My 2.2 HDi coupe is slow. Doser delete? MAF?

Discuss, ask, or get help with engine and mechanical queries in here.

Moderator: Moderators

Post Reply
Posts: 2
Joined: Thu Jun 13, 2019 7:31 pm

My 2.2 HDi coupe is slow. Doser delete? MAF?

Post by franster »

A bit of googling has brought me here and encouraged me to sign up, so Hi!

I have an 02 2.2hdi coupe, and it is seriously, problematically slow. On my first look under the bonnet, I saw some unusual pipework, which I presumed to be a bodge, but later seems to be an air doser delete. There are numerous blanked vac pipes, and I have no idea whether tis is what's causing the car to be so down on power.

I've also read that these cars are really sensitive to a good MAF, and that a faulty MAF can cause power issues.

Does anyone have any diagrams of vac pipes locations, etc, that might shed some light n whether everything is as it should be, or any advice on where I should be looking to try and solve this problem.

Thanks in advance. All advice much appreciated.

3.0 24v
Posts: 3282
Joined: Fri Apr 06, 2012 9:02 pm
Location: Bournemouth

Re: My 2.2 HDi coupe is slow. Doser delete? MAF?

Post by GingerMagic »

Hi, welcome to the forum :cheesy:

First thing I would check is the throttle cable clip, it fits on the ribbed part of the throttle cable near the airbox - without this then you would have slack in the cable, so no matter how hard you press the pedal, it's only part working....

Also check out the 'How to' guides on the main page, there are a few tips there, and also a guide to making the vacuum supply more efficient (hopefully the pictures are still there)

Worst case, take a few pictures of the pipework as best as you can and post them here for us to ponder over :cheesy:

Hope this helps.
1999 T4 family wagon
2005 Vauxhall Meriva
1998 406 V6 Coupe - Midlife crisis..!
PP2000 user, can help with faults / diagnostics in the Bournemouth area.

2.0 Turbo
Posts: 269
Joined: Sun Aug 24, 2014 12:18 pm
Location: Netherlands

Re: My 2.2 HDi coupe is slow. Doser delete? MAF?

Post by frog »

This document describes the 2.2 HDI engine.

Have a look at page 9, 10 and 11 (PDF document page 19, 20 and 21).
2.2 HDI overview diagram.jpg
The air doser is the "Throttle housing (EGR)" (57). It is operated by the "Throttle housing control electrovalve (EGR)" (56) which applies vacuum to operate the air doser. In your case, that vacuum pipe will be blanked off.

The other electrovalves applying vacuum are 8 and 9 which operate resp. the "variable geometry turbo control diaphragm" (10) and the "exhaust gas recycling valve (EGR)" (11).

On the 2.2 HDI, if there is no vacuum (e.g. due to leakage in the vacuum pipes), the "variable geometry turbo control diaphragm" is always such that the turbo produces its maximum boost. Applying vacuum reduces the boost.
Current "fleet":
2003 406 Estate 2.0HDi 110 - 7 seater
2001 Citroen Saxo 1.6i 8v 100

Previously owned:
2000 406 Sedan 2.0 HDi 90
2000 406 Coupé 2.0i 16v 138 - Riviera Blue

PP2000 user, can help with faults / diagnostics in the Netherlands.

1.8 8v
Posts: 47
Joined: Wed May 04, 2016 12:34 am
Location: New Zealand

Re: My 2.2 HDi coupe is slow. Doser delete? MAF?

Post by WillNZ »

My 2.2 had similar problems, turned out to be a combination of faults. Main ones were the variable vanes on the turbo were gummed up in the mostly "off boost" position and the MAF was faulty. Also, the vacuum system was leaking a bit and the actuator arm (item 71 in the schematic by frog above) for the swirl flaps was broken.
I firstly fixed the vacuum leak and reattached the swirl flap actuator arm. Then connected it to PP2000 and took it for a run with live readings displayed. This told me there was no real boost and also that boost available was constant, not varying as it should. So removed the turbo and found the vanes gummed up with carbon. Freed them off, tested the vane operation on the bench to confirm the vacuum system was working the vanes, reinstalled it and took it for a run with live PP2000. This showed me the turbo was now boosting better and turbo boost was varying, but still no real power. I then disconnected the MAF and rove with it disconnected. Immediate improvement in power.. so decided that the MAF needed replacement despite PP2000 not flagging it as faulty. The $tealers here in NZ wanted blood money for a new MAF so ordered one from a reputable diesel outfit in your neck of the woods (UK) as I assumed they would not sell rubbish chinese junk.. got one from them, fitted it and massive difference! Got it from ukdieselpartsltd on fleabay, part number Peugeot 2.0 / 2.2 HDi - Mass Air Flow Meter - 5WK9628 / 5WK9628Z
Still running beautifully almost 18 months later so MAF seems to be good...
I have also since blanked off the EGR and de-coked the intake which was VERY VERY VERY blocked with EGR crud, that again made a very noticeable difference to the running of the engine. Would highly recommend doing it.

Posts: 2
Joined: Thu Jun 13, 2019 7:31 pm

Re: My 2.2 HDi coupe is slow. Doser delete? MAF?

Post by franster »

Thanks for all the replies.

I gambled on a new MAF from dieselpartsuk. Fitted it this evening and the car is transformed. It goes like a scalded cat. I'm thinking it may have been played around with, as it feels like it's got way more than 136bhp. Are there any obvious ways to tell what may have been done?

Post Reply