Constantly Popping The EFI 15A Fuse

[Chambers]

Hi all, I was heading home yesterday and out of no where the engine shut off. I thought it was the TPS or AFM, so I tried to start it, it cranked but didn't start. I pulled over and checked under the hood, the 15A fuse in the main fuse block was blown. I looked over the harness and there was no evident wires touching or melted.

I had a few fuses and replaced it once, it started back up but stalled after a few seconds of running, I started it a couple of more times and it finnaly held a idle, but it wasnt normal. It was down at 500 rpms. After a min or two of idle the fuse blew, and the engine shut down. Tried another fuse and it ended to the same result.

I got it home late last night, and this morning I started to diagnose the problem. I went through per the TSRM, so far nothing is out of the ordinary except no power the to the ECU. I have eliminated the ignition switch, EFI Main relay, and TPS. Now, as soon as the ign switch is turned on it blows the fuse. I have checked the voltage at the 15A fuse, its at a steady 11.99 volts. When I get back home today, I plan to continue but for now this is what I have found to be possibly bad, so...

My question is, does anyone think this fusable link could be the cause of the problem? It looks like it is pretty messed up, so I'm heading to the dealership today to get a new one, I also plan to get some new of the 30A and 40A big boxy fues from there as well.

Hopefully that will fix it, also, where is the other fuseable link? The TSRM shows one that looks like it has a eye hole connector to where the battery should be, but I'm unsure of which is which. Thanks.

 

[shaeff]

Most commonly, the problem is the o2 sensor wires grounding out/melting on the turbo or exhaust manifold. Next, check for melted wires near the EGR system, especially at the back of the intake manifold.

If the fusible link is in poor condition, replace it, even if it's not actually fried. It doesn't just pull out, you need to pop the fuse box in half and unbolt it from the bottom.

 

[pogoism9]

Ran into the exact problem this weekend. Fuel pump was locked up. We verified all grounds, all connectors, tested components per the TSRM, they all checked out. I bridged the ports in the diag box to force the fuel pump. With the pump connected the fuse blew as soon as the key turned on, with it disconnected, the fuse would not blow. Took the pump out, gave it voltage, and it was locked up.

Once we replaced it, car was great.

 

[Poodles]

Don't have to go to the dealer for that fusable link, just replace it with the later model style (the style of that ornage one)

But if that's blowing, you're shorting the charging system...

 

[Chambers]

Thanks for the replies.

I did some searching before posting and I did check into the O2 sensor wire, but I have no turbo for it to lay upon, that didnt however keep me from checking it, there was no interferiance with anything so the O2 is ok. I looked over the harnness, especially around the EGR and therm housing, so far nothing looks melted or frayed.

I will try unpluging the fuel relay, and run some tests on it with the voltmeter to verify the relay is functioning properly and the FP isnt to blame.


I went ahead and orederd one from the dealer, only $4. I rather have exactly what needs to be there so I can eliminate that variable.

Thanks again for all your replies, I will post my results.

 

[Chambers]

Hi all, I got the new part in. Wow, what a difference to what was in there before.

The problem is, upon replacing it, the 15A EFI fuse still popped as soon as the key was turned on. I still have to do some more troubleshooting, but the fusible link was not the cause.

 

[jetjock]

Doesn't make sense it would be. Good that you replaced it though...

 

[crisp]

Try to "feel" the underside of the harness where it runs RIGHT OVER the EGR valve plumbing. Is the harness "drooping" down and JUST barely resting on or near the EGR valve pipe? FEEL THAT AREA and see if it's "rough" on the underside along there. You CAN'T see it without a small mirror and light, but you can feel it.


That kept me stumped for YEARS!:aigo:


(After a head swap... I didn't get the main harness CLIPPED to the afix point, and it "settled" down until it rested on the EGR pipe.)


G/L!



-crisp

 

[Chambers]

Yea, I didn't think that was the problem, but I wanted to be sure it wasn't a contributing variable.

I looked over the harness around the EGR, but I didn't feel it, I will be sure to do so though!

Thanks for the replies.

 

[TooGoode]

if you look at my post, i had the same problem. i checked around the throttle body and found out when i would floor the car, my linkage was hitting the wiring harness, slowly causing it to cut through the insulation and grounding out a wire....check around your intake manifold.

 

[supraguy@aol]

Try to "feel" the underside of the harness where it runs RIGHT OVER the EGR valve plumbing. Is the harness "drooping" down and JUST barely resting on or near the EGR valve pipe? FEEL THAT AREA and see if it's "rough" on the underside along there. You CAN'T see it without a small mirror and light, but you can feel it.

G/L!

-crisp

Bingo- That happened to me as well. I was driving, and the motor just shuts off. I coast to the side of the highway(this happened twice to me by the way) and find the EFI fuse blown. 3 fuses later, she still blows them. The car cools down for 15 minutes, and starts right up. The second time, I find the semi-melted sport on the harness near the EGR, and relocate the harness, and now no more problems.
Also- good to know about the fuel pump potentially causing the problem, pogoism9. I would definately check that possibility out as well.

 

[shaeff]

Try to "feel" the underside of the harness where it runs RIGHT OVER the EGR valve plumbing. Is the harness "drooping" down and JUST barely resting on or near the EGR valve pipe? FEEL THAT AREA and see if it's "rough" on the underside along there. You CAN'T see it without a small mirror and light, but you can feel it.


That kept me stumped for YEARS!:aigo:


(After a head swap... I didn't get the main harness CLIPPED to the afix point, and it "settled" down until it rested on the EGR pipe.)


G/L!

-crisp

Yep, that's why I suggested it. And oddly enough, (or not oddly, LOL) I just repaired a car that this happened to. That was...er... fun.

 

[Chambers]

Hi all, after some more troubleshooting I narrowed the problem down to one plug. Its the yellow 6 pin plug below the alternator. It looks like someone tapped the plug on one side and connected it to the AC compressor.

There is a lone plug, that looks like it belongs to the AC compressor, it has two blue wires going to it. Is this the right wire for the AC?

I'm still in the process of determining what other wires go through that plug, so if anyone knows off hand that would be great.

Thanks.

 

[Chambers]

Well, I removed the wire that was tapping into the plug, after fixing it, the fuse didn't pop and the car started but stalled instantly. I then cranked it and gave it some throttle, and it ran, but when I left off it stalled. So far it will not hold a idle and is not lighting up the engine light when its running. I just love a challenge.