P38 4.6 1996 Gems Not Starting Need Urgent Help

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DJ_B4L

DJ_B4L

New Member
Posts
118
Location
Kent Near Dartford Crossing
hi guys i got a 4.6 1996 Range Rover its converted to lpg

im having problems with it recently when i try to start it whether its hot or cold it doesnt start

i have checked & done the following

Swapped the Fuel Pump - it started one or twice but then back to square one

New fuel filter - started few times then same again

Had it tested on a Logic comp and No faults Found

Checked for spark all the leads spark when i tested them with a spare spark plug

Checked relays and fuses all are ok

Disconnected maf and same problem no starting

Checked 2 plugs and connectors on the intake manifold temp sensor and the one next to it.

Tried connecting direct earth from battery to engine same still no start

If i spray Easy start into the air intake starts each time and every time

what could be wrong

the second problem is once you get it started you cant drive it on petrol
it revs freely when parked up but when you drive off you cant rev higher than 2.5k revs as it just starts to pull back and wants to turn off and just pops like its got no power

if you take your foot off the pedal it will start going back to normal idle.

when i switch it to Lpg once it is started i can drive it on lpg with out no problems at all speeds.
 
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I have had the exact same problem, although it has only happend twice, and two months appart, not been able to trace the problem yet, it is however just a petrol fault, i am thinking it may be the maf sensor. i want mine to show the fault when i am off so i can trace it but no luck yet.

When it has played up i have started it on lpg by quickly flicking the lpg switch on the dash from lpg to petrol and back to lpg, do this with the ignition on just before you crank the engine, this should get you away if stranded some where.

Hope somneone else can come up with an answer.
 
Sounds like it is fuel related. Is your lpg system slaved off the petrol injection? Get the pressure checked at the fuel rail. Check the hose to the fuel Pressure regulator, make sure it is clear and not collapsed. Could be the pressure regulator itself.
 
overlandrover said:
I have had the exact same problem, although it has only happend twice, and two months appart, not been able to trace the problem yet, it is however just a petrol fault, i am thinking it may be the maf sensor. i want mine to show the fault when i am off so i can trace it but no luck yet.

When it has played up i have started it on lpg by quickly flicking the lpg switch on the dash from lpg to petrol and back to lpg, do this with the ignition on just before you crank the engine, this should get you away if stranded some where.

Hope somneone else can come up with an answer.
Click to expand...


hi mate thanks for the reply the only reason im not starting it on gas is because of the weather as it will freeze the vaporiser..

any one local to me at all who dont mind giving a hand or has any spare sensors i could try
 
rewmer said:
Sounds like it is fuel related. Is your lpg system slaved off the petrol injection? Get the pressure checked at the fuel rail. Check the hose to the fuel Pressure regulator, make sure it is clear and not collapsed. Could be the pressure regulator itself.
Click to expand...

hi mate yeah my lpg system is a bigas multipoint which slaves off the petrol injection.

il try and get the pressure checked and il check the hose to the fuel pressure regulator where abouts is it located on my engine?

couldnt be any sensor that could cause this?
 
From memory rear right hand side of the engine, check the Rave. If you have multipoint LPG, and it runs OK on gas then it stands to reason that the problem is with the petrol delivery system as the sensors and sparks are common to both. You have changed the pump and filter, so all that is left is the pressure reg and injectors. My money is on the reg.
 
hi mate just another thing i cant start it on gas stright what i have to do is if by luck it feels like it wants to start on petrol i quickly hold the switch down then it switches to gas

if i try pressing the switch frm gas to petrol then back and then try to start it doesnt

only way as i said above...

could a dirty or clogged injector cause this? i think it could be two injectors

any idea which injector the car starts from first or is it all squirt at once?

as i think it starts when you spray it couldnt it be 2 clogged/faulty injectors?
 
Hi, it des not start frm one injector then another the all working individually and pick up pulses as the engine is cranked over, so if at most two were faulty it would fire on the other six.

A problem that i have previously had was the fuse box under the bonnet, inside there, there is the fuel pump relay, amoungst others. the problem was with the circuit board, i have had it out and repaired it abot six months ago as it was causing gearbox problems, even though it has nothing to do with the gearbox. the majority of the under side of the solder joints were broken, i resoldered them and i has been good until last month.

the similar starting problem is petrol related as if the pump was going off intermittently, i fear the fuse board has developed problems again, a bad solder joint could be the cause.

you could try removing the fuel pump relay in the fuse box either swop the relay with another in the fuse box and also just slightly bent the pins on the relay to see if it makes a contact with the connections in the fuse board. you could also if quiet when near to your car, with the ignition on pull out the fuel pump relay and crank the engine then stop cranking and push the relay back in, you should be able to hear the fule pump prime up, may be best to get some one to go near to the fuel tank as the pump is in there.

the fuse box is not difficult to strip down to see any faults, the tricky bit is the repair, however i have just today ran the main stealer and ordered a new one, £129 + vat which is the cheapest price i have found for one.
 
overlandrover said:
Hi, it des not start frm one injector then another the all working individually and pick up pulses as the engine is cranked over, so if at most two were faulty it would fire on the other six.

