Hi - new to this but here goes. I recently had a flat battery after not using 1993 Jeep Cherokee 4.0l HO auto transmission for a few days. I jump started it and it now runs fine on petrol. Problem is it wouldnt switch over to LPG at 2000rpm every time as it used to and when it did the engine cut out due to low revs. I drove for a bit and it did it again at 50mph going downhill into a bend (not nice as power steering and braking were greatly reduced). I think the ECU on the LPG side of things is the problem. It seems a bit better after a 40 mile journey but still not 100%. Will ECU relearn idle and mixture properties and get better with time? Also whats the best thing to do when an auto car stalls at 50mph - jump on brakes and wrestle steering wheel until I come to a stop?

 

you might not get loads of replys when it come to lpg here mate as most of the guys are in the states but there are some running lpg including me what kind of lpg kit do you have all i can say is i have had my battery out for a while and the lpg did run a bit funny for the first few miles but not to the extent you describe if its inproving give it a bit of time see how you go where abouts in scotland are you im in angus

 

I'm in Ayrshire. I thought I might not get much response but good to hear from yourself. I will give it a bit of time to hopefully "relearn" settings etc. But it still wont always switch over at 2000rpm and without fail so far everytime I blipp throttle (at standstill) to 2000rpm and let revs fall the engine stalls. I can of course "catch it" and keep engine running then everything seems perfect when out driving. I'm pretty sure the ECU has suffered some damage due to dead battery. System appears to be OMVL.

 

Just had a thought - surely if I run out of LPG car should automatically change over to petrol and not cut out completely. Why doesnt this happen when Jeep is stalling on gas?

 

mine wont switch to petrol if i run out of lpg it just dies and vice versa if switch to petrol it will just run out this is normal as far as i am aware im no expert on the lpg but give it time see how you go

 

Well if you two have similar setups but johnny's is idling lowering it may be as simple as needing a tune up (or seafoam), what's both your tachs read while running on LPG?

 

mine idles at 800rpm

 

Mine idles at around 800 on petrol and slightly lower (lumpier) at around 750 on lpg. Just been out this morning and car switched over perfectly and ran 100% on both fuels. Only problem now is on switchover if stationary the engine dies everytime - suppose I'll just have to catch it or changeover when moving. Does seem to be better though.

 

i allways switch over while moving as i have to stamp on the pedal to change while still remember it is designed to switch when engine is hot