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[feeutfo]

start up from cold in hot weather and my infrequent chug is becoming more frequent. Sounds and feels like a missfire but pedal trick gives constant flashing, no codes. Vibration from the engine and lumpy running with low tickover. When it starts normally from cold it ticks over about 800rpm. When chuging, about 600. Always seems to sort itself out within 30secs or so. Dont think the lpg/and anything i did to fit it is related as it played up a couple of times last year, pre install, again in hot weather, but some long cranking on the key as well. Not had that yet this year. Fuel filter changed last july along with plugs etc as part of the service. Think crank sensor is still original afaict.
Is this the start of a crank sensor issue? Or fuel feed issue maybe. As said. No codes. :-(
Cheers

Chris. :-)

[Marks DTM Calib]

Is your MAF beginning to die?

[Kevin Wood]

Mine runs a bit grumpy if it switches over to LPG too early due to already high coolant temperature. Is it doing it on petrol too?

Actually, didn't we crank up your LPG switchover time to avoid this?

Kevin

[feeutfo]

Mine runs a bit grumpy if it switches over to LPG too early due to already high coolant temperature. Is it doing it on petrol too?

Actually, didn't we crank up your LPG switchover time to avoid this?

Kevin

Yes petrol only issue.
Yeah we did increase switch over time, 15 seconds now. And recently ive been turning off the lpg on start up to eliminate it, then switch over to gas once its settled down, some times it comes back a fraction when gas does kick in, but not overly worried about that. So basically dont think its a gas issue. Petrol only.

Could be Maf. I am concerned about it as i found the jubilee clip, maf to elbow/ air box to be loose when i first got the car. Vx history. Monkey changing the air filter, i expect, and forgot to do it back up again. So its been sucking in air wrong side of the filter but before the maf.

If it is maf, and continues to deteriorate, expect a fuel trim code, i guess? On the other hand the car has been heavily monitored via tech 2 since ive had it. Fuel trims where very close to 0%. I think Kevin tech2'd it about a month ago, and the issue has been there since last summer(3 or 4 times on hot days only) however weather was not hot on when tech 2 was connected and engine was warm. It only plays up when engine cold and air temp is about 20c. 19 on the cid last time. I keep pedal testing but still no codes. Strange.

[Kevin Wood]

Correct, a fuel trim error will be raised eventually if the MAF is playing up, but I recall being impressed that the fuel trims on your car were fluctuating only slightly  and centred around zero when we mapped the LPG.

Inlet air temperature sensor (built into MAF) is a possibility. Would make very little difference to the fuelling once up and running, especially once the Lambda loops have closed, but might significantly affect the startup enrichment strategy.

Kevin

[feeutfo]

Correct, a fuel trim error will be raised eventually if the MAF is playing up, but I recall being impressed that the fuel trims on your car were fluctuating only slightly  and centred around zero when we mapped the LPG.

Inlet air temperature sensor (built into MAF) is a possibility. Would make very little difference to the fuelling once up and running, especially once the Lambda loops have closed, but might significantly affect the startup enrichment strategy.

Kevin

Can tech 2 read the air temp the maf is seeing? Would have to reproduce conditions when tech 2 present i guess?

Friend of mine has a lexus that behaves similarly. But leaving the car long enough for the dash lights to got out seems to solve it. Lexus forum suggests fuel injectors need time to prime? Not had a chance to play wi.th mine that way yet. Anypoint?