A problem that i have previously had was the fuse box under the bonnet, inside there, there is the fuel pump relay, amoungst others. the problem was with the circuit board, i have had it out and repaired it abot six months ago as it was causing gearbox problems, even though it has nothing to do with the gearbox. the majority of the under side of the solder joints were broken, i resoldered them and i has been good until last month.

the similar starting problem is petrol related as if the pump was going off intermittently, i fear the fuse board has developed problems again, a bad solder joint could be the cause.

you could try removing the fuel pump relay in the fuse box either swop the relay with another in the fuse box and also just slightly bent the pins on the relay to see if it makes a contact with the connections in the fuse board. you could also if quiet when near to your car, with the ignition on pull out the fuel pump relay and crank the engine then stop cranking and push the relay back in, you should be able to hear the fule pump prime up, may be best to get some one to go near to the fuel tank as the pump is in there.

the fuse box is not difficult to strip down to see any faults, the tricky bit is the repair, however i have just today ran the main stealer and ordered a new one, £129 + vat which is the cheapest price i have found for one.
Click to expand...

il try and undo the fuse box to check the board any chance i run into any problems with any error lights coming on or need to resync the range with computer to get it working after disconnecting the fusebox
 
DJ_B4L said:
il try and undo the fuse box to check the board any chance i run into any problems with any error lights coming on or need to resync the range with computer to get it working after disconnecting the fusebox
Click to expand...

i did not have any problems like that, the only thing i had to do was put the radio code in as the battery had been disconnected, some may say you might have to do a re-sync, oh had to set the windows, but that is just open and close in one action on the buttons.
 
Has anyone suggested that the fuel 'trims' are out for petrol?

Basically when you are driving a long on petrol the ECU sets up the fuel injection to the right point and it constantly keeps a check on this. (but it never really varies much between two points) If running on LPG and and it's either running too lean or too rich (most likely too rich in your case) the fuel trims in the ECU will know from various sensors on the engine/exhaust that it's running too rich and will be trying to adjust the fuel trims to put less fuel into the engine, obviously the petrol fuel trims don't adjust the gas (unless there is some very fancy new piece of LPG kit that can do this) so the longer and longer you drive it the less and less petrol the fuel trims will be trying to put in the engine. Then when you come to start the engine on petrol there isn't enough of the stuff going into the engine to drive it and it cuts out. Yours isn't that bad, if it was bad the engine wouldn't idle on petrol.

BUT, gas is horrible when it goes wrong and running too rich or too lean on gas can seriously **** your engine. (slipped/cracked liners etc)
 
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Hello dj,
i'm only up the road from you , if its not sorted buy sunday i could pop round and give a hand , as they say 2 heads are better than one,, if thats any help, pm me .... Rob
 
My money is on the fuel trims, take it to LR and ask them to reset the fuel trims. It won't be cheap going to the main stealer and the car will run like a bag of ****e for at least 50 miles afterwards. Plus, you will need to drive on petrol for a good hundred miles from LR resetting the trims to give the fuel trims time to set themselves up. You need to do a mix of town driving and long distance driving to get a better result.

Go back to LPG and run on it for a while, if your original petrol problem comes back then you know it's the LPG running too rich.

I'm no expert on this but having owned a Disco II with LPG problems I got to learn quite a bit about it.

Give it a try, what have you got to lose? it's better to know for sure than buggering your engine.
 
I've just had another read through of your first post and am starting to think that it is an out of tune LPG system throwing your long term trims out as per Big Ps suggestion. Try starting on gas, if she's ok then I would get the adaptions reset and get your LPG reset , or better still get yourself the software and do it yourself, it's quite easy to adjust the carburation.
 
The_Big_P said:
Has anyone suggested that the fuel 'trims' are out for petrol?

Basically when you are driving a long on petrol the ECU sets up the fuel injection to the right point and it constantly keeps a check on this. (but it never really varies much between two points) If running on LPG and and it's either running too lean or too rich (most likely too rich in your case) the fuel trims in the ECU will know from various sensors on the engine/exhaust that it's running too rich and will be trying to adjust the fuel trims to put less fuel into the engine, obviously the petrol fuel trims don't adjust the gas (unless there is some very fancy new piece of LPG kit that can do this) so the longer and longer you drive it the less and less petrol the fuel trims will be trying to put in the engine. Then when you come to start the engine on petrol there isn't enough of the stuff going into the engine to drive it and it cuts out. Yours isn't that bad, if it was bad the engine wouldn't idle on petrol.

BUT, gas is horrible when it goes wrong and running too rich or too lean on gas can seriously **** your engine. (slipped/cracked liners etc)
Click to expand...

hi mate this might be related becuase i had the fuel trims checked by a lpg guy when the jeep was running fine on lpg and petrol back in July 2009
the guy did say one is different from the other by quite a bit. but at the time he suggested its not too much of a problem
 
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