jcasey007
Well-Known Member
- Joined
- March 17, 2009
- Messages
- 523
- Reaction score
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- City, State
- Stratford Upon Avon, Warwickshire
- Year, Model & Trim Level
- Jeep Commander 5.7L HEMI
symptoms are:
when first starting up after leaving it for about 5 hours, the idle is very low and erratic, but only before the Lambda sensor is up to temperature. If I immediatly switch to LPG the idle is fine (even though the Lambda is cold)
I know it is linked to a cold lambda as I have a realtime air/fuel ratio meter that shows when the lambda is up to temp.
The lumpyness on petrol only lasts about 20 seconds (until lambda is up to temp) and then it is fine, Hot starts are also fine and a restart with the engine still cold is fine once the lambda is up to temp the first time.
I can also force the engine to start on LPG again no idle problem from cold.
I assume the PCM has a default fueling map which it uses before it gets a realtime signal from the lambda (exactly the same as the LPG controller).
I've done the usual (clean MAF, disconnect battery for 10 mins) checked fuel pressure) it's been doing it for months and is a pain in the bum
It's got me stumped, any idea's?
cheers
Jim
when first starting up after leaving it for about 5 hours, the idle is very low and erratic, but only before the Lambda sensor is up to temperature. If I immediatly switch to LPG the idle is fine (even though the Lambda is cold)
I know it is linked to a cold lambda as I have a realtime air/fuel ratio meter that shows when the lambda is up to temp.
The lumpyness on petrol only lasts about 20 seconds (until lambda is up to temp) and then it is fine, Hot starts are also fine and a restart with the engine still cold is fine once the lambda is up to temp the first time.
I can also force the engine to start on LPG again no idle problem from cold.
I assume the PCM has a default fueling map which it uses before it gets a realtime signal from the lambda (exactly the same as the LPG controller).
I've done the usual (clean MAF, disconnect battery for 10 mins) checked fuel pressure) it's been doing it for months and is a pain in the bum
It's got me stumped, any idea's?
cheers
Jim