audi s6 engine surging fault

[slim100s4]

Hello can anyone tell me if they have have this fault as above and what is it. Car seems to be surging when on light throttle when i say surging picks up then drops when throttle just held in position.

cheers

[driftin jo]

Hello can anyone tell me if they have have this fault as above and what is it. Car seems to be surging when on light throttle when i say surging picks up then drops when throttle just held in position.

cheers

Most likely your ISV is sticking , try cleaning it and giving it some WD40.

[slim100s4]

thankyou very much will give it ago

thanks slim

[slim100s4]

Tryed cleaning the isv no luck still have the same fault. Has anyone else have any ideas, doesnt do it on tick over only when revs are held at a constant position.

[UrS4boy]

Tryed cleaning the isv no luck still have the same fault. Has anyone else have any ideas, doesnt do it on tick over only when revs are held at a constant position.

Constant as in sitting in neutral (or clutch in) or while underway, e.g. in 4th gear? Without boost I assume.

Either way, in addition to the standard air/boost leak tests, you might want to check out the connections on your Throttle Position Potentiometer (link to more info under diagram):

http://forums.quattroworld.com/s4s6/msgs/20405.phtml

[newsh]

Did you pull the codes?

[chris]

surging

had the same on my 3b 200q, resoldered the throttle pot connections and it improved, but i then changed the lambda , car has never run better since ,, 4 yrs or 60k on a lambda, @£65 from ces

[prj]

Changing random parts without doing proper diagnosis will be very expensive and may not solve the issue.
But if you just want to throw money at it until it works, I guess that's an option.

[slim100s4]

I am hopefully havin it pluged in sometime this week thank you for all the info will give it all ago.
cheers slim

[chris]

surging

i got a speed sensor code, so new speed sensor , guess what , still the same, codes aint everything...

[dm80]

As most people will tell you on here the speed sensor code always appears if you pull codes when the engine isn't running.

[chris]

surging

i found on a volvo site describing the lambda vs maf faults whilst driving, apparently a faulty lambda gives surging on light throttle according to the article and held true for me.
just to add, 2 weeks prior to my 3b surging symptoms, my car was code free on vag com.

[S2central.net]

Remember - a LOT of faults dont show up as codes on VAGCOM...

For better analysis you need to look at Group 0 - ten fields on VAGCOM during warm idle - this is a great way to spot MAF, ISV or Lambda issues - or some air leaks too.

Post up the 10 values from left to right and we'll see if they are in range or not.

[prj]

i got a speed sensor code, so new speed sensor , guess what , still the same, codes aint everything...

If you think *proper diagnosis* involves only reading codes, then I'd like some of what you are having.

I'll quote myself:

Changing random parts without doing proper diagnosis will be very expensive and may not solve the issue.
But if you just want to throw money at it until it works, I guess that's an option.

There, I bolded it for you.

[chris]

surging