Fuel Pump 3000gt VR4

[Nappien]

How can I check if the fuel pump is working?

I changed the IAC because of my car stalling. After the change I cant get my car to start again. I have a AEM EMS connected to where the ECU was.

Can it be a fuse thats the problem here? or one relay im not thinking about.
I can hear a relay clicking on the passanger side(MFI relay?). and there are some relays in the enginge compartment clicking when i turn the ignition key.

[Steve '92ES]

The easiest way to check the fuel pump is to locate the 3 test connectors located on the passenger side firewall tucked down beneath the wiper motor.
test1s.jpg
The wire with the black connector goes to the fuel pump (the tan is for setting timing and idle, the blue is the tach signal).
Take the cover off the Black connector (if it's still there) and connect a voltmeter to it.
On a stock system (I'm not sure about how the AEM works) there should be power on that connector WHEN YOU CRANK (turning the key on is not enough on a stock system). If there's no power you need to look at the fuses and/or MFI relay. If there is power than the fuel pump is getting turned on as expected.

The other thing you can do with that wire is test the pump itself by connecting it to the battery (+) with a jumper wire, which is handily located right near it. With battery power connected to the test connector you should be able to hear the pump humming in the fuel tank, and at least on the turbo models, you can hear fuel circulating through the fuel pressure regulator.

Good luck!

[mb3000]

With the default EMS settings the pump primes before initial cranking. Unless you messed with the settings, it will turn on with the key in the acc position.

[Nappien]

OK so i checked the fuel pump. I hooked up the black test connector to the (+) terminal on the battery and I could here the fuel surging.
But i cant hear the pump when I have the ignition in just ON, if i try to crank and release i can hear the pump(not sure if its actually running for 3 sec just by having the ignition in ON)

I get about 40psi/45psi when i try to crank.(pic only showing 20psi due to drop).


I can hear the MFI relay click.

Im not sure if i can hear the fuel relay click..but Im guessing its working when the fuel pressure is increasing.



Tomorrow im getting help to check for spark..maybe thats the problem?
What fuse should i look at? I found one fuel fuse in the main box in the engine compartment and it is ok.

thoughts?

[mb3000]

Bypass the relay in the engine bay, if you haven't already done so.

[Nappien]

isnt the relay working when i the fuel pressure is increasing and i can hear the pump when i try to crank?

so what you are saying is that it has to run before you crank, for 3 sec like normal?

[mb3000]

Stock it does not. With an EMS it does.

[mb3000]

Usually I let the pump prime before I crank. I have my settings set to 4 seconds. This fills the system with fuel and allows you to have a somewhat constant cranking condition.

[Nappien]

I want to check the fuel relay, before doing the bypass.

how do i hook it up with a 12V power supply? is it (+) to pin 5 and (-) to pin 1? how to check the continuity?

i heard that the fuel pump doesnt prime on our cars before cranking? i cant remember if it does or not when you have ignition in acc

[Steve '92ES]

Well, like I said I don't know much about the EMS but I think your problem is there.
Here's what I'm thinking..
With a stock system the fuel pump turns on with the starter relay. Once the engine starts the ECU takes over and keeps the pump running. There is no priming.
From what MB3000 is saying the EMS takes over right away, as soon as you turn the key on, and primes the pump.
From what you're saying it acts kind of like a stock system, with the pump turning on and off with the starter but without either an ECU or an EMS taking over to prime the pump and keep it running.
In other words there's something wrong with the EMS. It's probably not doing other things either, like turning on the injectors or spark.
I suppose this is kind of a Duh! post, since I admit I don't know anything about the EMS but I don't think your problem is a relay or the pump. I think it's the EMS itself. Check to make sure it's getting all the power it needs, and that you haven't knocked loose any input signal it uses (if this is a '91 or '92 the cam sensor is right near where you were working on the IAC..)