Hello everyone,

I would have like to have made my first post here under better circumstances but unfortunately my introduction to this fine forum is in the form of a cry for help.

I have a 1997 4.0l XJ Cherokee with a single point LPG conversion. Fuel is so expensive here in the UK that LPG at almost half the cost of unleaded makes running the 4.0 Jeep just about feasible.

Earlier this week the XJ suddenly decided to run rough and lumpy whilst on my way home. 2 miles from home I thought I would ease it home and take a further look. Half a mile further down the road there was a horrible clattering noise which to me sounded like a rod being thrown. I coasted to a standstill after suffering a loss of power and eventually the engine cut out.

I feared the worst and walked away from the Jeep with steam coming from the underneath the right side of the hood. I returned to the vehicle and checked the engine bay. No holes in the block as far as I could see, promising. Oil level was a little low as was the coolant level. It was getting dark so I thought I'd return in the morning. I disconnected the battery just in case the steam/smoke I saw earlier had any connection to something electrical.

It's been a few days since that happened and I went to investigate further this morning. I topped up the oil and coolant and decided to start her up. To my surprise there was no rattling/clattering and it started first time. Upon blipping the revs it switched over to LPG and it idled fine. I left it running until it was up to operating temperature and decided I would take it for a spin.

It pulled away fine and drove without issue for about a mile when I slowed down for a junction. The revs then dropped and the engine stalled. It refused to start and I blocked the road for several minutes as I attempted to get it started again. Eventually it started and I pulled into a side road so as not to cause any further obstruction. Momentarily the Jeep felt fine but not long after the lumpy rough characteristic returned along with a loss of power. A few hundred yards down the road it cut out again and I popped the hood to investigate.

The coolant level seemed fine although there was a drip coming from the lower rad hose which I've never seen before. I also noticed that there was oil seeping from the assembly which attaches the oil filter to the block. I undid the oil cap to see what lay beneath. Nothing mayo/chocolate milk looking but it was quite smoky. Generally the engine seemed particularly hot considering its short period of use, hardly a scientific observation I know...

I repeated this cycle two more times in order to get it home and the symptoms remain the same. I have absolutely no idea what it could be and I would really appreciate any advice or pointers from anyone who may have a clue as to what may be wrong.

I've attached an image of the engine compartment to illustrate the LPG install and how if differs from an OEM set up.

Thanks all

 

What is an lpg lol i'm not familiar... You might need a different ecu or something if it's messing up fuel regulation or something

 

Ha! I did wonder momentarily if Liquified Petroleum/Propane Gas has purpose in powering cars trans Atlantic. Pretty popular conversion over here especially on Jeeps (well, anything that struggles to get 20mpg). Regular unleaded here in London is currently £1.35p/l which works out to be $2.17 thus equivalent to $9.77 per gallon.

The conversion was done back in 2001 and has never been cause for concern. If anything it runs smoother on the 'lpg' than on normal fuel.

 

Check all of your sensors and connections. Check the fuel pump for the LPG system and all electrical for it. something may have cracked or maybe our doesn't like the heat. Btw, I payed $3.59/ gallon yesterday.

 

Right after it dies, disconnect one of the primary fuel lines on the fuel rail, there's a quick-disconnect plastic fitting, and see if fuel comes out. Do this with the ignition off and with a rag underneath.

 

Thanks, I'll need to go through the check list with a finer toothed comb. My initial suspicion was a blown head gasket but there's no obvious overheating issue as of yet although there is the new leak from the lower rad hose to consider.

Any other shared experiences would be appreciated. I can run the Jeep without the LPG system and the symptoms are all still there so although I'm not ruling it out I don't think it's the culprit.

If our fuel prices were in line with the US there would be no such thing as LPG and I'd run my V8 as a daily driver. Maybe it's time to emigrate...

 

May give this a try tomorrow. Am I checking to see if it's being starved of fuel? Will have to see how the LPG install affects this if at all.

 

Yes, you're checking to see if it's dieing due to lack of fuel. I wouldn't mind driving a V8 everyday, and yes, you should move here. You can defend yourself with a gun fairly in many states.

 

LOL I quite like having to not defend myself at all but that's not to say I wouldn't like to own fire arms. Purely for their aesthetic value if anything

So potential fuel starvation issue once the vehicle has been on the move for a few minutes, regardless of whether it's running on unleaded or LPG. Sounds like progress. Anymore for anymore?

 

My mom's ford pickup had a bad ignition coil. it would die after getting warm and wouldn't start until it cooled off, but it would just switch off, not sputter and die...

 

$3.65 /gallon 235 miles = about 10 MPG haha I might need a tune up..

 

You can get an OBD II scan tool and check for problems from the computer's perspective

 

I have OBDII hardware knocking around somewhere but not a laptop of required 'vintage' to run the software. I should sort this out, it should come in handy.

Oh, you guys need to stop your gloating with your fuel prices. It's making me feel extremely hard done by!

 

Lol I go four hundred miles - plus on a twenty gallon tank

 

Yeah, definitely break out an old laptop and get the computer codes.