20v Running Rough-Fault Codes!

[fazgti 0]

Took it to a vw specialist down here in Brighton and he said its the Lamba Probe and it also needs a Mass Airflow Sensor, now i am told these o alot on the 1.820vt engines but i found a receipt 6months ago for both these parts

could they already be knackered in such a short time?

[Crasher 3]

What is the engine code and car?

[fazgti 0]

AGU 2001 mk4 Golf engine

Just for the two sensors vw want £210+ and if its not the problem then....

thing is if you clear the fault codes the problem of the car holding back goes away then returns when the fault code comes up again(bout 10mins up the road)

[peteTDI 0]

check the colour of the temp sender (end of the head on the gearbox end) if its black change it for the new green one, also check the vac pipes on the inlet manafold theres two or three with 'u' bends that split and give maf and lambda fault codes

also try unpluging the maf and give the car a run see it it any better

if it is your maf they are £75 exchange from euro's or gsf and are the same bosch ones that vw sell

[fazgti 0]

Cheers pete, do you reckon that pattern parts are good to use, i will check pipes and sender

[fazgti 0]

Using the green sensor and cant find any air leaks, yet to try the air flow sensor off

[fazgti 0]

Right run the car with the MAF off and it made no difference, does that mean that it is faulty or it is not?

[fazgti 0]

anyone?

[Beaker™ 0]

If it runs good with the MAF unplugged but bad with it plugged in then i'd say yes, its had it. Know anyone who could log the airflow with vag-com just to be sure. Yes the MAFs are acommon failure on these, more often than not because a k&n or similar is being used. Lambda probes not such a common failure TBH. If it turns out not to be teh MAF then check your coilpacks? (another common fault) When they are on their way out they tend to produce a weak spark. And cause the car to hold back/hesitate. Only other thing would be a spit vac hose or intercooler hose.

 

Hopefully a quick easy fix with new MAF though.

[fazgti 0]

i did think it could be a coil any way to check?, it does'nt run any different with the maf on or off, it does have a K+N cone

[Beaker™ 0]

i did think it could be a coil any way to check?, it does'nt run any different with the maf on or off, it does have a K+N cone

 

If thats the case the MAF should be fine. If the MAF is faulty then the car should run better with it unplugged. As for coilpacks, no real way of telling until they get so bad the car splutters and struggles to idle. In which case you unplug each one, one at a time and start the engine. When the faulty pack is removed there will be no change to the lumpy idle but if a good one is unplugged then the car will die (as only running on 2 cylinders). But until they get to that stage i dont think there is a way to tell. Know anyone who could lend you a lambda probe to try?

 

What are the actual codes that are being thrown up?

[fazgti 0]

I will have to write the codes down cause i stuck it on the computer at the garage, the car idles fine and this problem happens at different times in the revs always changing, you could drive for a a bit and not notice it then it would happen a lot in a few minutes

[Beaker™ 0]

Hmm, my 20vt would hesitate and hold back soon after i got it. Would be very random as to when/where in the revs it would do it. Couldnt figure out for the life of me what it was, no fault codes. But somwhere in between changing the MAF, the remap and all four coilpacks the problem was solved. Yours remapped at all?

[fazgti 0]

Na that is on the to-do list very soon, not really sure what to do, spose i might have to do allthree that you mentioned

[Beaker™ 0]

Well as its not mapped it can't be a mapping issue. If you know of anyway you could borrow coiplacks and MAF that would save spending out. Another possibility is the N75 valve, that could cause a random boosting issue. You have a boost gauge?

[fazgti 0]

Nope no boost gauge, (i dont have anything do i) it just had a full service aswell, it revs freely while standing it just acts up under load

[Beaker™ 0]

Well it almost certainly sounds like a coil pack. Find out what codes were thrown up and stick em up here when you can :)

[fazgti 0]

Just remebered that a few months ago it did go in the garage and the bloke said that one of the codes came up with a misfire on one of the cylinders (cant remeber which one), but then the bloke started going on about lambas and stuff :?:

[Beaker™ 0]

Just remebered that a few months ago it did go in the garage and the bloke said that one of the codes came up with a misfire on one of the cylinders (cant remeber which one), but then the bloke started going on about lambas and stuff :?:

 

That sounds promising, usually coilpacks will throw up some kind of 'misfire under load cylinder #' etc when they are starting to fail. Simple fix if it is that :) If you check the part number of the coilpacks (pull off the plug at the top, its under that) you may find you have early revisions, ie the part number ends in the letter H, or I etc. The later revisions, ie higher letter are alot more reliable and last alot longer. IIRC the latest revision is 'L' for the 'AYP' engine code, not sure on 'AUG's TBH. But worth noting that if they are all the same revision on your car then they may all fail one after the other :( I've had all four of the early types go in as many weeks before now. Since fitting the 'L's i've had no problem (8 months ago now)

[fazgti 0]

Cheers Beaker i will get on the coils, you've been a big help

 

faz

[Beaker™ 0]

Cheers Beaker i will get on the coils, you've been a big help

 

faz

 

No probs, worth check codes again though one more time as it may be the lambda probe after all.

[fazgti 0]

ok m8

[Beaker™ 0]

Good luck :)

[fazgti 0]

Right i took each coil off and the car ran lumpy with all of them off so not a coil, i will have to plug it in tommorow and get the fault codes

[Beaker™ 0]

Right i took each coil off and the car ran lumpy with all of them off so not a coil, i will have to plug it in tommorow and get the fault codes

 

That method will only reveal a totally knackerd coil TBH. The 1st signs of a coilpack going are misfires under load. Which will not affect idle.