cold running problem

Post all your engine questions and issues here and get help from the members

Moderators: kamzcab86, CalAltaDubber

User avatar
gull
Posts: 817
Joined: Sun Feb 19, 2006 6:30 pm
What year is your cabby?: 1989
Do you own a Cabriolet?: Yes
Location: Auburn, WA
Contact:

Re: cold running problem

Post by gull »

One thing that jumps out at me that you didn't mention is fuel pressure. I really recommend you get a CIS gauge kit and check the system and control pressures. They're the basis for all the basic mixture settings in CIS; if they're wrong, then adjusting the mixture screw will only move the problem around, it will never fix it.

I use this one from J.C. Whitney:
http://www.jcwhitney.com/autoparts/Item ... 0000160266
(The picture they show is wrong -- the kit actually comes with a set of adapters for hooking up to CIS fuel lines, and the shut-off valve needed to do the tests in the shop manual.)

The suggestion to check the injectors is good. Also, make sure the sensor plate in the fuel distributor is centered in its bore and isn't hanging up anywhere.

If the duty cycle meter responds to adjusting the mixture screw than your Lambda system (oxygen sensor and associated parts) is functioning. I have had the experience of intermittent shorts in the O2 sensor wiring causing problems, though, so you may want to wiggle the O2 sensor harness with the engine warmed up and idling. If the idle changes when you move the harness you have a problem there.
VW fan who fell to the Honda side of the force
Image
jemery.wa
Posts: 12
Joined: Sat May 16, 2009 12:52 am
What year is your cabby?: 1981
Do you own a Cabriolet?: Yes
Location: vancouver, wa

Re: cold running problem

Post by jemery.wa »

i haven't checked the pressure, but so far replacing the WUR 3 times hasn't seemed to change much. originally the oxs sensor was one of the problems, it was shorted, i did replace it. i did replace 3 of the injector seals (haven't got to the 4th one yet, hard to reach).
User avatar
gull
Posts: 817
Joined: Sun Feb 19, 2006 6:30 pm
What year is your cabby?: 1989
Do you own a Cabriolet?: Yes
Location: Auburn, WA
Contact:

Re: cold running problem

Post by gull »

While the warm-up regulator is often the culprit if the control pressure is wrong, it's not the only item that affects fuel pressure.

This is why I really recommend that people just buy the gauge set -- once they start swapping parts to try to solve the problem they end up spending more money than it would cost to buy the gauge to begin with.
VW fan who fell to the Honda side of the force
Image
jemery.wa
Posts: 12
Joined: Sat May 16, 2009 12:52 am
What year is your cabby?: 1981
Do you own a Cabriolet?: Yes
Location: vancouver, wa

Re: cold running problem

Post by jemery.wa »

just ordered the tester, i plan on doing a motor swap on my 81 anyway so it might come in handy, even though i will be putting in a 1.8 from a scirocco that currently runs and drives good.

so if you know anybody that needs parts from an 84 scirocco i have them, all but the rear of the car (was ass ended hard).
jemery.wa
Posts: 12
Joined: Sat May 16, 2009 12:52 am
What year is your cabby?: 1981
Do you own a Cabriolet?: Yes
Location: vancouver, wa

Re: cold running problem

Post by jemery.wa »

think that i may have solved the mystery, the spring that holds the air plate at the bottom was stuck above the clip leaving the plate to far up. i fixed it so the air plate is in the proper position then re-adjusted the air/fuel mixture and got it to run good. i let it cool down for a few hours and when i started it everything went good. the true test will be tomorrow when i start it from cold.
User avatar
gull
Posts: 817
Joined: Sun Feb 19, 2006 6:30 pm
What year is your cabby?: 1989
Do you own a Cabriolet?: Yes
Location: Auburn, WA
Contact:

Re: cold running problem

Post by gull »

That would certainly screw things up! Glad you (hopefully) figured it out.
VW fan who fell to the Honda side of the force
Image
jemery.wa
Posts: 12
Joined: Sat May 16, 2009 12:52 am
What year is your cabby?: 1981
Do you own a Cabriolet?: Yes
Location: vancouver, wa

Re: cold running problem

Post by jemery.wa »

well the problem still exists but not quite as bad, it still sputters when warming up if you press the gas slowly and if you try to hit it harder it wants to die, but it isn't as bad and the problems goes away quicker. so i am still chasing my tail.
Post Reply