MK3 Golf - Mis-firing like crazy!

[Vincent Duffin]

Hey everyone. I'm a newey to the forum. I've recently bought a Mk3 Golf, N reg, 1.8 GL, engine code ADZ. Not long after buying it, it started to misfire as I was accelerating. Its been getting slowly worse over the last couple of months. I've changed the usual stuff, coil, leads, plugs, rotar arm, dizzy cap, also the fuel pump relay and fuel filter! Nothing has helped it. It will start up completely fine and tick over with no probs, but will jault and jerk once I start driving. It has cut out on me a couple of times now, and seems to be doing it at higher and higher revs! In the end, I took it into my local VW dealer for a diagnostic and they came back with some faults on the throttle body, however without spending a couple of hundred pounds on investigation by them, they couldnt tell me exactly what the problem was. He did say to change the coil, which I've done, but has made no difference. I actually changed the throttle sensor (well I think thats what is was, a plate on the right hand side of the throttle body! with a friends one that he was goign scrap, and also have the option of more parts from his car if I need them!). I've seen it mentioned on here about cleaning the throttle body etc. Is this difficult to do? If someone could give me some pointers, that would be wicked as I'm out of ideas with what to do next!

Cheers

[Crasher]

If you have moved the throttle position sensor plate that is the end of the lower section of the throttle body as according to the VAG manual, it should not be removed or adjusted although I have reset them in the past by noting the rest value in Measuring blocks 08 zone 2 and 3 before removal and reset the plate to that value. Cleaning the throttle body does not apply to the single point injection system. It is self cleaning as the fuel is sprayed directly onto the plate. If the HT parts you have fitted are good quality (cheap coils can be a problem) then I would suspect a faulty hall sender in the distributor, especially if the problem is more apparent when the engine is hot.

[Vincent Duffin]

Cheers for that reply mate. Yeah, it used to be more of a problem when it was warm, however now it does it straight away. Is the hall sender the sensor that sticks out the side of the distributor? I had a look at that but never actually changed it. So, you think I should leave the throttle body alone for the time being?

Cheers

[Crasher]

Well I would do a fault code read first but I doubt it would be much help. The hall sender is inside the dizzy and the plug sticks out as you say, it is responsible for telling the ECU when to trigger the injectors and coil with a little trimming from coolant and air temp sensors. In an older car it would have been a set of points.

[elation2776]

Hi. My girlfriend had 1.8 Mk3 golf with a similar problem. After many trips to the local mechanic i finally decided to give it a go. I spent ages stripping the car down and not getting anywhere, then one afternoon by pure chance i knocked the cable connected to the single point injector and the car cut out! Jackpot!! A bit of soldering and some tape later and the fault was fixed. Check it out.

[Vincent Duffin]

Hey guys, thanks for all your responses. Still having probs with this. I've been looking into where to get parts from and costs etc. It seems like I wont be able to buy a hall sender by itself, which is annoying really, but I checked the wires surrounding surrounding the ignition system and none of them seem to be playing up. I took the air supply off the top and noticed there was a lot of oil in the throttle body and also in the sensor that is on the front of the throttle body that leads into the wiring box just infront of it. I cleaned it all up but hasn't made any difference really, although it does feel slightly different somehow. Will keep you guys posted on the outcome, once I get some new parts for it!