digifant engine (2H)running rough

hello everyone, this is my first post. So the problem i have is with my golf cabriolet diginfant engine (2H) its sometimes idling high at 1400rpm, and after blip of throttle goes to 1000-1100. I cleaned throttle body, new oring in idle adjusment swich. But i cant adjust idle turning the screw, it doesnt make much, i know that it must be done with blue sensor off, and rpm should rise a bit, but mine rises 300-400 rpm. What could be wrong? timing is correct, its 6degrees BTDC. Wide open and idle switches work. Any ideas?? Thanks,
Julius.

Well the idle by-pass screw is roughby turning all the way in, then backing it out about 1/2 to 1 full turn.

Te set the timing you have to have 2 folks to do it by the book.  

Loosen the Dist. clamp
Plug off the Hose.
Start the car and get it up to temp where the fan cycles once.

unplug the blue sensor.
rev the engine to 3000 rpm 3 times then hold at 2250
Using a timing light set it to 6btdc.

or
You can set it statically with only a DVOM.
How, well you set the timing so the cam is at 0, the crank is at 0 the dizzy is in the middle.

Then. you rotate the crank to 6TDC.

loosen the dist lock bolt.

Carefully remove the plug off the dist.
remove the rubber boot
Insert your dvom +probe to the center green/white wire.
The neg probe to the negative battery post.

Key on and in the run position (DO NOT START THE CAR)

If the DVOM is at 10-11V clamp the dis, your done.
IF not Slighty turn the Diz until the voltage goes from 0-11, then back it up and do it again…. You will hear the Fuel pump prime, when the voltage is at the 0 to 11 sweep.  Lock the diz.
turn the key off.
remove the plug replace the boot and replace the plug.

read more about it
Static Ignition Timing on VW A1 and A2 DigiFant Engines.

Ruff running, unplug the o2 sensor faster idle, then that isn't the issue.

unplug the blue CTS sensor, better or worse.
worse, plug it back in, no better CTS is good.

CTS better, then change it.

The Blue CTS can cause no start hot, no start cold, and crappy running, they are only 12Bucks here.

Do you hear a whine from the rear wheel arch? when the car is running? if so that suggests that the intank pump is having issues.

What is the fuel pressure, get or rent a tester, and do the
Fuel pressure regulator tests to test for residual pressure.

Are you running Bosch Triple Plat plugs.  Toss them.
Install NGK BPR5EGP or BP6ET

Your Car will Love you long time….

I usually start with the blue CTS.
then time it.

You can also open the hood and start the car at night.
Then under the hood look for Sparking Fairies dancing about your HV lead to ground….  Could be a bad plug wire.

Thanks for the info, i will buy  stroboscope and then check my timing :) and the plug from the distributor must be disconected?

Juliusnav said

Thanks for the info, i will buy  stroboscope and then check my timing :) and the plug from the distributor must be disconected?

No, you only need to disconnect it if you are removing the Boot to use a DVOM Statically on the Green White Wire.

The Static way is way easier,,,,,,,

One more question. I read that after adjustment i must reset control unit to its base setting. Do you know if it must be done and how? as i dont have the manual.

Oh you need to get a Bentley, or a Haynes so you aren't shooting in the dark.



If you are doing it the Oldie way, to reset the ecu, you have to unplug the Blue CTS sensor, and Reve the engine past 3000rpm 3 times.  If you have the timing at 6TDC on the Strobe light at 2250  you are done.

There is no resetting of the ECU after that.

thanks mate, so i will do it just like you wrote ir your first comment. have a good day