Car stalling problem continues

[Dal]

*shot in the dark*

It's not had a new cat / exhaust recently has it? I had a Mondeo that would not rev as it had bit's old old broken cat clogging up the exhaust. Maybe rather than an input fault, it's an output restriction fault?

Like I said, just a thought.

 

[GenesisRed]

you're thinking exactly the same as me tbh... it HAS had a new exhaust recently... and it was fairly soon after that it all started going pete tong.

My first impression was that it was exhaust related, but would that make sense for the on start-up aspect?

Another thing to throw in there was that when the RAC guy had the computer reading what was going on, the variable valve timing shenanagans were - at idle - switching between high and low over and over. I've no idea when (if) the cam belt was replaced but could that be it? If so, that Puma is going no where for a bit...

or maybe a sensor / solenoid that tells the engine how much to send through?

sigh

 

[GenesisRed]

does the fact that the oil pressure light sometimes takes about 8 seconds to go out after starting (when warm) mean anything to anyone?

 

[danielz000]

hi mate

can't you get a bar on the engine and try and move it (to simulate torque) and see if it causes the problem? that would suggest a wire somewhere...

also, do you know anyone else with a puma? you could try starting both from cold and putting your hand over the exhaust and seeing if you can feel much difference in pressure... if not try again at 2/3k revs... maybe if there's less pressure in yours the exhaust is blocked...

both total long shots tho i guess...

oh one other long shot... disconnect the battery for 10 minutes...

 

[danielz000]

might also be worth giving your ICV a clean and making sure the throttle body ain't seizing... long shot again.

 

[GenesisRed]

Thanks Daniel, the idea of rocking the engine is a good one - i'll have a crack (or since the garage has it at the moment, i'll ask them to do it!)

Cheers

 

[yippeekiay]

A long shot from me as I'm not sure whether I read about a similar problem or not which ended up being the clutch sensor above the clutch pedal. Have a look at that and see that it's connected properly and not loose from it's bracket. It costs nothing to check so worth a look and may be the reason it all works fine when stood still but as soon as you try to drive it goes belly up.

 

[Voa]

does the fact that the oil pressure light sometimes takes about 8 seconds to go out after starting (when warm) mean anything to anyone?

Yes lack of oil pressure or faulty sensor, what is the mileage on you puma?

 

[GenesisRed]

About 85 from memory. Sounds worrying... i prefer the idea that it's the clutch sensor!

 

[Voa]

Has anyone tried to see if there are any error codes on the ECU ?

 

[Voa]

I guess you have checked the usual , oil level is ok ? Car isn't using a lot of oil? Oil isn't leaking? Car has had an oil change recently

 

[GenesisRed]

oil level is fine now, not using a particularly large amount (although it does like a drink), and no oil leak that i've seen.

Haven't had oil changed, but three seperate mechanics have said that its fine as it is - engine seems to function 100% - unless you're in the car!

I'll have a word with the garage tomorrow on their findings and run all of the above past them too. Thanks all for your help, and i'll let you know!

I think they were thinking along the lines of the variable valve timing being off... whatever the implications of THAT are! ( I dread to think )

 

[Voa]

lf it is in the garage ask for a compession test? just for peace of mind on the engine.

 

[mrMechanix]

Again a shot in the dark without being able to see it, but it could be your fuel pressure regulator. If the reg isn't maintaining proper pressure it may still have enough to rev while not under load then die when it wants extra fuel to move a car. Just a thought. Two bolts and a push on pipe changes it and most cars have the same type. Any would do to check it if your garage doesn't have fuel pressure testing equipment.

Again does it have any fault codes in the ecu? If it does tell us and we can point you in the right direction.

 

[GenesisRed]

the mechanic gave most of the sensible sensors a clean, and tested some things, but it looks like it comes down to the timing.

When the RAC guy put the computer in, it was reading - AT IDLE - that it was changing between high and low constantly. It shouldn't do that (should it?). That would make sense of the drop in power at the changeover threshold (about 60 in 5th), and also the inconsistency of when it happens (usually when the engine starts to take strain but not consistently then).

As for why it only does it when hot, i'm still not sure i understand.

So, the question is, what is it that would control that switching... ECU? is it an option just to switch it out? Or is it likely that, with all the changes its had recently, it just needs to be restarted (in which case, how)?

Thanks for your continued support and feel free to tell me i'm barking up the wrong tree if i am!

Incidentally, there is no tapping from the engine...

Cheers

 

[martinthrapston]

when and who last did the cambelt change?

 

[GenesisRed]

No guarantee that it ever has had it done. I bought it, very green, at about 75k on the clock, with no history. Are you thinking it could be slipping or something like that?

It's not making any bad noises, it all seems to switch between high and low with no problems, just possible that its doing it at the wrong times...

 

[GenesisRed]

A further though on reflection and research is the crankshaft sensor. The first time it broke down, it gave error code for that, so we had it changed but has made no/little obvious difference.

Since that sensor tells the ecu when to inject fuel and so on, could it be that it needs to be restarted to recognise the new sensor properly? Or is that sensor error message a symptom of the ecu going wrong (can they even go wrong)?

Or would the crankshaft sensor appear to read wrong if there were problems with the cam belt?

 

[martinthrapston]

need to do an ecu reset,disconnect for at least a min of 30mins,then reconnect,start engine and let idle for 5 mins then take for a gentle drive for 5 mins then it should start to relearn again and adjust to your driving style

 

[JonB]

I was just going to say,
"To reset the ECU you have to disconnect the battery for a while, I believe 10 minutes is the minimum time but I leave it for 30 minutes to be sure. Then you can restart let her sort out her idle for a while and recheck the error codes as the old ones should have cleared."
But as usual I type too slow and was not quite right.
It was quite common for my old Puma to throw up fault codes as sensors got dirty, usually a clean of the intake side of the engine sorted it along with an ECU reset.