Fp/inj 15 A Fuse Keeps Blowing!!

[quicker6]

Hello All,
I have a 1986 GN that keeps on blowing the FP/INJ 15 A fuse. I dont know why yet but, plan on finding out through research unless someone else here can help.

My car is basically stock with the exception of a thrasher 92 chip and walbro 340 (hotwire kit not yet installed and Ive tried switching chips and same problem). However, when I swap in a 20 A fuse it seems to be ok but, I dont want to keep running it like that and risk melting wiring or something. Anyone have any ideas?? Anyone have the same problem?? Let me know your thoughts and TIA!!

Happy Holidays,
Derek

 

[quicker6]

Ok, I think that I may have figured it out. Looks like (according to the electrical diagram on gnttype.org) the fuse is what gives power to the fuel pump relay. Because I have the walbro 340 installed, it must be drawing a bit of power. I suppose I should install the hotwire kit. When I think about it, does the 340 really draw that much current to blow that fuse?? Maybe I still have a problem?

Ive also got to figure out why the cig/clk 20 A fuse blows. Thats a lot of areas to check for shorts though.

Thanks,
Derek

 

[Razor]

Unplug the injector harness under the coil pack and reinstall the fuse.. see if it blows? If it doesnt.. look for melted wires around number 3.

HTH

 

[chevyII]

do you have a piece of gum wrapper in the cigarett lighter socket? seen that many times the wrapper is made from metal.

 

[HighPSI]

Check the 3 wire plug at the oil pressure sender. If it has melted and is grounded it will pop this fuse.

 

[Quigs]

I had the same problem with my 87 GN. Except the bigger fuses started blowing the instant I turned on the ignition.

You should look at the driver side exhaust manifold and make sure there are no wires melted to it. That was my problem.

 

[quicker6]

Thanks for all the info guys!! I appreciate it! Im gonna take a look at those things tomorrow.
Derek

 

[83ttypecooled]

pops

Hi,
If you have the wiring diagram handy, as it seems you do,start with the fuel pump itself and work back. As far as your interior light fuse, I think the other respondant had a good idea to look at the lighter socket first. They don't have to have a penny or such in them to short to ground. Good luck!

 

[chevyII]

I would say Cal is on the right track with the oil sender.. also see if its full of oil. If the sender leaks it will short the pins and blow the fuse. I have seen this many times over the years with alot of late 80's cars.

 

[rb68rr]

When mine kept blowing the inj. fuse it was a wire that came out of the harness right behind the alternator with a bare spot on it touching the exhaust manifold.

 

[quicker6]

I tried to check out the wires for #3 Inj. and they seem alright. I used a screwdriver to jostle it while the car ran but nothing happened. I looked around the engine compartment for anything obvious but no luck.
I can't really do much work to my car that I would like to because I only have one good hand and thats a long story but for those of you interested heres the link: http://www.turbobuick.com/forums/showthread.php?s=&threadid=141903

Ill do what I can with my one good hand but, Im afraid thats not enough.....

Thanks a lot for the help guys!!
Derek

 

[HellOnWheels]

Derek,

Unplug the oil sending unit, if it starts you've found the problem.


HTH

HOW

 

[quicker6]

The car runs fine until the fuse goes. Sometimes it takes 10 mins and others 15 mins. Either way seems to do it after the engine warms. Ill try to check out the oil sender unit too though.
Thanks,
Derek

 

[quicker6]

UPDATE!!

Hey guys,
Thanks for all the info!! I forgot to write back that I found the problem to be the oil pressure sending unit. Thanks HOW!! I had no idea that it was on the same circuit.
Thanks,
Derek