1999 P38A 2.5 dse hunting at low revs and won't idle

Hi I've got a 1999 P38 2.5 dse
It's hunting at low revs upto about 1-1500 but fine at higher revs, it won't idle at all just dies and takes a long time to fire up, so far I've replaced tank fuel pump and fuel lines as there was air in the lines but that's sorted now, I've replaced no.4 injector which made starting a little easier, replaced glow plugs checked there getting correct voltage, replaced all injector leak off pipes and injector return pipe, had codes read which comeback as needle lift sensor hence why I replaced no.4 injector, I'm now a bit stumped as to what to check next, I did crack off injector pipes with engine running and they seemed a bit low on pressure because I've done this on my 300tdi disco before and that had fuel flying.

Any help would be greatly appreciated

Thanks Matt

Needs diagnostics live data IMO to see what is going on.

Fuel quantity servo fault i would think diag only way forwards. Unless you have had the centre section off the pump and it's in the wrong place.

Pipe to MAP sensor OK?

Intercooler flushed out?

Grrrrrr said:

Pipe to MAP sensor OK?

Intercooler flushed out?

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Nothing to do with MAP sensor at idle. If intercooler was a problem it would be sucking top pipe in.

I've had the codes read again today since I fitted new no.4 injector, I wanted to make sure the injector wasn't still at fault and that's all clear now but it's come back with a new problem saying electric idle reset code 148 is what I've been told, I've had a look online and on the forum but can't find anything to do with this. Any ideas??

Munka said:

I've had the codes read again today since I fitted new no.4 injector, I wanted to make sure the injector wasn't still at fault and that's all clear now but it's come back with a new problem saying electric idle reset code 148 is what I've been told, I've had a look online and on the forum but can't find anything to do with this. Any ideas??

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What diag is being used on this vehicle. Do you not know anyone with a Nanocom. On a Nanocom the idle setting is 128. Raising that will increase idle speed reducing it will lower idle speed. Sounds to me like you have a fault on the quantity servo feedback pot.

I don't no what diag is being used, there's a couple of good Landy specialists around so I'll have a word and see if they've got a nanocom, the other thing I was thinking is if it's injection pump related would getting that reconditioned fix the prob?

Thanks for your help.

Munka said:

I don't no what diag is being used, there's a couple of good Landy specialists around so I'll have a word and see if they've got a nanocom, the other thing I was thinking is if it's injection pump related would getting that reconditioned fix the prob?

Thanks for your help.

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Yes of course it would, but you need proper diag used by someone who knows how to interpret it before you start splashing out £600.00 or so on a refurbed pump. If the pump centre section has not been off and put back in the wrong place, my money is on a quantity feedback malfunction. Which proper diag should pick up on straight away. Electric idle code 148 although i have never heard that one before would be telling me that idle control is not working, that could be pump or ECU.

Try adding an earth wire to the engine ECU metal casing.

Ok so on close inspection I can see that the injection pump has been apart before, I haven't touched it yet and I don't no if the previous owner had it apart or not, I'm still trying to find someone with nanocom who can run diags on it, A local Landy garage uses auto logic, does anyone no if this will can do the idle reset?, I don't want to be loading be loading truck onto my trailer and paying for it to be read just to find that the diags can't do it.

Munka said:

Ok so on close inspection I can see that the injection pump has been apart before, I haven't touched it yet and I don't no if the previous owner had it apart or not, I'm still trying to find someone with nanocom who can run diags on it, A local Landy garage uses auto logic, does anyone no if this will can do the idle reset?, I don't want to be loading be loading truck onto my trailer and paying for it to be read just to find that the diags can't do it.

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Did the car ever run well, if so what was the idle speed when it did?

its had this problem since I bought it and I've had it for a couple of months, I bought for my girlfriend as a cheap runaround and thought the problem was down to air in the fuel system but was proved wrong, it's going in today to have codes read on auto logic diagnostics by an auto electrician and diesel specialist, I will post what the results are. I also tried running an earth to ecu casing but it's still the same.

Well it's come back as not having any fault codes, so the bloke played about with it and changed the idle settings but all it did was increase or decrease the speed of it idling so it was still hunting just slower or faster depending on the settings, he said it will be a mechaninical fault in the pump and said its probably a broken or warn out actuator, so looks like it'll be needing a second hand injection pump.

Munka said:

Well it's come back as not having any fault codes, so the bloke played about with it and changed the idle settings but all it did was increase or decrease the speed of it idling so it was still hunting just slower or faster depending on the settings, he said it will be a mechaninical fault in the pump and said its probably a broken or warn out actuator, so looks like it'll be needing a second hand injection pump.

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The top is in the wrong place, the idle control is bouncing about like a whippets dick trying to adjust fuel. That is my take on it.

Is there a way of putting it on correctly? I've got nothing to lose so may as well try and get it working if I can, do you have a guide as to what needs to be done or could you link me to one please?, I've done a search and found a thread about changing the seals in the injection pump and it looks pretty Useful but if there's anything better that would be a great help, thanks for all your help and advise I will get this problem sorted one way or another.

Munka said:

Is there a way of putting it on correctly? I've got nothing to lose so may as well try and get it working if I can, do you have a guide as to what needs to be done or could you link me to one please?, I've done a search and found a thread about changing the seals in the injection pump and it looks pretty Useful but if there's anything better that would be a great help, thanks for all your help and advise I will get this problem sorted one way or another.

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You need idle setting to it's normal position, that would be 128 on a Nanocom. Then remove the manifold. Slightly loosen the bolts holding the centre section of the pump on. NOT the top. Using a suitable length of wood and an hammer gently tap pump top either backwards or forward until engine will start and run, make sure before you try to start there is nothing that can get sucked into inlets, then tap very slightly back or forth until you get a rock steady 750 idle with engine hot. Tighten bolts. Replace manifold. Enjoy.

The idle was set to its normal setting earlier, I undid the bolts only slightly and tapped the top back slightly, I then started the engine to see if I was in the right place and there was fuel ****ing out from side of the pump is there suppose to be fuel in that area of the pump??, or am I just a complete spanner and suppose to tighten bolts each Time after adjustment as I though I was suppose to slightly loosen the bolt start engine and move pump top until revs were in the correct area,

So turned engine off quickly and tightened the bolts up again I then moved pump top forward and backwards tightening bolts each time before starting engine but the problem still persists, the only difference is that it'll idle while hunting where as before it would just idle for less than a min before dying, I'm thinking I now need to get it booked in and have it live data read to get a better picture of what's going on.

How much are you paying per garage visit? Buying a Nanocom is starting to look the sensible option.
Every P38 should have one.

Well the first couple were done by a garage a couple of units down from mine and he did it for free, but I'm sure once I get it in for live data reading it's gonna start adding up.