GolfGTIforum.co.uk
Model specific boards => Golf mk3 => Topic started by: Justins145bhpMK1 on 04 February 2005, 14:24
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OK, now most of you on here will know ive had terrible problems with stalling and missing under acceleration. I have replaced relays, cleaned throttle bodies, replaced coils, lambda's the lot. 2 times on Diagnostic couldnt sort it.
Then today I disconnected my MAF. Ive just driven back to work with a big smile on my face, not a hint of stuttering, goes so much better!!!!!
So I can only gauge that the air mass meter is at fault!!
So who knows if these are repairable as I know they arent cheap!!!
A very happy Justins145bhpmk1 :grin:
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Can anyone throw any light on repairing the MAF?? the car goes like a rocket now. Much faster than it used to, doesnt idle properly and is thirsty, its fun though!!!!!
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Hiya folks..
Just to give you a little heads up on a problem I had with my MK2 8V recently.? Ever since I had the car (1 month) I have had this annoying misfire whilst travelling down the motorway to and from work.? I did the normal things like change the leads dizzie cap, rotor arm etc, but this didn't cure the fault.? I was tempted to change the coil, but as it wasn't failing under load I was reluctant.? I checked the coil at night for the usual signs of 'blue glow' but nothing was seen.
Well last Friday I was bombing down the motorway as usual and the misfire came back again, something triggered in my mind to dip the clutch, blip the throttle a few times and lift the clutch again.? Suddenly the misfire went!? Hmm this is strange... Okay about 5 mins later the misfire came back again, so I did the same.? Same thing happened and the misfire went.? So I knew I could cure the fault by doing this and it only happens at fairly constant speeds.? First thoughts were the MAF (Mass Airflow) which might be giving off spurious readings to the ECU and cutting off the injectors, so at lunchtime I took out the airbox and put it on the bench at work.? Stripped it down and took off the black cover to the MAF and had a look inside.
The potentiometer seemed okay, and I placed an AVO (moving coil meter) across the tracks and moved the airflow trap.? The needle went all over the place, so this was indicative of bad contacts.? Therefore I cleaned the tracks and needles with switch cleaner and tested again.? It was still moving eratically but no where near as bad as before.? There does seem to be some laser cut resistors along the track so it somehow changes the range of resistance when moving from one side of the track to the other.? Also it is in a 'bridge' configuration so the sensor in the air filter side of the network also comes into play.
Anyway I cleaned it all up, re-siliconed the black cover back on and put it back in the car.
BINGO!!!? No more misfiring and the car is running alot smoother.
Not sure if you folks have come across this problem before, but I thought I would add this to the forum for future reference.
Paul..
From "The Garage" forum. I'm going to be doing this this weekend as I think this could be to blame for my problems with my MKII.
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Unplugging the MAF can sometimes cause problems, depends on the car.
For example, on my mk3 vr6 the car won't accelerate properly unless it is plugged in.
But on my dad's Audi 90 quattro, i accidently left it unplugged once and the car drove fine, it just kept trying to cut out at idle.
I don't think you can repair MAF's, apparently they can be cleaned. But its probably better to replace it.
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Cheers '6 thought that'd be the case. Im going to swop my MAF with a mates to make sure thats deffo the problem first and then ill get a new one. ?70 exchange from Eur, not bad.
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Well I just cleaned mine up (MAF) and refitted it and it seems to be loads better. Gona take it on a nice long run tomorrow and see how I get on.
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What did you use to clean it?
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Some cleaning solvent spray from the workshop at work and then used a can of compressed air to blow everything out. It would seem however that this has not solved my problem. The car started to miss again when up to temperature on the way into work this morning. :cry:
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I read... Unplugging the MAF will cause your CAT to die quicker...
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I'm going to get the car up to temp at lunch today, hopefully bringing on the missing fault and then unplug the MAF to see what happens. As I'm running an 87 MKII I don't have a CAT to kill. I'm only posting in here as I'm hoping that whoever fixes their car first might lead to the others fixing theirs.
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ahh.. you need this site ;)
"Ken's Digifant Page"
http://www.members.tripod.com/~fuelie/tuneup.htm
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What an excellent read! I've printed that off and will be going through it tonight.
Many thanks,
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no probs.. cant remember how i found it last night.. i'd seen it before though..
most of the stuff on that list has been done to my motor (inclcidng regular "italian tune-ups") apart from checking the PSV for a leak.. i might check the distributor sometime too..
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I'm picking up some new leads, dizzy cap and rotor arm at lunch to, so hopefully (everything crossed) I'll be on the road to recovery!
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I cant see how disconnecting the MAF would have much of an effect on the CAT to be honest.
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You'll be running a much richer mixture as the ECU will default to a richer setting. Rich settings cause to much unburnt fuel to pass into the CAT which over a period of time will damage it.
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^ Yup! :cool:
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Right I have reconnected the MAF for the time being, back to sh*tty performance till I get a new one!!
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thing is.. you could find that it is inadvertently making the problem going away.. replacing it could do nothing as the cause could lie elsewhere..
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You'll be running a much richer mixture as the ECU will default to a richer setting. Rich settings cause to much unburnt fuel to pass into the CAT which over a period of time will damage it.
You shouldn't be able to damage the cat, as a lambda sensor will be fitted. This will automatically lean out the mixture.
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Well im going to try it by swapping the maf with one off a mates car and see what happens before buying a new one.
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Your airflow meter could be to blame. As I understand it the ECU probably relies on the throttle position sensor for load if it's disconnected. See if you can log some voltages under different loads, you should see a fairly linear reading between 0 and 5v. On my '97 idle is around 1.32v, higher load 4v+. If you're not seeing the higher end (or lower end, if the sensor starts at 5v), then your car will not run very well under load.
