Hi All,

Quick question, posted here a while back about popping / missing P38 that I have had a load of work done to now (New Coil Pack, Plugs, Leads, lambda sensors) to then be told I had low compression. Head Gaskets done heads skimmed.

Long story short... running much better on petrol although still popping slightly. Cuts out almost immediately on LPG.

Have booked it in to have the LPG trim levels reset next week and was asked if I have had the adaptive values reset since the head gasket replacement....

I haven't! Do I need to? If so is this a plug in job?

Thanks guys

Hi,

When i had my HG's done i was told to run it on petrol for approx 30 miles to allow the fuel trims to re-set before switching to LPG. I was told no manual re-set was required & all has been fine with mine. Can you explain the 'popping' a little more?

I think I would want the adaptive values re-set after that amount of work.
The big problem with LPG on the P38 is that the fuel trims that tailor themselves to running on one type of fuel, are not suitable for the other type Hence, the car will probably never be as efficient as it could be if you were just constantly running on petrol and the ECU was adapting constantly as it should.

I always thought the adaptive values wouldn't make much difference.. but when I fitted a new Air Mass Meter on my 4.6, the thing wouldn't even run when it had warmed up.

Incidentally, I think the ECU learns its new trims within a few seconds of running.

I'd say yes. After changing the plugs, leads etc the ECU should be reset. This will clear any previous adaptive setting that might of allowed for any fault picked up previously.
This procedure resets the ecu back to factory settings.
The LPG complicates things a little & will need to be calibrated after a reset for best results.

Thanks guys, the LPG is due to be done on Tuesday so I better get the adaptive values done on Monday. Is it a main dealer plug in jobby?