P38 2.5DSE possible timing issue. Lack of power.

Grrrrrr · Jun 4, 2019

Sorry. We tend to use a lot of slang. Yes, tick-over = idle. 750 is good. If the top of the pump has been off and not put back quite right that can cause issues.

No MAF on mine so not sure what shape the plug is. Should run without it on default values. You have RAVE downloaded? Picture should be in there.

If you have the VIN then I think @RangeRoller dt knows of a member on here who can tell you what your car left the factory with.

kretslopp · Jun 4, 2019

I looked through rave. Maf sensor is called X105. It’s plug is C504. Round plug with six pins.

The plot thickens...

Let’s say my car sometime before 2004 got it’s engine swapped for some reason for the pre -99 engine. Shouldn’t also the engine ECU been replaced as well? My inlet manifold has the intake air sensor. So the wiring loom must have come with that older engine. But then why is there a plug for the MAF hanging there (if it really is that plug)? It ought to be a part of the wiring loom for the engine as well.

Henry_b · Jun 5, 2019

The car should have an engine number stamped on it somewhere.

On the V's its on the block deck drivers side above the manifold..

No idea on the Derv..

It should correspond with a number either in the service bootlet or V5

RangeRoller dt · Jun 5, 2019

Grrrrrr said:
@RangeRoller dt knows of a member on here who can tell you what your car left the factory with.

I can never remember who he is but can look it up in Grrr’s posts for you

He tells people with flat tyres about it anorl

kretslopp said:
I looked through rave. Maf sensor is called X105. It’s plug is C504. Round plug with six pins.

The plot thickens...

Let’s say my car sometime before 2004 got it’s engine swapped for some reason for the pre -99 engine. Shouldn’t also the engine ECU been replaced as well? My inlet manifold has the intake air sensor. So the wiring loom must have come with that older engine. But then why is there a plug for the MAF hanging there (if it really is that plug)? It ought to be a part of the wiring loom for the engine as well.

Early engines have alloy manifold with no MAF (Mass Air Flow) later types have black plastic manifold with wiring/MAF by air filter.
You may have an EGR (later with MAF) engine, that has had an earlier cylinder head etc bolted onto it? There should be a vacuum pipe coming from under the alloy inlet manifold to a MAP (Manifold Absolute Pressure) sensor - is it there/plugged in?

Picture of your engine bay would help

Grrrrrr · Jun 5, 2019

kretslopp said:
I looked through rave. Maf sensor is called X105. It’s plug is C504. Round plug with six pins.

The plot thickens...

Let’s say my car sometime before 2004 got it’s engine swapped for some reason for the pre -99 engine. Shouldn’t also the engine ECU been replaced as well? My inlet manifold has the intake air sensor. So the wiring loom must have come with that older engine. But then why is there a plug for the MAF hanging there (if it really is that plug)? It ought to be a part of the wiring loom for the engine as well.

As RRDT says, depends how much was swapped. I've never done it but as you say, ECU and loom then new security code into BECM would be my guess.

I'm trying to remember the differences. One of the temp sensors is set to -38C on the later models. MAF sends readings but it runs on default without it. There's an extra temp sensor but I think that just pulls in the aircon fans to help with cooling. Guess loom not strictly necessary. Think most Omegas had ally manifold and many of those had 994 pump. Fuel maps were different as different performance required for 2.5ton 4x4. @wammers or @kds or @Datatek know so much more about these engines.

RangeRoller dt · Jun 5, 2019

My first thought was I smell Omega.
Cooling pipes are all different so perhaps it’s just head work?

Could be neither we don’t know yet

kretslopp · Jun 5, 2019

I had a spare engine from an Omega where I got the pump from. And by comparing the engines I can tell that the engine in the car has Range Rover spec inlet manifold, covers, hoses and coolant pipes.

