sounds like its wired correctly. The PCM primes the pump for a second and then shuts it off until there is a crank signal from the engine to tell it the engine is turning and needs more fuel. If it stayed on all the time then it would eat the battery charge up while there was no need for fuel being pumped. I believe its also a safety feature for vehicles envolved in accidents, sure don't want a fuel pump supplying fuel for a fire.
See my truck data in the "My Garage" section here... http://www.ls1truck.com/forums/my-ga...tml#post191709
exactly
I asked nitrous but didnt get a reply, how would a five terminal relay sense a voltage drop or load and initiate one terminal over the other 87 vs 87A, how does that work?
Last edited by LSXmyford; 08-17-2008 at 04:11 PM.
LSX conversions, so easy a caveman can do it.
The 5 position relay would switch off from 87a and on to 87 when power is applied to the coil inside the relay. So it sounds as if the 4 wires is correct on your harness. The pcm is looking for a reason to supply fuel(oil pressure??)
1991 Silverado ECLB
LM7-T56
It won't see it unless you apply it. 87a isn't hooked to anything so just forget it's even there, pretend you have a 4 pin relay. 87a is a test point on the relay which has to be applied with an external source of power.
When current flows across pin 85 and pin 86 the coil will close contact 87 to 30.
Does this answer your question?
97 GMC, 2002 LS6.
1991 GMC Syclone #1428
Like r6z4o6 said, I wasn't quick enough.
97 GMC, 2002 LS6.
1991 GMC Syclone #1428
Wiring schematics are one thing, PCM logic is another.
1991 Silverado ECLB
LM7-T56
Whew I can't wait for this thread to end!Anyway, I hope things work out.
97 GMC, 2002 LS6.
1991 GMC Syclone #1428
three pages and 28 posts and we have confirmation, the relay was bad.
Last edited by LSXmyford; 08-20-2008 at 03:01 PM.
LSX conversions, so easy a caveman can do it.
Omg.
wow!!!!!
Vortec Performance Tuned
LQ9 built 4L60 LTs and a billion miles on the speedo!
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