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1.9 tdi aaz idling

Posted: 21 Jul 2020, 14:40
by marc
I have a 1986 T25 with an1.9 AAZ engine coversion and Bosch VE diesel pump.  It runs fine starts well but the idling speed once set either increases or decreases after a few hundred miles. Once reset via the idling screw thre same thing happens. 

As a matter of interest what is: -

a). the electrical connection on the pump just below the "unleaded" print on the rubber hose at the bottom of the picture?
b). the electrical connection in the centre of the injection pipes at the back of the pump, which is obscured by the throttle cable?

mant thanks

Image

Re: 1.9 tdi aaz idling

Posted: 23 Jul 2020, 11:53
by colinthefox
marc wrote: 21 Jul 2020, 14:40 As a matter of interest what is: -

a). the electrical connection on the pump just below the "unleaded" print on the rubber hose at the bottom of the picture?
b). the electrical connection in the centre of the injection pipes at the back of the pump, which is obscured by the throttle cable?
Can't help you with your idling issue but......

The injection pump was designed to operate with a very basic form of Electronic Control Unit (ECU) [E D I T] but the AAZ is not a tdi [/E D I T]

a) is the commencement of injection solenoid which adjusts the timing according to what the ECU is telling it.
b) is a sensor which sends a signal to the ECU when pressure rises in the pipe to the injector.

As you haven't got an ECU these bits won't do that, and the pump will behave pretty much like the older version which didn't have them. The timing setting might be slightly different, but I don't have any experience with that.

This picture is relevant.

Image
Not my picture, so thanks to whoever posted it.

Re: 1.9 tdi aaz idling

Posted: 23 Jul 2020, 20:14
by marc
Thanks.