P38 Diesel power issue

landyboots · Jul 30, 2019

Hi all. Was just wondering if there is any way to squeeze a bit more performance out of the M51 without fitting a power box or chipping the ECU. A friend has an Auto and is convinced she heard somewhere that unplugging something will give a bit better performance?.

Thanks people.

RangeRoller dt · Jul 30, 2019

Chip or PSI power box will get more oomph but auto box will wear faster.

Generally M51 will shift well if they are maintained to a good standard. What mileage is your friends’ P38??
150,000miles injectors/pumps can start to tire, renew leak off pipes and swill the crap out of the intercooler would be my first port of call, and check fuel flow from lift pump as in Wammers’ test in tech section

Only chip/box a healthy engine, chipping an engine to make up for lack of power due to wear won’t end well

landyboots · Jul 30, 2019

RangeRoller dt said:
Chip or PSI power box will get more oomph but auto box will wear faster.

Generally M51 will shift well if they are maintained to a good standard. What mileage is your friends’ P38??
150,000miles injectors/pumps can start to tire, renew leak off pipes and swill the crap out of the intercooler would be my first port of call, and check fuel flow from lift pump as in Wammers’ test in tech section

Only chip/box a healthy engine, chipping an engine to make up for lack of power due to wear won’t end well

Thanks RangeRoller dt.....It's on 195k miles and sounds good with little smoke on dipping the throttle. It was well maintained. She had heard from someone about disconnecting something to help get a bit more oomph but I know it wasn't the EGR. She recalls that it was either a plug or a pipe from the fuel or air system... :-/

RangeRoller dt · Jul 30, 2019

Best thing for them to do is get it plugged into something called a ‘Nanocom 06 diagnostic’ device. (There May be help on here with that)
This will tell you exactly what is wrong and be cheapest solution rather than buying bits and hoping for the best - there are a lot of expensive bits on these. Price up a new MAF and you’ll understand what I mean - there are 100 of bits like that and it could be any one or more of them.

will also tell you if in fact it is the engine or if the gearbox/torque converter is the reason for your sluggishness

RangeRoller dt · Jul 30, 2019

There’s also simple checks that cost nothing to test, and pennies to replace if you do find something if you are interested.

Wammers pump test would be my priority and check clear pipe for bubbles while you are there.

Few pics of the engine would be nice...

Grrrrrr · Jul 30, 2019

Sounds like BS.

Might be someone thinking of unplugging the MAF if it has EGR? Or maybe they think unplugging temperature sensor will trick it into thinking engine is cold and bung in more fuel?

Best thing is a good service. Filters, intercooler flush, maybe clear out the cam cover filter.

Or you could adjust the turbo waste gate to get a bit more boost if you want to dice with blowing it.

Datatek · Jul 31, 2019

There is nothing you can unplug to get more power. If it smokes on lift off, it sounds like the valve oil seals are worn, at the mileage stated, the engine maybe a bit tired.

wammers · Jul 31, 2019

Datatek said:
There is nothing you can unplug to get more power. If it smokes on lift off, it sounds like the valve oil seals are worn, at the mileage stated, the engine maybe a bit tired.

Worn valve stem seals don't have the same dramatic effect on diesels as they do on petrol engines, as no vacuum is generated in the manifold when the throttle is closed. He could try an air filter and clean out the intercooler and cam cover as a first step. But i agree there is nothing to unplug to get more power.

RangeRoller dt · Jul 31, 2019

maybe MAP/MAF is goosed or something so runs better on nominal value? it’d probably show up on a nanocom.

P38 Diesel power issue

landyboots

Active Member

RangeRoller dt

Well-Sprung Member

landyboots

Active Member

RangeRoller dt

Well-Sprung Member

RangeRoller dt

Well-Sprung Member

Grrrrrr

Technician, Bodgit & Scarper Ltd

Datatek

Well-Known Member

wammers

No longer with us, RIP

RangeRoller dt

Well-Sprung Member

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