Tunning Advise

[98_VW_Fox_Wagon]

Hello, i need some help tunning up my stock 1987 VW Fox.
so it runs, it drives, it stops, only problem is when i start it eather it idels really high and then when warm it idles really lown. or some days when i start it, it idles very low to where if i dont have my foot on the gas it will die.
im new to these and have herd the way the fuel systems are in these cars it takes some practice and learning.to understand.
And when i have it running it runns really rough. ive done a full tune up.on.it and that helped a little bit.but nothing where it should be. the MPG isnt where it should be.
I know there are 2 screws one deals with the idle amd the other deals with the fuel distribution block.
i was just wondering if anyone had any quick tips for tunning these two screws along with just tunning the hole car to run better.
Thank you.

[myboxyfox]

Try checking your timing. These motors seem to come out of timing sometimes, it should be at 6 degrees at the very least. 8 should be no problem, unless you are running your car on apple juice/

I also recommend servicing the throttle body as well. Remove it right from the car and clean it thoroughly with mineral spirits. cis is very sensitive to gummed up t bodies.

To properly tune cis tho, it's best to have a co meter, but some people are really good at using there ears and nose while messing with the mixture (3 mm allen key I think....)

If you just type in 'how to adjust cis mixture on an 8v 1.8 vw' into google or the like, I'm sure you will find the answer there and if all that fails, then why not throw on a carb? It's all the rage!

Oh and do you have a Bently's yet? That will help alot. Great book!

good luck!

[kerensky]

Actually, before you do any of that, check for vacuum leaks. These cars are very sensitive to additional air getting into the intake stream. Check for loose or split hoses. Check the idle air screw by putting your finger over the boss it hides in while the engine is running - if you feel vacuum, that's bad. Some DAPO probably messed with the screw and now the o-ring has dried out. You can replace the o-ring, and follow the procedure in the Bentley to readjust it.

Also, check the intake boot. I like to use a small propane torch - with the car idling, turn the gas flow on but don't light the torch. Slowly pass the torch around the intake boot. If there is a leak, it'll draw in the propane and you'll hear the idle speed up.

Let us know what you find!

[redone17]

great tips! I need to fix my idle adjustment screw - my o-ring is definitely toast.

[voxwagen88]

The CIS Forum has some advice...

http://forums.vwvortex.com/showthread.php?3070507

[98_VW_Fox_Wagon]

Thank you for all the help.
i will try everything to make sute everything is good.
if i cant i guess ill just eather have to pay for someone or hopefully have someone tune it to get it to run right.
and i have herd about the bently manual, but have not bought it yet.
ill let you know what happens with her.

[insanebuslady]

I see a problem with your username

Yea try messing with your timing. I advanced mine a couple degrees recently and it made a huge difference

[DubsesdA3]

For everyone with CIS:
Do yourself a favor and go to cabbyinfo.com
I have faith that you can find the section you need to tune and diagnose your CIS car. It's very definitive and makes your problems easy to figure out.

[ziddey]

To my knowledge, there were no cabbys with cis-e injection. So instead of using a dwell meter, you check dpr current.

Otherwise, if you're going by lambda readings to tune, that always "works" as well.

[alaincopter]

In Canada, the 1987s came with CIS basic - maybe they did in the US as well? If so, there would be no lambda or differential pressure regulator, and fuel injection problems could be due to a faulty control pressure regulator. It would be a little unit bolted to the driver's side of the engine block, with two stainless steel braided hoses going to it from the fuel distributor. It also has an electrical plug.

If indeed your car has this, try unplugging it when it is running rough and see if it makes any difference. There is also a way to properly diagnose the control pressure regulator outlined in the Bentley if I am not mistaken...