Engine misfire

[MickCheese]

Hi

I have a 1999 TSport 1800 with a misfire and it is getting worse.

I'll try to explain.

About a month ago I was driving up the motorway when the car stuttered just once, it really was just a missed beat.

Over the next week or so the mild stutter became more frequent, just missing a single beat and always while on a light throttle and cruising along.

Last week the car went in for a service where the air filter and plugs were changed as part of the service. I mentioned the misfire but as usual it was not happening while that had the car and nothing showed up on the diagnostics.

The service had no effect on the missfire so I conclude it was not plugs or a clogged airfilter.

The last few days the misfire has got much worse. Now every now and again whilst sitting at a set of lights the car shudders and I need to blip the throttle to raise the revs and stop the shuddering. I thought it may have been worse today as I was getting low on fuel but filling the tank made no difference.

The car has had a new MAF sensor within the last year.

It seems worse on a gentle throttle and seems to be around the two thousand rev mark. Occasionally I will be doing a steady 70mph in fifth gear when the engine hesitates and the only thing that will make it pick up cleanly is changing down a gear.

There is a ticking from the area around the charcol filter, is that relevant?

My thoughts are either the throttle body needs cleaning or a possible problem with the turbo although it is like one cylinder only is misfiring.

At work I do have access to a portable bosch diagnostics system and I am wondering if linking that up to the car and driving until it misfires will provide any answers?

Sorry this tale is so long, anyone any thoughts?

Regards

Mick

[mrjolly]

hi, a mate had a similar problem the other day. although coilpacks are a common faliure his turned out to be the ignition amplifier (located on the passenger side bulkhead with a plug either and) amp fault did not show up on 3 different diagnostic machines inc vag-com. hth
sid

[MickCheese]

Did you replace it and if so how much was it.

Mick

[1.9mk1golf]

ive had a problem on 1.8t golf, i dont no if this will help , check the main air hose [ from air filter to turbo inlet ] , pull it fofward or push it back if the engine changes , the seal is gone on the pipe where it goes into the turbo. hope this will help

[MickCheese]

Thanks, I'll give it a go.


This morning I took the MAF sensor off to inspect it. Not much in there really! If just the look means anything it looked OK.

I keep coming back to the coil packs but I really need to get it on diagnostics so I can tell where the misfire is.

Mick

[Clach]

hi, a mate had a similar problem the other day. although coilpacks are a common faliure his turned out to be the ignition amplifier (located on the passenger side bulkhead with a plug either and) amp fault did not show up on 3 different diagnostic machines inc vag-com. hth
sid

It does not sound like an amplifier, that judder would be more noticeable, similar to a failed coilpack. They cost about £120! A dirty throttle body perhaps, or coilpack on the way out I would say is more likely.

[Clach]

It does not sound like an amplifier, that judder would be more noticeable, similar to a failed coilpack. They cost about £120! A dirty throttle body perhaps, or coilpack on the way out I would say is more likely.

Having thought about it abit, what about a fuel pump problem or clogged fuel filter. Can you hear a whine from under your seat? i changed my fuel filter as a preventitive measure and it sits much nicer at low revs. A fault fuel injector may also cause this, but they are usually pretty reliable on the A3, and I am pretty sure it would show a code

[S3 beast]

i have a s3 225 and i had a very similar problem, after much checkin n headbashing i put it on a bosch diagnosis machine, all it said was "cylinder1 missfire"..
so, in my trial n error i swapped numba 1 plug lead with numba 2 n it now was numba 2 missfiring.. had to be coilpack!
each cylinder has its own pack and as it was numba 1 it was easy to change.. only cost £27 n its a genuine Audi part, some people said i should've changed all 4 but so far its been great..
Give it a whirl mate, worth a go!

[MickCheese]

Thanks for all the advice.

When I took the MAF sensor off at the weekend I did clean it with a good blast of carb cleaner and the problem seems to have dissappeared.

I am not totally convinced that was the problem though as I also straightened out a twisted coil pack feed wire and by removing the MAF sensor noticed the sealing ring was a little bunched at the bottom so straightened that as well.

Reminder to myself, do not fiddle when trying to locate a problem.

Anyway it seems to have gone away, hopefully for good.

Mick

[rickrobbo]

I have a similar problem. My 1.8t misfires when first started. When engine is warm and revs settle then it is mostly fine. It just occasionally misses at around 2000 revs. Done loads to try and get rid of problem -new cat, landa sensors, coolent switch etc but struggling to solve it. can anyone help?

[MickCheese]

Ok

After over a year the problem re-surfaced and I decided to do something about it.

Some googling revealed that the ignition module on the rear of the air box in the engine bay in front of the passenger side could be a culprit and I found details of how to test it.

This I did and found one of the pins not the same resistance as the others.

A new one from Euro Car Parts was £67.

Problem cured.

Just thought I would resurrect this thread for the benefit of others.

Here is the link I used for the test http://forums.audiworld.com/showthread.php?t=211086

Mick