Underhood Fuel Pump Fuse?
 

So I picked up an '87 Wagon that didn't run. The guy I bought it from mentioned that it was running fine and then suddenly stopped running. So he had already swapped the in tank pump and bought an inline pump to install but never got to it. So I wrestled through getting all the rusty crap removed under the car and managed to change out the pump and filter. Went to start the car and NOTHING...

1. Tested the pump I removed and it was fine,
2. Dug through the owner's manual and checked the under dash fuse,
3. Finally found the blade fuse under the hood by the coil.

Needless to say from the picture I attached, a hack job of wiring was done and I am trying to correct it. What is it supposed to look like? What size wire and what amp fuse should I use?

If anyone has a picture of what it is supposed to look like it would be appreciated.

get a generic waterproof fuse holder for a ATC style blade fuse, they usually even come with the appropriate 25 amp fuse, and splice it into the circuit to replace what you got there... I use marine grade fuse holders and marine grade crimps generally.

https://lh5.googleusercontent.com/pu...CJNK6KA=s220-c

if that fuse holder melted down like it looks, there's probably a short somewhere in the power wiring for the fuel injection or ignition or associated stuff (thats all on that 25A fuse).

before changing fuel pumps, always test the fuel pump relay, which is under the glovebox on a 240. 50% or more, thats all thats wrong.

Pierce,

Appreaciate the info. I was just trying to verify what size the fuse was. I will get a waterproof fuse to put in place. I need to do a search and try to find the wiring diagram for the car too.

The previous owner had a 30 amp fuse in there, I am not the most capable with electrical issues, but I will try and find if there is a short anywhere.

Could a simple broken wire cause the melting? Could have just been a bad splice where the guy before me put the fuse block in originally?

He did use much smaller wire then the stock harness used. Also, the other end (power side) is simply mashed into the battery lug, could there be an issue there?

a 'broken wire' is a 'open circuit', unless its a hot wire and it touches ground, then its a 'short circuit'.

re fuse size, 25a or 30a isn't that much difference. in fact, I could be wrong about the 25a, I replaced my daughter's 240s fuse holder about a year ago. the wiring on the replacement fuse holder was about the same gauge as the factory harness wiring. IIRC (and I might be forgetting something), there's at least 3 wires on the + battery terminal...

1) really fat one that goes to the starter and on to the alternator
2) medium gauge one that goes to the "positive terminal"
3) medium gauge one that goes to this fuse and on to the main relay for the fuel injection and fuel pumps (this relay, often called the fuel pump relay, is in fact TWO relays in one can, one for the fuel pumps, and the other for the fuel injection itself)..

the "positive terminal" is a flat black rectangular plastic cover over a terminal strip to which a whole pile of red wires are connected that go various places, these wires are unfused and always-on.

Thanks so much!
 

I have been taking my 1988 Volvo DL wagon to several mechanics over the last two years and no one has been able to figure out the problem.

My car would just turn over again and again. But I would wait a few days it it would sometime start. Now after reading this forum I had them check out the fuse that sends power to the fuel injection system and that did it. It was an aftermarket part and wasn't crimped all the way correctly! Starts like new now.

Thanks so much for your help!

Hi All! :)

What I thought was the fuel pump relay turned out to be this, too (photo attached) ...now, granted this is an old post but is there an updated way to fix this in 2020?
My 1990 Volvo has been running ideally up until this--and had the 30-amp variety fuse in the wiring harness:
https://cimg6.ibsrv.net/gimg/volvofo...6027a536f4.jpg
Burnout

Additionally, if the fuel pump relay were to have failed--would this have caused the meltdown in the fuse??

Thanks in Advance for any & all help-- great forum!~

Russell

That should be a 25 amp fuse. When you have a bad connection it can overheat even at the normal current draw. Having an open fuse design in that location was a bad idea from the start since it is exposed to the weather. Water and salt get in there causing corrosion which leads to a poor connection. That's why Pierce suggested a marine fuse holder. Make sure when you splice it in that you have good waterproof connections on your crimps or you are just passing the problem down the wire.

Thanks 'Act'. Could you also address what Pierce says about "...if that fuse holder melted down like it looks, there's probably a short somewhere in the power wiring for the fuel injection or ignition..." and the likelihood of a short? I'm prepared to buy a meter for some electrical testing... RW

My thoughts were that the melting is more likely due to a poor connection. Even with a 30 amp fuse in there, a short would blow the fuse or melt a wire. I would put it back together with a proper fuse holder and the correct value for the fuse. If a short occurs the fuse should blow.

I believe Pierce is an EE - your thoughts?

yeah, you're right, its likely corrosion caused resisstance at that fuse pin, which caused it to get real hot.

that fuse holder is already not a 'real volvo' one, the original ones were white and rather slim and funky.

slather a good dose of silicone dielectric grease all over the new fuse before inserting it. and use 'marine' grade crimps, not the cheap auto parts or hardware store ones... or solder it, paint the connections in 'liquid electrical tape', and put shrinkwrap over it and heat-shrink before the liquid tape sets.

Huge Thanks to everyone who chipped in here; cost to repair -- about $20 ...

car kicked right over with a new 25A in a waterproof ATO holder.

I LOVE THIS FORUM

RW