thoughts on rough idle on cold start
 

1985td - when it is cold 40'sF and below, car wont start unless i push the accelerator pedal to give it some fuel, but when i do it starts right up, however i need to keep giving it some fuel via the pedal or it will cut off. after a minute its fine. when the weather is warm its ok. had one plug test bad and replaced it - no change in behavior. replaced injector nozzles - problem persists. car runs like a dream in all other respects. could GP's that test ok need replacing anyway ?

CHeck your valve clearances. Intakes tighten up on the turbo engines. Let your glow plugs glow longer after the light goes out then start.

Check your fuel filters also... it could be a sign of low fuel pressure.

If the idle is set too low it will stall, I had to raise the idle slightly on both of our SD's to help them in the cold. At "moderately cold" temps they did ok, but in super cold temps (below 20F) they'd struggle to stay running unless you helped them along for 30-40 seconds. Raising the idle slightly (to about 800ish) made them both much smoother in general and eliminated the cold idle issues.

valves adjusted 2500mis ago, i do let the plugs glow longer, sometimes twice if its in the twentys. both fuel filters recently replaced.

my tach is broken so im unsure about my idle. My indy told me not to fool with idle adjustment cause it would mess up my shift points and ruin my transmission ???

How is the rack damper? Is it the new style with the gold colored tip, or the old with the silver tip?

never had to look at a rack damper before. is it a bit on or in the ip having something to do with throttle control ? Ill look into it.

The adjustment is minor, loosen the locknut and turn the screw like half a turn clockwise and re-tighten the locknut, see how much of a difference it makes. On my car it was enough to smooth it out and allow it to idle without help in subzero temps. It will not affect the transmission, the bowden cable does that. My shifts/feeling during putting it into gear etc....are unchanged. The transmission will not notice a difference between an idle speed of 700ish and 800ish rpm. You'd probably need to go to about 1000-1100 rpm before it'd put extra strain on the torque converter....as thats around where the stall speed lies.

Benefits:

-way smoother in the car at idle at all times
-warms up faster if you go out and start it before you leave to go somewhere (car fully warm after less than 10 mins at 0F outside cold start)
-more off the line power (at least it seems that way)
-idles fine on its own when its extremely cold out
-sounds cooler. :D

Spec is between 650-800 i think so that won't do anything most older vw and the 240's have the idle up knobs to help in cold starts it wouldn't be any different mainly when it's cold i bet the higher idle helps keep the rpm drop from the cylinders from stalling the engine i'm having the same problem with my 1982 300D i changed gp's and adjusted the rack dampner which hadn't been touched in 200K miles which worked in warmer temps to keep it running. now it's hit 10-12 degrees mine isn't happy for like a minute my idle's 700-710 steady normally only other thing as mention could be the fuel filters or valve clearance you'd think as cold as everything is everything would change specs going from 70 degrees to 0 - 10 - 15 degrees etc..

pawoSD are you talking about a rack damper bolt adjustment or adjustment of the bolt with the slotted head on the side of the ip by the motor ?

The slotted bolt on the side by the motor. Thats the idle adjustment screw. Use some penetrant on it first as it is often pretty stiff. I usually adjust it while its running so I can hear what it sounds/is running like.

Doesn't sound like a RD bolt problem. The past couple of days, I used a two complete GP cycle, started.
I live less than an hour away, in Hopewell, happy to help.

Funny you mention this..

My 83 300D is the *exact* same way. On a cold start, she has one hell of a time getting going. This morning (it was -10C out) I had to give it gas, double-glow, and crank it for a good 8 seconds before it wanted to turn over.. which I suspect means I have some dead GP's that are giving me a hard time..

At any rate, when the car starts on a colder day, it will idle pretty roughly until the engine reaches operating temperature. Since we're on the subject, maybe I can get some ideas what may be causing my rough idle issues, too? Here's a few things:

* I need new GP's. This will help with rough starts, but I don't think it will smooth out the idle THAT much. Remember, the car idles poorly until it reaches about 55-60c.
* My #5 injector leaks around the base. I suspect the injector housing, and will probably need to replace it. At first, I thought it was the braided line, but after changing it, it still leaks at the base.
* Turbo works fine (about 10psi boost?), and valve adjustment was done by the PO, not more than 10,000 miles ago.
* Rack damper pin changed to the new style, 4,000 miles ago.
* Battery is in OK condition. Not perfect, but hardly a "weak" battery, either.

This issue has been bugging me for months now!

I had the identical problems. I did a valve adjustment and all was right with the world. A couple of days ago it got down to 12 degrees(could for us Virginians) and my lovable POS fired up instantly. Prior to the valve adjustment it would take multiple try's and minutes of cranking to start @ 40 degrees or lower. My humble advice would be to re-check your valve clearance. RICHMOND REPRESENT!!!!!!!!!!!!!!!!