D5 (D5244T to 2005) Turbo governor - possible cheaper replacement

[Richjace]

hi yosser
how did you wire the new connector? is it critical on polarity ? is there a correct way round?
or is it fine to connect them however....
all the best
richard

[Yosser]

Originally Posted by Richjace

hi yosser
how did you wire the new connector? is it critical on polarity ? is there a correct way round?
or is it fine to connect them however....
all the best
richard

I honestly can't remember now, but I'd be fairly certain that polarity is crucial.

If you have both the old and new valves in front of you when making the final connections on your patch lead then it should be fairly straightforward to ensure the polarity is maintained.

The pin positions on the valves will be the same albeit the connector type is different.

[JohnL]

I have followed this article with interest, but there is something that is bugging me, what does this valve actually do, I presume with the power connector it must either open or close the valve at the end, and at what speed/rpm of the engine allowing vacuum to the other connection presumably.
Is there a description any ware of how this valve should work, then I will be able to test its function, rather than just replacing it.
Any info would be rally helpful please.
John

[R-P]

It is a PWM valve. Pulse Width Modulation.

Modern powersupplies switch on and off with a very high frequency. This is what makes e.g. a modern switching welder a quarter of the weight of one from 30 years ago.

Think of it this way: if you switch 12V on and off fast enough on a lightbulb, you can dim it to half its brightness when you turn it on for 1/100th of a second, then off for 1/100th of a second, then on, then off, etc.
But if you turn it ON for 5/100th of a second and then off for 1/100th of a second, it will burn at near full brightness.

This valve does something similar with a vacuum. By switching a vacuum fast enough (actually switching between vacuum and environmental pressure I think), it can regulate the vacuum in the tube to the turbo between a high vacuum (= very low pressure) and environmental pressure. With this it regulates the position of the vanes in the turbo in 100's of steps.
I think you can meassure between the governor and the turbo and it should be 25mmHg at 2000rpm or so. It should be somewhere in other posts about turbo problems.

On a side note, when my 'governor' was broken (tear in the membrane inside), I did not notice any problems. I opened it up hoping to put it back together and seal it again and luckily I found the tear (or I would have screwed up a totally good governor...very little chance of putting it back together). But the new one made no difference whatsoever.
What it did do was cause severe vibration in the needle of the analog vacuum meter I had attached to see how the vacuum was holding up.

[davebb]

Originally Posted by R-P

It is a PWM valve. Pulse Width Modulation.

Modern powersupplies switch on and off with a very high frequency. This is what makes e.g. a modern switching welder a quarter of the weight of one from 30 years ago.

Think of it this way: if you switch 12V on and off fast enough on a lightbulb, you can dim it to half its brightness when you turn it on for 1/100th of a second, then off for 1/100th of a second, then on, then off, etc.
But if you turn it ON for 5/100th of a second and then off for 1/100th of a second, it will burn at near full brightness.

This valve does something similar with a vacuum. By switching a vacuum fast enough (actually switching between vacuum and environmental pressure I think), it can regulate the vacuum in the tube to the turbo between a high vacuum (= very low pressure) and environmental pressure. With this it regulates the position of the vanes in the turbo in 100's of steps.
I think you can meassure between the governor and the turbo and it should be 25mmHg at 2000rpm or so. It should be somewhere in other posts about turbo problems.

On a side note, when my 'governor' was broken (tear in the membrane inside), I did not notice any problems. I opened it up hoping to put it back together and seal it again and luckily I found the tear (or I would have screwed up a totally good governor...very little chance of putting it back together). But the new one made no difference whatsoever.
What it did do was cause severe vibration in the needle of the analog vacuum meter I had attached to see how the vacuum was holding up.

You answered 4 years to late,
Dave