Hi people. I really need some help with my car. It is currently 300 km's from home, stuck at a friends house because it wont start. This is the story so far.
While on holiday at a relatives place my mum tried to move my car, it would not start. She called me and I went to look with my cousin who is pretty good with cars.
The engine turns over but would not fire. We can smell fuel out the exhaust and pulling the plugs showed fuel on them (the plugs are new). We checked the ignition and it seams ok. All plugs are sparking. My cousin checked the injector pulses with a tester and they showed ok. We checked the fuel pressure out the pump and it was ok. Now for the strange bit. We can actually get the car to start by pulling the plug off the fuel pump. It will start and run till it runs out of fuel. Putting the plug back on makes it not start again. We got it running by pulling the plug off, starting it and when it was running putting the plug back on. It seamed to run ok but lifting the accelerator pedal resulted in the engine stopping I.e we can get it to run but not idle. It does not blow smoke like it is running too rich. We even borrowed a computer out another magna with the same result. My computer started the other car fine.
Because of the location I cannot put a computer on it to check codes or anything like that. Any tips would be great.

So did you have a flat battery or anything..??? Also check the two fuses in the engine bay fuse box that sit inside the little yellow fuse holder that holds the two fuses together.

Would really help us if you can please advise on what model you have

Would really help us if you can please advise on what model you have

It's a 1998 (TE I think) 3L V6 auto. The battery was not flat and we checked the fuses and they were ok. In summary.

Turns over but won't fire.
Disconnecting fuel pump allows engine to start but won't idle.
Reconnecting it again causes engine to not start again.

Injector pulses seam ok
Fuel pump pressure seams ok
Ignition seams ok
Computer replaced and fault remains
Fuses ok
Battery not flat
No engine check light

Any ideas?

When was the last time the fuel filter was replaced?
Have you checked out the MAF sensor? Maybe try cleaning it with some MAF cleaner/spray.

Hey mate. Got the same problem at the moment, and I think the problem is the wiring somewhere inbetween the ECU to the Immobilizer, my car wasn't starting for a couple of days, and I threw in a Scanner Tool and bypassed the Immob first time cranked it started right up. So that's where you should start, check all the wiring.

Sounds like an immobiliser issue. Lock and unlock the car. You might be surprised.

IF there is an injector pulse (which by the sounds of things there is) then the immob has absolutely nothing to do with this at all. Immob cuts injectors, no injectors no start regardless if the pump is plugged in or not

I would be doing a fuel line pressure check with the engine switched off. May be a case of the fuel pressure reg being jammed, floods when tries to start thus the pump being disconnected allows the excess fuel to bleed off and the engine fires, once running and fuel pressure is gained again the engine can cope with the extra fuel while revving but then stalls out when back on idle as again is way too rich.

Can you explain your reply in a bit more detail. Did you connect a scan tool and pull a code, and how do you then bypass the immobiliser? I have code 54, (immobiliser), but have read the imobiliser cannot be bypassed in any way.
Thanks

Mine is fixed now mate, she's running perfect again. Tell your mechanic to check the wiring in the ecu, mine has loose wires that were causing it to short which was telling the immob not to start. :)

Hi JakeyC. Do you mean the connectors to the ECU, or wiring within the unit itself? Did your mechanic have to pull the ECU out, or did he work on it insitu? Thanks for any help.

Connectors to the ECU i'm pretty sure, and I don't think he did no. Check the wires around the immobilizer too, it's the immobilizer that's giving you grief, nothing else. It's shorting out somewhere and in my case and in yours there are loose wires floating around somewhere, that's why it will only start sometimes when it doesn't decide to short out.

Car starts when fuel pressure is reduced, is not the immob as the immob CUTS fuel pulse regardless if the pump is plugged in or not, it cuts the injectors

Then how is mine fixed when we fixed the immob wires lol

Because you had a different issue, not every non starting magna has immob issues, comes as a shock I know but can be many other reasons as well

Simple, if was immob in this case car would not start when pump was disconnected full stop other than for perhaps a second to clear fuel poss from a dribbling injector

To rule out the battery as a problem and further point towards the immobiliser, wouldn't it be feasible to connect your battery to another vehicle while attempting to start, thus ensuring you are not dropping voltage while cranking?