toledo misfire mystery! Help please!!

[alex99toledo]

Can anybody help please!? I've had a misfire on my 1999 1.8S 20V Toledo for nearly a year!!! Nobody I've taken it to can pinpoint the problem and now it's failed to pass it's MOT as the CO2 emissions were way too high - so now I'm stuck without a car :-(

I don't know too much about engines so please bear with me as I try and list the symptoms and the work that's been carried out on the car to date.

The first sign of a problem was the day after a 240 mile motorway trip the car seemed juddery, this gradually got worse and then the car started to hold back for a second or two under acceleration, then the car would suddenly accelerate - quite dangerous when turning right at traffic lights as the car would just die as I tried to turn right before the oncoming traffic! A few days later the problem had got much worse so I called the AA out and they found that the spark plug on the 4th cylinder was all carboned up - black as you like. He reckoned I could have a faulty exhaust valve and that could be causing the build up. We cleaned it and the car ran again. ..for a few days until it carboned up again. I then had all the spark plugs replaced. The car ran ok for a few weeks, but was still juddery. My brother in law works at a dealership so he got a vw mechanic to investigate the problem. I had a Ignition coil / transformer replaced and the number 4 injector. I'm sure he also checked the compression, which was fine. He couldn't think of what else could be causing the misfire. The car ran ok for a few weeks, but then gradually deteriorated again, so in desperation I took it to my local SEAT dealer to run a diagnostic. They told me that there was a "faulty temperature sender and possible fuel in the engine oil". They replaced the temp sender, seal and coolant. This did not solve the problem. They said that there was nothing else they could do based on the diagnostic. Great - the best part of £200 down the drain! I'm currently having another garage next door to where I work look into the problem. They say the misfire had switched to the number 2 cylinder this time. They have checked the compression again and said that its fine. They're talking about the problem possibly being the no2 injector, the ECU or the lead(?) connecting them. So they're going to test these parts to see If they're faulty.

I'm absolutely desperate to get this sorted now, so any help would be very much appreciated!!!!! Thanks.

 

[nak]

Hope this helps, i believe it is the same engine
have been having trouble with my passat 1.8 20V turbo 1997 R plate, about a week ago I was doing the home run from work stopped once, and when i started again the engine was juddering, rather like a mis-fire. I got home and took each plug off each coil to see which one it was. I found that it was piston 2 which was not firing, as a result i changed the spark plug, but it was still the same. I then changed around the two of the coils still the same. I have since call out a mobile tuning / diagnostics company, but he could not find the problem on his scanner. I have since checked the wiring from the coil plug back to the air flow module and from the module back to the ECU, the result being that i have good continuity through the wiring. Does this problem sound like ECU or air flow module. Can any body help?

I would suggest the coil driver amplifier is faulty.It is fixed to the top of air cleaner housing.(under plastic cover).Also a good idea to replace the original faulty coil.(this amp is approx £180)

Coilpack faliure on the VAG 4 cyl engines is commonplace, much to the annoyance of VAG engined car owners!

Agree with elekie, you have done the detective work by substituting a known good coil and the fault stays on the same pot. I would just check the compression on this cylinder to be certain before shelling out on a new amp. Surprised your diagnostic man couldnt find the problem, possibly too much reliance on fault codes being the be-all and end-all of diagnostics much like the main agents instead of pinpoint testing the inputs and outputs directly on an oscilloscope. I have had an instance of this problem on a 1.8 20v golf and it had lost a switching output from the amp.
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Hi Elekie. can these amplifiers be bought second hand / refurbed £180 is a lot to pay.Also are they hard to find on the air box,as i hav'nt got a clue what they look like. i will also have a look around a couple breakers yards, thanks for your advice.

It is a small device ,approx 7cm/5cm ,usually made by Bosch.Part no.0227 100 211,fixed to air intake housing by 2 screws.There are 2 connectors attached to it;one is a 4 pin .the other is a 5 pin.


Thanks to you all for your help, i will do some investigation into price etc. i will let you know the out come. thank again.
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New Wed 20 Oct 04 16:28 VW Passat 1.8 20v Mis-Fire - chriss
Hi mate, hows it going, after your advice i have done some investigation, and i had quotes for around £120 from VW, second hand around £35, Today i had a good find though, i think, i came across a Audi A4 1.8T, the parts look very similar, with the 5pin and 4pin plugs, but this one has been made by Hitachi. The part numbers on the Amp look very similar,the amp was not displaying the 0227100211 part No. but there was another No 2D0 905 351, and on my part it shows a 4 instead of the 2. Do you think this is the same part but just another manufacturer, should i risk putting it on the car or not.
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New Wed 20 Oct 04 19:05 VW Passat 1.8 20v Mis-Fire - DL
Hmmmm tough call....

If we say "fit it" and it melts your ECU.......can you see my predicament?
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Thought i would give it a try, and it worked, done 700 miles down to cornwall and back, thacks for all your help.
i hope i will be able to help one of you guys some time

Hope this helps

 

[alex99toledo]

Thanks for your help nak. The guy at the garage has tested the individual parts (ECU, wiring to the ECU and the injector) with an oscilloscope and reckons it is the no.2 injector. He says the ECU and wiring is absolutely fine. Now I just have to wait 3 days for the part to be delivered!! I've had one of the injectors replaced before however (no. 4), so I'm a little sceptical as to whether the injector could be the cause of the problem or just a symptom of some other underlying fault somewhere else?! I'll let you know what happens...

thanks again!

 

[andycupra]

hope thats sorts it. However this was thought to be the issue on the other cylinder wasnt it?

interesting how its changed cylinders. Has anything been changed between them?

 

[alex99toledo]

Me too - but I'm doubtful - as like you say, the problem seems to have switched cylinders. sorry, I'm not sure what you mean If anything has changed between them (I don't know too much about cars!). Last time I had the no 4 injector replaced though, the car ran fine for a while afterward so I'm hoping at the least the emissions will come down and It can pass the MOT'd and I can get it taxed. I need to get on the road again asap!

 

[nak]

I also suggest, treat the engine to a good injector cleaner, some will treat all the top end, use lucas myself, a american product, sold at our local A TO Z parts

 

[alex99toledo]

sounds like a good idea - will do. thanks.

 

[alex99toledo]

Result!

After the injector was been replaced, the misfire stopped, emmissions came down enabling the car to pass the MOT. I've since done a 600 mile round trip to cornwall and the car has been running great since. Fuel economy has gone up by at least 20% too! Car is now running better than ever. Lets hope the problem really was something as simple as the injector. Thanks for all your help guys!