Outer Limits 4x4 Board

1991 Mk1 2.5 TDI V5MT1 5 sp
Greetings. Working on the 2.5 today noticed a stray wire so started hunting. Then I noticed the wastegate plumbing. All the other diesels I had the boost compensator and wastegate ran off the upper deck pressure. That way the govenor can introduce more fuel volume when needed and the wastegate can dump the exhast gases. This engine has a pipe going from the boost compensator to the wastgate actuator. That's it. So how in gods name can the wastegate or boost compensator operate without manifold pressure sense. This engine run like a dream, plenty of grunt and can cruise comfy at 100kph and seems there is some left over. So never needed to look at the system at all. Another thing I noticed was a small black box mounted on the induction manifold. Four wires going into an OEM loom. Almost looks like some CHT setup.Never thought to question this either. It has no EGR valve, nor boss on the manifold. 1991 4D56 2.5 TDI. I have noticed other differences on this vehicle but put it down to being ex military. But now I am wondering what is going on. Compared to the other 2.5 this one is a "racehorse". But am concirned now because there is no way I can see that the wastegate actually works!???
Boost dump valve dumps at 15 psi and manifold pressure is around 13 psi according to the boost gauge. Any thoughts please?

Can you take a photo of what you are describe?
NJ

Thank you for replying NJ. What is accepted practise here do I post photos direct or a link to photos.

I usually use Photobucket

yeh pics would be good
photobucket is the go

turbine wrote:Thank you for replying NJ. What is accepted practise here do I post photos direct or a link to photos.

Create an account with photobucket.com (free) and they will host photo's for you. Then click the IMG button above, paste the link into the message then click the IMG* button again.
As in [img]leave%20no%20spaces%20but%20put%20link%20here[/img]

NJ

An import or import exchange motor ?
The late 80's and early 90's Mitsu made lots of running changes until things were standardised.
Doesn't surprise me one bit.
For the Gen 2 the 2.5TDI had some changes to the injection/intake system resulting in a little more power.
I know of someone who has 91 Gen 1 import 2.5TDI and he reckons it flies compared to other 2.5TDI's he has owned/driven.
Japan usually has higher quality fuel than here so engines tend to be in a higher state of tune over there although I think that gap has closed now (or almost).