Underpowered diesel

[Eddie Nuff]

Maybe someone can see something I can't:-

Wife's Ford Focus but with the PSA 1.6HDi in it. Was really underpowered, running at about 40% of it's power so I've had the egr valve off, given it a damn good clean out and freed off the valve itself. Result is that the engine is much more responsive at low revs and the black smoke has gone, but still nothing at med/high revs. The turbo is fine having replaced it some 26k miles ago. The vanes are good and the centre shaft is solid, so I removed the Turbo Boost Solenoid which was replaced at the same time - 26k miles ago. Solenoid tested as working and the internals are clean and the valves working, so refitted and now the engine feels a lot less restricted, pulls at low revs and tries at c2000rpm+ but the turbo is very soft and intermittent. There used to be a real kick in the back of the seat before but now it feels much more like a soft turbo. I'd say the engine is now performing at about 80% of its true performance.

If the turbo and TBS are working okay what else could have an effect on the lacklustre performance at med/high revs?

[vborovic]

Air intake/doser?

[elma]

Brakes binding?

[RichardW]

Probably the MAF - they often don't set a fault code, but lack of power is the obvious symptom. You need to check on lexia to see what it is reading, and that it rises smoothly with the revs.

[Eddie Nuff]

Air intake pipes are fine, air filter clean. Brakes not binding. No fault codes showing on a generic reader. Will Lexia work on a Ford, even with a PSA engine?

CMIIW but from memory if I remove the connector to the MAF and the power situation is the same when driven the MAF is toast - yes?

[vborovic]

Will Lexia work on a Ford, even with a PSA engine?

Of course it won't work, Ford uses VCM II I believe

[Paul-R]

How many miles has the car done? What year is it? Do they have a particle filter?

[Eddie Nuff]

DPF removed years ago when new cat fitted. Also removed from ECU. Had no problem with it in this respect until the past couple of months when the engine has been sluggish.

[GiveMeABreak]

Air intake pipes are fine, air filter clean. Brakes not binding. No fault codes showing on a generic reader. Will Lexia work on a Ford, even with a PSA engine?
CMIIW but from memory if I remove the connector to the MAF and the power situation is the same when driven the MAF is toast - yes?

Yes, that's one way to test the MAF - disconnect the wiring plug temporarily and see it that improves anything, but getting a diagnostic check will also help to save guessing. The Lexia / Diagbox will only interface with PSA vehicles, despite the engine being the same.

[citroenxm]

Neil.. the turbo solinoid is controlled by vaccumm... exactly the same as the xantia..

you can even use the xantia ones on these engines.. now even if the solinoid opens - I assume from solinoid valve you mean wastegate thats directly under the turbo?? Now even if the wastegate closes.. indicated when the engine is running the rod next to the oil feed pipe is fully down.. pull the small vac pipe off the side it should open or go right back up.
what I was comming to though is if the vac control electrovalve isnt functioning properly it can give issues.. it lives down the back of the block above the drivers side half shaft housing.. I do it by feel from the top.. I dont think theres a way to test them.. only replace..

[Eddie Nuff]

Looks like the MAF sensor is kerpluncked. No difference in performance when I unplugged it so took it off and cleaned it down with contact cleaner. No difference when I put it back on. See if I can find another one.

[GiveMeABreak]

If you haven't got access to a Lexia, disconnect the MAF plug and go for a spin and see if the symptoms are still there. If they are it may not be the MAF. If you have access to a multimeter, here's a guide on testing it:
http://easyautodiagnostics.com/misc-ind ... t-basics-2

[Eddie Nuff]

You got an English language version of that link? I couldn't make head nor tail of it.

[GiveMeABreak]

You got an English language version of that link? I couldn't make head nor tail of it.

I just realised I linked to page 2 - in case you didn't figure it, here's the link to page 1:
http://easyautodiagnostics.com/misc-ind ... t-basics-1

In case you weren't taking the Michael (:-D ) it is in English ??

[Eddie Nuff]

I was most definitely taking the mick as anything electrical goes straight over my head.

I'll have a read, see if it means owt to me.