AEB engine cyl 1 misfire
05-18-2009, 07:47 PM
#1
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AEB engine cyl 1 misfire
Hi there,
I've got a friend who has a 98 A4 and he asked me to help him troubleshoot his "rough idle." It's your usual 1.8T AEB engine. It's got heavy miles on it (150k), but I changed the timing belt/tensioner and other associated parts when he bought it at 110k miles.
After a couple of minutes it was clear that cylinder 1 isn't firing at all. So I swapped coilpacks with cyl 2. The miss is still in cyl 1. Did the same with the plugs and even the fuel injectors. I've also compression tested all 4 cylinders and they're all at about 170psi plus or minus a few percent. So I'm scratching my head. Has anyone seen an ECU failure mode where this kind of thing happens?
I haven't owned a B5 1.8T in a number of years, but I don't recall reading anything of this nature on the forums where one cylinder had fuel and compression, but no spark while the other 3 were fine.
According to my VAGcom, the only code is the obvious "cylinder misfire".
Suggestions?
Best,
I've got a friend who has a 98 A4 and he asked me to help him troubleshoot his "rough idle." It's your usual 1.8T AEB engine. It's got heavy miles on it (150k), but I changed the timing belt/tensioner and other associated parts when he bought it at 110k miles.
After a couple of minutes it was clear that cylinder 1 isn't firing at all. So I swapped coilpacks with cyl 2. The miss is still in cyl 1. Did the same with the plugs and even the fuel injectors. I've also compression tested all 4 cylinders and they're all at about 170psi plus or minus a few percent. So I'm scratching my head. Has anyone seen an ECU failure mode where this kind of thing happens?
I haven't owned a B5 1.8T in a number of years, but I don't recall reading anything of this nature on the forums where one cylinder had fuel and compression, but no spark while the other 3 were fine.
According to my VAGcom, the only code is the obvious "cylinder misfire".
Suggestions?
Best,
05-19-2009, 03:49 PM
#4
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Thanks guys,
I think that's a very reasonable guess. I recall now that I had a similar problem with my 2.7T a few years ago and needed to replace an ICM to deal with it. Totally slipped my mind.
Also, thanks for the link to the purems cart. It's actually quite a bit cheaper than the Bosch unit at ECS.
Best,
p.s. My friend took the car to New Country Audi in Greenwich, CT while I was out of town (before I had a chance to look at it) and they told him he needed a new ECM ($1500+labor) as well as a bunch of other completely un-needed and unrelated crap that had nothing to do with the miss at all. I guess some things never change. LOL
I think that's a very reasonable guess. I recall now that I had a similar problem with my 2.7T a few years ago and needed to replace an ICM to deal with it. Totally slipped my mind.
Also, thanks for the link to the purems cart. It's actually quite a bit cheaper than the Bosch unit at ECS.
Best,
p.s. My friend took the car to New Country Audi in Greenwich, CT while I was out of town (before I had a chance to look at it) and they told him he needed a new ECM ($1500+labor) as well as a bunch of other completely un-needed and unrelated crap that had nothing to do with the miss at all. I guess some things never change. LOL
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