I am looking for the factory fuel pump fuse? I located the relay, any way to test? Does anyone know what wires to test to see if you are getting power?
I have no fuel pressure, I have a ati boost pump it is not getting power. I am getting power to boost pump relay(direct from batt) but no power coming out, due to no (ign) power from factory pump, wire wires are good, splice is good to relay also. Trying to trace this down.

 

Some information about your car might be appropriate. There are some wiring differences between years.

 

96Z
Trying to see if getting power, the only fuse I think is in line is the pcm batt,.
Any way to test relay, before and after relay.

 

PCM BATT is the fuse.

Your relay has 5 wires to it.

Orange- +12v (should be hot all the time)
Red- to fuel pump prime connector by pcm
Drk Grn/White- fuel pump relay control from pcm (should be hot for 2 seconds when key is turned ON and hot when engine is running)
Grey- +12v to fuel pump (hot when relay is operated)
Blk/White- ground--same grey wire that comes out of the plug under the car to go to the fuel pump.



When you turn the key ON, you should hear the relay operate and see +12v on the grey wire to the fuel pump.

 

shoebox
Your the man!
Thanks for the quick response!
I have 0 fuel pressure, The relay going to Ati boost pump has of course hot going in, ground, and power coming out, and a splice from the gray wire under car.
The car has had no problems. Went out to warm her up started fine ran a few min. then died 0 FP., I checked under the fuse (pcm) batt ok.
No power to boost pump, power good, fuse good. Just nothing coming out of relay(boost). I hope it is just the Stock Pump Relay.

 

If the relay is stuck, can you apply 12 v to the fuel pump prime connector and current would run the stock pump and(BOOST PUMP) which I am spliced into also should run also. I should have FP. Correct?
What function does the FP prime connector have? will it work for me, should it let me know if the relay is a bad and my pumps are good?

 

On the 1996 and up cars, the prime connector connects through normally closed contacts in the relay when the relay is INOPERATED. So, if you jumper 12v to the prime connector, it should provide power all the way to the factory pump. If the relay is OPERATED the prime circuit is disabled at the relay.

The prime connector will not necessarily tell you if the relay is bad.

 

No luck with the prime connector.
I ran a jumper from with relay removed from orange to gray nothing.
The orange is hot, test light on.
I am spliced into the gray in the rear to my boost pumps relay, shouldn't that run? When being jumped?
I noticed a purple, black, gray wires in same harness, near tank.
Whats next?
I can't understand it car was running great, then nothing.

 

Yes, jumping the orange to grey should provide the same thing the relay does when operated. I would open the connection at the connector under the car and see if your power is getting to that point. If your aux pump is connected before that, disconnect that, too. Check your fuse again to make sure that it has not blown.

 

My aux has it's own power wire (fused) directly to the aux boost pump, fuse ok. aux relay gray from rear no power to relay.
So should I run a jumper from orange to gray (relay removed) and check power at harness near pump?

 

I would. You have to isolate the problem somehow.

 

I'll get on on it tommorow.
Thanks for being patient.
I'll keep you posted.
Frank

 

Shoebox
I ran the orange to gray at the relay and I had power back there.
I was probing around and noticed the boost pump wasn't getting a good ground, to the relay and the pump itself. I went ahead grounded at another location and the pump is running.
I snapped the relay back in turned the key heard the pump and gauge reads 40 ish, so I went to start her up runnig fine but I noticed the fuel pressure gauge fluttering from 40 ish to 20 back and forth. Car was kind of surging. I hit the gas and the pressure drops to near 0 and car wants to die. Let off gas pedal and pressure builds to 40 and then back down to 20.
Could the factory pump not be running? Never blew a fuse but bad ground to boost pump and relay.
Any hints what to check or where. If it is not one thing it is another.

 

I have read that it if the stock pump is not running, that an inline pump will not be able to pull fuel through it properly. Take power off your aux pump and see if you can get normal readings from the stock pump.

 

Can the stock pump flow threw the inline?
I'll pull the fuse. and check.

Would losing a ground to inline pump cause the stock pump to fail?