P38A P38 DSE Manual (non-EGR) No turbo boost

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twilliams4174

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Morning all,
I'm new to the forum so apologies if this is in the wrong place. From lurking I have seen that sluggishness/lack of power is a common theme with these old diesel p38s but I've tried a lot of the advice seen on similar threads so thought I'd outline my problem in more detail to see if anyone could share their expertise on the matter.

My P38 is a 94 Diesel Non-EGR model in manual guise.

Back in August I was driving back from a trip to Blackpool UK to Newcastle upon Tyne - anyone who's done that route will know it's a fair climb up the M6 through the lakes. It was the hottest day of the year, and climbing up shop summit I suddenly started to lose power and blowing black smoke - to the point where it wouldn't go more than about 5mph uphill (Temperature dead-on half way the whole time). I managed to limp it to relatives I have in the area and left it with their mechanic who diagnosed the fault as a bad turbo and seized actuator and replaced it. When he returned the car it was much better but not perfect - he said that it needed a new actuator still as the turbo supplied was sans-actuator - so he reused the old one - but it should still get me home. One good second hand actuator later I assumed all would be dandy but on my fortnightly commute to Barrow-in-Furness the problem arose again - no power uphill, black smoke out of the rear, won't rev above about 3000 RPM. RAC called out, reading a boost pressure sensor fault - after reading through similar threads I understand that this is a common fault. After being recovered home I ordered two - one second hand LR OEM part and one cheap Chinese one, on the basis that one of these would likely be ok. Since then I have also:

-Cleaned out the intercooler
-Replaced all turbo outlet hoses
-Replaced the MAP line
-Cleaned the MAP outlet under the inlet manifold
-Tested the lift pump, all good

After replacing the MAP sensor with the s/h LR item the situation is such: Starts first time, idles perfectly, loads of power low end, revs freely, no smoke - running well. But after the revs hit about 2000 rpm where I'm used to the turbo giving it a kick up the arse there's nothing, like it's being held back. There's a very slight whooshing sound like the boost is escaping somewhere but this could just be my imagination.

Does anyone have any idea what else it could be, something I haven't checked? I had a look in the usual spots for a power box/chip but all I found was a 30s timer relay with what looked like a 555 chip next to the BECM - glow plugs presumably?
 
Your method is good with what you’ve checked so far.
Have you checked the actuator recently to make sure it’s not seized up? Take the air intake to turbo off temporarily and see if it works revving up at a standstill without it fitted. delamination of the pipes internally is common, which usually then only shows itself under boost
One main difference between egr/pre egr is you have an IAT sensor fitted. I have no idea what happens when those go kaput but I doubt that’s your issue.
 
Morning all,
I'm new to the forum so apologies if this is in the wrong place. From lurking I have seen that sluggishness/lack of power is a common theme with these old diesel p38s but I've tried a lot of the advice seen on similar threads so thought I'd outline my problem in more detail to see if anyone could share their expertise on the matter.

My P38 is a 94 Diesel Non-EGR model in manual guise.

Back in August I was driving back from a trip to Blackpool UK to Newcastle upon Tyne - anyone who's done that route will know it's a fair climb up the M6 through the lakes. It was the hottest day of the year, and climbing up shop summit I suddenly started to lose power and blowing black smoke - to the point where it wouldn't go more than about 5mph uphill (Temperature dead-on half way the whole time). I managed to limp it to relatives I have in the area and left it with their mechanic who diagnosed the fault as a bad turbo and seized actuator and replaced it. When he returned the car it was much better but not perfect - he said that it needed a new actuator still as the turbo supplied was sans-actuator - so he reused the old one - but it should still get me home. One good second hand actuator later I assumed all would be dandy but on my fortnightly commute to Barrow-in-Furness the problem arose again - no power uphill, black smoke out of the rear, won't rev above about 3000 RPM. RAC called out, reading a boost pressure sensor fault - after reading through similar threads I understand that this is a common fault. After being recovered home I ordered two - one second hand LR OEM part and one cheap Chinese one, on the basis that one of these would likely be ok. Since then I have also:

-Cleaned out the intercooler
-Replaced all turbo outlet hoses
-Replaced the MAP line
-Cleaned the MAP outlet under the inlet manifold
-Tested the lift pump, all good

After replacing the MAP sensor with the s/h LR item the situation is such: Starts first time, idles perfectly, loads of power low end, revs freely, no smoke - running well. But after the revs hit about 2000 rpm where I'm used to the turbo giving it a kick up the arse there's nothing, like it's being held back. There's a very slight whooshing sound like the boost is escaping somewhere but this could just be my imagination.

Does anyone have any idea what else it could be, something I haven't checked? I had a look in the usual spots for a power box/chip but all I found was a 30s timer relay with what looked like a 555 chip next to the BECM - glow plugs presumably?
The 30s timer is a hot start fix which indicates that the FIP timing is out due to chain stretch which could if it fails cause the engine to run on cold star settings which would give smoke..
The fact that the dash gauge shows the temperature is OK does not mean that the temperature sensor for the EDC has not failed.
It really needs diagnostics as there are a lot of things that could give the symptoms you describe.
 
Appreciate the advice, thank you - will have a look at the turbo intake hose this afternoon.
Re diagnostics, before I shell out for a nanocom - does anyone know of any garages in the north east that has the equipment for a p38? I’ve tried spanner monkeys after a recommendation and they no longer keep the equipment sadly.
 
Appreciate the advice, thank you - will have a look at the turbo intake hose this afternoon.
Re diagnostics, before I shell out for a nanocom - does anyone know of any garages in the north east that has the equipment for a p38? I’ve tried spanner monkeys after a recommendation and they no longer keep the equipment sadly.
Bite the bullet and get a Nanocom, no point in wasting money on garage diagnostics.
 
If you can get the vacuum pipe off the turbo bidy connection and get a vacuum pump on the pipe you'll see if its a damaged diaphragm inside. These turbos supply a vacuum from themselves and are independent of an external vacuum source. 👍
1727783040867.jpeg
 
The actuator should have been tested before being refitted.
Can you ask the garage this over the phone.
If they say yes knowing the fault was there then this could give you a good indicator as to test the actuator.
If they say no then there is a good chance the old turbo core was ok🤔
 
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