98 940 2.3lpt auto stalling, not starting

[zchael6]

Originally Posted by Laird Scooby

Cleaning the mating surfaces, even without heatsink compuond has almost given you a respite. However, experience has taught me that once they get so hot the car cuts out (not just misfires), doing this is only a temporary solution.

With that in mind, i'd fit the new one and call it good, keep the old one in the car for a while as a temporary working one in case it happens again - if it's still on a heatsink you can simply swap the plugs over for instant diagnosis if it stops.

Right with the old one in I braved a trip to the village shop. The car cut out again literally as I was wheeling the car into the parking spot at the shop! I whipped the old ignition amp out and put the new one in and the car started first time. It’s still running. See if she dies on the way home

[Laird Scooby]

Originally Posted by zchael6

Right with the old one in I braved a trip to the village shop. The car cut out again literally as I was wheeling the car into the parking spot at the shop! I whipped the old ignition amp out and put the new one in and the car started first time. It’s still running. See if she dies on the way home

That's pretty conclusive, would be surprised if it does it again Will.

[TonyS9]

Originally Posted by Rversteeg

According an official Volvo publication:
In the last series 940 (1998) Volvo changed the type of fuel pump from a gear type to a turbine type. The pump is smaller and lighter.
This turbine type pump was also supplied as a spare part to replace the gear type pump and could be installed in MY95 and later by using a modification kit.

This seems to have solved the problem of failing fuel pumps. It is of course anecdotal evidence, but after over 400K miles my 98 LPT is still on its original fuel pump (turbine). Moreover it is an LPG car, so it is not uncommon that the pump is running for a long time at (very) low fuel level, a condition it was not designed for.

I noticed zchael6 also runs a 98 940, so presumably with a turbine type fuel pump as well. A failing fuel pump therefore seems less likely.

Interesting, but I don't see how changing the pump bit would help if you still have a brushed commutator. Changing to a brushless type would help, but it would need driver to convert to 3 phase.

[zchael6]

Originally Posted by Laird Scooby

That's pretty conclusive, would be surprised if it does it again Will.

Right more updates!!

So the car got me out of the village shop, then about 200m down the road, it cuts out again. This time it doesnt restart. Then i replaced the radio suppression relay, still doesnt start, Then replaced the fuel pump relay (which was hotish) car still doesnt start.

So i replace the CPS at the side of the road, takes about 15 mins, thanks for the tip about the bolt! Managed to swap it over without dropping anything into the bell housing, a miracle.

Car started straight away! got me home which wasnt very far! Ill brave another test run tomorrow. Ill be screwed if it’s happens again as I’ve now run out of parts to swap in or out!

Here are a few snaps of the old CPS

[Laird Scooby]

Originally Posted by zchael6

Right more updates!!

So the car got me out of the village shop, then about 200m down the road, it cuts out again. This time it doesnt restart. Then i replaced the radio suppression relay, still doesnt start, Then replaced the fuel pump relay (which was hotish) car still doesnt start.

So i replace the CPS at the side of the road, takes about 15 mins, thanks for the tip about the bolt! Managed to swap it over without dropping anything into the bell housing, a miracle.

Car started straight away! got me home which wasnt very far! Ill brave another test run tomorrow. Ill be screwed if it’s happens again as I’ve now run out of parts to swap in or out!

Here are a few snaps of the old CPS

Doesn't surprise me one little bit WIll and was the reason Ash suggested getting the ignition amp module as well. I'd say it was fairly safe to say, now i've actually seen the CPS that both it and the ignition amp were faulty. It wouldn't have restarted instantly if the CPS had stopped working when you refitted the module as you found out yet did previously.

Hopefully that's the problem solved, keep us posted of progress, even if only to confirm it's still running as it should.

[zchael6]

Originally Posted by Laird Scooby

Doesn't surprise me one little bit WIll and was the reason Ash suggested getting the ignition amp module as well. I'd say it was fairly safe to say, now i've actually seen the CPS that both it and the ignition amp were faulty. It wouldn't have restarted instantly if the CPS had stopped working when you refitted the module as you found out yet did previously.

Hopefully that's the problem solved, keep us posted of progress, even if only to confirm it's still running as it should.

Thanks for all the time helping with this issue. I hope its sorted! If it isn’t then it doesnt matter i have time on my hands! It’s just the being stuck on narrow country lanes than is slightly anxiety provoking but better than being stuck on A roads or motorways!

Thanks again

[Rversteeg]

Originally Posted by TonyS9

Interesting, but I don't see how changing the pump bit would help if you still have a brushed commutator. Changing to a brushless type would help, but it would need driver to convert to 3 phase.

I am no electrical expert, but I do know that the start-up torque of a turbine pump is almost zero compared to a PD type gear pump. An electric motor will therefore need a much higher current to start up a gear pump.