93 s15 jimmy fuel relay location moved to S10-S15 forum - The 1947 - Present Chevrolet & GMC Truck Message Board Network

po_bird · 12-28-2009, 04:18 PM

All of a sudden my fuel pump doesnt turn on.. So i suspect a bad pump. Before i drop the tank i would like to check the relay and make sure it is working. I just drove the thing to work and back. 1hr later it doesnt want to work. I beat on the fuel tank and nothing different.

ChevLoRay · 12-30-2009, 02:42 PM

Somebody needs to help a brother out and tell him what he needs to know.

Basically, I'd get another person to listen to your gas tank for the sound of the fuel pump and switch the key on. If you think the relay is the issue, it shouldn't be a big deal to find the relay and tap on it while the key is on and someone is listening at the tank. If tapping on the relay doesn't cause the pump to run, I'd say it's the pump. But, I'd also be checking the connectors to the pump circuitry at the tank. There have been instances where that was the issue....and/or the ground(s). At least you'd know.

ChevyTech · 12-30-2009, 03:06 PM

If the fuel pump relay is bad the computer should have stored a trouble code 54.

A code 54 happens when the computer does not see power on the circuit from the fuel relay to the fuel pump, when the computer is sending power to the relay to apply the relay.

Have you checked the computer for trouble codes?

FLEET72 · 01-04-2010, 02:59 AM

Driver's side fender. This is an 89 and I know the 91 is in the same spot. The 93 may be different but I doubt it. Orange (440) should have 12vdc at all times, gray/white stripe (120) is the wire to the pump.

clinebarger · 01-05-2010, 12:25 AM

93 Fuel pump relay location & some info on how the curcuit works.

*** UPDATED BY TSB 893206E, DATED OCTOBER 90
When the key is first turned ON, without the engine running, the ECM will turn the fuel pump relay ON for two seconds. This builds up the fuel pressure to normal operating pressure. If the engine is not started within two seconds, the ECM will shut the fuel pump OFF and wait until ignition reference pulses are present. As soon as the engine is cranked, the ECM turns the relay ON, which powers the fuel pump. The ECM continues to power the fuel pump during engine operation. If the fuel pump relay fails, it is backed up by the oil pressure switch, which continues to operate the fuel pump as long as oil pressure remains above 28.0 kPa (4 psi).

RESULTS OF INCORRECT FUEL PUMP SYSTEM OPERATION

A faulty fuel pump relay can result in long cranking times, particularly if the engine is cold.
An inoperative fuel pump would cause a no start condition.
A fuel pump which does not provide enough pressure can result in poor performance.

12-28-2009, 04:18 PM	#1
po_bird Registered User Join Date: Oct 2005 Location: MUSKOGEE, OK Posts: 229	93 s15 jimmy fuel relay location moved to S10-S15 forum All of a sudden my fuel pump doesnt turn on.. So i suspect a bad pump. Before i drop the tank i would like to check the relay and make sure it is working. I just drove the thing to work and back. 1hr later it doesnt want to work. I beat on the fuel tank and nothing different. Last edited by po_bird; 12-28-2009 at 08:53 PM.

12-30-2009, 02:42 PM	#2
ChevLoRay Old Skool Club Join Date: Jun 2001 Location: Benton, AR "The Heart of Arkansas" Posts: 10,880	Re: 93 s15 jimmy fuel relay location moved to S10-S15 forum Somebody needs to help a brother out and tell him what he needs to know. Basically, I'd get another person to listen to your gas tank for the sound of the fuel pump and switch the key on. If you think the relay is the issue, it shouldn't be a big deal to find the relay and tap on it while the key is on and someone is listening at the tank. If tapping on the relay doesn't cause the pump to run, I'd say it's the pump. But, I'd also be checking the connectors to the pump circuitry at the tank. There have been instances where that was the issue....and/or the ground(s). At least you'd know. __________________ Member Nr. 2770 '96 GMC Sportside; 4.3/SLT - Daily driven....constantly needs washed. '69 C-10 SWB; 350/TH400 - in limbo The older I get, the better I was.

12-30-2009, 03:06 PM	#3
ChevyTech Registered User Join Date: May 2004 Location: Minnesota Posts: 4,621	Re: 93 s15 jimmy fuel relay location moved to S10-S15 forum If the fuel pump relay is bad the computer should have stored a trouble code 54. A code 54 happens when the computer does not see power on the circuit from the fuel relay to the fuel pump, when the computer is sending power to the relay to apply the relay. Have you checked the computer for trouble codes?

01-04-2010, 02:59 AM	#4
FLEET72 Registered User Join Date: Jan 2007 Location: Sonoma, CA Posts: 521	Re: 93 s15 jimmy fuel relay location moved to S10-S15 forum Driver's side fender. This is an 89 and I know the 91 is in the same spot. The 93 may be different but I doubt it. Orange (440) should have 12vdc at all times, gray/white stripe (120) is the wire to the pump. __________________ Oscar '72 Shortbed Fleetside '95 Jimmy 4X4 '69 GMC Custom Camper Last edited by FLEET72; 01-04-2010 at 03:09 AM.

01-05-2010, 12:25 AM	#5
clinebarger Senior Member Join Date: May 2009 Location: Fort Worth, TX Posts: 6,370	Re: 93 s15 jimmy fuel relay location moved to S10-S15 forum 93 Fuel pump relay location & some info on how the curcuit works. *** UPDATED BY TSB 893206E, DATED OCTOBER 90 When the key is first turned ON, without the engine running, the ECM will turn the fuel pump relay ON for two seconds. This builds up the fuel pressure to normal operating pressure. If the engine is not started within two seconds, the ECM will shut the fuel pump OFF and wait until ignition reference pulses are present. As soon as the engine is cranked, the ECM turns the relay ON, which powers the fuel pump. The ECM continues to power the fuel pump during engine operation. If the fuel pump relay fails, it is backed up by the oil pressure switch, which continues to operate the fuel pump as long as oil pressure remains above 28.0 kPa (4 psi). RESULTS OF INCORRECT FUEL PUMP SYSTEM OPERATION A faulty fuel pump relay can result in long cranking times, particularly if the engine is cold. An inoperative fuel pump would cause a no start condition. A fuel pump which does not provide enough pressure can result in poor performance. Attached Images



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