Hi again,

I was wondering if anyone good with wiring could help me. My wife's 245 turbo had an intermittent battery drain due to grounded/shorted wires at the alternator. I cut and replaced the frayed ones with new, using new wires, connectors, and heat shrink tubing. I also did the 2 going to the oil press. switch. I also repaired some at the grey firewall plug in the engine compartment. Lastly, I had quite a few bare wires at the starter, so I did a very nice job on those too. Upon initial inspection (before performing any work), I noticed that some kind fellow had done a lot of "patchwork" to the lower wiring harness between the starter and the firewall plug. Insulated wire was not even used, just a whole lot of electrical tape.

Anyway, after all this work (been working on it for days), every time I start the car the 16A #6 fuel pump fuse blows immediately after the motor starts, killing the motor. I am at my wits end. I really have tried to do a good job, but it is very cramped and greasy under there. I have a Bentley manual, and it says under CI injection elec. tests, to check the elec. fuel system via the fuel pump relay. All the tests which follow immediately under that check out OK ( the tests involving checking for current/ground/continuity at the F.P. relay terminals). I even opened up the relay, but it appears good. I used a test light and my digital multimeter (IPD)...still learning how to use that one......

I feel like I am 99 percent sure I have a short somewhere. I have looked hi and low for hours, and I can find nothing. I am almost ready to "take her in" to my friends Volvo garage tomorrow. Is it a bad idea to "jump" the fuel pump fuse just to get it over to the garage (about 10 mi.), or should I have it towed? I would really, really like to fix this myself, but I have run out of ideas.

Thanks for the posts.

I will NOT attempt to "jump" the #6 fuse.

I DID have the car running correctly, if I remember, at one point nearing the end of my repairs. I was trying to remember what I did AFTER I did a "test run". I think that's when I replaced the 6 gau. wire from the alternator to the starter with a new 8 gau. wire. I remember leaving the old red wire in the harness.. I assume that wire didn't branch off anywhere else. I also did a lot of "fiddling" with the grey firewall plug (8)... I will try to hook up the old wire back, and then try it before doing the test with the 4 and 6 fuse. I really appreciate you taking thge time to look over your wiring diagrams for me. I am not much good reading those things (but am trying to learn). If all else fails, I will take it to a local Volvo garage that I trust tomorrow. I already called the owner today and he said that they would need to run tests to find the short, also. I was a bit embarrassed because I was trying to do a good job by myself. Well, at least I have oil press. and I fixed the original short (causing an intermittent battery drain).........I'ts just such a greasy, cramped mess under the intake manifold....lots of electrical tape from the previous owner....

Thanks,

Ted (Bundy) Y.

Hi Ted -

I had a look at the Fuel Injection System, Turbo page, in my Volvo Service Manual Wiring Diagrams 240 1985. Book TP 30808/1 4500.7.85

Tracing where the power goes after fuse #6, here's what I see:

The red lead goes to the Pump Relay (terminal #30), where it goes through two sets of contacts to two outputs.

(1) from terminal #87, (Y-R) to fuse #4 then (Y-R) to the in-tank pump; and (Y-R)to the main fuel pump,

(2) from terminal #87b, (BL) to the grey connector on the firewall and thence to the control pressure regulator and also to the auxiliary air valve.

The contacts close when the pump relay gets power from the ignition switch and a signal from the coil. Then all that out-bound stuff has power, so any of those wires or units could be the shorting culprit.

The wires to the rear for the in-tank fuel pump goes through two separate connectors that appear to be in the area of the fuse panel or up above the driver's right toe. A nine-pin connector has a Y-R wire in and out from position #2, where #1 is a single GR wire and #3 is a double GR wire. Then the Y-R wire goes to a four-wire connector. There it is the only Y-R wire.

Disconnect the blue wire in the under-hood connector, and pull fuse #4. If #6 still blows, it's the main pump wiring. If #6 OK, then check with a test light across #4. Full bright means that's where the short is. If #4 is OK, that leaves only the under-hood components which also includes the possibility of crumbling insulation along the route.

Good Luck,

Bob

:>)

PS You might consider owning this book. www.volvocars.com/lit, choose service.

I'd pull out the back seat and check to see if the wires running through the hole in the metal of the floorpan hasn't become frayed or grounded out. These wires go directly to the main pump below, and they should be covered with a jacket to prevent fraying, but if it were missing, they would fray easily. I had a big short right next to the pump itself, if you pulled on the wires at all during your other repairs you may have caused this short to occur. Other than that I'm at as big a loss as yourself, aside from being near positive that you've allowed a wire to touch bare metal. Considering that this is likely the case, I would strongly recommend against jumping the fuse. You will cause severe damage to innumerable electrical components if the shorted wire is connecting well enough to the chassis. At the very least, you would probably catch the fuel pump wire on fire from severe amp draw.