I just finished a a4 to m6 swap and a motor swap at the same time. The only thing holding me up now is the fuel pump. The pump itself works outside of the car, but it isnt pumping fuel when in the car. The fuse up front is not blown and there is no problem with the relay up front. Does anybody know what my problem could be? The car ran before the swaps. Also the fuel guage shows empty even though the tank is 1/4 to 1/2 full.

 

Works outside of the car as in you're letting it run without it being submerged in fuel?

 

No I had it in the tank and hooked up a hot to it

 

Sounds like a wire's been pinched when you did the conversion then.

 

I dont believe a wire is pinched because when I bypass the fuel pump relay it will pump. I also just checked and fuel isnt the only problem. I am also getting no spark. Could this be a problem with the BCM? I did swap computers from a '00 a4 to a '00 m6 with a tune in it. BTW I have tried with both computers, no luck with either

 

Soooo then it could be the relay?

 

No we have switched with a known working relay.

 

You gettin any codes from this?

 

dunno it will be at my shop in about 5 minutes

 

The computer is not getting comunication to our scanner. Any ideas ?

 

Check the powers and grounds of the PCM. Make sure the grounds are connected properly to the back of the drivers side head. Sounds like the PCM is not activating the fuel pump relay. When you turn the key to the on position (dont try to start), have someone put their finger on the relay and see if it clicks as the key is turned on....after approx. 2 seconds it should click again and turn off power to the pump.

If its not clicking, the PCM isnt sending the signal, or it cant...IE broken wire, bad ground, etc.

 

it is clicking. We also have the ground on right. I am getting a good ground to the obd2 and a good power. Still no fuel pump turning on and we are also not getting any spark.

 

Do you have power at the pump when the relay is on for 2 seconds?

 

not sure yet i am going to check that next and the power at the crank sensor. I am getting the computer pin out right now.

 

ok i have the fuel pump working and good fuel pressure and still no spark. It just cranks and cranks

 

How'd you get the fuel pump working?

Are you getting power to the coils?

 

dunno the pump just started working. We are getting power to the coils but nothing out of them. We tested this through a modis and an ignition scope so we know there is definately no spark.

 

Crank the engine while monitoring engine RPM on the scan tool. Are you getting any RPM?...if so your crank sensor should be ok. Security lamp on by chance?...check that too.

With a test lamp connected to ground, probe both sides of the following fuses with key on engine off: INJR1, INJR2, ENG CTRL, ENG SEN, A/C CRUISE. If all the fuses dont light on both sides of the fuse, you may have an ignition relay problem.

If all fuses are ok, use the scan tool to make sure the ECT sensor is reading correctly. If the engine is cold, compare to the IAT sensor for a similar temp.

You may also try to disconnect the MAF and then try to start. Let me know what you find on these steps and we can go from there.

 

We have called it a night. Tomorrow we're going to change the ECT sensor and possibly the crank sensor (even though we were getting a reading). Any other ideas?

 

Alright get this. This morning i came in and checked a few sensors and tested the computer for power. Pin 57 on the computer. Anyways as soon as we cranked to see if the light would flicker on the test light it fired right off. So we changed computers to put the computer with the tune in it and same thing happened. No spark and no fuel so we tested the wire at the computer and it fires right up.