EFI fuse blowing

[bentandbroken]

Ok i know what part of the issue could be, which is a wire is grounding out either by a pinch or melted insulation.

I know many of you have heard this before, but here it goes anyway. I stalled my car last night and it blew the EFI fuse. Replaced the 15A fuse and it cranked but doesn't like to idle. The idle is low, around 400-500 RPM and if i rev it the motor just dies. Now, whenever i get close to redline the fuse pops.

My other issue is i don't have a wiring diagram in my hands and we all know that reading a one is easier when it's on paper and not separated on different pages on the internet. I check the part of the harness back by the EGR valve and it's not melted. Are there any other popular places for the harness to pinch/melt. Oh, and the O2 sensor is ok. One last thing, the main relay is warm to the touch. I don't know if this is because of it and the EFI fuse being neighbors

Any help would be greatly appreciated.

 

[bentandbroken]

This is my only ride and i need to get home for Christmas so there is a mild sense of urgency

 

[Nomad707]

bumping a post after 2 minutes is silly... but if it only pops at redline... dont redline it. that will get you home. Check the harness above the valve covers.. sometimes i see people with harnessess laying over the valve covers...

 

[s383mmber1]

Cam position wires touching together and arching? Or touching the valve covers?

Thats were my EFI problem was

 

[shaeff]

double check the o2 sensor wires, as they're most commonly the problem in this situation. (right near the exhaust, melted, crispy wires)

check all of the wires thoroughly.

 

[Dr Tweak]

Put a multimeter on it, one probe in the EFI circuit (at the relay, for example) and the other to ground. (If there's a short, you'll have a reading). Then just start unplugging things one at a time until the reading goes away. When it does, you found your short.

-Doc

 

[ForcedTorque]

Good info Doc! I'm sure one day I will need this info.

 

[dbsupra90]

just as doc said, everything that B+ goes to, unplug one at a time.

here are my diagrams, much nicer than the tsrm online. note these are for 89+, not sure what year you have. but should be close enough to use to figure out your problem.

http://www.mk3.us/dave/tech/ecuwire1.gif
http://www.mk3.us/dave/tech/ecuwire2.gif
http://www.mk3.us/dave/tech/ecuwire3.gif

the main relay is getting warm because of an excess in current. not because its next to the fuse.

 

[bentandbroken]

Sorry i wasn't trying to bump the thread 2 minutes after posting, just didn't feel like editing my post. I replaced the main EFI relay and now it will idle, but i'm still blowing fuses. I tried "wiggling" the harness with it idling trying to get it to make that magic short and couldn't get the fuse to blow. I'm thinking it might be the fuel pump drawing too much current. Not really sure. Don't know the last time the filter was replaced, but i've put 30k on it since february.

 

[MDCmotorsports]

Unplug the o2 sensor and take her for a drive. See if it does the same thing...