Mk3 Issues.... A guide to the common faults and fixes

[nhop10]

I'd just like to say a massive thank you to every body that has posted on various threads on rough running Mk3's, reading all of them has saved me hundreds of £££'s at a garage in labour costs.

Just got a Mk3 GL but beleve it is the same problem as some rough running GTI's

I'm a very novice DIY mechanic and only solved this problem through GolfGTI.co.uk so anyone else can do it too.

Got my golf and it was running pretty rough so the first thing that went on was a new cambelt (a mate did this for me) I now knew the engine was at Top Dead Centre TDC.  The car was really lumpy when accelerating but once you got up to the chosen speed it would cruise without a problem.

Straight away the two new relays went in #30 and #167.  Went for a road test and the ECU had clicked into safe mode 5000rpm then cut out.  Checked the timing.  Draper timing light only £20 from Amazon, Euro car farts wanted £45! Also you can't check it though the pull out cap just unscrew the whole plastic cap, loads easier.  I had to rotate the dizzy about 10mm to get the timing in the right place.

Road test again, running very lumpy again BUT this time it would fly up through the rev range, still a little lumpy but alot better.  When you tried to cruise it just wouldn't have it.  Really lumpy ( the only novice way I can describe it is like your struggling for petrol).

The next thing I read somewhere and can't remember where.  Was to unplug sensors and go for a road test.  When I unplugged the Mass Air Flow sensor located just behind the air filter housing the thing went like a rocket.

Just coughed up about £110 (you also have to exchange your old unit) at my local VW dealership praying this was the answer.

She now runs pucker!!!!

Not in the same league as my old Mk1 1800 Gti I had five years ago, but still a sound old vw.  Drove company civics for 5 years and nice to be back in a dub.

If this helps just one person I'll be happy.

When checking the timing as well it doesn't seem to be an exact science.  My timing mark would not hit the indicator but I got it as close as I could and as consistant as I could.  Just done the timing on my mates mk3 8v GTI track car with piper cams.  His was exactly the same.  Just got the line as close as we could to the indicator and with the most consistancy.  My machanic mate reckons with an older car it will rarely be cock on.

I also bought Vag.com off ebay for £13.  After a bit of messing around I finally got it set up.  When I scanned for faults it came back with nothing!  Any feedback on this would be greatly appreciated.

Cheers,

James

im needing to change the two relays 30 and 167 to sort out starting issues, does that mean my car is likely to go into 'safe mode' and what will i have to do if it does.. cheers

[dixie180]

Hi bud,i changed both 30 and 167 relays without any problems whatsover.Also check and change ECU temperature sensor as they are cheap to buy.Plenty on Ebay and i would suggest using a guy called tierod69 he's really good and his stuff is genuine.

[nhop10]

wicked, cheers bud!

[nhop10]

http://www.gsfcarparts.com/929vg0110 this the one?

[dixie180]

Depends what engine you have bud.Mine is the ADY 8v engine and i fitted this one http://www.ebay.co.uk/itm/VW-GOLF-MK3-GTI-POLO-THERMO-TEMPERATURE-SENSOR-C687-/190495196514?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2c5a660562
Check to see if yours if 4 pin or 2 pin.

[fed up]

Hi hl have mk3 golf 2 :cry:ltr have a problem with it . It started cutting out when at proper running temperature I have changed distributor coil ht leads had dionogstic to be told ecu 2-4 drive faulty sent away had test done by ecu doctor , to be told ecu is ok also changed thermostat sensor I still have same fault . DDionogstic man said lamda and crank shaft sensor are ok no breaks in wiring . So do not know what else to do pls pls pls if possible help me on this problem

[itavaltalainen]

can you format that properly and add some punctuation?

which mk3 2.0 engine? 2E, ADY, AGG?
can you post a log of fault codes?

can be a number of things but that will depend on model year and engine.

[boneybradley]

Hi hl have mk3 golf 2 :cry:ltr have a problem with it . It started cutting out when at proper running temperature I have changed distributor coil ht leads had dionogstic to be told ecu 2-4 drive faulty sent away had test done by ecu doctor , to be told ecu is ok also changed thermostat sensor I still have same fault . DDionogstic man said lamda and crank shaft sensor are ok no breaks in wiring . So do not know what else to do pls pls pls if possible help me on this problem

try these two, along with the ecu temp sensor. all cause similar issues to what you've said

2 faulty ecu relay no 30 rough running
Check them by feeling how hot they are after 15 minutes of driving. they should be warm to touch. so cold relays means faulty relays!

3 faulty fuel pump relay no167 check as above

[fed up]

Already checked relays they were warm to touch also no fault codes came up . Their is no rough running it just gets up to proper running temperature stalls to get it started again have to let it cool down or put foot hard down on accelerator , to get it going but will still cut out when cold . I have spoken to ecu doctor and dionogstic men today both say they are right no problems with ecu and dionogstic man says its ecu ...phoned up vw eastbourne they can do a dionogstic for £100 vat included and more or less guarantee they can find problem ...its the more or less I have a problem with cause you cannot guarantee that .so picking your  brains for now ...

[thai-wronghorse]

Still sounds like the crank speed sensor to me.