diagnostic question on fuel system.

[JOSHM]

Hello all,

My question is regarding an inop fuel pump. Stopped working yesterday at the supermarket, left vehicle there and returned at midnight to work on it in privacy. Before I started I decided to try it just one more time...It worked, started and ran fine. I got it home and tried it the next morning and it again would not start and there was little to no fuel pressure and once again the pump could not be heard.

I searched in the archives and did some research on the wiring and components. I can hear a relay clicking at the relay control module above the fan. So i checked for power at the inertia switch in the trunk. I have 5 to 6 volts coming in and out of the switch yet still no pump sound. My question is will the pump run on 5 to 6 volts. If this is the right voltage then I suppose I will proceed with ordering a new pump. I did however find it strange that the pump worked, stopped working, and began working again. I have heard one member on this forum state that his plug kept coming loose at the pump.

Any help is greatly appreciated. I don't post much because I don't care for smart ass people. So if you are one of those please keep your comments to yourself. For the rest of you...thanks again for the help.

 

[NotSoSlowSHO]

Doesnt quite answer your question directly.... but...

Quite often, a failing fuel pump will show such erratic behavior. Seem to fail, then work okay later (probably when it cools down).

How many miles on he car? When was the fuel filter changed last? Any record of the pump being replaced before?

 

[JOSHM]

car has 225K miles, owned since 165K, I personally have never changed the pump but I don't know about previous owner. I have changed filter. I did however ground the lower right pin on the EEC connector to see if the pump would come on with the key on, and it did not.

 

[Mr Anonymous]

Trying a known good CCRM is easier than changing a fuel pump, and you should be seeing more like 11+ VDC at the IFS switch with the car off and test connector jumped as long as your battery is good so I'd start there first.

 

[JOSHM]

thanks for the info guys, it has been helpful. I jumped 12 volts to the output of the inertia switch going directly to the pump and still nothing. So I will likely buy a new pump tomorrow. I was thinking about the walbro 155L

 

[pjtoledo]

Not so fast. Getting power to the pump is only half the circuit. After going thru the pump the current then has to go to ground. A bad ground after the pump will show voltage at the shut-off switch, but the pump will not run. Try a continuity reading from the shut-off switch thru the pump to ground. My experiances are about 50-50 pump vs ICRM being bad.


Perry

 

[SHOtime2511]

this should save you some time
http://www.shophoenixproject.com/fueldoor/fueldoor.htm

 

[tominos]

i just cut the fuel door to my sho a few days ago after the car died at an intersection. still running on the same pump but the connector harness on the fuel pump was loose/came undone, plugged that back in and it runs again.

also, when i checked voltage going in and out of the ifs, i had around 9 volts.

and if you decide to cut the fuel door, use tin snips. took all of 5 minutes, with my generic dremel took me about 20 minutes to cut about 3 inches.

 

[Black '93]

**** yeah. tin snips are the ****. I have a bad ass pair and they cut through that metal like butter.