After asking lots of power engine lacks it

[JaapRoskam]

Hi all: I have a Range Rover 3.5 with LPG. A while ago I had to race after some bulls , the engine revved very high and pulled well. But ass soon I drove normal again the engine sputtered and had no power at all. Since then it remained troublesome. On the Hwy it cruises OK but as soon I aks power ( uphill , rough terrain ) it protests and lacks power. So I worked my way trough the ignition system , replaced some parts , it made no difference. Then re-adjusted all I could on the LPG system , wow that made the engine a lot better , it now goes well uphill , and permits some power usage in rough terrain. But as soon I go into high usage , ( getting uphill out of a bog for instance ) the engine sputters as before. When I switch off the gas a few seconds by placing the gas / petrol switch in neutral , and then revert to gas the engine is back to normal and ready for the next heavy pull... Where should I start to clear this issue?
I never had this with my old County on LPG , the difference between the two is the gas line from tank to converter. The County had a fairly wide flexible hose. This range Rover has a fairly narrow copper line. ( inside about 4-5 mm ) . Could that be a clue ? Any advise will be greatly appreciated. Thanks !!

[bee utey]

Hi all: I have a Range Rover 3.5 with LPG. A while ago I had to race after some bulls , the engine revved very high and pulled well. But ass soon I drove normal again the engine sputtered and had no power at all. Since then it remained troublesome. On the Hwy it cruises OK but as soon I aks power ( uphill , rough terrain ) it protests and lacks power. So I worked my way trough the ignition system , replaced some parts , it made no difference. Then re-adjusted all I could on the LPG system , wow that made the engine a lot better , it now goes well uphill , and permits some power usage in rough terrain. But as soon I go into high usage , ( getting uphill out of a bog for instance ) the engine sputters as before. When I switch off the gas a few seconds by placing the gas / petrol switch in neutral , and then revert to gas the engine is back to normal and ready for the next heavy pull... Where should I start to clear this issue?
I never had this with my old County on LPG , the difference between the two is the gas line from tank to converter. The County had a fairly wide flexible hose. This range Rover has a fairly narrow copper line. ( inside about 4-5 mm ) . Could that be a clue ? Any advise will be greatly appreciated. Thanks !!

The 1/4 inch gas pipe is adequate for a 6 litre engine. LPG is very free flowing. You might have a blocked filter or the valve at the gas tank end is tripping the excess-flow valve. When you next run out of power, pull over and leave the engine idling. Feel the main gas lock under the bonnet,then the gas valve at the LPG cylinder. If either is colder than the surrounding parts, ie dripping dew or ice covered, you have a blockage/tripped valve.

Also what is the brand/part number/gap of the spark plugs? They are a major cause of power loss problems on gas and need to be chosen carefully.

Oh and pictures are always helpful in identifying your type of gas system.:)

[JaapRoskam]

Thanks , that will be a good point to start the day with tomorrow. Will keep you updated and we'll solve it. Cheers; / Jaap

[JaapRoskam]

Well that turned out a bigger job as thought: Did the same trick , revved high up our hill , engine worked ok ten started to sputter. Quickly got out to feel the valves for freezing. Then the engine stopped ... for ever . Never got it going again. Completely puzzled. It always started first time. Ignition again checked - Spark very strong - Timing spot on - LP Gas reaches carbies. - Petrol pored out when I undid fuel line. Just before the engine stopped , at high revs I heard a sound as if a piece of paper got caught in the fan. A few seconds only , could have been leaves I thought then. Today took the manifold off , checked the valley cover tin. Cleaned what ever I could clean. Checked compression all OK . Checked movements of rockers - all OK. Then checked the timing chain. It has a slack of a about 6-8 degrees on the crankshaft pulley. Is that to much ?
Anyway the spark-plugs: NKG- BP6ES - 0.75 mm ( 0.030 " ). The LP converter is an Italian one but could not find a real brand name.
Tomorrow re-assmble by the book .... xFingers please ;-)