Help - Pinking valver? / Air flow meter

[matthewb1985 0]

since i got my C 5 months ago the tick over and pinking has slowly got worse. today on the way home from preston was sat in traffic with the idle bouncing between 1000 - 1100 revs quickly. then when i was driving it kept jerking, when i was taking my foot off the accelerator the car just jerked to a halt. also the pinking has got really bad now and i dont know what it could be ran vag com on it today and it picked up airflow meter?? could this be the problem?? and lastly does any body have pics of the knock sensor so i can chewck that?

 

cheers in advance

 

 

 

 

 

 

 

 

Edit: Hope you don't mind me making your title a little clearer. Might mean the thread is viewed by someone that can help. VR6

[TREVR6 0]

I would reckon air flow meter has to be first stop, especially with it showing up faults, also when the car is hot as it will have been today sat in that damd traffic the pinking will get worse the hotter the engine is. Don't mean to ask the obvious but have you checked your timing, is it a dizzy and if so is auto advance working OK?

[kongo127 0]

It seems to me that your fuel pump it dying...

I would check it first of all.

[matthewb1985 0]

the pinking is just as bad whatever the temp. the timing has been checked 3 times. i think airflow meter looks like the culprit. il check fuel pump as well

[matthewb1985 0]

so can some body point me in the direction of the airflow meter then??

[h100vw 0]

The bit under the bonnet with all the pipes on it.

 

What was the faukt code from VAG COM? Who checked it for you, RW1? Did he not suggest anything?

 

Gavin

[matthewb1985 0]

yeah RW1 checked it on sunday he said it could be an old code so cleared it but, cant get any body local to check again to see if it comes up. cant remember the code but it said ariflow meter. h100vw where is the knock sensors located??

 

cheers

[corradophil 3]

where is the knock sensors located??

 

On the front of the block between no. 1 & 2 cylinders and 3 & 4. They are black and round, approx 20mm dia. with a bolt going through the centre and one black cable coming off them. If you cannot find em, do a search, I posted photos of them in a previous thread.

[matthewb1985 0]

i have searched but cant find the thread thanks i will locate them and see what condition they are in

[corradophil 3]

Have a look at page two of this thread

 

http://the-corrado.net/.archive/forum/viewtopic. ... r&start=15

[matthewb1985 0]

good man just what i needed so if they look a bit of a state shalll i replace them? how much do they cost??

cheers

[corradophil 3]

The first thing I would do is clean the multi pin plugs on them.

 

The torque of the bolt is very important too, make sure they are both at the correct torque.

 

Are you sure your valve timing and ignition timing are correctly set?

 

I bought one for my MK2 Golf and that cost around £50, so you really want to be sure they are faulty before replacing them.

[matthewb1985 0]

well i have had my timing done by the local vw specialist. i will clean them 1st then and see i guess this could defo cause the pinking. would the airflow meter cause pinking and the stupid intermittent high idling??

[h100vw 0]

Personally I don't think the Airflow meter is your man.

 

Before you spend any money, please check the basics. I doesn't take long. You need to confirm that the crank and cams are timed correctly. Set the engine to TDC on number 1, use the crank pulley for reference but don't but believe it on it's own.

 

Take out the plug from number 1 too and stick a long bladed screwdriver down the plughole. As you approach TDC by the crank marks make sure the screwdriver tops out at the same time. As you turn the engine past TDC the screwdriver should start dropping immediately.

 

As another reference you can use the timing mark on the flywheel instead of the crank pulley.

 

The cam timing can be checked by removing the top belt cover.

 

The reason for all the above is the common occurance of bottom pulley bolt failure. When the bolts snaps/come loose the bottom pulley moves and the timing between the crank and cams changes and no amount of resetting the ign timing will recover the performance. It may reduce the pinking.

 

#1 I have had this myself on my syncro passat, everything appears to line up by the marks but the crank pulley can be miles out. Also, as I was setting the engine to TDC, I went past the mark, on backing the engine up, the bolt came undone. The pulley had no woodruff key left in it.

