[Malky]

Well what do you know, a few months after my original topic was locked, back comes the problem!!!

Drving home from work a couple of times this week, I've noticed a missfire in the first 10 mins of the drive home. This describes it:

Driving at 40MPH, pedal half-way down, car missfires and lacks any power... Push the pedal further down and get the revs up and it's OK!! Only did it twice, then wouldn't do it again!!

My original topic is here.

http://www.uk-mkivs.net/forum/topic.asp?ARCHIVE=true&TOPIC_ID=16960&SearchTerms=,engine,missfire

I've got a new MAF...

Anyone know where the missfire table is on the 1.8T (AGU)

Any ideas chaps? VW as usual are so useless I'm not even going to attempt it, last time I knew more than their master techs...

Going to log coolant and intake temp tempeartures see if the sensors are acting funny.

 

[tylerama]

Quote: posted by Malky on 12/10/2004 23:28:48

Well what do you know, a few months after my original topic was locked, back comes the problem!!!

Drving home from work a couple of times this week, I've noticed a missfire in the first 10 mins of the drive home. This describes it:

Driving at 40MPH, pedal half-way down, car missfires and lacks any power... Push the pedal further down and get the revs up and it's OK!! Only did it twice, then wouldn't do it again!!

My original topic is here.

http://www.uk-mkivs.net/forum/topic.asp?ARCHIVE=true&TOPIC_ID=16960&SearchTerms=,engine,missfire

I've got a new MAF...

Anyone know where the missfire table is on the 1.8T (AGU)

Any ideas chaps? VW as usual are so useless I'm not even going to attempt it, last time I knew more than their master techs...

Going to log coolant and intake temp tempeartures see if the sensors are acting funny.

Hey.. I had a diagnosed misfire on my car in june.. finally managed to get it to the dealers whilst it was doing it.. plugged the 1553 into it misfire, cylinder 3. They took it in, swapped the plug to cylinder 2 and the coil to cylinder 1. It's been fine ever since, apart from a few seconds last week. If it happens again, i'm going to take it back and ask them to replace all the coils and the plugs on the premise that the car hasn't been right since I bought it from them.

 

[james]

I had this happen on mine ages ago.

Did the same kind of testing, bought new plugs and swapped over the coilpacks

but the misfire stayed on the same cylinder (number two from left looking at front)

VW put it down to sensor failure, replaced this and it went away for a bit, then

came back a couple of times, then disappeared completely. Have now sold the car so

never did get to the bottom of it, but if it's always on the same cylinder, this should

completely rule out things like temp senders/mafs etc as a fault in these would produce

a more sporadic misfire on random cylinders ( I think! ) It must be something more

directly connected with the ignition system such as a crank position sensor or

whatever controls the spark plug firing mechanism.

 

[Malky]

Weel it's not the coolant or intake temp sensors... See log below, looks fine to me...

So could be; Coilpaks, amp module, spark plugs...

Anything else???

 

[Gti Fly]

Does the Misfire have anything to do with the ignition amplifier thingy which is located near the airbox???

 

[tylerama]

Quote: posted by Gti Fly on 13/10/2004 17:11:59

Does the Misfire have anything to do with the ignition amplifier thingy which is located near the airbox???

That's what i'm beginning to wonder too Jason. Might enquire how much these are at the stealers.

 

[Malky]

?230!! BTW

 

[tylerama]

Quote: posted by Malky on 13/10/2004 17:18:27

?230!! BTW

Your kidding ? For that thing ????

 

[Malky]

Right, so I was almost right...

Coilpacks for an AGU 1.8T

058905105: ?40 EACH

Amp int stage module.

4D0905351: ?220.

Ouch...

 

[ADi Nuff Valves]

ouch indeed. Mine has just started misfiring. Seems to only happen when its damp. As soon as the cars warmed up its fine. Hopefully will get it plugged into vag com to see what it says.

 

[Malky]

So I have been able to find a source for some bits...

Coilpacks for an AGU 1.8T

058905105: ?40 Dealer; ?26.43 from another source.

Amp int stage module.

4D0905351: ?220; ?92 Delivered (from US!)

I will post details of the sources for above parts when I can gurantee they are the correct parts etc...

 

[Malky]

So I think my cat seems pretty bad when cold and gets better when it warms up a bit!

This is why I suspected the coolant temp sensor. Defo not that though. It's either a spark firing issue or another sensor.

I have a known good MAF, good temp sensors (intake and coolant). I suspect the O2 sensor in the exhaust, Coilpack, intermdiate amp module. All wiring looks OK.

Any more ideas? I'm going to pickup the coilpacks tonight anyway, then some investigations over the weekend before I splash out any more money!

 

[Malky]

Well bit the bullet over the weekend and bought the following...

