Rough idle - checked IQ - What do you suggest - Page 2

whitedog · April 15th, 2012, 20:48

I don't know what to say. I have a drawing of all of the stuff to the injection pump. Here is a link.

vwdieseling · April 15th, 2012, 21:33

Checked out your schematic easy enough to read. I am learning how to use this site. I am replacing my front struts. This Beetle I bought was ran into the ground by previous owners. I have replaced axles on it and driver side ball joint. The struts are shot all way around. I got quick struts for front two for $158.00 was quoted a price of $1600.00 at local shop to do the fronts. I said I would think about it. I do all my work myself, but I like a brake once in awhile.

db252 · April 16th, 2012, 22:45

Ok. I don't really get it cause I'm pretty sure I did this already without the same result. I rehooked up vcds to check on a few other things on the car and decided to go back and mess with the IQ settings again. It was currently doing everything I expressed before. Lowered the adaption value by 100 and walaa, the IQ locked in at a maximum of 2.4 and was steady. I couldn't believe it and thought this won't last. Drove it around here and there for the day and was just waiting for that erratic idle to return in park or neutral but it never did. Soooo, fixed I guess. I am still going to do some fuel treatments but this case is closed. On to the next.....new post so I'll be looking for advice there to. Thanks for the help and suggestions.

vwdieseling · April 18th, 2012, 14:06

I had the same symptoms as you did. I have noticed some drift in mine. After our posts, I checked mine. I am worried about pump failure. I have heard that if the IQ is set by vcds that it will drift. My IQ is currently at 3 mg/ but was lower. In some cases when there is pump failure the ecu will increase IQ to compensate. I replaced my sending unit as well due to my fuel situation. I will keep posting on my IP situation because it sounds like we are sharing the same problem. By the way my IQ was off the wall too, until I reset it lower, this is when my idle stabilized as well.

db252 · April 18th, 2012, 18:44

I am having a perfect and stable result still. It's staying right at 2.4 in idle at normal operating temp. Even though the baseline setting is supposed to be between 3.0 and 5.0 I'm happy cause it is as smooth as can be. I maxed out on lowering the adaption value through vcds and from those results don't see the need to do the hammer mod just to get in that range. Hopefully your attempts get your idle stable and that an IP is not in your future.

mk3 · April 18th, 2012, 19:28

Are your nozzles and pump OEM? or modified?

Have you checked the injector balance? I don't know off the top of my head to check this but when you do this in VAG you get a reading for each of the 4 injectors at idle and they are supposed to be within +/2 but normally they are much better than that. I think mine are within .5

vwdieseling · April 19th, 2012, 14:24

I agree I replaced my injectors on GP. I would Diesel Purge the pump and tank. Mine was due to bad fuel and when I purchased my car it didn't have a fuel cap. The sending unit and tank had dirt in the bottom of them. So far my IQ has drifted .5 is at three still idleing fine. I an restoring mine so the added posts were in reference to some other issues. Hammer mod requires that special socket for the IP cover.

turbocharged798 · April 20th, 2012, 05:15

I had the bouncing IQ/shuddering issue and it turned out to be a bad DMF.