Range Rover fuel problems
Discussion
I’ve got 3.9 V8 Rangie that refuses to start, the ignition system is in tiptop condition, this leaves the fuel/EFI system. I’ve gone through all the checks in the manual for the multiplug on the back of the ECU and come up with nothing wrong. So next suspect is fuel pressure, the only fuel pressure testers I can find are £400+ so that’s out of the question. Any one know where I can get one a bit cheaper?, for that price I could change the pump and regulator and still have plenty of beer money. The pump primes when the ignition is switched on, does this turn of after a set time or when a pressure has been reached? If so is there a pressure switch for it that can be checked. Would trying to start it by pressurising the fuel line (with fuel in) with compressor damage the injectors?. Would taking the fuel return pipe of the regulator and changing it for blanked pipe damage anything? And would this prove the regulator faulty? Any help and advice would be appreciated.
Ta, Rich
Ta, Rich
Has anything been changed on it recently? Does it have an immobiliser? If so are you absolutely sure it is working properly?
Basic problem diagnosis will be the same for all engines.
Assume you have tested the spark and have shown you actually are getting a good spark at the plug, and that the timing is somewhere about right. If you pull a plug out you can get some idea whether it is flooding or fuel starvation. Standing by the tail pipe while somebody cranks the engine over and smelling petrol vapour is a quicker but less conclusive test.
3.9 Rangie classic should have the same engine management as the V8 TVRs I would guess? If so, the pump should run for a fixed time (about a second) each time you switch the ignition on, to pressurize the fuel rail. Realistically, there is no way to confirm you have fuel pressure without getting into some pretty dangerous territory. What you can do is get hold of a NOID test lamp and put this in series with one of the injectors, this will tell if the injector is triggering. Similarly put a spark trace in series with one of the HT leads and this will show you if the plug is actually getting a spark while it is cranking. If the injector is triggering but the plugs stay dry, this suggests a fuel supply problem. If the injector isn't firing, more likely an ECU or immobiliser problem.
Basic problem diagnosis will be the same for all engines.
Assume you have tested the spark and have shown you actually are getting a good spark at the plug, and that the timing is somewhere about right. If you pull a plug out you can get some idea whether it is flooding or fuel starvation. Standing by the tail pipe while somebody cranks the engine over and smelling petrol vapour is a quicker but less conclusive test.
3.9 Rangie classic should have the same engine management as the V8 TVRs I would guess? If so, the pump should run for a fixed time (about a second) each time you switch the ignition on, to pressurize the fuel rail. Realistically, there is no way to confirm you have fuel pressure without getting into some pretty dangerous territory. What you can do is get hold of a NOID test lamp and put this in series with one of the injectors, this will tell if the injector is triggering. Similarly put a spark trace in series with one of the HT leads and this will show you if the plug is actually getting a spark while it is cranking. If the injector is triggering but the plugs stay dry, this suggests a fuel supply problem. If the injector isn't firing, more likely an ECU or immobiliser problem.
Well, i've blown the fuel line through and its clear i've converted my pressure bleeder into a fuel pumpand measured the fuel pressure from the pump and it's ok. all the sensors air flow meter etc have been tested as per the manual. good spark at the plugs. Only leaves the ECU and the injectors but the way it stoped i would think its the ECU 
.
Time to bite the bullet and pay some one to fetch it and fix it.
. Time to bite the bullet and pay some one to fetch it and fix it.
seaton said:
the ignition system is in tiptop condition,
I'd like to retract that statement, I'd stuck an old plug in one of the H/T leads to check and it was fine. But the plugs themself were sooted up to the point they didn't work. They're ony 6 weeks old as well so i still think theres a fuel problem.
spnracing yeh my dad's name is Bob and is in london at the mo, Tell him if he wants to use the rangie he needs to buy some plugs
Turn the ignition on and flick the throttle buterfly. If you hear a tick, all the injectors have just fired (the ECU thinks you just floored it). If you disconnect the cold start injector you can hang your pressure gauge here to verify the rail pressure (should be about 2.5bar).
If you have fuel pressure and flick the throttle as above, and you hear the tick, you MIGHT just be able to see the pressure fluctuate as the fuel being sprayed drops the rail pressure a tad.
If you get the tick, try doing it a few times, then crank the engine. If it catches but won't run, the sparks have ignited the fuel you just sprayed. So now it may be that the ECU isn't getting a trigger signal from the distributor, or the ECU is faulty (less likely as it did fire the injectors), or the temp sensor is duff.
I can check the ECU out for you if it helps. Temp sensor is about £12 from Landrover.
Ian
390SE, Teesside
If you have fuel pressure and flick the throttle as above, and you hear the tick, you MIGHT just be able to see the pressure fluctuate as the fuel being sprayed drops the rail pressure a tad.
If you get the tick, try doing it a few times, then crank the engine. If it catches but won't run, the sparks have ignited the fuel you just sprayed. So now it may be that the ECU isn't getting a trigger signal from the distributor, or the ECU is faulty (less likely as it did fire the injectors), or the temp sensor is duff.
I can check the ECU out for you if it helps. Temp sensor is about £12 from Landrover.
Ian
390SE, Teesside
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