Hello,
I was wondering if anyone could offer me some advice.
My Dad has a '91 940 GLE, 2.3 Litre with bosch fuel injection. It is also fitted with an LPG system.
The first problem is that it will not start. There is a spark, and fuel is reaching the fuel rail. It turns over but won't fire. However, it will fire if you spray 'quickstart' in the intake.
Once started, it runs reasonably well except that the emissions are high (CO varies between 2 & 6%)
The only fault code is for a rich mixture.
I've tried a few things, but to no avail. Replacing the MAF, for a known good one, seemed to bring the CO right down, but it went right back up again a few minutes later.
As the CO did come down, I assume the cat is fine.
I suppose a faulty lambda probe is a likely suspect for the raised CO, but could it be responsible for the starting problem?
Could the LPG system have a fault which would cause the problems?
Any help would be appreciated.

Hello,
Thanks for the advice.
Replacing the relay, as suggested, was one of the things I'd tried (I should have listed everything, but I tried so many things).
Anyway, I've now found that the fuel injection ecu was faulty, so I replaced it. The result is that it now starts and the emissions are legal (about 1%), but are still higher than they should be with the cat. Also, the idle is still rough when cold, particularly when it's in gear (auto), and it seems a bit gutless.
I'm fairly sure there aren't any induction leaks!
Do you think the timing could be out, and could that cause the symptoms?
Thanks,
James

I would suggest that the radio suppression relay is not allowing the injectors to pulse preventing the car from starting. I am not sure where your relay is located. The image below shows the location of the relay in a 1991 745 turbo wagon. Yours may be located there or beside an identical relay on the passengers shock tower (the second relay is for the auxillary fan on the radiator).

You can swap them out to check or simply remove the relay and use a piece of wire to "jump" between the female connectors of the two heavier wires on the plug. If it starts with the jumper in place the relay needs to be replaced or simply resolder the circuit board.

Good luck.

Randy

Hello, With the LPG system, your radio suppression relay plays a role in the ability to start. The rich condition may be caused by the temp sender not reading the engine temperature correctly You may also have a slight leak in the intake manifold gasket that would cause a lean reading on the "O2" sensor which would then cause the computer to richen the fuel mixture. Good luck, Pauli