Hey whats up guys,
I went to start my car the other day and it wont start (98 z24).I dont hear the fuel pump prime itself when i turn the key on.I checked the fuse and the relay and they are good.Theres no power going to the pump when i turn the key on.When i jumper the wire to the pump,it turns on.I checked the wires going to the relay and it seems like its not getting a signal from the ecu when i turn the key on.Any ideas?The car drove fine when i last drove it.I have a feeling it has something to do with the vats or maybe the ecu is fried.
Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust
If you had a problem with VATS, your security light would blink, but the car would still start for 2-3 seconds before the fuel injectors shut off. How exactly did you test your fuel pump? Take the A/C relay and swap it with the fuel pump and try again.
Yeah,thats true about the vats.I tested the fuel pump with a volt meter.I think it was gray wire.When i turned the key on,i was looking for some voltage for a sec or too until the pump was primed.I got not voltage at all.I tried swapping the relays and it still didnt start.
Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust
nope
Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust
Try bumping the bottom of the gas tank with a rubber mallet without jumping the relay. If your fuel pump has an short in it, I wouldn't prime. My question is why would it prime when the relay is jumped? I would say check you fuel pressure after jumping it and seeing if the rails are holding pressure. I checked my chilton's diagnostic diagram and it's not telling me much, just testing the fuel pump relay circuit, but requires scan tools.
I think i pretty much ruled out the pump because theres no juice going to it.I also tried banging on the bottom of the tank.Im gonna try and mess with it tommorow and see what i can come up with.Thanks for looking in the book for me.I have the factory service manuals but i let my friend borrow it.
Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust
Yeah they come in handy.Im gonna pick one up for the cobalt too.
Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust
ignition switch?, see if you can get a noid light to illuminate when cranking
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Yeah,the ignition switch has crossed my mind too.This is the first time in the 10 years that i owned the car that im actually stumped on something.
Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust
Well i narrowed it down to the ignition switch.i jumpered the fuel pump relay to an ignition source and the car starts up.When i first did it,the car started and shut off in 3 seconds and the theft light came on.So i dropped the column cover and found a broken wire to the vats.I was like ok cool,i found the problem.Fixed the wire,tried to start it and it wouldnt start.So i jumpered the relay again and it starts right up.I gotta pick up an ignition switch now.For now i have the fuel pump relay jumpered to the ign fuse under the hood,so the car runs fine now.Seems to be a common problem.My friend knows of like 3 other gm cars where the ignition switch goes bad and the car does pretty funky things.Im glad the car broke down where i parked it because if it woulda done it while i was driving,i woulda junked the thing,lol.
Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust
Your welcome
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cavmania wrote:Your welcome
Yeah,thanks kid.
*
Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust
So the ignition switch killed just the fuel pump function?
Everything else still worked??? I am having this problem now and just ran across this post.... hopefully i'm understanding this correctly.
FOR SALE
wow, that's crazy....I'm having the exact same problem right now too...
Replaced my fuel pump with another "stocker" and it is up and running again. Down for a week trouble shooting but it is all working great now and a few new parts to boot!
FOR SALE
Well,i replaced the ignition switch today and that wasnt the problem.I knew it had something to do with the ecu,so i went under the car to check it out.I thought maybe the terminals on it were corroded,so i got a can of contact cleaner.So,when i get under the car to check it out,i see 3 or 4 wires just dangling there.Turns out a mouse or something decided to eat the wires on me.They were cut in half and all chewed up.Soldered in some new wires,and the car started right up.Id return the ignition switch,but i had to remove the dash board/gauge cluster to replace it,so i left it in there.The splash shield on my car was broken,so the little bastard just crawled up there and decided to feast on the wires.If any of you are experiencing the same symptons,id check it out if i were you.
Peter
'06 Cobalt ss/sc W/G85 Package
Gm Stage II W/2.79" Pulley
K&N Drop In Filter
Custom Magnaflow Dual Exhaust
my car will start sometimes and when it does it runs like its runnign out of gas,i know its not out, i recetly put 2 gallons in it, new fuel pump, new relay, fuse is good, new coils, new plugs and boots, new filter...sometimes the pump just doesnt turn on when i cylce the key... how would i jump the fuse box to make the pump run? and hat about the ecm? is that in the passenger fender?
Good luck with it man.