 

#2 A friend had a 2 litre 16V mk2 Golf. The engine had been built out of an 1800 and the pulley bolt had been reused. It came loose and the pulley was rocking back and forth with each start and switch off cycle. You could tell it wanted to fly but anything over a whiff off throttle had it pinking it's head off.

 

Fortunately, the oil seal started leaking at that end of the crank, which was when we discovered the loose bolt and damaged pulley.

 

#3 A fella on the forum had the same problem recently, crap performance and pinking from his newly purchased project 16v. Same thing again, loose bolt, knackered pulley, leading to incorrect timing.

 

Check that lot and let us know what turns up.

 

gavin

[RW1 0]

What was the faukt code from VAG COM? Who checked it for you, RW1? Did he not suggest anything?

 

Gavin,

 

It was "mixture" pointing to the airflow potentiometer, no other fault codes. Knock sensors OK. Rev to the engine to see if it was immediate but it wasn't so cleared the fault down & advised to run a day or two and re-investigate as VAG-COM wasn't showing anything else. See if the fault returns. ECU diagnosis too basic but it generally wasn't pointing to a problem in that area.

 

Good idea to make sure the basics above are OK and go from a level playing field.

 

Chris

 

.

[flusted 0]

I had same prob as above,car done 121bhp on rollers,changed pulley and got 162bhp

[h100vw 0]

Chris, the mixture can be adjusted though, cloudy memory from reading too many books on the subject. The potentiometer is adjustable, some voltage can be altered IIRC??

 

Could the pot be just a bit out of limits and not need replacement..

 

Gavin

[corradophil 3]

The potentiometer is adjustable, some voltage can be altered IIRC??

 

Yes thats correct, although I've not done it for about a year and a half so my memory of it is a bit vague now. You need to disconnect one of the connections on the airflow meter and connect an ammeter (not voltmeter) between the connector and where it was plugged in. Basically the current fluctuates, you need to check it fluctuates within a certain range, if not you adjust the mixture untill it does. I set mine up using this method and it went straight through it's emmision test on the mot with no problems, and it drives very smoothly too.

 

Slightly off topic, does anyone know about adjusting the fuel pressure on the Ke-Motronic? There is a very small adjuster screw, which apparently controls fuel pressure, and supposedly you can do the equivalent of the wur mod on it, but although I no exactly where the screw is, I don't know anything about making accurate adjustments to it. I experimented with it a little but but did not notice any difference, so I returned it back to it's original position.

[RW1 0]

The potentiometer is adjustable, some voltage can be altered IIRC??

 

One of the possible causes. Talking to Matthew on Sunday, I think the set-up may be not easy for him. Pilot rather than mechanic.

 

You have to disconnect the connector on the engine side of the flow meter head and connect a current meter across the pins but also maintain the other connections of the plug connection. The current value is 2.5 +/- 2.5mA.

 

Other causes are an air leak in the intake after the airflow metering head to the engine intake manifold or an earth connection between the ECU and the engine intake manifold is open circuit.

 

.

[corradophil 3]

The current value is 2.5 +/- 2.5mA.

 

Yes, thats sounds right, the current fluctuates too. I managed to get mine between 0-5mA.

 

Pilot rather than mechanic.

 

I best buy an aeroplane then. :lol:

[matthewb1985 0]

good idea its not that i dont have a go my dad always helps i just dont get any bloody time off well im off for two weeks over christmas so should get it sorted then cheers for the advice

[corradophil 3]

Once you have organised some cables and an ammeter/multimeter and connected it all up it is quite an easy job. Do you have a manual for the 9A? I think the info I got was from a Haynes manual for the Passat with a 9A.

[matthewb1985 0]

im just watching one on ebay at the moment so i can do things myself.

[matthewb1985 0]

dont know if it makes a difference but it only pinks when there is more than just me in the car