate. I tried to start it a 2nd time, cranked but no start. Noticed I did not hear fuel pump prime when key turned over, so I started looking at the relay again, noticed the wires in the pigtail were literally hanging onto their connection by a thread . Replaced pigtail connector for fuel pump relay.
Now I cannot get the pump to prime at all, where it would with a lol nudge on the wires at the connector; and it kept blowing the ACC fuse.
After replacing it with all the 20-25amp fuses I had, it had gotten dark outside and I just happened to notice the cig lighter was arching over to itself causing a short, blowing the ACC fuse. Unplugged cig lighter but still not priming when I turn key over, cranks but no fuel to rail. Checked fuse by battery and it is good, and ACC fuse as well as all others are good.
Check engine light illuminates with key turned on so not the VATS I don't think. I'm lost and ready to give up on her for a while.
Any help would be greatly appreciated.

mcgarnicle

iTrader: (14)

Vats doesn't stop the fuel pump from priming and running. Are you basing everything on not hearing the pump? Have you checked your fuel rail pressure? Do you have power at the relay?
ACC fuse doesn't have anything to do with fuel pump circuit

I would think the 20 amp fuse next to the battery, but you say the CEL comes on so maybe not. Probably going to have to get out a test light and multimeter and start checking wires. power, and grounds.
I kind of suspect the ECM coolant sensor may be bad and causing your cold start/ idle issue.

ASE doc

Make sure the ECM is activating the relay at key on. Have you checked the ECM/FP fuse by the battery? It's the 20 amp in line shown in the diagram above. Also, check spark and injector pulse just to be sure what you have. The ICM or pick up coil could be causing you to lose Crank Ref to the ECM. This won't prevent fuel pump prime but it will prevent the fuel pump running while cranking. If you have injector pulse, you know Crank Ref is okay.

mcgarnicle

iTrader: (14)

A pretty cut and dry way to check for ignition/injector pulse from the pickup coil is to watch the tachometer during cranking. It should bounce or raise up off the peg, if it is completely still during cranking then you know the ECM is also not receiving a signal.

MiROC_89

Hi guys,
finally seem to have solved the problem. I'dcome to find that i was intermittently losing spark until eventually i had a complate no spark condition. Id test the differemt points; coil, ICM, etc...
It ended up being the ICM. i had felt like this may be the issue early on but hated to get into throwing parts at the gremlins, so i just kept with the diagnostic flow charts, testing, testing and re-testing. Just my ICM always came to a satisfying result each test
12v everywhere it needed to be, all grounds where checked over n over, and my finger scratched through my skull from the beginning to the end of this ordeal. i even took it to autozone to have them test it, not like they an authority on any matter, jk, but it kept coming up good.
Ive heard that different sensors can test good on their machine, but its be like a false positive so to speak.
...but, It was the ICM for my issue. I know it sure was damn frustrating an hope everybody else eventually finds s quick solution to their starting issues.
Thanks again for the help guys. greatly appreciate it.
i wouldve posted this earlier... there just wasn't an "earlier". I actually just saw a glimmer of light at the end of this tunnel not more than 20min ago, an everything seems hunky dory for now.
If she hoes back to dead, ill be sure to update...

mikeceli

iTrader: (2)

Glad you figured it out! THX for updating!