P

P38 2.5DSE 1998

New Member
Hello there!
I own a P38 with a 2.5 diesel. It is from June ‘98. Automatic gearbox.

When I bought it last year, the previous owner told me that the occasional dip in rpm that was present, is caused by the fact that it had an upgraded ECU.

As the upgrade results in more torque and the dip in rpm every now and then was not really an issue for me, it was ok.

But since recently the dip is more often (every 2 minutes) and the engine frequently stops completely now. Normal driving is still ok, it has enough power and starts perfectly.

I am under the impression that it has to do with the replaced ECU. I have the original ECU cable system but not the original ECU. I checked the type that is in place now, and this is an ERR 7301.
I want to replace this with the original, and I think that this is an ERR 7300.
My local Land Rover specialist looked it up through my VIN number and is quite sure that this is the one, but not confident... He says the ERR 7113 might also be ok.

Can any one confirm that the ERR 7300 is the right one?

Other tips concerning the issue (dip in rpm) are also welcome...

Best regards,
Bouwe
 
If you swap ecu`s you will need to have the code from the new ecu entered in to the becm with the right diag or it will not start, its not just a straight swap.
are you sure its the ecu and not a fault elsewhere, as there are allsorts of items that will cause the engine to stop.
 
Quantity servo on FIP? When was fuel filter last changed? In tank fuel pump? Does it do it when fuel level low or at any level
 
Thanks for the replies.
I suspect the ECU, but not 100% sure. Reason that I think it is the ECU is that the previous owner mentioned this as the cause for the dips in RPM (which now got worse, but same type of issue). So I assume that the issue was not there at all before the ECU was upgraded/changed. And I have the original cables etc to reconnect the original ECU...
 
P38 2.5DSE 1998 said:
Thanks for the replies.
I suspect the ECU, but not 100% sure. Reason that I think it is the ECU is that the previous owner mentioned this as the cause for the dips in RPM (which now got worse, but same type of issue). So I assume that the issue was not there at all before the ECU was upgraded/changed. And I have the original cables etc to reconnect the original ECU...
Click to expand...

When you say you have all the cables to reconnect the ecu is this the one in the box behind the battery or somewhere else
 
brianp38dse said:
When you say you have all the cables to reconnect the ecu is this the one in the box behind the battery or somewhere else
Click to expand...
From the battery, so starting with the (black) plug that connects directly on the metal colored ECU. I know that there are several plugs that are not universal. The original that I have does not fit the current (7301).
 
I read that there was an upgraded version of the ECU for the 2.5DSE which was initiated after mid 1998. Mine is from June 1998, so I think originally it has the 7300 and it was later fitted with the upgraded (7301) and that causes issues.
 
P38 2.5DSE 1998 said:
Thanks for the replies.
I suspect the ECU, but not 100% sure. Reason that I think it is the ECU is that the previous owner mentioned this as the cause for the dips in RPM (which now got worse, but same type of issue). So I assume that the issue was not there at all before the ECU was upgraded/changed. And I have the original cables etc to reconnect the original ECU...
Click to expand...

That smells a bit like BS. Might be wrong. If it is hunting then I suspect a fault somewhere. It all works off maps so if the inputs are steady the idle should be steady.

As far as I know there were 2 main versions, pre-EGR and later models with EGR. Which isn't to say they might have done the odd tweak along the way but yours aounds like it has EGR?

I'm no expert on diesel but my understanding is that at idle, at least, the revs will be dependent on fuel going in. This will coarsely controlled by the engine timing chain with fine tuning by the quantity servo in the top of high pressure Fuel Injection Pump. That in turn will be controlled by a mix of inputs depending on the engine but essentially inlet air temperature (or MAF on later engines), MAP sensor reading, cam sensor reading combined with pulse from #4 injector sensor and throttle (not much use at idle). With a stretched timing chain the quantity servo gets to its maximum extent and if it goes out of range the car will stall and throw a fault. Usually you stall approaching roundabouts on a manual or you see the injector light on the dash light up on the automatic. Some people put off the inevitable (replacing FIP for a refurbed one at around £650) by sneaking up the idle by increasing the idle fuelling slightly.

First things I would check is the pipe from the inlet manifold to the MAP sensor (on the fuel filter housing) is attached and all good and that the lift pump is chucking out the required amount as per Wammers' How To in the Technical Section. The 3rd thing is the clean out the intercooler and give it a fresh air-filter. The 4th is more of a pain but if you do have EGR it may well be caked up, along with the filter along the top of the cam-cover. Ideally you'd clean the lot out. I'm not sure I would blank off the EGR if I had it but I know many on here do so they don't have the clean the damn thing ever again.

After that see if you can get some diag on it. Ideally a Nanocom and record a trace but you might not get that far.
 
Last edited:
Sounds like someone telling you porkies. Could be fourth injector, could be the pump needing calibration. Try find someone locally with a nanocom to see if anything is amiss.
 
P38-DFX said:
Sounds like someone telling you porkies. Could be fourth injector, could be the pump needing calibration. Try find someone locally with a nanocom to see if anything is amiss.
Click to expand...

Just seen he's in the Netherlands. Suspect P38s are a bit rarer there.
 
+1 BS, or that is their understanding, which is wrong rather than trying to mislead you. Low line and hi line becms are not that different.
I’d check see if it has a tuning box fitted, if so remove it. Would explain the ecu upgrade explanation as an old power box can fault and cause ‘dips’.
 
RangeRoller dt said:
+1 BS, or that is their understanding, which is wrong rather than trying to mislead you. Low line and hi line becms are not that different.
I’d check see if it has a tuning box fitted, if so remove it. Would explain the ecu upgrade explanation as an old power box can fault and cause ‘dips’.
Click to expand...

Thats why i was asking about where the ecu was and the bit about having the wiring to put it back, if it has got a tuning box rather than chipped ecu its an easy swap:).
 
brianp38dse said:
Thats why i was asking about where the ecu was and the bit about having the wiring to put it back, if it has got a tuning box rather than chipped ecu its an easy swap:).
Click to expand...

ERR7301 is the engine ECU for the automatic. I think the manual is different. They may well have made one that does both later on.

They're cheap on the Bay as they never go wrong. Doubt you'll find a new one now unless some dealer has one in stock gathering dust.
 
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