DEZERTKAOS

94' 3vze

I wasn't getting any spark or power to the fuel pump. I put a jumper wore on the +b & fp it still did nothing.. I switched the COR with another one(problem persists) I switch it with a relay that has the same prong configuration and that solved the problem but now as soon as I let off the key it dies instantly.. Any thoughts?

scope103

Jumpering fp to B+ bypasses the COR, so if that doesn't work (and you did it properly) your COR has nothing to do with your problem. So, first, did you have key-on when you jumpered? If so, did you use your multimeter to check for 12v at B+? (B+ is fed through the EFI fuse).

Replacing the COR with the wrong relay won't get you anywhere (I'm guessing you already figured that out). The COR has two coils; one activated with key-to-start, the other by the VAF. Your substitute ignored the VAF signal, and when you let go of the key it did exactly what it was supposed to do: shut off the fuel pump.

Spark? Could also be the EFI fuse (which powers the ECU, which is necessary for IGT.)

DEZERTKAOS

I will let you know tomorrow.. I have to switch out the relays so that hey are correct before I proceed.. It does not get spark or power to the fuel pump.the only time it does get spark is wen I have the jumper wire in. I have double checked and triple checked my fuses and all look and test out good... And also I tried checking for trouble codes with the jumper wire and the engine light doesn't come on

RJR

Also check the 7.5 amp ignition (IGN) fuse (in the driver's side kick panel). That has to be intact for the EFI relay and subsequently the COR to work.

If the IGN fuse were blown, it could be that, when you installed the "wrong" COR relay, you shorted the output of the starter relay to the EFI bus (pin 3 to pin 2 of the COR), which would allow everything to work until you released the key, at which time the ECU would lose power causing instant shut-down.

As scope says, the thing to do is to turn on the key (fully ON, not just ACC) and check if there is +12V on the B+ terminal of the diag port. If there is, you have verified that the IGN fuse, the EFI fuse, and the EFI main relay are all powered up and healthy.

DEZERTKAOS

I tested his theory and I am not getting any power at b+

I will check the ign fuse again and switch it out just to be sure

RJR

Not sure how easy it is to get to the pins of the EFI relay (under the hood in the passenger side fuse/relay box). If you can, here's what you should measure with the key on.
(You can pull the relay to measure pins 1 and 5, and do a continuity check from pin 2 to ground with your multimeter in "ohms".)
- pin 1 -- 12v. (0V means nothing is coming from the IGN fuse.)
- pin 5 -- 12V. (0V means nothing is coming from the EFI fuse.)
- pin 2 -- ground.
- pin 3 -- 12V (same node as B+ in diag connector). (0V here and everything OK on other pins means the EFI relay is bad or needs to be reseated in its socket.)

DEZERTKAOS

So I ohmed the fuse out and I got tone.. So I replaced it anyways and it fired up! I can't believe that it was something so stupid and simple.. It had me thinking it was a wiring issue... THANX TO ALL WHO REPLIED! 👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻 👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻👍🏻

RJR

So a couple of learnings from this.
- The "continuity tone" on a multimeter can be misleading, especially for automotive use where we care about the difference between .1 ohms and 50 ohms, for example. Most continuity tones on multimeters start beeping below a hundred ohms or so. That's still way too much resistance for a working fuse. Best to actually look at the numbers on the meter.
- A little bit of logical troubleshooting with a meter can usually point you in the right direction pretty quickly, especially if you have a wiring diagram or are communicating with someone who does.

You did a great job of quickly making the measurements we asked you to. Congratulations on a successful conclusion!

Final thing. Not to throw a wet blanket on this, but fuses usually blow for a reason. Keep an extra fuse in the glove box and a flashlight handy so you can put it in in the dark. Don't be surprised if it happens again. If it does, it means you have an intermittent short somewhere, probably due to damaged wiring insulation. Hopefully that's not the case, because that will likely be a bear to find.

DEZERTKAOS

I always carry spare fuses and what nots but thanx for the tips!! 😎

scope103

It is possible that the fuse WAS good (did you save it?), but the fuse holder contacts weren't gripping it well enough (or were corroded, etc.) Pulling it out and pushing it back in (a new one, but the old one might have worked) made a good contact.

Why do you care? You might have such a bad fuse holder that it will just wiggle out again in the future. So if you have this problem again, pull the fuse, LOOK AT IT, and if looks okay try pushing it back in. If that solves the problem, it's only a temporary solution and you'll need to fix the fuse holder.

RJR

Yeah, scope, that's actually more likely than the fuse going "high impedance" but not fully open.