xantia HDI Intermitent turbo lag

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Dannyboy
Posts: 62
Joined: 10 Jul 2010, 17:24
Location: Dublin Ireland
My Cars:

intermittent boost

Post by Dannyboy »

Tks HDI............I need to get cracking on my vac system so.....thk for the explanation............dannyboy.
Dannyboy
Posts: 62
Joined: 10 Jul 2010, 17:24
Location: Dublin Ireland
My Cars:

Developments !

Post by Dannyboy »

On first start up and when driving out my driveway I noticed the car had no power and the engine management light was staying on....oh..oh...Pulled in down the road and did a restart......all back to normal. Felt it was now worth reading the codes and may help me sort the intermittent turbo boost snag. Dropped in to a friendly Independent Citroen Specialist I know and he read the codes.....only one ...P603....he showed it to me and it read ECU. he advised a reset and it was 60/40 it would stay away...if not it means a replacement ECU. I asked about checking the vac pipes and he advised always a good idea. Intermittent boost prob was much improved on the way home.....now boost avail all the time except appears a bit weak in 2nd gear for some reason . I checked the vac pipes when I got home and all seemed clean and unblocked. . Couldn`t watch the waste gate while I sucked on the pipe but it held suction and kept my tongue firmly stuck to the pipe...so no leaks. Started the engine ( tongue removed obviously ) and there was suction from the pump but seemed a bit weak....I replaced the air filter, was somewhat dirty and car seems noticeably zippier............fingers crossed snag seems to be gone.........anybody any experience with this problem ? .......if it returns is it an ECU ( gulp ! ) replacement ?.....what is the cost of a new one and can they be repaired ?
citroenxm
Posts: 8061
Joined: 30 Dec 2004, 23:10
Location: Somewhere in North Wales, Anglesey
My Cars: M reg Xm S2 2.1td Auto Exclusive. 269k and rising
L reg XM S1 V6 12v Manual SEi
L 94 XM 2.1 TD auto total resto

2008 Peugeot 207 Sw 1.6 16v hdi. 217k and rising
2010 Peugeot 207 SW 1.6 8v HDi 161k and rising
x 70

Post by citroenxm »

If it puts the engine light on on boost, but then goes out after an engine stop then the Solinoid valve as talked about above is NOT working, and too much boost is going into the engine, or too little..

Yes BOTH solinoid valves can go at the same time, this blue one Ive got in had this!!

From what Ive just investigated I think the turbos work in the opposite way to earlyer ones, in that when the turbo is staionary the wastegate is OPEN then upon starting the Vac sucks the wastgate Closed eneableing it to work.. then when the boost pressure set in the ECU is sensed, the ecu switches the solinoid valve and it releases the wastegate OPEN to prevent excess pressure...

I always thought they worked theother way and that the gate is nautrally closed.... but its NOT...

The Suction pipe with the T joint goto the MIDDLE pipe, then the EGR and Turbo waste gate go to the outlets to the side of the tops of the solinoid valves..

Paul
Sharing a pug 207 1.6 hdi Sw 16v.
M reg Xm 2.1 td auto exclusive S2 269k and rising
L reg XM V6 12v SEi auto .. Light project

A very sad...
1994 XM 2.1 d auto
Dannyboy
Posts: 62
Joined: 10 Jul 2010, 17:24
Location: Dublin Ireland
My Cars:

turbo boost

Post by Dannyboy »

Good gen Citroen xm......tks for that......the eng management light has only come on once and that was just after start up.........crawled out the drive and hadn`t really given it any throttle when I noticed it.....so doesn`t appear to be an over boost........fingers crossed.....has stayed away along with intermittent boost problem for 2 days now after ECU reset. . Any idea how much suction should be from the vac pump ?.....with eng running @ idle and with the tee piece to the egr and boost control valves from the vac pump disconnected and touched to my hand it will suck against the skin but not uncomfortably so.........I expected it to be stronger......perhaps above idle it is ....hard to know without having a vac gauge and knowing the required figures.....................Dannyboy
citroenxm
Posts: 8061
Joined: 30 Dec 2004, 23:10
Location: Somewhere in North Wales, Anglesey
My Cars: M reg Xm S2 2.1td Auto Exclusive. 269k and rising
L reg XM S1 V6 12v Manual SEi
L 94 XM 2.1 TD auto total resto

2008 Peugeot 207 Sw 1.6 16v hdi. 217k and rising
2010 Peugeot 207 SW 1.6 8v HDi 161k and rising
x 70

Post by citroenxm »

I dont actually know Danny... It should be reasonable for the size of pipe..

I dont know figures myself..

My diagnostics above was worked out from when I had the exhaust off this HDi here. When the valves were NOT working and the engine running there was no turbo noise. When I changed them to working ones as soon as I started the engine I had the - um, how can I explain, low inertia noise, a sort of turbo whistle it idle, I know Straight away it was all working then.. so thats why I say the electro valves apply a suction to operate, then release to open the wastegate..

Paul
Sharing a pug 207 1.6 hdi Sw 16v.
M reg Xm 2.1 td auto exclusive S2 269k and rising
L reg XM V6 12v SEi auto .. Light project

A very sad...
1994 XM 2.1 d auto
Dannyboy
Posts: 62
Joined: 10 Jul 2010, 17:24
Location: Dublin Ireland
My Cars:

follow up

Post by Dannyboy »

Tks for that citroenxm......The snag is still there but not asbad after ECU reset. I would like to check out the vac system.......they seem to give control problems on high mileage diesels. A Diesel vectra I had for a couple of months was in a mess because of vacuum system leaks. The fix was simple eventually. My local friendly Independent sorted it and I know he has a vac tester......I think I`ll pay him a visit. ......rgds.....dannyboy.
Dannyboy
Posts: 62
Joined: 10 Jul 2010, 17:24
Location: Dublin Ireland
My Cars:

Occasional turbo lag

Post by Dannyboy »

Got around to having another look......suspected the EGR might be sticking intermittently so disconnected the vac pipe to the EGR solenoid and blanked it ............no difference Initially it appeared to solve the problem but back to problem on the second drive. Put a blank where the exhaust pipe connects to the inlet manifold ( EGR gas ) and made no difference either. There appears to be a third vac solenoid.......where the throttle cable comes out to a drum where it is converted to electrical input there is a vac servo which controls a butterfly in the intake pipe.........I was surprised to see a butterfly valve ..........didn`t think modern ( by my standards ) diesels used them .....could this butterfly valve / servo be my problem ? ....rgds...dannyboy
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