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Re: My Citroen XM 3.0 PR-Vestige

Posted: Mon Aug 28, 2017 8:41 pm
by Dean
Thank you Paul, we may need to strike a deal on a new hydraulic pump too, i will txt you later in the week.

D

Re: My Citroen XM 3.0 PR-Vestige

Posted: Mon Aug 28, 2017 8:43 pm
by Dieselman
Dean wrote:Only 30 miles today but so far so good, the belt is holding up fine with no chirping or slip evident.

D
The issue is with the Gates belt, 6208MC. It is only 9.5mm wide instead of the proper 10mm an SPZ belt should be and it has an operating temperature range of +70c maximum.
You have now fitted an XPZ belt, which should perform properly as it has a higher load index, a higher operating temperature and is 10mm wide.

I have one to replace my Gates belt, but not fitted yet. At 2 for £5, getting a spare seemed like a good idea. ;)

Re: My Citroen XM 3.0 PR-Vestige

Posted: Mon Aug 28, 2017 8:52 pm
by Dean
Unfortunately, Will i have tightened that new belt twice since fitting and this afternoon i noticed it was chirping again on a cold start, certainly better as it is not destroying itself in minutes but not perfect either. I have noticed the pulley is not centred on the shaft....somehow, i wonder if the shaft is bent.

D

Re: My Citroen XM 3.0 PR-Vestige

Posted: Mon Aug 28, 2017 9:10 pm
by Dieselman
If it looks aligned, I would reduce the cut out pressure to standard before going further. A slight mis-alignment isn't going to be much of a problem as there is no idle roller. You can forget pulley angles as an SPZ belt has a standard pulley geometry.

Re: My Citroen XM 3.0 PR-Vestige

Posted: Mon Aug 28, 2017 9:15 pm
by Dean
Yep done that and fitted the SPZ belt when it all went back together, completely stripped and re-set the regulator and diverter.
The new belt is not shredding though, just slipping a bit every now and then.

D

Re: My Citroen XM 3.0 PR-Vestige

Posted: Mon Aug 28, 2017 9:19 pm
by Dieselman
Dean wrote:Yep done that and fitted the SPZ belt when it all went back together,
SPZ or XPZ.
It's going to need the XPZ.

Does your pump bolt have the proper tensioner bolt fitted?

Re: My Citroen XM 3.0 PR-Vestige

Posted: Sat Sep 23, 2017 6:30 pm
by Dean
Now the best of the weather is behind us i have decided to strip the wiring loom out of the car and try and solve my jerky throttle response problem out which i believe is related to the ECU not correctly interpreting the TPS signal.

The other issue is no reference voltage for the front knock sensor leaving the ECU, i get zilch at the knock plug.

I went into this thinking i had a short in the loom, hopefully with some part of the TPS wiring which was dragging down the reference voltage to nothing and upsetting the TPS signal, i can now confirm this is not the case and the loom and all my wiring is fine, I even powered the ECU direct from the batter by making a small power supply loom and i can confirm it is outputting no reference voltage from the board, this means the ECU is a wrong'un.

I fitted the Manual ECU John gave me and the car started and ran great, BUT I still have no reference voltage to the front knock sensor and this is not correct, the ECU cannot see the output of this sensor without a reference voltage surely? other problems this ECU has is a poor hot start, I need to crank a good couple of seconds before the engine fires and it doesn't catch cleanly when it does if that makes sense. The final issue is two-fold, although the jerky transition between trailing throttle and accelerating and vice-versa has gone which is good with this manual ECU i have another issue.
when pulling away the engine idle drops, so the car is in D and idling happily, i apply a little throttle and the revs drop and the dash warning lights come on for a second as the engine nearly stalls then it recovers and the car lurches forward and then nearly stalls again before pulling itself together and I can drive off normally, when I do get going its ok until I want to accelerate briskly (50%+ throttle) and then the engine coughs and hesitates like mad, the more throttle is applied the worse it gets. To me, this is a classic bad TPS sensor issue but the sensor is working fine, it is the ECU that is not interpreting the signal correctly.

This evening i found Johns thread on Fenix ECU mods and one of the recalls was for exactly what the Auto ECU was doing, jerky transition between trailing and applied throttle.

Unless anyone has some pearls of wisdom i am going to source a 3rd ECU before going any further, there is always the chance these ECU's are incorrect for my loom/engine combination or both knackered, if i had problems outside of the ECU i would not expect an ECU swap to solve one set and introduce a new set of problems.

Matthew/Paul, i will PM you both tomorrow when i am at the laptop, it's a pain on the phone, i need to source another ECU and find out if anyone else is getting a reference voltage on the front knock sensor.

D

Re: My Citroen XM 3.0 PR-Vestige

Posted: Sat Sep 23, 2017 6:53 pm
by Dieselman
It sounds like a lean mixture issue.

Re: My Citroen XM 3.0 PR-Vestige

Posted: Sat Sep 23, 2017 7:48 pm
by Dean
It feels like lean mixture under load as the more you push it the worse it gets yet i put the Auto ECU on and it will pull fine so in my head that rules out any of the hardware.

D

Re: My Citroen XM 3.0 PR-Vestige

Posted: Sat Sep 23, 2017 8:07 pm
by citroenxm
Dean.. what loom are you useing on your car.. yogs or another... this deepens.. ill let you into another secret.. yog does have her original harness on her. As the engine fitted was a later engine the was differences in harness between them.. how ever the later engine harness had circular engine to main loom plugs as per later cars where yogs were square. So i had a later engine with early harness original to yog. Some of the engine components were in slightly different places