Electrical Demons

[gma0408]

95 GSX/ 6bolt

I am really, really frustrated guys as I'm sure most of you know how difficult wiring problems can be. This has been a week long, day in, day out process with no results. I seriously have headaches from all the countless thread I've read on electrical problems.

My car has been sitting since last summer awaiting the built longblock. Everything withe the swap went smoothly. Of course I primed the motor when it was out of the car, but I decided to crank the engine over with out the 20amp enigine fuse.

I went to put in the key, and get it to the acc and thats when I noticed some very odd things.

-I'm missing the the blinking from the cluster lights for the radiator fluid and the oil pressure. Its as if the bulbs were out.
-I'm also missing the "buzz" (priming?) I usually hear from the fuel pump.

Hmm, well ok. I go ahead and crank it over. THE OIL PRSSURE GUAGE NEEDLE ISN'T MOVING. After installing a mechanical oil pressure guage, i can confirm that the engine is getting oil. So that means the oil pressure gauge isn't working.

I also noticed the stock boost gauge isn't working and the power windows don't work either.

It took a couple of cranks to fire her up, but she started. It stumbled and would slowly die after 5 min. One of the times I tried starting it, by buddy swore he smelled something like an electrical short.

I got a cel and looked it up via dsmlink. P1500 Alternator FR Terminal Circuit.

I checked out the plug, and it looked bad from the downpipe being so close. I replaced the plug, and the cel went away but the car is still having the electrical problems and the car still slowly dies.

I UPLUG the 4 wire plug at the alternator and the car will stablize. Why is this? Is there a problem with the wiring?

I looked on my dealer manual and the 2 outer wires the green and the white of the 4 wire plug go to pin 33 and 41 of the ecu. Where do the other 2 go? I know if i have them unplugged the alternator will stop charging the battery. I've already replaced the alternator, and its putting out 14.5 volts

HELP me please. What do I do to check the wiring? Where do I begin?

 

[luv2rallye]

IF THE GENERATOR RELAY IS MISSING (it often gets distroyed for some reason) AND THE BATTERY AND BRAKE DASH LIGHTS ARE BURNED OUT (or there's no complete circuit thru them), THE ALTERNATOR WILL NOT CHARGE THE BATTERY (due to no electricity getting to the alt's field coil)! This may be your problem. You can live without the relay (they didn't even put it in my car or later years) but then you MUST have those lights working. Generator relay stuff: http://www.dsmtuners.com/forums/new...e-charging-system-relay-2g.html#post151081889.

I sent a reply to your pm to me for the other stuff and things to try. I just wanted to mention the "generator relay/dash lights issue" here for others sake who may look here since this is a "not so easy to find problem" and is probably never mentioned in any aftermarket manuals.

 

[gma0408]

I assume this is the 95 GSX with 6 bolt swap and not the 96 GSX listed in your profile? I also assume you put the 20A fuse back in for the following discussion?
Sorry, its the 96 Gsx/ 6 bolt swap. Yes the 20A engine fuse is back in.

ACC key position does nothing so I assume you meant the ON position (also not Start position)? On my 99 only the brake, oil, and battery lights stay on with key to ON. The fuel pump only runs when engine has spark. Battery light should be on.

Yes, I did mean the ACC key position. The brake light is on because the E-handle is up, but the the oil and battery lights do not flash or go off at all. Is there a way to do a voltage drop test for the wiring for these lights or a voltage test to see if a signal is being sent? Where do these wires go to? Directly to the Ecu? I have an extra cluster, so I'll pop that in to see if that does anything. And maybe its not the fuel pump priming, but I used to hear a 1-2 sec buzz from the pump area when the key would be turned to the ACC position.

The oil pressure gauge won't move on cranking. It barely even moves when idling. You can test the guage by grounding the sensor wire to give full deflection. Stock boost guage should go midway with key to just ON. You may have an ECU problem as this is one result of a successful ECU power-up

When I used to prime the engine with the 20A engine fuse out, within 2-3 seconds of cranking I could get the needle to go 1/4 of the way up....now, nothing. Also, the stock boost gauge needle won't even go to the 0 mark when in the ACC position. Are you saying that I can ground the Oil sender wire and should be able to see the needle move? Again, do the oil gauge and boost gauge wires go directly to the ecu? The ecu is perfectly fine. I've tested it in another 95 GSX and have used another 95 GSX ECU in mine with no changes.

You may want to check (ohmmeter) that the green goes only to ECU pin 41 and the white goes only to ECU pin 33. They should not go to either +12 or ground or anywhere else. The green is a sensing wire while the white is a control wire. Disconnect battery first and then ECU before testing this (ECU must NEVER be plugged/unplugged with battery connected or you risk blowing it). The red goes thru the 40A fuse to battery positive. The black/yellow (sometimes blue) goes to the generator relay and then becomes a blue to the battery and brake dash lights (thru diodes).

Would the wires grounding cause my problems?...I will definately check though. The red wire on the alternator 4 wire plug goes to the 40a fuse on the fuse box? I looked at the generator relay. It seems as if the black wire from the Alternator 4 wire plug does go to this. Is it possible to just bypass the relay and simply connect the blue and black wires together. I will definately check the wiring though. Aside from the diodes, does the blue wire from the generator relay go through or power anything.

I am positive the alternator is working though. I've had 3 in the car already, and have had them bench/load tested....as well as the battery.

 

[gma0408]

I took apart the splash shield on the drivers side and found the whole section of wiring from the abs to the dash crispy! Some of the wires were melted together!

Its definately been like that for a while though. I guess if finally corroded enough to where it gave me problems.

I'm gonna splice in new wiring from a junk car I found. I dont think I can take out completely the old wiring. It wrap all the way around the engine bay up through under the dash.