[Thomassen]

Hello everyone,
I am planning a trip from the Netherlands to Italy this summer and I would like to go with my beautiful p38. Before I go on holiday however there is an issue to be fixed.
When it is hot outside (>25 Celsius) it has problems starting up (it is standing in the sun). It starts but there is a lack of power and it wants to stall. Also when in a traffic jam with warm weather and regular weather (havent been in a traffic jam while it is cold outside) it starts doing the same, lack of power and almost stalling. If I shut down the car and start it up again the problem is still the same. If I start driving again it slowly goes away. The temperature meter isn't going past the halfway point!
Also very important to mention. The car is a 4.6 with a Prins VSI LPG system and all of the previously mentioned problems occur both on LPG and petrol.

I hope someone can help me out!

Hidde

 

[mad as]

sounds like a fuel problem check pressures 38psi on fuel rail for petrol do not know about gas, somewhere to start

 

[chris no 10]

As it’s doing the same on petrol or lpg, I’d suspect either a sensor ( cps or tps ).
the cps is known for breaking down when warm, is easiest check is get the car warm until the problem appears, spray some water on the cps to cool it down and see if it improves.

 

[marty_nz]

If it's a Bosch Motronic system then I'd be looking at the MAF sensor. I had issues with mine when I first bought it that it would run lumpy as anything and try to stall itself at idle. Tried changing a number of sensors, and eventually the MAF made a difference.

Also from my experiences - cheap aftermarket MAFs on the Bosch systems are no good - they aren't made to the same tolerances as the genuine Bosch ones, so it's worth paying the extra up front, rather than having to do it all again!

Also, I was having issues on mine (Bosch system with LPG) where the LPG tuning was out a bit, so it was causing the petrol fuel trims to drift (the LPG systems just piggyback on the petrol system and most of them won't do their own adaptations - so if the LPG map is out, it will bias the fuel trims). I had issues at idle and with it feeling gutless once the fuel trims had adjusted so much they were at the end of the adaptivity. Resetting the adaptive values, and giving my LPG system a bit more of a tune, so it was running more in line with the petrol side of things has cleared that up for me.

As Chris says, the crank sensor can fail too, when warm - though in my experiences, this usually results in the engine stopping, or if you shut the vehicle off, it won't start again when hot - but pouring water over the crank sensor is enough to cool it down and allow the engine to start again.

If you have an earlier GEMS vehicle, then ignore the bit about replacing the MAF at the moment - the GEMS ones seem to respond better to cleaning - so that would be worth trying first. Also on GEMS the IACV can coke up which will affect running at idle, but shouldn't make so much of a difference when you put your foot down! The LPG tuning is also something that could affect GEMS vehicles too though.

Hope this helps,

Marty