XUD Bosch help

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EathanR
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Joined: 15 Feb 2017, 23:25

XUD Bosch help

Post by EathanR »

We've fitted a Bosch pump on our 1.9XUD in a ZX Estate today. Wiring is the only problem. Would also like to know what these two bits of the pump are, what the purpose is etc. It was a Lucas but we have a few Bosch pumps in stock so we swapped the two- we'll recon and store the Lucas pump till one day we may use it.

Anyway, if anyone could please advise that'd be marvellous, I've spent hours today sat in a freezing cold workshop trying to find out and have either missed the answer or as I expect can't find it.

PS, the Lucas pump had two plugs, with combined 7 wires. The Bosch pump will take one of the plugs from the wiring loom but we've joined it to one of the wires and it runs and stops. Is the one wire all we need connected to make it work properly? Seems a bit crazy. This is the newest car we've worked on in this fashion for ages, our forte is 70s Datsuns so this wiring stuff has messed us up.

EathanR
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Joined: 15 Feb 2017, 23:25

Re: XUD Bosch help

Post by EathanR »

Forgot the pictures. To clarify, its the black unit with the microswitch thing on top of the pump and the unit with one wire going to it on the front bottom edge that we want to know about please.
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KennyW
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Re: XUD Bosch help

Post by KennyW »

Can you tell us what model of Bosch pump it is as there several types ?

As this will tell what is required and assist in answering your question.

When CitroJim comes online he will certainly be able to give advise but the model of bosch pump will be needed.

Kenny

moizeau
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Re: XUD Bosch help

Post by moizeau »

Testing the memory here but I think the Bosch pump's stop solenoid only has a live feed and was earthed through the body, the Lucas has earth as well. The micro switch is linked to the cold start / wax stat lever, not sure if it keeps the plugs on for longer or something....? Maybe talking out of my armhole mind

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CitroJim
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Re: XUD Bosch help

Post by CitroJim »

The first picture is the cold advance solenoid... Activating this advances the timing slightly to improve cold starting and running... It should be deactivated when the coolant temperature hits 60degrees C.

When I've done conversions I've connected this solenoid to the glowplugs so that it's activated all the time the glowplugs are burning...

The second is a microswitch used to control glowplug post-heating. Some call it the part-load switch and it's function is to detect when the throttle is under halfway depressed. Under such conditions glowplug post-heating should continue until the coolant is above 60 degrees but above halfway, it is assumed the vehicle is under way, under sufficiently heavy load and therefore post-heating can be suspended.

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white exec
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Re: XUD Bosch help

Post by white exec »

Hi Eathan,
This Bosch publication does a good job in explaining the construction and working of a range of their pumps:
https://injectionpumps.co.uk/pdf/bosch_ve_pumps.pdf.
Also covers the ECU-controlled ones fitted to XM.

EathanR
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Re: XUD Bosch help

Post by EathanR »

Thanks for all the info. Went in and sorted it with the information on what the parts are. Have a nice running, driving Bosch powered ZX estate now, with all the cold start stuff seeming to work too judging by how lumpy it ran at first start in our worshop yesterday compared to today, after sorting the wiring. Thanks Kenny, Moizeau and Jim, very helpful. Also thanks Chris for that, will save that document and go through it at some point, before asking another question publicly lol.

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CitroJim
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Re: XUD Bosch help

Post by CitroJim »

Excellent news :D