Fuel pump hotwire

[Chris26]

Its a 90
arctic white with grey interior (snake skinner)
#1457

Give me a day or so...I'm tired!!!

[geezer]

Chris 26: Where in PQ are you. How far from Ottawa? Don't let the frustration get to you. The 'brotherhood' is here for you!!

[Chris26]

I'm 10 minutes from MTL... One hour from Ottawa...The car's previous owner did

not know what an lt-5 was so go figure.

[Paul Workman]

Originally Posted by Chris26

I got 0.46A with FP1 pulled.

Well, if connections are good now, this reading indicates FP#2 is drawing only 1/10th the current it should be. That is a problem.

Either FP2 is bad, or there is a bad connection somewhere between the battery and FP2. (Refer to the two schematics)

I suggest you "ohm it out". But FIRST(!) I recommend we verify the ground, measured from the pump (input side) BLACK wire terminal to ground, i.e., the frame (or some other good ground location) - just to avoid assuming anything. It should read less than an ohm (I would think - having not actually done this particular test myself). If the ground is OK, then we can proceed with confidence.

• With a test lead (alligator clips on each end) ground the pump prime connector (under the hood) and
• read resistance between the GREEN-WHITE lead and the BLACK lead on the input (battery) side of the pump connector, and do the same on the GRAY wire. Both should read close to zero to 1 ohm.

Note: This test includes the various wire connections, and resistance of relay FP1, and for FP2 it also includes resistance of relay FP2 as measured on the GREEN-WHITE wire at the fuel pump connector at the tank. If there is a problem with FP2 circuit, resistance would be approx 28 ohms ± (battery voltage/.46A to be precise.)

If the circuit to the pump connector checks out, then connections to FP2 and the fuel pump itself is all that is left. You could swap the pumps and see what the FP1 current draw is when plugged into the FP2 slot (after reconnecting the pump prime connector to the VOM (configured again to read amperes).

If FP1 (now in FP2's position) works as before, then FP2 or its wiring is bad.

[geezer]

Sent you a PM.

[Chris26]

OK

Ground reads about 29ohms...Black input to common ground

green white to ground reads about 1 ohm

tan white to ground reads about 1 ohm

[geezer]

Chris: Did you check your PM's ( private messages)?

[Chris26]

FYI The pump was not under load when tested(connected to injectors and rail).....

[Paul Workman]

Originally Posted by Chris26

FYI The pump was not under load when tested(connected to injectors and rail).....

Just to be sure we're on the same page....

The connector at the fuel pump (for the record) is "C450"

With all circuitry connected normally, AND that includes the fuel lines to the injectors via the fuel rail(s), WITH the battery (pos) is passed through the VOM (configured to measure Amperes) to the FUEL PUMP PRIME CONNECTOR (the red wire/connector near the windshield wiper motor, jutting out of the big wire loom), you should read between 8 and 10 amperes (approx 1/2 of the current to each pump, is how that works).

However, if the current is NOT where it should be, by pulling the FP1 fuse you cut off the current to the FP1 circuit and what is left is the current flowing to FP2 only. Now, if FP2 is normal, under load (pumping fuel) it should read between 4 and 5 amperes.

CHECKING OUT THE HARNESS TO THE FUEL PUMPS:

With C450 disconnected (at the fuel pumps), separating the harness from the fuel pump apparatus, the ignition switch still in the OFF position, and the FUEL PUMP PRIME CONNECTOR no longer connected to anything, and all other connections, etc. in their normal condition/state (i.e., no jumpers or whatever else being present), the VOM configured to read resistance should read zero to 1 ohm or there 'bouts between the GRAY and the DARK GREEN/WHITE (harness) wires (feeding from the battery-side of the C450 connector, NOT the wires leading into the tank).

Again, reading resistance of the ground connection, the resistance measured between the BLACK wire (on the harness side) of the C450 connector and ground (e.g., the frame) should be very close to zero to 1 ohm (i.e., the amount of resistance one reads when the test leads are shorted when measuring ohms).

IF the above is true, i.e., the resistance reading recorded between the GRAY and the DARK GREEN/WHITE (harness) wires was at/near zero, AND the resistance between the BLACK ground wire of C450 of the harness is at/near zero, the harness "ohms out" FOR NOW.

Let's hear what you find/found.

[Chris26]

Thanks again!!! Any tips on how to remove bolts with cracked off heads from the coolant pipes to the injector housing??? I do not have a torch or anything like that. The car was a gift and TBH this is not going the way I planned it out...I'm supposed to be on vacation but instead have a s@#$load of parts on my kitchen table....If i had a garage ...proper resources...cool neighbours ...then I would not be complaining!!!!