testing fuel pumps

[Yeehaw]

have 0 fuel pressure, relays are good (ASD and fuel pump), power to relay and from relay to pump.....but pump does NOT make any noise and still clicks 0 psi and vehicle will not start. Vehicle was in an accident in which gas tank was hit hard, new tank and new fuel pump are in but yea i got nothing. Is there an easy way to jump a fuel pump to see if it will power?

[Russ Jerome]

Make model motor?
There are inertia switchs on fords..like the pic above.

[Yeehaw]

its a 98 grand cherokee with the 4.0,

[That_Guy]

we had a jesus Chrysler van that we beat the hell out of there is some sorta switch that kills the fuel pump when the car is in an accident i suggest finding that relay or switch that is the source of your issues i would bet.

[-stew-]

Any codes in the computer? Was there an airbag deployment? Did you jumper power to the fuel pump to see if the fuel pump comes on? (Easiest to do @ the fp relay)

And the above post by numbnuts might be the least informative poast on the board.

[That_Guy]

Any codes in the computer? Was there an airbag deployment? Did you jumper power to the fuel pump to see if the fuel pump comes on? (Easiest to do @ the fp relay)

And the above post by numbnuts might be the least informative poast on the board.

thanks stew i was just saying we had a beater van that had a fuel pump kill switch that was linked to the airbag deployment sensors.. this maybe something similar. i never figured it out and we scrapped the van.

[Yeehaw]

no kill switch they just run the pump off the relay, have not tried to jump the pump yet will try tomorrow or thursday, no air bags and no codes

the truck was t-boned hard and the rear axle went into the gas tank, my customer replaced the axle, tank and fuel pump...no kinked lines and harness is good all the way up to the front of the truck

[-stew-]

no kill switch they just run the pump off the relay, have not tried to jump the pump yet will try tomorrow or thursday, no air bags and no codes

the truck was t-boned hard and the rear axle went into the gas tank, my customer replaced the axle, tank and fuel pump...no kinked lines and harness is good all the way up to the front of the truck


If it was stoved hard on the side, I'd bet there is a pinched harness and the wires are broke and or shorted to ground. Check all the fuses. Check for continuity (also known as resistance) from the power wire at the pump to the relay. Same thing for the ground wire, check it from the pump to where it actually grounds to the frame. Once you've done that and you've found where it grounds; clean the ground. Check the power wire for continuity to ground (there shouldn't be any.) Do this at the pump, and at the relay.

If you in fact do have power and ground at the fuel pump (but it still won't turn on), make a test light out of a sealed beam headlight. If the headlight doesn't light up bright like it should, you have a bad wire/ground in the circuit.

[Irish]

we had a jesus Chrysler van

I know your aren't talking shit about Jeeps when you drive a sub-base model N/A cobalt.

[Irish]

Could it just be a bad pump? I know you said it was new, but I have had "new" parts be shitty before.

[That_Guy]

I know your aren't talking shit about Jeeps when you drive a sub-base model N/A cobalt.

no we called it the jesus chryster because it was a friends parents car and they where very chruch going. it was a joke. if actually really would like to trade my car in for a jeep or a Colorado.. my car is awful in the winter

[Yeehaw]

yea the new pump only has 3 terminals not 4...pulled one off the self at work and figured it out