cold start

[gunrtd]

How does one set up the cold start lever? pulling the lever does nothing to rpm as it says it should in the manual. It has full travel, extends and retracts easily, but it has no effect on the engine.
GPs work but some mornings it is hard to start.

[8v-of-fury]

have someone stand outside and peer in to the hood in between the engine an the injector pump. and see if the cable is connected and it is actually moving the little lever it is supposed to be attached to.

[jtanguay]

first of, which year of car do you have?  some do not have the idle speed boost.

if you have it though, it will be on the rear of the pump (closest to injector no. 1) there will be two nuts visible.  one of them controls idle speed boost.  i'm not sure which one, but i think its the one on the passenger side.  best way to find out, is to pull the cold start, and adjust while the motor is running.  i gave my car a 300 rpm boost, and cold starting was so much better.

[Rabbit TD]

How does one set up the cold start lever? pulling the lever does nothing to rpm as it says it should in the manual. It has full travel, extends and retracts easily, but it has no effect on the engine.
GPs work but some mornings it is hard to start.

Are you saying the cable extends and retracts easily or the lever itself also moves easily both directions. If you haven't looked at the lever to see if it moves or not it has probably came unhooked from the connector.
If the lever itself does actualy travel to full extend and retract and has no effect then there could be a problem with the advance in the pump.  On my 1.6 N/A using the dial indicator to time the pump at the 1.0 M/m setting with the cold start lever in the {off position} if you then move the lever to the full advance position the dial goes up a good ways on mine showing that the advance mechanism works, exactly how much in actual measurement though I forgot to write down.  First you have to make sure the lever moves with the cable which most likely is what's wrong

[gunrtd]

the lever on the pump moves back and fourth with the cable. I can see it move through the detents to the stop.

the car is a 95 Jetta TD 1.9L

[Vincent Waldon]

Many AAZs have a vacuum-driven fast idle rather than one operated by the cold start lever.... does your pump have the black canister shown in the upper right hand side of this picture?

[gunrtd]

Yes that is it! It hasthe vacuum can off to the side.

But it does have the lever in the dash, and on the pump too.

[Vincent Waldon]

Ok, then the cold start handle merely advances the timing a bit on your car... and your fast-idle is vacuum-actuated (as opposed to being activated by the cold-start handle).... the engine control module, located on the fuse panel, monitors engine coolant temperature and activates the black canister thru a solenoid valve.  If your car has A/C it will also up the idle a bit when the A/C is on.

Assuming it's all working correctly, of course. :wink:

[gunrtd]

so is this system adjustable?

[Vincent Waldon]

Depends what you mean by "adjustable"... the "fast idle speed" is adjustable via screws on the back side of the pump:



The thresholds (when it will decide it needs to call for fast idle) are built into the engine control module and not adjustable as far as I know... the thing is a sealed block and $$$$ so I've never pulled one apart.

[Rabbit TD]

Many AAZs have a vacuum-driven fast idle rather than one operated by the cold start lever.... does your pump have the black canister shown in the upper right hand side of this picture?

How much advance does the cold start lever actualy give the pump?  When I was timing my T/D I set it to 1.00 M/M in the off position of course and after I locked everything down I moved the lever to on position just to see how much it does advance.  It did move the dial a good bit but I just didn't wite it down and I can't remember but I'm curious as to what it actualy should be.  I figured if anybody on here knew it would be you from your pump exerience.  Oh, one more question about the advance, why doesn't if affect the way the motor idles or runs or mpg if you have the advance on when the motor is warmed up.  I always wondered about that one

[vanbcguy]

Oh, one more question about the advance, why doesn't if affect the way the motor idles or runs or mpg if you have the advance on when the motor is warmed up. I always wondered about that one

There's a piston inside the pump that advances the timing more the faster the pump is spinning, kind of like a distributor in a car.  The big difference is it adjusts itself with hydraulic pressure inside the pump body rather than with springs and weights like a typical distributor.  When you pull the cold start lever it pokes a "finger" in to the end of the timing piston. It pokes it about 2.5 degrees in the "advanced" direction, but all it changes is the stop point of the piston - so really it's only changing the "idle" timing, not the timing through the whole pump RPM range.  As soon as you're off idle the pump would normally be advancing the timing as much or more than 2.5 degrees so the cold start lever has no effect... It really only makes a difference at idle speed or less (not started yet for instance)

If you've ever put a timing light on a gas car that's a bit older and not exactly in "factory fresh" condition you'll probably notice the timing jumps around a fair bit - definitely more than 2.5 degrees at idle yet they can often still run pretty smooth... It's really about adding "just enough" to get the car started rather than a whole bunch of extra advance throughout the whole driving range.