Clearing up some contradictions...

[Bean]

Okay, I have a 1.6D N/A, and was browsing through these forums for power mods.
All very clear and understood almost everything - except one thing...

How to adjust idle PROPERLY. As far as I can see, there are a few ways to do it. However, only one way seems to apply to my pump.
I read on the "Make your 1.9TD a faster car" thread that the idle should be adjusted with the service idle screw - in my case, this screw is in fact a 7mm hex-headed bolt with a spring round the top of it, which moves downwards when the cold start is pulled out.
If I unscrew this, it makes no difference and just feels as if I'm removing it. I can only tighten it up to a point, were it's just 'screwed in'. It doesn't seem to adjust anything.

The other place I can see to adjust something is two screws on the back which seem to be linked to a see-saw mechanism. What does this control? Would I need to loosen one to screw the other in?

And finally - what's labelled as the "residual fuel screw" in the "make your 1.9TD faster" thread. This was the one I adjusted to lower my idle after increasing fuel, and it worked up to a point but it still needs to go a tad lower.


Can anyone clear up where the idle is supposed to be adjusted, and why my "service idle screw" seems to do nothing (and isn't even a screw)?

Also, I'm doing the governor mod this weekend and read that you're only supposed to do the "max rpm" mod on it if it's an N/A, and not the part load mod. What does this entail? Just pre-loading the main spring and leaving the part load/intermediate spring in tact?

Many thanks,
Sean.

[jtanguay]

Okay, I have a 1.6D N/A, and was browsing through these forums for power mods.
All very clear and understood almost everything - except one thing...

How to adjust idle PROPERLY. As far as I can see, there are a few ways to do it. However, only one way seems to apply to my pump.
I read on the "Make your 1.9TD a faster car" thread that the idle should be adjusted with the service idle screw - in my case, this screw is in fact a 7mm hex-headed bolt with a spring round the top of it, which moves downwards when the cold start is pulled out.
If I unscrew this, it makes no difference and just feels as if I'm removing it. I can only tighten it up to a point, were it's just 'screwed in'. It doesn't seem to adjust anything.

The other place I can see to adjust something is two screws on the back which seem to be linked to a see-saw mechanism. What does this control? Would I need to loosen one to screw the other in?

And finally - what's labelled as the "residual fuel screw" in the "make your 1.9TD faster" thread. This was the one I adjusted to lower my idle after increasing fuel, and it worked up to a point but it still needs to go a tad lower.


Can anyone clear up where the idle is supposed to be adjusted, and why my "service idle screw" seems to do nothing (and isn't even a screw)?

Also, I'm doing the governor mod this weekend and read that you're only supposed to do the "max rpm" mod on it if it's an N/A, and not the part load mod. What does this entail? Just pre-loading the main spring and leaving the part load/intermediate spring in tact?

Many thanks,
Sean.

you can play around a bit with the seesaw mechanism... i believe the passenger side one is for the cold start idle boost? but i could be wrong... i just can't remember.

[Bean]

They can't be for seperate things can they? (The two screws that control the see-saw thing). Surely it just controls one thing, and you have to adjust both screws accordingly?

Which way do I want to adjust it to lower my idle?

Also - I'm going to be running 50/50 veg oil/diesel as of the weekend, do I need to make any adjustments to the pump to accomodate it? Advance timing or anything?

[Bean]

Thanks guys, thats cleared up a couple of things.

I can't see a residual fuel screw though? Anyone got a pic of one?
It was the idle stop screw that I adjusted then. That worked well, but when the engine is warm it idles higher than it should be and when unscrewing the idle stop screw it doesn't make a difference anymore (I don't think - I'll check again tomorrow.)

Had exhaust problems earlier so I just cut most of the back section off  :lol:
Now it sounds like a tractor. No worries though, I'm getting a custom exhaust on saturday with the stack going through the bed  :twisted:

[Vincent Waldon]

It's also known as the "fuel" screw and is the first large picture on the second page of the "make your 1.9TD faster" thread.

[Bean]

Ahh right, yeah I know where that is. That's what I adjusted in the first place to increase the fuel (obviously).

Thanks for clearing it up

So is there a point where adjusting the idle stop makes no difference anymore due to too much fuel coming in? It's not revving high or running away at all, it's just a little above where it should be when the engine's warm.

[blackbird82]

hey vince, that see-saw device has no connection to the cold start handle on most AAZ's. it is conencted to the vacuum pot to the electric high idle solenoid. You can use it ot set your high idle when cold. IT is automatic in the aaz's through a solenoid

[Vincent Waldon]

True dat... mechanical fast idle linked to the cold start handle much more common pre-AAZ.

Having said that, most AAZ pumps have the socket on the fast idle cam for the required pushrod, and my pump came with the full cold start fast idle...no vacuum pot.

[Smokey Eddy]

So stoked on life right now because Vince said "True dat".

[Vincent Waldon]

Hey, I'm hip.  I know all about you youngsters, with your Facetubes and your Youbooks.

Now get off my lawn.   

[blackbird82]

Vince. If I am ever in Edmonton. I will rev my vw in front on your house and do donuts on your lawn.
True Dat

[burn_your_money]

Here's my opinion on the matter.

That see-saw thing on the back of the pump controls both the fast idle and normal idle. When it is rocked one way it is fast idle, and rocking it the other way is your normal idle. Fast idle is adjusted with the screw closest to the timing belt. Normal idle is the other one. TYPICALLY you can and should just rotate the 7mm nut on the end of the rod to adjust your idle. However once you've fiddled with the max fuel screw there may not be enough range on the rod. This is when you would need to adjust the screw farther back from the drive end.

The residual fuel screw does not usually have an effect on idle. It controls how quickly your RPMs drop. If it is screwed in past a certain point it will have an effect on the idle. Ideally you shouldn't be playing with this screw unless you've fiddled with the max fuel screw.

[Dakotakid]

Please put this in FAQ.

[burn_your_money]

Please put this in FAQ.

Done. It's worth noting that older pumps that don't have the fast idle are adjusted by using the throttle stop screw.

[Vincent Waldon]

Yeah, to make the FAQ-worthy it really should have some pictures... I'll see what I can dig up on the couple different pump configs I've got in the shop.

We should also change the title... since it won't naturally tell folks what's inside.