Revs dropping, car juddering - MK4 Golf 1.6

reddwarf2002

I can't see where the photo you are referring to?

Things that would cause the engine to stall off the top of my head:
- Faulty alternator
- Faulty Crank sensor
- Faulty Throttlebody/throttle position sensor
- (EDIT - Engine speed sensor is another one)
-(EDIT - Blocked Catalytic converter)

Having re-read one of your earlier posts, I'm beginning to think there's a problem with the Throttlebody. I haven't read all your posts properly as I didn't have time...let me do that now and I'll chime in again.

reddwarf2002

Ok, I've re-read your post about cleaning the throttlebody. So the problem was present before cleaning? Has it been worse since cleaning?

If you clean/disconnect the throttlebody electrical connector you need to carry out a TBA (throttlebody alignment). This would be the first thing I do. Make sure you erase all fault codes before doing so as otherwise it will not work.

Follow the instructions here: http://wiki.ross-tech.com/wiki/index.php/Throttle_Body_Alignment_(TBA)

Make sure these conditions are met:
There are certain test conditions that must be met before doing a TBA:

• No DTC's in the Engine Controller
• Battery voltage at least 11.5 V
• Throttle must be at idling position (keep your foot off the gas pedal)
• Coolant temperature must be between 5 and 95C
• If fault codes were cleared cycle the ignition off and back on prior to running Basic Settings.

JustAnotherSaver

Sorry my mistake. The pictures must've been on a Golf forum as I tried there also but I'm no further forward. I also can't post here the pics at the moment as I'm at work using my mobile.

You may be on to something with the TB although I remember reading years ago an argument on a forum where some said it needed aligning after cleaning & some saying it didn't.

My Astra TB has been removed numerous times over the past 8 years & I just put it straight back on. Some times I even re-use the gasket & have never had a problem.
Though I appreciate Volkswagens / Golfs may be more technical / sensitive.

I actually took the throttle body off last year & cleaned it. I can't honestly say whether the juddering happened immediately afterwards or not. I don't think it did but I'm not 100% sure.

As for this time it's no worse afterwards but also no better.


Regards the fault codes, I'll have a problem clearing ALL the DTCs. If you look on page 1 I think it is there's a list. Every time I clear them the radio codes & heated mirror codes re-appear. There may be some interior light codes that reappear too. Nothing engine related but they always come back immediately.

So since they're not engine related will I still be able to go ahead with the aligning?

Or does it have to be literally 100% clear of ALL codes whether they're engine related or not? In which case who knows what will fix those codes.

reddwarf2002 wrote: »

Ok, I've re-read your post about cleaning the throttlebody. So the problem was present before cleaning? Has it been worse since cleaning?

If you clean/disconnect the throttlebody electrical connector you need to carry out a TBA (throttlebody alignment). This would be the first thing I do. Make sure you erase all fault codes before doing so as otherwise it will not work.

Follow the instructions here: http://wiki.ross-tech.com/wiki/index.php/Throttle_Body_Alignment_(TBA)

Make sure these conditions are met:
There are certain test conditions that must be met before doing a TBA:

• No DTC's in the Engine Controller
• Battery voltage at least 11.5 V
• Throttle must be at idling position (keep your foot off the gas pedal)
• Coolant temperature must be between 5 and 95C
• If fault codes were cleared cycle the ignition off and back on prior to running Basic Settings.

JustAnotherSaver

Sorry I haven't woken up yet. I just realised you said engine controller so I should be good when I clear the codes.

Just need to find out which of those KWP things this car is as to which procedure to follow.

If it helps then it's an X reg 1.6 16v (so year 2000).
When I plug it in I have to select 1J.
Obviously not CANBUS
It's also DBW - no throttle cable.

reddwarf2002

JustAnotherSaver wrote: »

Sorry I haven't woken up yet. I just realised you said engine controller so I should be good when I clear the codes.

Just need to find out which of those KWP things this car is as to which procedure to follow.

If it helps then it's an X reg 1.6 16v (so year 2000).
When I plug it in I have to select 1J.
Obviously not CANBUS
It's also DBW - no throttle cable.

Look on the top left hand corner of VCDS screen under "Comms status" and "protocol".
e.g. http://www.ross-tech.com/vcds-lite/manual/screens/open-screen.png

You are right, I've seen people argue over whether TBA is necessary or whether the ECU self adjusts. My thinking is that 99% of the time it is not necessary as it re-learns over a few miles of driving. However when the ECU is unable to do this for whatever reason then it becomes a necessity.

parking_question_chap

Regulator is part of the alternator.

If the regulator is on its way out you will have electrical issues.In this case power steering failure and the engine cutting out. Electrics do so much in a car. Possibly it was starting to fail, hence the erratic revs, and worsened to the point the car cuts out.

Whilst a faulty MAP could in theory cause a rough idle, it would not impact on power steering. I seriously think your issues are all electrical related.

imo the regulator or the whole alternator is faulty and possibly even damaged the battery if it has not been charging properly. Wether you want to replace both to test this is up to you.

That said a car electrics specialist could probably identify the issue.

reddwarf2002

I think Kwik Fit do a free battery and alternator check. Perhaps it's worth taking it to them to rule out the alternator?

JustAnotherSaver

Right well i had this in at a local garage/auto electrical place & they couldn't find anything wrong with it - in other words it didn't act up for them. They said the only real way would be to have a laptop plugged in permanently & just record live data but this would rack up the bill so.....

Took it on a long drive up north, all was good until it came time to come back home .... judder judder judder.



Juddering on & off in the weeks that passed until yesterday it juddered quite bad & the engine light came on. Then it started flashing, then it'd just stay constant, then it'd flash again. Engine off, engine on light still there but this time no flashing.

Ran VAGCOM.....

all other codes the same as before but this time.......

Chassis Type: 1J - VW Golf/Bora IV (1998 > 2006)
Scan: 01 02 03 08 15 16 17 19 22 29 35 36 37 39 46 47 55 56 57 75
76

Mileage: 131680km-81822miles

---

Address 01: Engine Labels: 036-906-034-AZD.clb
Part No: 036 906 034 BH
Component: MARELLI 4MV 3773
Coding: 00031
Shop #: WSC 00684
VCID: 59B9E87FC3A32F8AEE-4B4E

2 Faults Found:
16687 - Cylinder 3
P0303 - 35-10 - Misfire Detected - Intermittent
17582 - Fuel Trim; Bank 1
P1174 - 35-10 - Injection Timing Deviation (Balance Fault) - Intermittent
Readiness: 0000 0000

So this coupled with the descriptions & codes from earlier .... is anyone any wiser?