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
Hi all
I've a 1997 Explorer 4.0 with dual fuel (petrol and LPG).
Whilst the LPG side has been running fine, over the last few months, I've been battling with the petrol side of things. So up until last week I had been making good progress, I've spend a lot of time on the inlet manifolds (I had leaks) and sorted that, I had a leaking injector so I fitted a set of reconditioned ones. All in all it was running very well on Petrol and passed the emissions test 3 weeks ago.
Then last week the Petrol running started going crazy and either running very rich or very lean.
I know this as I have fitted an O2 meter that shows real-time the feedback from the upstream Lambda Sensor. I fitted this in preparation for fitting a new gas vaporizer so I can set up the Gas mixture.
So the petrol side is doing the following, from cold, the mixture is spot on and stable, and it is running well, as the engine warms up, so the mixture control gets more and more erratic, swinging from very lean and very rich, If I switch to Gas (on the go) mixture control quickly stabilizes and is fine.
Last night running on petrol (as I was out of gas) it was running like a dog and I got a CEL which I read as P0175 (rich mixture)
Driving it on petrol, Acceleration is poor (feels like 2 cylinders are out) and it hunts when on light throttle cruise)
The closed loop gas system (which is fine) uses the TPS, tacho and Lambda Inputs so I know these are fine. I have replaced the MAF and intake air temp sensor, I have even looked at more inlet leaks so got the can or electrical cleaner out but no joy.
So where to look next, can someone tell me why it runs fine when cold? What inputs does the PCM ignore when cold? I have on order the Engine coolant sensor which arrives before Christmas, what else I should check please
Any help and advice appreciated
Happy Christmas
Jim
I've a 1997 Explorer 4.0 with dual fuel (petrol and LPG).
Whilst the LPG side has been running fine, over the last few months, I've been battling with the petrol side of things. So up until last week I had been making good progress, I've spend a lot of time on the inlet manifolds (I had leaks) and sorted that, I had a leaking injector so I fitted a set of reconditioned ones. All in all it was running very well on Petrol and passed the emissions test 3 weeks ago.
Then last week the Petrol running started going crazy and either running very rich or very lean.
I know this as I have fitted an O2 meter that shows real-time the feedback from the upstream Lambda Sensor. I fitted this in preparation for fitting a new gas vaporizer so I can set up the Gas mixture.
So the petrol side is doing the following, from cold, the mixture is spot on and stable, and it is running well, as the engine warms up, so the mixture control gets more and more erratic, swinging from very lean and very rich, If I switch to Gas (on the go) mixture control quickly stabilizes and is fine.
Last night running on petrol (as I was out of gas) it was running like a dog and I got a CEL which I read as P0175 (rich mixture)
Driving it on petrol, Acceleration is poor (feels like 2 cylinders are out) and it hunts when on light throttle cruise)
The closed loop gas system (which is fine) uses the TPS, tacho and Lambda Inputs so I know these are fine. I have replaced the MAF and intake air temp sensor, I have even looked at more inlet leaks so got the can or electrical cleaner out but no joy.
So where to look next, can someone tell me why it runs fine when cold? What inputs does the PCM ignore when cold? I have on order the Engine coolant sensor which arrives before Christmas, what else I should check please
Any help and advice appreciated
Happy Christmas
Jim
