P38 diesel down on power

Littelwill

Well-Known Member

Posts

3,065

Location

Lincolnshire

• Mar 8, 2014

• #1

Hi everyone. Just a quick one... Whilst trying to determine if my MAF sensor is faulty I unplugged it and test drove it, it made a good deal of difference I then unplugged the MAP sensor pipe that leads to the inlet manifold this made a massive difference to the way the truck drove. Could anyone please explain why it would make such a big difference.

W

 

wammers

No longer with us, RIP

Donater

Posts

58,170

Location

Preston Lancs.

• Mar 8, 2014

• #2

If you unplug the MAP sensor the ECM does not know the manifold boost pressure so cannot fuel properly. Large loss of power. MAF disconnected, or misreading, although it has no direct bearing on it, can cause the ECM to misinterpret air conditions.

 

Littelwill

Well-Known Member

Posts

3,065

Location

Lincolnshire

• Mar 8, 2014

• #3

Thanks for that Wammers. To me it felt better without the MAP pipe connected to the manifold.

 

Datatek

Well-Known Member

Posts

46,450

Location

Near Poitiers SW France

• Mar 8, 2014

• #4

Littelwill said:

Thanks for that Wammers. To me it felt better without the MAP pipe connected to the manifold.

Click to expand...

You need to look at the MAP sensor on diagnostics. Check the pipe is not perished and the spigot in the manifold is not blocked with crap.

 

Littelwill

Well-Known Member

Posts

3,065

Location

Lincolnshire

• Mar 8, 2014

• #5

Ok I'll go check that now thank you.

 

Littelwill

Well-Known Member

Posts

3,065

Location

Lincolnshire

• Mar 8, 2014

• #6

Ok just poked the spigot on the bottom of the inlet manifold with a pin and had to force it in. There was some baked on crap on the end off the pin so did this a few more times hopefully this will have helped thanks for the tip Datatek

W