Hi folks

 

My car has stopped firing. The PTU was replaced so I have narrowed it down to either the fuel pump or fp relay which may be busted. A replacement pump is on its way to me but I thought that perhaps it could be the fp relay.

 

How do you test the relay? Would bypassing the relay be ok?

 

I shall do an ECU test but sure it'll give code 55. Also I shall clean the temp sensor connector and others properly.

 

Thanks in advance

 

Van

could it not be your CAS?

 

Vijay

ECU gave code 55. Not thought much about the CAS, Vijay.

 

If the replacement fuel pump doesn't solve the problem then I'll check the fp relay then CAS & TPS. I suppose then it'll be the MAF.

 

Here goes....

http://home.swipnet.se/e-solutions/IdleTech2.html there's a bit about the CAS where Maciej says it might not show an ECU error unless you crank the engine while in test mode.

 

The MAF should still let your car rev to 2500rpm even if it's faulty.

 

Vijay

ECU gave code 55. Not thought much about the CAS, Vijay.

 

If the replacement fuel pump doesn't solve the problem then I'll check the fp relay then CAS & TPS. I suppose then it'll be the MAF.

 

Here goes....

Deffo test the other items 1st before replacing fuel pumps mate.

Just to add to maciej's great write up, when checking the CAS, (after marking 1st the position of the 3 bolts that hold it in position) pull the CAS out, turn iginition on and turn the spindle at the back slowly, you should here all the injectors "clicking" if you don't, then it suggests this is the problem, i'll happily send you a spare to 100% confirm if that happens.

As well as that, have someone turn the iginition on whilst your at the back of the car with yer head near the bumper or in the boot, you should here the pumps "buzz" for a few seconds.

Also the fuel pump control unit has been known to go bad without warning, this link should help you do a temp fix and prove if thats what it is.

http://www.aus300zx.com/tech/fpcu/fpcu-2%2B2.html for a 2+2

http://www.aus300zx.com/tech/fpcu/fpcu.htm for a 2 seater.

Finally, in the drivers footwell is a relay for the fuel system, which does not show as a fault on the ECU, though it takes a reading from it. My ECU had a fault some years ago and did not send a signal to the relay to complete the circuit, bridging the wires on the relay worked fine for over a year until i fiited another ECU, again this is easy to 100% confirm with another working ECU.

hth

cheers

smithy

Excellent work chaps.

 

I will earth the white wire to the fuel pump to give it full power and if it starts then I'll replace the fpcu. If this doesn't work then it'll be the fuel pump itself which needs to be replaced. Of course it could also be a faulty fp relay next to the drivers footwell above the removable panel for the fuse box.

 

Thank you Vijay and Smithy.

Well, I replaced the fuel pump and it still doesn't work. I then earthed the white wire to the negative battery terminal but still no go.

 

The fp relay made some clicking noises though. Can this be bypassed temporarily and how?

 

After this it will be CAS and TPS I guess.

 

Cheers

 

Van

As I recall there is also a fuel pump fuse in the small box in front of the master cylinder. Have you checked that? Mine kept blowing when I had a faulty pump. The fuse is a funny cartridge type shape with a window in the top...

 

HTH

 

Gareth

Gareth, I tried that already but will check again, cheers.

Well, I replaced the fuel pump and it still doesn't work. I then earthed the white wire to the negative battery terminal but still no go.

 

The fp relay made some clicking noises though. Can this be bypassed temporarily and how?

 

After this it will be CAS and TPS I guess.

 

Cheers

 

Van

Flippin eck mate, checking the CAS is only a 10min job with a 10mm or 12mm spanner, do that one.

Relay, you mean the one in the drivers side footwell ? if so when mine wasn't getting a feed, a wire was simply wedged in the back of relay to bridge the terminals and i ran it like that for over a year, you could of course whip the relay out and look for a matching type one within the car and swap em over.

smithy

Cheers Smithy. Will do.

are u getting a spark?

you seem to be going between the fuel and ignition systems. the fuel pump should still buzz as the ignition is turned on for the first few seconds whether the cas is working or not. and if your not getting a spark then theres little point in worrying about the fuel pump

the resisters in the controll module under the back seat burn out. as these cars work on negative feedback the only thing to do is ground out the earth side of the pump itself see if its working, check the operation of the relay in the drivers footwell.

if they are both working the controll module is black box material and i have never heard of the resisters being replaced.

You do know that there is a fuel pump control box, under the rear seat on the RHS if I remember correctly.

 

I'm not sure if it's your problem but they do tend to blow power transistors.

 

HTH

 

Tim

I have checked the CAS. Took it off and turned the spindle which created some clicking noises from the engine- resumably it was the spark plugs.

 

Also checked TPS was checked and seems to be ok.

 

When I turn the ignition to on, I do hear a quite buzzing noise from the boot (fp) which continues rather than stopping after 10 seconds. Could this be a problem?

 

I am running out of ideas now. I have booked the car in at Zedworld and hopefully Jeff will sort it out.

 

Thanks for all your advice.

Hi Van,

 

*UPDATE*

 

Your car sorted, fuel pump ecu was to blame. will call you Monday.

 

Jeff TT

Hi Jeff

 

Thanks! Excellent work.

 

I look forward to your call Monday morning.

 

Regards

 

Van