could anyone help, i fitted donour engine couple of month ago and since then it struggles to go up the gears it changes up at about 3,500 revs. i have been told i need a new throttle pedal. could it be electric problem, my alarm keeps setting itself off and keep getting key code lockout message on dash. forgot to mention, i need to give it 3 turns of the key before it will start. ive changed heater plugs. thanks in advance
p38 2.5 lack of power
- Thread starter Jonkeepin
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zzr1200
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Do you know any history of the replacement engine, which vehicle/model was it removed from?
Does it use oil or smoke and what engine bits did you have to change over to make it fit???
hi there mate, mine is 1996, the engine came from an omega 1997, i put my old turbo, intercooler, and manifold on it as i knew they worked on other engine. i did not change fuel pump! i had to leave air con pump belt off for now as the pump did not line up. could it be either of these causing problem?
zzr1200
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The usual reasons for poor starting on these is either the injector leak-off pipes leaking, that would give you a small diesel leak, or a poor in-tank pump.
With the alarm problems etc. How's your battery? Low battery can give many weird problems.
With the alarm problems etc. How's your battery? Low battery can give many weird problems.
update, have changed leak off pipes, still a leak on start up but cant see where from. had abattery test on it, and battery is good. how do i get to in tank pump. thanks for suggestions lads. anyone know place in newcastle that works on p38s. the garages ive been to dont want to know. thanks again
Have you changed the fuel filter recently?
If the lift pump (the one in the fuel tank has failed, it won't just struggle to start, it'll struggle to run at all. You might get a few minutes of idling out of it if it starts at all, but that's about it, and even that only if you have a full-ish tank. And I seriously doubt you'd get it to 3500rpm if your lift pump wasn't working. When you turn the key (but not start the engine), the fuel tank should be buzzing. If it isn't, the lift pump isn't working. You can also check on the lift pump relay whether it is drawing any amps. I'm assuming you checked that the fuse and relay are OK.
If you are leaking fuel on start-up, the chances are the seals on the injection pump need replacing, which would also explain poor starting and lack of power.
If the lift pump (the one in the fuel tank has failed, it won't just struggle to start, it'll struggle to run at all. You might get a few minutes of idling out of it if it starts at all, but that's about it, and even that only if you have a full-ish tank. And I seriously doubt you'd get it to 3500rpm if your lift pump wasn't working. When you turn the key (but not start the engine), the fuel tank should be buzzing. If it isn't, the lift pump isn't working. You can also check on the lift pump relay whether it is drawing any amps. I'm assuming you checked that the fuse and relay are OK.
If you are leaking fuel on start-up, the chances are the seals on the injection pump need replacing, which would also explain poor starting and lack of power.
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Lift pump only runs when glow plugs are lit. When engine is being cranked or when engine is running. Providing FIP is in reasonable condition engine will run quite happily with no lift pump, although it will get harder to start as tank level drops. There will also be a lack of power. Sounds like you have FIP problems.
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Absolutely not true. The lift pump runs most of the time. There is a pressure sensor in the fuel filter head (that's what the wiring loom plug on it is for), that cuts it out when the pressure is sufficient, but that never lasts more than a few seconds unless you are idling or coasting.
Pull the lift pump relay (innermost front in the fuse box behind the battery) and try driving the car. Once the fuel in the fuel filter is depleted, the engine will cut out. It may actually get to 25mph if you have a full tank, but that's about it. Having had this failure necessitate getting home on the back of an AA truck twice in the past 3 months, I'm pretty sure I know what I'm talking about.
There is also a difference between a dying lift pump and a dead lift pump. With a dead one the car won't be going anywhere under it's own power. With a dying one you may not notice if you drive relatively gently and stay < 60mph. The fuel filter acts like a big fuel "capacitor" that will get you through short bursts of full throttle, but if you are at full throttle on a hill at 80mph for more than 20 seconds or so you'll start noticing very obvious power surging.
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I am sure you don't know what you're on about. There is no fuel pressure sensor on filter. There is a fuel heater and bolted to filter a manifold pressure sensor but no fuel pressure sensor. The pump runs only when glow lamp is lit, when engine is being cranked or when engine is running. Providing FIP is reasonable engine will run without lift pump. But will lack power. Please don't try to tell your granny how to suck eggs.
PS Before you start giving people advice on here please make sure you know what your talking about first.
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From what I can tell, not all fuel filter heads are heated. The heated ones have 2 plugs, according to the parts manuals. The old part number with a single plug appears to have been superseded by the part number with two plugs. So can you please explain what each of the two plugs is for? The manuals don't actually explain what the 3-pin plug is for and I haven't dismantled a filter head to find out. Then again, the diagrams might just be wrong - if they are then I'm wrong, too.
But I can vouch for the engine not being capable of much more than idling with the lift pump disconnected, with the tank less than 1/4 full, and I doubt it will do much better with a full tank. Contrary to what you said in your original post, it will not "run happily", and there is a matter of the distinction of it being capable of idling and it being capable of moving the vehicle.
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You will note i said IF the FIP is reasonable. Engine will run happily without a lift pump. Providing there is no air lock FIP will suck fuel from tank BUT engine WILL lack power and maybe difficult to start on low fuel. If you run engine, pull fuel pump relay and engine stops you have FIP problems. Look at the wiring diagrams for vehicle before deciding what a particular plug is for. All UK P38s have had fuel heater on filter since first made in 1995. What other fitments there maybe abroad does not concern this particular thread. I would think if your particular vehicle has trouble running without the lift pump, you have far more problems than you percieve.
Davie F
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Only way I found out my pump was not working is when I did a long run and it went below a 1/4 tank then was a bitch to start, before that it was never below 1/2 tank and it ran and started perfectly. When I checked the pump it was dead, by the way I cut the access hatch but ended up dropping the tank to replace a fuel line and wished I had just dropped the tank to start with because it was a piece of **** to do.
Cheers
Davie
Cheers
Davie
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Only way I found out my pump was not working is when I did a long run and it went below a 1/4 tank then was a bitch to start, before that it was never below 1/2 tank and it ran and started perfectly. When I checked the pump it was dead, by the way I cut the access hatch but ended up dropping the tank to replace a fuel line and wished I had just dropped the tank to start with because it was a piece of **** to do.
Cheers
Davie
Yes Davie just so. Either he has a seriously knackered FIP or he is trying to run it off peanut butter.
Dropping the tank is not that trivial when you don't have a ramp and have to do it with two trolley jacks with the car on axle stands. Triply so if it hasn't been removed in 15 years and all the bolts are seized up solid and prone to shearing off because nothing was copper greased, and when you find that studs are knackered and nuts won't come off, and you can't get a nut splitter on them and have to chisel them off instead.
Having done all that, I'll take an access hatch in the floor any day, even if i know that all the bolts will come out easily this time around.
Having done all that, I'll take an access hatch in the floor any day, even if i know that all the bolts will come out easily this time around.
roddy4
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that is a very sure way of identifying fip problems,does that mean pump is knackered or requires re-timing? can they be adjusted to compensate for wear?
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Well Roddy it is and it isn't, i was talking about a engine running off diesel, not Asda chip oil. Yes pump can be retimed to compensate for stretch in timing chains, but it is a very precise proceedure done with an DTI (dial test indicator). It is not something you can do at home without all the special tooling. And some knowledge.
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rrc2doorclub
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I had the same problem with my 2.5 dt , 1/4 full it would start , the rear brake pipes went so when i took the tank out i put a new pump in , Happy days starts now just needs the hot fix kit on it and it will be sorted
