P38A DSE autobox - ideas please. It was going too well.... SOLVED

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M

Mukiwa

Well-Known Member
Posts
472
Location
Winsford, Cheshire, near Oulton Park
Hi all,

Just asking for sage advice here (from the 3 wise men, and any others as well :cool:).
  • I have changed ATF oil after 6 months - it was almost black
  • Changed the in tank fuel pump as I found it had failed
  • Changed the fuel filter as well
  • So I don't think it's a fuel starvation issue - but could be wrong
  • No faults showing on Nanocom
So my problem is that I have a loss of power and the car won't pull at all, it maxes out at 50mph. It was pulling like a train then I had a loss of power on the motorway. I can push the pedal to the floor but it still doesn't go any faster. Kick down works, rev's climb but no increase in speed. It rev's freely in neutral. It's currently changing gear at 3,500rpm but maxes out at 50mph. Sometimes, not every time, from stop it pulls ok like normal then I can feel the power dying off. It's feeling like clutch slip.

If it is what are the options apart from replacement box, Ashcroft route or can it be repaired?

ta :D
 
If the rev's climb but no increase in speed and the ATF was black, is the Torque-Converter shagged-out and just not err...converting?
 
Could be so many things without knowing more - autobox clutches, Tconverter, Does auto have DMF?, map sensor/pipe, tired MAF/FIP, injectors list goes on...
Check easy things first sensors/connectors, breather pipes, air/fuel filter etc -you may have disturbed some crap doing your pump

One thing that got my P38 to start shifting was take the intercooler off (not hard) and swill it out with petrol/acetone/turps. Keep flushing til it's clear (I plugged it up overnight to soak) then let it dry completely before refitting.
Then stick a load of inj cleaner in tank and give it some stick. 90L tank so it will be more than average 1dose stated on bottles. I have manual tho so it can take the lead foot
 
I'll start looking at things again this afternoon.
6 months ago I did the following:
  • cleaned intercooler out
  • changed broken water pump
  • fitted new serpentine belt and the a/c belt
  • new air filter
  • new oil filter
  • re-sealed FIP
  • changed all leak off pipes (again)
  • oil & filter change on gearbox (plus full Lucas transfix)
  • diff oil change (1/2 a transfix in each)
  • transfer box atf change (1/2 a transfix added)
  • I add injector cleaner every 2nd tank full
4 weeks ago swapped out inj #1 as it was leaking up the threads
Friday night last week I cleaned the MAF/MAP sensor with proper MAP sensor cleaner - it was playing up only on 2 -3rd upchange on the box at this point and this smoothed it out.
Saturday morning at 70mph joining a motorway I felt the sudden loss of power when I put my foot down.
Tuesday I changed the ATF only. I'm going to change it again and filter swap next week to see if any more crap comes out.

  • When I started the car Tuesday I noticed it was very lumpy and out of balance and it sounded like it wasn't firing on all cylinders. I could hear pop pop pop pop from under the inlet manifold. It sounded like an old Lister single pot water pump. So I checked the fuel flow from the in tank pump once it had cooled down. No fuel on turning the key. I have a sloping driveway and it would start up facing down the drive to the road but got difficult facing up the drive. That's why I fitted the NRV. No starting problems since, but it did mask the failed in tank pump hahaha
  • New pump ordered and fitted yesterday.
  • Started up nicely and no lumpiness nice and smooth and firing on all 6.
  • Test drive - still no power.
  • Time for asking for advice.
 
Mukiwa said:
I'll start looking at things again this afternoon.
6 months ago I did the following:
  • cleaned intercooler out
  • changed broken water pump
  • fitted new serpentine belt and the a/c belt
  • new air filter
  • new oil filter
  • re-sealed FIP
  • changed all leak off pipes (again)
  • oil & filter change on gearbox (plus full Lucas transfix)
  • diff oil change (1/2 a transfix in each)
  • transfer box atf change (1/2 a transfix added)
  • I add injector cleaner every 2nd tank full
4 weeks ago swapped out inj #1 as it was leaking up the threads
Friday night last week I cleaned the MAF/MAP sensor with proper MAP sensor cleaner - it was playing up only on 2 -3rd upchange on the box at this point and this smoothed it out.
Saturday morning at 70mph joining a motorway I felt the sudden loss of power when I put my foot down.
Tuesday I changed the ATF only. I'm going to change it again and filter swap next week to see if any more crap comes out.

