Misfiring Mk2 - Help a mod in need !!

[davidhawkins_78]

Read this through first ...

http://www.golfgtiforum.co.uk/index.php?topic=13065.0

After some cleaning and trial and error the ISV and coolant temp sensor can be ruled out i think, and the problem is still happening with them both unplugged!

So just to recap - no bouncing revs, but erratic loss of power and mis-fire (spluttering) at what seems to be various throttle positions and revs. Beating the throttle doesn't seem to solve it, but eventually it 'clears' ??

Seeing as the revs aren't bouncing about (I can't say I've checked this, but I'd thin I'd notice the rev countered on a mission!), I'm not sure it's dizzy / hall sender related - I'm thinking MAF (Mass Airflow Sensor) ... seem sensible

I've read people taking these apart and cleaning them - is it easy??

Also with having electrical testing equipment is there a way to test it to show it's faulty. I'm just loathed to go round the houses replacing way to many parts and spending a fortune !!

Cheers for any help

 

[topher]

Completely different car i know, but what you describe is exactly the same as what mine was doing, and was indeed a faulty MAF sensor.
Cleaning them is easy (although i finally had to replace mine) , just use carb cleaner, probably dont even have to take the sensor out of the housing to do it, i didnt !

Chris.

[davidhawkins_78]

I like the sounds of that !!! 

I must say if it is that, i'll probably have to replace it as you did - but after just getting my design 90's this month I hadn't planned on forking out for more parts !!

Carb cleaner and toothbrush it is - Topher, how long did u manage before you had to shell out ??

[topher]

worked for about 2 weeks, then got stung with the ?250 bill for a replacement  :'(
not sure if it applies to mk2 parts but vw offer maf exchanges on mk4's for about ?75 now, they introduced this scheme 2 months after mine went. How convenient   

[davidhawkins_78]

'Awesome' do new units for ?99 - alot less than the ?290 rrp.

I still have this nagging feeling that i'll shell out for it and it'll not fix it - I had nigglin problems like this !!

Cheers for the help topher

[Blue MK2]

Is the mass air sensor on the airbox?

If you need that or the dizzy then ive got them for you Dave

[davidhawkins_78]

Cheers Blue - you got a spares shop going you're keeping quiet 

[Blue MK2]

Cheers Blue - you got a spares shop going you're keeping quiet?

 

I took the cover off the airsensor box and gave it a clean with WD40. Just dont take the spring off or your car will run even worse. It did run better after cleaning but i dont think this will solve your problem.

Probably Dizzy/sparks/leads related.

I had this problem a few months back and the garage didnt even know what was wrong with it. One day it just started and they handed it back to me and now ive got lots of spares?

I even changed the ECU and ignition moduel which sits ontop of the ECU. Might be worth checking

[davidhawkins_78]

So in the end it was a drop it off at the garage job and you get a large bill eh blue ...

Didn't you ask what the source of the problem was in the end ??

[Veedubgt18v]

mine does this particularly in fourth and fifth gear, i reset the timing, make sure its all good and done with the blue sensor disconnected and at 2000rpm. i then took the cover off the maf and cleaned the tracks inside, it made no difference. so i moved the spring mechanism round 1 notch (you will see what i mean when you open the maf up) and it still does it just a lot less now. i think my maf is on the blink. so i will follow this post.