No fuel pressure

[dynoman]

Hi guys , new to the forum , just bought DCVING's WH1 and it's a great looking car. I went to take it around the block before the weather changed and it would not start, no fuel pressure. The relay has power to it but it is not getting the signal from the ECM to energize . Any help would be great , thanks Sam

 

[87NAT]

If you have spark + no FP= Cam sensor

No FP + no spark= crank sensor

 

[dynoman]

How do I check both sensors ? I'm at work right now and can't check for spark.

 

[dynoman]

shouldn't I have pressure with just ignition on ? I don't.

 

[TurboDave]

The fuel pump should prime for 2-3 seconds with just the key on. If it's not even priming the cam or crank sensor have nothing to do with this.

How's the fuel pump relay? If it were bad, there would be no prime, HOWEVER, the car would eventually fire when the oil pressure got high enough to bypass he fuel pump relay.

Also, check your fuses, fp/inj fuse, ecm fuse, etc.

There's got to be an electrical issue why the fuel pump isn't even priming.

 

[dynoman]

Will I have power (signal) to turn on the relay as long as the ignition is on ? Pump power is at the relay but no signal. Fuses are all good. Schematics from alldata show power to turn on the f/p relay come straight from the ECM (electronic switching)and thats where I have no power. Can I turn on the relay from a manual switch if it turns out to be a ECM problem?

 

[TurboDave]

Will I have power (signal) to turn on the relay as long as the ignition is on ? Pump power is at the relay but no signal. Fuses are all good. Schematics from alldata show power to turn on the f/p relay come straight from the ECM (electronic switching)and thats where I have no power. Can I turn on the relay from a manual switch if it turns out to be a ECM problem?

If I recall (and that's no guarantee) the ECM provides power once the engine gets over 400 rpm

The prime signal only lasts a few seconds after key on.
If after the pump stops priming, you turn the key to crank the engine, oil pressure starts to build, and once past a point that relay provides fuel pump power during cranking, when the engine fires and gets over 400 rpm the ECM then provided constant fuel pump power.

You can test if the fuel pump is working at all, by providing a temporary source of 12v to the fuel pump prime connector. The black one wire connector hanging loose a few inches behind the alternator. The underhood light source connector is a good source of 12v to jumper over to the prime connector. Try that and see if the pump runs. If it does the wiring to the pump and the pump its self are good. Otherwise.....

 

[Celiking]

Does the "CHECK ENGINE" light come on when the is turned to "ON"?

 

[bmackinnon]

If I recall (and that's no guarantee) the ECM provides power once the engine gets over 400 rpm

The prime signal only lasts a few seconds after key on.
If after the pump stops priming, you turn the key to crank the engine, oil pressure starts to build, and once past a point that relay provides fuel pump power during cranking, when the engine fires and gets over 400 rpm the ECM then provided constant fuel pump power.

You can test if the fuel pump is working at all, by providing a temporary source of 12v to the fuel pump prime connector. The black one wire connector hanging loose a few inches behind the alternator. The underhood light source connector is a good source of 12v to jumper over to the prime connector. Try that and see if the pump runs. If it does the wiring to the pump and the pump its self are good. Otherwise.....

Dave is right, as usual... the ecm provides the timed prime signal (to the fp relay), which should create enough pressure to fire the engine, and also provides the signal once the engine reaches 400 rpm. As the oil pressure builds during the crank/start sequence, the oil pressure switch then provides a parallel supply voltage to the pump so that if the fp relay fails while driving, the car continues to run. If the relay is bad, you have to crank the engine long enough to build oil pressure which then energizes the pump, finally starting the car. If the pump doesn't prime when the key is turned to 'on', but will run off the test jumper dave noted above, either the relay is bad, or the ecm is fried.

 

[dynoman]

Well it looks like I have a bad pump, I put power to it right at the last connector before the pump and not a sound or pressure. The car has a hotwire kit so it was a little more involved . Looks like I've got lots of time to drop the tank, it's snowing like crazy out !! Thanks for the help.

 

[87NAT]

My bad....meant to say injector pulse.

 

[pajo]

try

Hey Dyno try this -- before you drop the tank completely, unplug your pump and the tank and have somebody turn the ignition on for you and check for juice or voltage at the plug comming from the relay.Just my two 0.$.

 

[dynoman]

After pulling the tank & pump assembly I found the problem. It was a bad connection on the bulkhead fitting. I touched power to just the pump and it ran. I ordered the tank harness kit from Racetronics to complete the hot wire kit thats already installed. Thanks again for all the help. Sam