  • When I started the car Tuesday I noticed it was very lumpy and out of balance and it sounded like it wasn't firing on all cylinders. I could hear pop pop pop pop from under the inlet manifold. It sounded like an old Lister single pot water pump. So I checked the fuel flow from the in tank pump once it had cooled down. No fuel on turning the key. I have a sloping driveway and it would start up facing down the drive to the road but got difficult facing up the drive. That's why I fitted the NRV. No starting problems since, but it did mask the failed in tank pump hahaha
  • New pump ordered and fitted yesterday.
  • Started up nicely and no lumpiness nice and smooth and firing on all 6.
  • Test drive - still no power.
  • Time for asking for advice.
Click to expand...
At the start you said that the ATF came out of the box black and that the symptoms were like a slipping clutch.
That would suggest the box is fecked.
The cheapest option is the fit the stronger HP24 box from the 4.6 V8 obtainable from a breaker for around £200.
 
MAF sensor does nothing for engine running on diesels it is for EGR exhaust gas ingestion measurement. MAP sensor does and if it is duff you will not get proper boost fuelling. Injectors can only leak gas up threads they cannot leak fuel. So if number one is full of fuel or fuel is running down the head and block from the others look at the spill pipes. Other than number four which can leak from the injector itself where the sensor joins.
 
Last edited:
MAF sensor failure (the one in the pipe from the air filter) :D cheaper than a gearbox & tc.
Unplugged and it's going like a rocket again. I can never remember which is MAP & which is MAF.
With regards to the injector #1, I took it out, cleaned up the threads in the head properly and re-torqued the injector, no more fuel in the well round the injector.
I'll do another ATF change on the gearbox next week and add the transfix.
Thanks for the advice guys:p:p
 
Last edited:
Datatek said:
At the start you said that the ATF came out of the box black and that the symptoms were like a slipping clutch.
That would suggest the box is fecked.
The cheapest option is the fit the stronger HP24 box from the 4.6 V8 obtainable from a breaker for around £200.
Click to expand...

I will be lining one up soon Keith, plus tc and transfer box for when the inevitable happens, and on a P38 it's when not if as we all know ;)
 
Mukiwa said:
MAF sensor failure (the one in the pipe from the air filter) :D cheaper than a gearbox & tc.
Unplugged and it's going like a rocket again. I can never remember which is MAP & which is MAF.
With regards to the injector #1, I took it out, cleaned up the threads in the head properly and re-torqued the injector, no more fuel in the well round the injector.
I'll do another ATF change on the gearbox next week and add the transfix.
Thanks for the advice guys:p:p
Click to expand...
Unplug the MAP sensor electrical connection, that's the sensor located on the fuel filter and it sure as hell will not go very fast. The MAF, the one in the air intake, is a different matter, they run fine with it unplugged.
 
Datatek said:
Unplug the MAP sensor electrical connection, that's the sensor located on the fuel filter and it sure as hell will not go very fast. The MAF, the one in the air intake, is a different matter, they run fine with it unplugged.
Click to expand...
The MAF plugged in I get no power, unplugged I get a very fast (for an oil burner) car.

Any recommendations for a replacement? Prices go from cheap crap at about £20 - £400!
Bosch, Lucas etc...
 
I'm glad you found it :)
We are pretty much at the same point in P38 development but I have manual & pre EGR. I would give it good run let the Gbox oil run through rad and tiny ports in auto before dropping 2nd time. Mine seems to be coming alive more I run it after first change recently. Really got some pull
 
Mukiwa said:
The MAF plugged in I get no power, unplugged I get a very fast (for an oil burner) car.

Any recommendations for a replacement? Prices go from cheap crap at about £20 - £400!
Bosch, Lucas etc...
Click to expand...
The cheap ones are NBG and £400 is way too much. Have you though of a second hand one from a breaker? They don't often fail so second hand is not a bad bet. Is your EGR disabled? If not pull the vacuum pipe off the EGR valve at the manifold and plug the rubber pipe with a screw.
 
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