300tdi cruise control vacuum issue

Russ6334 · Sep 11, 2021

Hi all

just working through some niggles on my D1
The vacuum hose from the brakes goes all around the engine to the front near side where it’s open ended.

there is a vacuum control system that I understand does the EGR which I’m about to delete.

where does this hose go? Nobody seems to be able to tell me

thanks
Russ

lynall · Sep 11, 2021

Iirc one was egr, and other was recirc flap in heater box in the car?
I think if you follow the main servo vac pipe to the fat t piece, the small pipe used to split on that T all the time.

Russ6334 · Sep 11, 2021

lynall said:
Iirc one was egr, and other was recirc flap in heater box in the car?
I think if you follow the main servo vac pipe to the fat t piece, the small pipe used to split on that T all the time.

Not quite sure I understand you re the T, so from the brake T it goes to the front near side, where does it connect to at the front near side?

thanks

lynall · Sep 11, 2021

Russ6334 said:
Not quite sure I understand you re the T, so from the brake T it goes to the front near side, where does it connect to at the front near side?

thanks

I could be talking bollacks here, but as I remember it the main vac line from vac pump to servo has a t piece in it, and everything else is fed off of that t piece, egr/recirc/cruise.
Tbh long time since I saw one.
In think there is another mag valve under the spare battery tray behind pasenger side headlamp?

Mine was a late 97 EDC auto, reg Iirc R342PRD.

Russ6334 · Sep 11, 2021

lynall said:
I could be talking bollacks here, but as I remember it the main vac line from vac pump to servo has a t piece in it, and everything else is fed off of that t piece, egr/recirc/cruise.
Tbh long time since I saw one.
In think there is another mag valve under the spare battery tray behind pasenger side headlamp?

Mine was a late 97 EDC auto, reg Iirc R342PRD.

I may not fully understand this then,

What I thought was connected to the throttle and cruise doesn’t move when you depress the acceleration photo attached, this is one side of the T on the drivers side, the other side I can’t find anything?

where is the vacuum pump [GALLERY=][/GALLERY]

Russ6334 · Sep 11, 2021

Right I’ve blanked the open end and poured wd40 down the cable from the cruise vacuum controller.

if I put my foot on the pedal the throttle cable returns to normal if I pull the cable from the vacuum controller it accelerates but returns to about 1800 rpm

possibly need a new cable as it’s stiff however haven’t been able to test on cruise on the road as daughter in bed will try tomorrow

lynall · Sep 11, 2021

Russ6334 said:
Right I’ve blanked the open end and poured wd40 down the cable from the cruise vacuum controller.

if I put my foot on the pedal the throttle cable returns to normal if I pull the cable from the vacuum controller it accelerates but returns to about 1800 rpm

possibly need a new cable as it’s stiff however haven’t been able to test on cruise on the road as daughter in bed will try tomorrow

From memory the throttle pedal drives a potentiometer mounted on driver side inner wing, this then has a cable attached that goes to a bracket on the injector pump, but has nothing to do with injector pump, then another cable goes down from that bracket to the gearbox for the kickdown.
The adjustement on the injector pump bracket had to be spot on for it all to work smoothly.

Russ6334 · Sep 11, 2021

lynall said:
From memory the throttle pedal drives a potentiometer mounted on driver side inner wing, this then has a cable attached that goes to a bracket on the injector pump, but has nothing to do with injector pump, then another cable goes down from that bracket to the gearbox for the kickdown.
The adjustement on the injector pump bracket had to be spot on for it all to work smoothly.

Yeah the vacuum pulls the lever back which pulls the accelerator down to increase revs only on mine it doesn’t spring back to no throttle it keeps the revs up where as the foot throttle returns to normal so I guess the cruise hasn’t worked for so long the cable is sticky, I’ve put loads of wd40 down it but may need replacing

lynall · Sep 11, 2021

Russ6334 said:
Yeah the vacuum pulls the lever back which pulls the accelerator down to increase revs only on mine it doesn’t spring back to no throttle it keeps the revs up where as the foot throttle returns to normal so I guess the cruise hasn’t worked for so long the cable is sticky, I’ve put loads of wd40 down it but may need replacing

You can get them cheap motorcycle cable lubers from ebay, might do bicycle oens as well, bet the cable wont be cheap.
WD40 aint much of a lube as it dries out real fast.

Russ6334 · Sep 11, 2021

lynall said:
You can get them cheap motorcycle cable lubers from ebay, might do bicycle oens as well, bet the cable wont be cheap.
WD40 aint much of a lube as it dries out real fast.

It’ll do to make sure it works then if I can get it going will look at doing something permanent

next job is sort the AC out! I’ll have probably sunk it in a river by the time I sort this haha

lynall · Sep 12, 2021

Russ6334 said:
It’ll do to make sure it works then if I can get it going will look at doing something permanent

next job is sort the AC out! I’ll have probably sunk it in a river by the time I sort this haha

I dont remember the cruise being that good tbh, the engirne isnt really powerful enough to maintain a steady speed, a trait the D2 also suffers from, and the D3 is also far from perfect on cruise.

300tdi cruise control vacuum issue

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