1.8T Running Lumpy

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Nige P

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Wife came home last night saying the car was 'juddery'. As this could mean a multitude of things I just went and checked it out for myself. Sure enough, juddery under power. Feels like it is running on 3 cylinders so assumed one of the coils had gone.

Brought it into work this morning and plugged in VagCom, but no errors! Then I unplugged each coil in turn expecting it not to start on 3 of them and be the same on 1, but not so. Seems to be the same all the time ie either with all the coils connected or any single one disconnected :wtf:

Any ideas what the heck is going on???????
 
AGU

Just been having another look and disconnected the fuel injectors one by one. Each one made it worse except for No3!!

So, looks like it is the injector. Is this normal?
 
welcome to the joys of AGU engines! could be ignition amp (on the side of airbox). Common fault giving all sorts of miss fire related problems.
 
Yup, found that on here, but I thought this controlled the ignition coils so I struggle to see the connection with the injector!

I guess the best thing to do is remove the injector and see if it squirts anything in my eye!
 
No! bad idea haha!

You can put an amp meter across the terminals on the injector to check if its actually working. Cant remeber exactly what the readings should be but do a google and see what comes up. I think you check the resistance...

Also check the wiring to the injector, not the best bit of audi's work to be fair.
 
Well, actually, after reading the post before mine I have spotted that that link may NOT of been what you were after. I pasted the wrong link and now I can't ****** find it again!

Not my day today. :mad:
 
Ahh, Welly, you are such a tease!!

Thanks Ash, will have a look at that.
 
Nige P said:
Ahh, Welly, you are such a tease!!
Click to expand...

I wish more women would appreciate my teasing skills. They just tend to slap or punch me.

Sorry bud. I'm still looking for it, problem being that my browser automatically removes my history on exit *cough* for work security purposes *cough*. :busted_cop:
 
Just checked the resistance of the injectors and they are all the same.
Stuck a LED into the plug and watched it happily flash away with the engine running.

So unless it is physically blocked then this could be a Red Herring. Probably is the ignition amp but at £150 I really want to be sure!
 
They are expensive, I believe mine is the cause of a few small issues I'm having.

Best bet is to get a second hand one off a low miler. www.motorsinmotion.co.uk are a good bunch to get in contact with, for pretty much anything VAG related.

You need to be sure which N122 (amp) you have as there are 2 types. They have the same part numbers except one starts with a 4 and one starts with an 8. AGU engines normally have the 4D0 905 351 part number.

When I checked with MiM about two weeks they only had the 8D0 905 351 amps, but several of them at about £40.

I don't know what the difference is between the two, no one seems to have been able to give me a conclusive answer, so I would hold out for the right one personally.

Sorry for the long reply....
 
first things first... get some carb cleaner or electrical contact cleaner (better!) and some cotton buds. Clean all the contacts on both sides and give the wiring conectors a good spray (ignition off though!) try this might just be some crap stuck.

If you have to buy a replacemnt try gsf or eurocarparts their normally alot cheaper. And remember to get some thermal paste (pc world or maplins) and put a good amount on the back of the sensor. They get quite hot hence why there mounted on the airbox.
 
If you've got a multimeter, you can test it using my teaser link....

Ash, good should about the thermal paste! I mounted mine to something plastic and it melted it after a while.
 
haha, mines mounted on some 5mm ally as i have a sealed carbon airfilter. it does get quite warm.
 
ash_pearce said:
haha, mines mounted on some 5mm ally as i have a sealed carbon airfilter. it does get quite warm.
Click to expand...

Same problem I had, I've fitted twin mushroom filters onto mine, which leaves little room. I have nowhere to put the N122, so mounted directly to the power loom enclosure heading into the cabin. Jobs a good un!

Till it melted it.

****.
 
i almost mounted mine there, glad i didnt now! off topic again haha
 
Think I found that link Welly Clicky

Will have a go at this tonight on the kitchen table and if inconclusive will start pulling the injectors out tomorrow, in the rain!! If that fails then I will just tell her that its 'terminal' and she will have to buy one of those S3 things as I hear they are more reliable!!

Many thanks for your input guys!
 
Just completed the test procedure on the ignition amp and sure enough I get an open circuit on one of the pins, not the one I expected but still pretty sure this is the cause.

Many thanks for your help Ash/Welly.
 
Nige P said:
Just completed the test procedure on the ignition amp and sure enough I get an open circuit on one of the pins, not the one I expected but still pretty sure this is the cause.

Many thanks for your help Ash/Welly.
Click to expand...

no worries bud! hope you get it sorted:thumbsup:
 
Was just about to call the Stealers first thing this morning to order the part, but thought I'd give GSF a go first. Was very surprised to hear the guy say they had one in stock for £55 +vat. So took the afternoon off work to sort it out.

Was doubled surprised at the GSF counter when they handed over a genuine Audi module, exactly same part number & the 4 rings!! That's where my luck ended.

Plugged it in there but the engine didn't fire at all, checked everything again and tried again. Still nothing. Walked back in and told him it didn't work and was told that because I had fitted it to the car I couldn't take it back, it was mine!!

After a polite conversation with the Manager and trying to explain that if I had diagnosed incorectly then it would still run on 3 cyls, but as it is the only thing we are changing the the law of elimination rules and the module is faulty, he finally agreed to change it, but not til tomorrow after he had discussed with his techies, in case I had fried it!

I can't believe that this module is OK but I am slightly concerned that I get another faulty one tomorrow and not be able to prove otherwise. Will let you know.
 
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