P38a acting up

Vincechristopher · May 29, 2023

Hi all hoping for some help and advice.

Ok so to start I'll give some background information. Customer of mine has a p38a 4.6 petrol auto that's stood for about 8 months he's called me up to swap the battery over for him as it's gone flat and since he's on the mature side and recently done his hip he can't do so himself. So I've swapped the battery and done a key sync but the car turns over but won't start. So I check no fuel, pumps not running ok so I check fuses and relay, both good and if I run power directly to the pump it kicks in and works fine. Strange but ok then I check and have no spark either so I try a code scan no communication and no EML light on once key is in position 2. So I take out the fuse box to check for damage and also check the wiring going to the ecu all of a sudden EML comes on and car starts but runs rough then no EML and no start and so on.

I then leave it for a couple days as I've got other work to carry out and when I go back EML comes on all the time and it cranks and fires but runs really rough and I'm getting a code for idle speed actuator - open coil.

The area we live in is quite remote and there's no land rover specialist and I don't like sending people away if I can help it. So any ideas what I could test next to try and get this beast running, I was tempted to just change the idle speed actuator but that didn't explain the original fault that seems to of vanished.

Thanks in advance for any advice, and sorry about the wall of text.

Chris

Datatek · May 29, 2023

Vincechristopher said:
Hi all hoping for some help and advice.

Ok so to start I'll give some background information. Customer of mine has a p38a 4.6 petrol auto that's stood for about 8 months he's called me up to swap the battery over for him as it's gone flat and since he's on the mature side and recently done his hip he can't do so himself. So I've swapped the battery and done a key sync but the car turns over but won't start. So I check no fuel, pumps not running ok so I check fuses and relay, both good and if I run power directly to the pump it kicks in and works fine. Strange but ok then I check and have no spark either so I try a code scan no communication and no EML light on once key is in position 2. So I take out the fuse box to check for damage and also check the wiring going to the ecu all of a sudden EML comes on and car starts but runs rough then no EML and no start and so on.

I then leave it for a couple days as I've got other work to carry out and when I go back EML comes on all the time and it cranks and fires but runs really rough and I'm getting a code for idle speed actuator - open coil.

The area we live in is quite remote and there's no land rover specialist and I don't like sending people away if I can help it. So any ideas what I could test next to try and get this beast running, I was tempted to just change the idle speed actuator but that didn't explain the original fault that seems to of vanished.

Thanks in advance for any advice, and sorry about the wall of text.

Chris

The original fault would be to do with the battery going flat which may have caused confusion in the BECM, I wouldn't worry about it as it has cleared.
I can't help with the other problem other than to suggest it needs diagnostics, I am happily ignorant about the V8

Grrrrrr · May 29, 2023

Vincechristopher said:
Hi all hoping for some help and advice.

Ok so to start I'll give some background information. Customer of mine has a p38a 4.6 petrol auto that's stood for about 8 months he's called me up to swap the battery over for him as it's gone flat and since he's on the mature side and recently done his hip he can't do so himself. So I've swapped the battery and done a key sync but the car turns over but won't start. So I check no fuel, pumps not running ok so I check fuses and relay, both good and if I run power directly to the pump it kicks in and works fine. Strange but ok then I check and have no spark either so I try a code scan no communication and no EML light on once key is in position 2. So I take out the fuse box to check for damage and also check the wiring going to the ecu all of a sudden EML comes on and car starts but runs rough then no EML and no start and so on.

I then leave it for a couple days as I've got other work to carry out and when I go back EML comes on all the time and it cranks and fires but runs really rough and I'm getting a code for idle speed actuator - open coil.

The area we live in is quite remote and there's no land rover specialist and I don't like sending people away if I can help it. So any ideas what I could test next to try and get this beast running, I was tempted to just change the idle speed actuator but that didn't explain the original fault that seems to of vanished.

Thanks in advance for any advice, and sorry about the wall of text.

Chris

Have you tried the EKA code?

Datatek · May 29, 2023

Grrrrrr said:
Have you tried the EKA code?

Why would he need that? He's got the engine running.

Grrrrrr · May 29, 2023

Datatek said:
Why would he need that? He's got the engine running.

Oh yes, didn't see that part at the end. Just saw the no fuel and no spark. I wonder if the RF unit is unplugged?

Running rough might be all sorts if it has been sat for 8 months. Might be damp but also the cats might be blocked if they are cheap aftermarket ones.

Datatek · May 29, 2023

Grrrrrr said:
Oh yes, didn't see that part at the end. Just saw the no fuel and no spark. I wonder if the RF unit is unplugged?

Running rough might be all sorts if it has been sat for 8 months. Might be damp but also the cats might be blocked if they are cheap aftermarket ones.

I'm sorry but I don't see what the RF unit has got to do with it at his stage?

pwood999 · May 29, 2023

+1 on RF receiver has nothing to do with engine running.

The V8 is relatively simple. Cranking, starting & engine management light behaviours depends on the year, so not always a good guide. My experience is mainly GEMS up to 1998. Thor is similar, but more sensitive to MAF & IACV issues.

If IACV is open circuit, it needs replacing. While you're there check the throttle position sensor. Throttle body might need a good clean as well.

Randomly not starting might be crank sensor. Check this is good as it's used for spark timing. Cam sensor only comes into play for fine tuning the fuel when it's running.

Check condition of spark plugs, HT leads & connections to the coils. Makes sure there's good even spark on all eight.

MAF will affect running & engine stops if you unplug it while running. I think the engine should start & run if you unplug it first, but this varies between GEMS & Thor. If it runs smoother without the MAF then try cleaning it first, and then check OBD readings.

Long & short term fuel values might also give a clue.

How remote are you ? There could still be someone nearby that can help ?

Grrrrrr · May 29, 2023

Datatek said:
I'm sorry but I don't see what the RF unit has got to do with it at his stage?

Because it sometimes runs and sometimes doesn't. If it didn't get a valid code it would stop the fuel etc. Thenit started working, albeit running rough.

Datatek · May 30, 2023

Grrrrrr said:
Because it sometimes runs and sometimes doesn't. If it didn't get a valid code it would stop the fuel etc. Thenit started working, albeit running rough.

Once he got as far as having the engine running, the RF and FOB code were irrelevant.

Grrrrrr · May 30, 2023

Datatek said:
Once he got as far as having the engine running, the RF and FOB code were irrelevant.

Yes

P38a acting up

Vincechristopher

New Member

Datatek

Well-Known Member

Grrrrrr

Technician, Bodgit & Scarper Ltd

Datatek

Well-Known Member

Grrrrrr

Technician, Bodgit & Scarper Ltd

Datatek

Well-Known Member

pwood999

Well-Known Member

Grrrrrr

Technician, Bodgit & Scarper Ltd

Datatek

Well-Known Member

Grrrrrr

Technician, Bodgit & Scarper Ltd

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