1. 4 X Coilpaks

2. Iridium Power spark plugs (Denso)

3. New reciculating dump-valve (OEM)

I will monitor this over the next couple of weeks and see how the car goes...

Next up will be the Int amp module and O2 sensor I guess...

What you lot think?

 

[tylerama]

Quote: posted by Malky on 19/10/2004 09:22:04

Well bit the bullet over the weekend and bought the following...

1. 4 X Coilpaks

2. Iridium Power spark plugs (Denso)

3. New reciculating dump-valve (OEM)

I will monitor this over the next couple of weeks and see how the car goes...

Next up will be the Int amp module and O2 sensor I guess...

What you lot think?

No other advice matey, but i'm watching this closely, had the very same problem since i've had my car.

 

[EddyH]

I had a misfire problem on the Octavia and it turned out to be a dodgy fuel pump. JBS have the facilities to check this and other things on the RR as well as having and a large stock of parts to swap out for diagnosis. 1hrs diagnosis on the RR including vagcom logging, parts swapping etc.. is ?45+vat.

My problem wasn't intermittent though so was easier to replicate.

 

[dan933]

I had the same problem with mine for about 3 years, VW could not find the fault.

They replaced the coil packs (all 4) on six seperate occasions, replaced the Plugs and lead but with no luck.

In the end a small garage found that the earth terminal below the battery was attached to a painted connector and therefore was not providing sufficent earth. The car does not misfire anymore.

Good luck

 

[NBirkitt]

Quote: posted by tylerama on 13/10/2004 17:28:00

Quote: posted by Malky on 13/10/2004 17:18:27

?230!! BTW

Your kidding ? For that thing ????

Solved a misfire on No 4 on my AGU a couple of months ago, after good advice from the forum, by simply unplugging and scratching the conecting pins of the Ignition amp with a penknife. had already replaced a coil pack and spent over ?80 on diagnosis at dealers + injector cleaner etc etc

Costs nothing to try...

 

[tylerama]

Quote: posted by NBirkitt on 22/10/2004 13:19:29

Quote: posted by tylerama on 13/10/2004 17:28:00

Quote: posted by Malky on 13/10/2004 17:18:27

?230!! BTW

Your kidding ? For that thing ????

Solved a misfire on No 4 on my AGU a couple of months ago, after good advice from the forum, by simply unplugging and scratching the conecting pins of the Ignition amp with a penknife. had already replaced a coil pack and spent over ?80 on diagnosis at dealers + injector cleaner etc etc

Costs nothing to try...

So you do that to (presumably) clean the contacts giving a better conduction ?

 

[Malky]

Yep, sounds like a good idea.

Check all the earthing points you can see. There is one on top of the egine near the coilpaks as well, so I woulkd start there. Wire-brush or sanpaper them clean. Then connect them back up and put a little grease on them like you do on the battery connection. this will keep the mositure out!

 

[tylerama]

Well.. the misfire came back with a vengeance today [V] []

So, called out VW assistance. The guy turned up 45 mins before they said he would.. goin' well so far []

Explained the history to him (been doing it on and off since I got the car in jan 2003.. been in a few times, swapped coils and plugs about last time it was in, in june.. been fine since then.)

He plugged the 1553 in (or VAS 5052 as it said on it.. runs on win 2k as well ! [xx(]) .. didn't show any faults.. but he said that's not surprising as it may need to run for a while before it picks up a fault or throws a code.

He took all the coils out (he explained that sometimes they can break out of the plastic shroud that encases them and hence earth onto the engine [:O]) I held his torch for him whilst he did all this, they all looked okay and no obvious faults there. Retightened them all.. undid the ignition amplifier.. cleaned the contacts.. did it all back up and gave all possible electrical bits a good coat of WD40.. he undid and cleaned the earth connection next to the coilpack head (as mentioned above). He agreed with me that it was gonna be difficult to diagnose and fix purely because it was intermittent.

He said in just over a year of doing VW assistance, he's never come across another early 4 (i.e. AGU).. that has this problem. He said he's seen literally hundreds of later ones.. (i.e. post coil pack recall). He showed me the difference between the modified coil packs and mine.. basically, the new one is metal instead of plastic going right down to the plug.. but he finds these give more problems than the earlier (supposedly faulty ones).

He told me something that made me go [:O] too.. VW give their mobile tech guys a box full of new coil packs and they've been told that even if they go out to someone to change a tyre at the roadside, they are to try and change the coils, even if they're aren't faulty, just as a precaution !

How worried must VW be to do that ?

Anyway, the car is great now.. gave it a spin up and down the road and it's now back to normal. When I get the cambelt and water pump done on thursday i'm gonna ask the garage who swapped the bits about last time to actually replace the coils this time, instead of just swapping them about.. the techy guy agreed that that's reasonable given that ever since i've had the car it's never been perfect.

Sorry for that essay but thought something might be useful to someone.. if only to document my experience with it. []