This morning before I drove to work I looked at the loose plug for MAF. It is a round plug with room for 6 sockets but only 5 installed. Just like the wiring diagram says.
That connector enters the loom where the MAP sensors wire enters the loom.

However, at the same place the wires for the IAT sensor exit the loom. That one looks homemade like it’s spliced in to the loom. Insulation all the way to the IAT sensor is electric tape.

I’ll snap some photos tomorrow and post. I wanna clean up the engine bay first now that the pollen season is nearly done.

Grrrrrr · Jun 5, 2019

kretslopp said:
I had a spare engine from an Omega where I got the pump from. And by comparing the engines I can tell that the engine in the car has Range Rover spec inlet manifold, covers, hoses and coolant pipes.

This morning before I drove to work I looked at the loose plug for MAF. It is a round plug with room for 6 sockets but only 5 installed. Just like the wiring diagram says.
That connector enters the loom where the MAP sensors wire enters the loom.

However, at the same place the wires for the IAT sensor exit the loom. That one looks homemade like it’s spliced in to the loom. Insulation all the way to the IAT sensor is electric tape.

I’ll snap some photos tomorrow and post. I wanna clean up the engine bay first now that the pollen season is nearly done.

That would make sense. Pre-EGR needs the IAT temperature in order to calculate fuelling. EGR uses a preset -38C so that is good news. I think it would probably need the ECU swapping over as well which probably happened. Just need one of the gurus to make an appearance now.

wammers · Jun 5, 2019

Looks like you have a bit of a mixture here. Losing power on hills is classic of failed lift pump, but you may also like to change the fuel filter and the air cleaner and see what you get. Hot start will be masking problems to some degree.

Datatek · Jun 5, 2019

Grrrrrr said:
That would make sense. Pre-EGR needs the IAT temperature in order to calculate fuelling. EGR uses a preset -38C so that is good news. I think it would probably need the ECU swapping over as well which probably happened. Just need one of the gurus to make an appearance now.

The EGR version uses a thermistor in the MAF for temperature. The -38 signifies tha IAT is not present.
It is perfectly possible to run without the MAF connected, so fitting the earlier manifold/head would just need the IAT spliced in as the OP has said is the case, although it will still run OK with no IAT but emissions would be off.
Lack of power could be many things but the MAP sensor is one possibility as are turbo pipes, waste gate etc. As Wammers says, the lift pump is also a possibility. Diagnostics are really the only way forward.

RangeRoller dt · Jun 5, 2019

I’m interested to see this,
I prefer pre EGR but this is a whole new level

kretslopp · Jun 6, 2019

Today I’m spending some quality time with my Rover.
I did some road testing on my way to work.
First I unplugged the MAP sensor. Car ran a lot worse.

Reconnected MAP and instead disconnected IAT sensor. That caused no change.

Then I removed the lift pump relay. No change there either. So maybe lift pump is the cause.
Went to the truck workshop and started some fault finding. As promised I took some photos of my engine bay as well.

I first tested when the lift pump runs on my car. The relay is energized for 15seconds while glowplug light is on and when the engine is running. It starts so fast so I didn’t have time to see wether it runs while cranking but I suspect it doesn’t.
Next I disabled the hot start fix and test started while hot. It started as fast as without. So I’ll probably leave that disconnected for the time being.

Measured the plug for the IAT-sensor. No voltage with engine running.
Sensor itself had 3.9kOhm resistance with ambient temperature. Sounds reasonable.
As you can see from the pictures the wiring look suspicious. Will check them to the engine ECU later.

Next I tested the flow rate of the lift pump.
After the filter I got merely 150ml.
Before the filter it flowed 250ml in the same 10 seconds.
I should try a filter change then. But looking through my service notebook I replaced both fuel and air filter merely 15000km ago which is half the interval for the fuel filter at least.
The filter I bought from island 4x4 and I chose the expensive one named Cooper.

wammers · Jun 6, 2019

Fuel filter should be changed every 18,000 miles or every 18 months which ever is the sooner. But it's condition will depend how much gunge you have in the tank. Looks like someone has fitted an early head to a late engine.

kretslopp · Jun 6, 2019

Got a hold of a new fuel filter. Mahle this time.
Did the 10s test again and got 200ml after the filter this time.

