Friday, April 24, 2009 - 08:51 am, by: Tim Appleton(Timbo)
Hi guys and gals. I'm having trouble starting my car at the moment and I suspect it's the fuel pump but want to get some ideas.
The problem started when the engine was warm. When going to restart it, it would fire but then cut out after a second or two. Usually letting it sit would fix it. Then it started to cut out while driving, at which point I bridged the diagnostics port and bought a new fuel pump ECU. I took a while to install the fuel pump ECU but then I had power steering pump / alternator issues so car has been off the road for a while. Now I'm getting the same issues with the B+ and FP bridged as I was before although it's intermittent. The engine will fire but then cut out after a couple of seconds. The new fuel pump ECU didn't fix the problem.
Could this be the fuel pump dying? I can't hear the fuel pump running as I used to when I first bridged the diagnostics port. I think a new fuel filter might be in order as well as it hasn't been changed since I've owned it. What other issues could it be?
Thursday, April 30, 2009 - 02:56 am, by: Michael Brown(Volksoarer)
Hey there mate,im having very similar problems. Try cleaning the idle stepper motor,make sure the top coil connecter is in all the way (the non ht one) and see how you go. Other than that,im lost. My car runns great,just no idle.
Mike Beck Goo Roo New Zealand Soarer Limited UZZ31 V8
Friday, May 01, 2009 - 03:12 pm, by: Tim Appleton(Timbo)
Thanks for the responses guys. I've now swapped in a new fuel pump and filter and that doesn't appear to be it either. I should have checked power to the pump with a multi-meter before installing all this stuff, would have saved me a bit but the filter was due for a change.
Michael, you can tell if it's getting fuel by checking the little screw on top of the fuel pressure regulator. It's on the back of the fuel rail on the passenger side of the engine. If it rises then it's got fuel, if it drops then you're not getting any fuel pressure.
Mike, I'll check all the ignition bits and pieces but I can get it to run with fuel so I'm leaning towards that side of things. Can't hurt to check ignition anyway so thanks.
Joe Russell TryHard Marlborough 4.0 V8 GT-L(UZZ31)
Friday, May 01, 2009 - 05:13 pm, by: Joe Russell(Joe_r)
Is it dying at idle or during throttle? If at idle/off throttle, check your idle air pipe(you too Micheal), it may be blocked. The idle air pipe comes of the intake just after the flexible connection from the afm and is the larger(diameter) of the two pipes attached to the intake.
Friday, May 01, 2009 - 07:05 pm, by: Tim Appleton(Timbo)
It's dying a few seconds after starting. I figure if it's the air pipe or the idle air control valve then I'd be able to keep it running by using the throttle, and it dies even with partial throttle.
Joe Russell TryHard Marlborough 4.0 V8 GT-L(UZZ31)
Friday, May 01, 2009 - 07:48 pm, by: Joe Russell(Joe_r)
Have a look just in case, also is your alternator ok now? Just suggesting from my own experience... lol. I just re-read what you've written, and its sounds like a heat related problem perhaps, is your cooling system ok? Maybe some wires have melted or something odd along those lines...
Tuesday, May 05, 2009 - 08:21 am, by: Tim Appleton(Timbo)
Thanks for the input Joe. The alternator was reconditioned and is charging fine. I'm suspecting it's a wiring issue now.
I've checked the voltage going to the fuel pump and it seems to die off once the engine starts. I've got to check the wiring diagrams but something in the system is causing the voltage to drop off. The fuel pump ECU has been replaced so I assume that's not it. I'm thinking maybe the main ECU is playing up. I still have to investigate but that's where I'm at for now.
Joe Russell TryHard Marlborough 4.0 V8 GT-L(UZZ31)
Tuesday, May 05, 2009 - 07:16 pm, by: Nathan Richardson(Richtheblack)
I have had similar problems. Mainly intermittent, but warm normally ok, cold wouldn't idle at all.
I cleaned and replaced the bearings in the idle stepper motor, problem fixed.
Loosing voltage to the fuel pump after start though is interesting. Maybe loss of RPM signal? But I would think that, that would come with other problems as well.