3.5 V8 EFI trouble

Ok, this is my Dad's car- and he's the real engineer not me, but I have the computer.

He is annoyed that he can't figure this out himself, but I've told him there are loads of experts and people who have had problems on here and experience from fixing them.

He has a 3.5 V8 EFI. It has professional gas conversion.

He doesn't think this is a gas problem, but I'll let you decide.

He got shunted up rear the other day and since then has had problem, but could be coincidence.

Engine will start, EVENTUALLY. Not its usual self at all. Once started, it is rough, he can get it up to 2000RPM eventually and then it switches over to gas and runs ok.

Flick switch to go back to petrol, and it stalls. So it is not running on petrol properly at all in other words. He says you guys may say "check your injectors" - but he doesn't have the gear for that.

We were kind of hoping someone might have an idea what's going on coz he is going nuts trying to figure it out.

He has checked the 'electronics pack' under the MAF meter - taken apart and cleaned, but it has made no difference.

He has borrowed a fuel pressure gauge, but needs to make an adaptor to use it (he is on the lathe now I think).

Thanks for any answers.

Have you tried reseting the fuel shut-off solenoid? Its designed to shut the fuel supply off in the event of a shunt. In a post '95 model, its under the bonnet behind the washer resevoir. Earlier models had it under the drivers dash, left of the steering column. Press the rubber tit on top should reset it.

He says the engine wouldn't start at all if that was the case and the engine does start after a few goes, just not run for long.

After a day of looking with 2 or 3 mates round (all LR nuts) he has decided to do a pin check from the back of the ECU - I just need to print off the pages from a manual for him to read off the voltages.

Hopefuly it will yield some clues - a real tricky one this.

Still no joy today.

Mate has given me the wrong manual on cd rom so couldn't do the continuity test procedure to figure out what the pins were saying.

Fuel delivery is ok.

Runs on gas ok, so ignition system assumed ok.

Starts on petrol after loads of cranking.

Real haed scratcher for us this one.

Oh for the old Series 2 landrover with carb and distributor.