HTH
Phil
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I had another thought. If you're cruising in 3rd/4th and stab the throttle to the floor, does it hesitate? If you do the same test again but gently accelerate does the problem go away? If so check the throttle position voltages, you may not be getting the acceleration enrichment that you need and going lean.
Phil
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YEs the car does do exactly what you described when crusing ie hesitates. Unfortunately Phil im not quite as Technical as you and have no idea what you are on about regarding the voltages!!!!! My skills go as far as unbolting bits and putting new ones on!!!!!!
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Where in the country are you? Can anyone get hold of a proper workshop manual as used in Dealerships?
Thanks
Phil
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Im on junction 14 of the M1, newport pagnell. Dont know of anyone who can get hold of such a manual though.??
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Just a thought...
Is anyone with our stuttering problems running their engine with an aftermarket induction kit fitted (such as 'K&N')? If it is and air intake problem we are all having, would one of these units make any difference in any way?
My problem has seemed to improved (http://www.golfgtiforum.co.uk/index.php?topic=14233.10) over the last two weeks for no reason. Its gone from messing up every 50 miles or so, to about 150/200miles.
I dont know about everyone else but my problem is intermittant, when the problem happens if I switch the engine off and back on its fixed for another couple of hundred miles. Because the problem isn't happening when its switch on in the garage the diagnostic it shows up 'no fault'. It rather annoying at ?20 a go. I need to plug the diagnostic m/c in when the problem is happening before the engine is restarted. I've seen a basic fault finding unit for golfs in CPC for ?18. Has anyone used one of these and if so are they any good?
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I bought VAG-COM , and it works very well , but you need to beg/borrow/steal a laptop really .
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Justin - I'm only down in Uxbridge, so I don't mind helping you out, in fact I could try and find the fault with mine, drop me a mail if you need further help.
Resevoirfrogs - A filter panel shouldn't make the slightest bit of difference. I friend of mine had a 2001 Cupra that was playing up. Took it to AMD who diagnosed it as the MAS because of a aftermarket filter. They said the oil had damaged the element. I can see where they are coming from with a hot wire MAS, IF the filter was over-oiled. K&Ns should be pre-oil and shouldn't find it's way to the MAS. He had Coil On Plugs on that model, one was faulty.
Intermittent faults are the most difficult to trace simply because they can only happen days, if not weeks apart. This is what happened to mine, probably 10 months ago. If would cut out all of a sudden once in a blue moon. Wait 2 minutes or so and then fire up and been fine for 2 or 3 weeks. Now you can't drive it more than 5 minutes. Don't waste your money on Diagnostic test, if your haven't found a code on the first one, you're unlikely to find one at all. Cleaning out throttle bodies, fuel injection cleaner etc is also a waste of time. If the car cuts out, and I mean one second it's fine (driving or idling), the next it's dead, it's electrical, normally a sensor. If it's more of a case when you pull up to a junction and it slowly dies and starts back up ok, that's another issue, something to do with your idle speed, throttle position sensor or clutch switch (this tells the ECU you're likely going to be idling shortly as you've just disengaged the clutch).
adyh - A laptop isn't a problem, what's the VAG-COM? Does it show all fault codes? Newer cars will have to be able to display Emissions and Emission Codes for the MOT, so you're be able to buy a tester from Halfrauds or a like. The trouble is, that's all they're legally bound to show, so the other fault codes can only be read by a VAG Card. I assume the Mk3 shows all codes?
I work on MX-5s as my business (www.performance5.com), but may be I should offer a service to Golfs, seeing as there's quite a few problems, and it's cost people money on parts that clearly don't need replacing!!! Where can I obtain a Factory Service Manual from?
Thanks
Phil
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http://www.ross-tech.com/
you can normally buy a lead from E-bay for about ?40 . [it needs opto isolators in it ]
the software can sometimes be found on the web . :wink:
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OK, this sounds very much like the problem I am having at the moment with my mk.3 1800 Driver, can't seem to find the MAF, and the reason may be that it may not have one on the 1800 SPI engine. Anyone know for sure either way, and any thought on what it could be otherwise after replacing most of the ignition system (bar ECU), air and fuel filter. Its been on diagnostics, but nothing could be found. Just about to give up on it.
Cheers
Jamie
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I've got a mk3 bentley manual if thats of any use, should have all the test procedures in it.
Philgti, i've never heard of a clutch switch, is that fitted to mazda's?
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Latest update on my ill car...
As you can guess the car messed up again last night in the middle of rush hour traffic, :embarassed: but unlike usual where i switch off the ignition and switch it back onto clear the fault, it wouldn't re-start. :cry: The starter motor was turning over ok, but the engine would not fire (no 'chugging' as if it was trying to turn over) and the oil light began to flash...
AA to the rescue!
Called out the men in yellow. He diagnosed the problem within 2min saying he'd seen it before. The spark plugs weren't firing. He put some fancy machine on the distributer and had it running in minutes. He said it was a fauty regulator on the back of the coil. By stroke of luck he had the exact part in the back of the van. Unfortunately you cant buy it separately as it come as part of the coil assembly. ?87 and 5 minutes later the car was running again.
Hopefully this will have cured my problem. He said that the intermittent fault wouldn't show up on a computer because it doesn't occur when the car is warm, which ties in with my problems only occurring within the 1st 5 minutes of driving.
Dont know if you guys have change this part yet? May be worth a try?
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sort of.. mine conked out one day (when ragging it :laugh:) and needed the coil replacing.. up to then it would stutter/stall before sometimes. fine since.