P38 woe - diagnosis ideas please?
Discussion
I know that major P38 problems can pretty much arise from anything from a split pipe all the way through to the dreaded cracked block or ECU issues etc etc, but I'd be grateful for any ideas on my current predicament whilst I wait for the mechanic to come back from holiday....
Was driving along motorway in France at 70, aircon on interittently. Had travelled several hundred miles and the weather was hot. Mid day, and the engine started spluttering and misfiring, so moved into slow lane. Engine temperature was bang in the middle where it should be, and there was plenty of fuel. Not wanting to stop on side of road, I managed to work out that if I kept the revs high, the car could continue to drive smoothly. Therefore dropped it into 2nd gear, and drove at about 4000 revs (doing 40/50 mph) for several miles until a service station luckily appeared. Once I pulled in and the revs dropped down again, the engine died. There were no warning lights showing. Thereafter was towed off the motorway on a flat bed recovery truck.
The engine will start, but misfires badly and has no power whatsoever. It you try to increase revs, it dies. The car has fuel, and water and oil levels appear fine. Spark plugs have been changed, but to no avail.
I'm guessing it could be as simple as HT leads, but also possibly ignition coil or lamda sensor?
Any other ideas please?
Many thanks
Was driving along motorway in France at 70, aircon on interittently. Had travelled several hundred miles and the weather was hot. Mid day, and the engine started spluttering and misfiring, so moved into slow lane. Engine temperature was bang in the middle where it should be, and there was plenty of fuel. Not wanting to stop on side of road, I managed to work out that if I kept the revs high, the car could continue to drive smoothly. Therefore dropped it into 2nd gear, and drove at about 4000 revs (doing 40/50 mph) for several miles until a service station luckily appeared. Once I pulled in and the revs dropped down again, the engine died. There were no warning lights showing. Thereafter was towed off the motorway on a flat bed recovery truck.
The engine will start, but misfires badly and has no power whatsoever. It you try to increase revs, it dies. The car has fuel, and water and oil levels appear fine. Spark plugs have been changed, but to no avail.
I'm guessing it could be as simple as HT leads, but also possibly ignition coil or lamda sensor?
Any other ideas please?
Many thanks
What did the old plugs look like? Wet with petrol? Difference in colour? Any of them looking unusually clean compared to the others?
Compression test carried out? If not, do one.
Try removing the fuel tank cap. Does the in-tank pump sound OK or rough?
After that you need to get a diagnostic done as guessing & changing parts at random isn't the way to go so you may be best waiting for the mechanic to get back.
Compression test carried out? If not, do one.
Try removing the fuel tank cap. Does the in-tank pump sound OK or rough?
After that you need to get a diagnostic done as guessing & changing parts at random isn't the way to go so you may be best waiting for the mechanic to get back.
Edited by paintman on Monday 24th August 17:29
I have a p38, and this isn't a problem I have experienced on that car, but the symptoms do sound familiar as had it on another car I had.
It could possibly be the pressure return valve on the fuel rail. When this doesn't regulate properly, the injectors don't receive enough fuel. Strangly when rev'ed the fuel pump delivers more fuel, enabling sufficient to keep the engine running properly.
Just a thought may help with your diagnosis of the problem.
It could possibly be the pressure return valve on the fuel rail. When this doesn't regulate properly, the injectors don't receive enough fuel. Strangly when rev'ed the fuel pump delivers more fuel, enabling sufficient to keep the engine running properly.
Just a thought may help with your diagnosis of the problem.
So french mechanic has now looked at the car. He said that it starts fine when it is cold, but that the trouble starts as it warms up. It won't start agains once it is hot.
It's not throwing any fault codes on the diagnostics. They think its the ignition coil, but are not 100% certain, so have suggested starting by replacing this as a process of elimination.
I think that I've read somewhere that an ignition coil fault won't trip any warning lights, so this sounds promising. Can anyone say whether the symtoms that I got are consistent with this?
Cheers.
It's not throwing any fault codes on the diagnostics. They think its the ignition coil, but are not 100% certain, so have suggested starting by replacing this as a process of elimination.
I think that I've read somewhere that an ignition coil fault won't trip any warning lights, so this sounds promising. Can anyone say whether the symtoms that I got are consistent with this?
Cheers.
I know that people don't always update threads like this, so I thought I'd share. After initailly trying to fleece me 660 euros for a new ignition coil without labour (available for around £80 online!), and after having received my suitably robust letter in response, the french mechanic looked again and traced the fault to the crankshaft sensor, and a more reasonable 150 euro remedy.
Went back down to collect the car yesterday and it didn't skip a beat on the drive back up to the ferry. Moral of the story - don't break down in France!
Went back down to collect the car yesterday and it didn't skip a beat on the drive back up to the ferry. Moral of the story - don't break down in France!
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