TZD Turbo timing advance device repair or delete

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assembled
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TZD Turbo timing advance device repair or delete

Post by assembled »

Hi, my TZD Turbo BOSCH pump seems to have two timing advance/correction circuits:
1. coolant controller wax device.
2. altitude controlled electronic valve at the bottom of the pump. Controlled by a round altitude switch on the bulkhead.

The 2nd device is not connected. 1st device is not working, I think. Does anyone know how exactly these are supposed to work and if they could be left disabled? Should they be fixed?

What is their effect on cold/warm climate, altitude, etc? If the altitude switch is set to 0,1 bar (read that somewhere), then it should switch at approx 800 m altitude. What would it actually do? Is it worth fixing for a mountain trip, for example?

Also, what is the correct configuration of the timing devices when adjusting pump advance?

Thanks!
1992 TZD Turbo berline, aircon, ABS
1991 TZD Turbo berline
1989 GTi 4x4 berline, ABS
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Jaba
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Re: TZD Turbo timing advance device repair or delete

Post by Jaba »

The waxstat is there to advance the injection a tad when the engine is cold to aid cold starting and running. Once the coolant has warmed up it does nothing at all. From which you can deduce that it does not matter too much if it is non functional as long as the car starts promptly that is.

Your altitude device was never fitted to UK cars so I have no experience with it I am afraid. But as altitude affects air pressure then there will be less oxygen being taken in the higher you go. I assume that the device increases turbo pressure to force more air and 02 in. The difference would be marginal I imagine. For several years when I had a TD I took it every winter to stay in the Alps for my transport there. My local Col was 2100m and the TD went up that without any noticeable loss of power. Whereas my GTi which replaced the TD was noticeably weaker, demonstrating (to me) that with a turbo the altitude has a reduced effect on performance.
A nice gadget to have though if you live in mountainous territory, enjoy playing with it.
The Joy of BX with just one Citroën BX to my name now. Will I sing Bye Bye to my GTI or will it be Till death us do part.
assembled
Confirmed BX'er
Posts: 91
Joined: Thu Jan 05, 2012 2:21 pm
Location: Arendal, Norway
My Cars: 1991 Citroen BX TZD Turbo
1989 Citroen BX GTi 4x4
x 2

Re: TZD Turbo timing advance device repair or delete

Post by assembled »

Thanks for your input, Jaba, I appreciate it.
1992 TZD Turbo berline, aircon, ABS
1991 TZD Turbo berline
1989 GTi 4x4 berline, ABS