Took the car for a spin and it feels better now. Wanted to try the usual hill on my way home to see if I could accelerate past 140km/h but there was too much traffic. Will test tomorrow morning on my way to work as a reference.

One mystery remains though.
The IAT-sensor cannot be wired correctly. According to the wiring diagram IAT (X311) is supposed to be connected to the ECU via pin 52.
But it’s not there.

I don’t know if I have the correct ECU for IAT or if I have the one for MAF.

wammers · Jun 6, 2019

kretslopp said:
Got a hold of a new fuel filter. Mahle this time.
Did the 10s test again and got 200ml after the filter this time.

Took the car for a spin and it feels better now. Wanted to try the usual hill on my way home to see if I could accelerate past 140km/h but there was too much traffic. Will test tomorrow morning on my way to work as a reference.

One mystery remains though.
The IAT-sensor cannot be wired correctly. According to the wiring diagram IAT (X311) is supposed to be connected to the ECU via pin 52.
But it’s not there.

I don’t know if I have the correct ECU for IAT or if I have the one for MAF.

Have a look at this. https://www.nanocom-diagnostics.com/downloads/preview/p38-bosch-edc-nanocom-evolution

Datatek · Jun 6, 2019

kretslopp said:
Got a hold of a new fuel filter. Mahle this time.
Did the 10s test again and got 200ml after the filter this time.

Took the car for a spin and it feels better now. Wanted to try the usual hill on my way home to see if I could accelerate past 140km/h but there was too much traffic. Will test tomorrow morning on my way to work as a reference.

One mystery remains though.
The IAT-sensor cannot be wired correctly. According to the wiring diagram IAT (X311) is supposed to be connected to the ECU via pin 52.
But it’s not there.

I don’t know if I have the correct ECU for IAT or if I have the one for MAF.

As your car originally had a MAF, I suspect that the IAT will have been wired into the circuit for the temperature sensor that was in the MAF. Unfortunately if that is the case, the temperature readings will be wrong, inlet air at the MAF will be ambient temperature, air in the manifold after the turbo is likely to he hotter than ambient.

kretslopp · Jun 6, 2019

Likely is an understatement. Isn’t a typical charge air temperature with intercooler around 150 degrees C?

Does all engine ECU:s have the possibility to read both inlet air temp in the manifold and ambient temp from the MAF?
At the moment I have neither.

I wonder what will happen to the performance when I get the IAT sensor working? On the correct pin that is.

Grrrrrr · Jun 7, 2019

kretslopp said:
Likely is an understatement. Isn’t a typical charge air temperature with intercooler around 150 degrees C?

Does all engine ECU:s have the possibility to read both inlet air temp in the manifold and ambient temp from the MAF?
At the moment I have neither.

I wonder what will happen to the performance when I get the IAT sensor working? On the correct pin that is.

I would imagine the MAF ECU is different. If you look at the Rimmer Bros website are there different part numbers? Or there's a Russian autocat site somewhere.

kretslopp · Jun 7, 2019

I did a google search for the Bosch number on my ECU: 0281001273

I get several hits referring to used parts or someone trying to chip a P38 model -97 and -98.

Like this one -97 from a parts recycler in Sweden:
https://www.bildelsbasen.se/se-sv/L...iesel-Styrenhet/Alla/ID-23746880/OEM-2245333/

It has the same Bosch number and the same number beneat: 2245333
And also same type number: 4070

It should mean I have an ECU earlier than -99 right?

Grrrrrr · Jun 7, 2019

Sounds plausible to me.

P38 2.5DSE possible timing issue. Lack of power.

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