1. Home
  2. Volkswagen, everything else
  3. VW Golf 4 (2001) idling issues

VW Golf 4 (2001) idling issues

My Golf 4 (1.6L) has some strange idling problem. Sometimes as the car drops to idle (take the car out of gear/or clutch pressed in), the revs tend to drop below the idle point and then the car compensates for this and tries to correct itself creating a seesaw type of effect as the revs bounce above and below the idle point. This sometimes goes on for a few seconds before settling (after it has settled it is fine). Even worse though is that sometimes (as the car is taken out of gear/or clutch pressed in) the revs drop below the idle point and the car is too slow to react and just dies (this can also happen while the revs are bouncing around as above). This is most frustrating as it only happens sometimes (typically it didn't do it when i took it to the dealer). I have taken it back to the VW dealer who has changed the MAF and air temperature sensors but still the problem persists.

The diagnostic software (VAGCOM) only reported an intermitted fault with the MAF (which was replaced).

Just want to get any ideas as to where the fault could be..

Any feedback appreciated.

Reply to
spaz
Loading thread data ...

I was having very similar problems with my 2.0 MK4 Golf.

One suggestion I was given was to cut out the snow screen in the duct that leads into the air box (it tends to get clogged with bugs and leaves). When I went to do that, it turned out that it was already removed (I guess by the previous owner).

While I was doing that, I cleaned out the air box and shook out the air filter (although only 15k miles (rated for 20k miles I believe) old, it was really dirty). Then the car seemed a bit better for a week or two, but then started idling roughly and stalling again. So I decided to try a new air filter.

I grabbed an OEM air filter and dropped that in. Since then (it has been several months at this point) it has been fine.

So maybe grab a new air filter and see what happens. You can get them online for about 10$ a piece.

-Pete

Reply to
Pete Foley

IMO neither the temperature sensors nor the MAP/MAF is likely to cause the problem you've been having. ISTR that there were mechanical and drive-by-wire throttles variants of the 1.6 around 2001. The problem is likely to be associated with the throttle body assembly. This has a couple of potentiometers, switches and a 'stepping motor' (and is priced like it is made of solid gold). When you take you foot off the throttle, the stepping motor is supposed to intervene to prevent the valve closing too rapidly, an electronic version of the damper on a carburettor. At idle, the stepper motor should intervene to maintain idle.

I would start by getting the throttle body cleaned and re-adapted, and check its connections using an ohmeter at the ECU connector and a wiggle-test of the wiring. I suspect that you have an intermittent connection to the stepping motor. It would be possible by using a datalogger, which is not standard equipment at a dealership, and a bit of intelligence to identify what the problem is. However, last time I checked, dealers will only sell the throuttle body as a complete assembly. I would therefore try to negogiate 'a loan unit' to confirm it really is the problem rather than buying a new one on-spec.

Good luck

Charles.

P.S. The above makes a couple of assumptions about which engine you have. e.g. I don't recall the 1.6 having a MAF, I thought it had a MAP.

Reply to
Charles DH Williams

Thanks for the replies, most helpful and interesting.

Some notes: My Golf has a MAF (not MAP) but is not drive-by-wire (later models of the 1.6 are however - in this country anyway).

At least i have some direction with which to argue with the dealer now. :)

Later.

Reply to
spaz

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.