Symptopms is this isv, maf or summit else?

[jonnaz]

ok had a play with the tps it was only clicking somtimes when the throttle was closed so adjusted the postion. used a multimeter to do the tests on the tps resistace is good across pins 1+2, 2+3 and 4+6. the voltage is good on pins 1+2 and 2+3 reading 4.8V on 1and 2 when closed and same on 2 and 3 when throttle is open. the high idel is sorted however im still getting the oscillating revs when i press the throttle a little. will do this @ around 1100 rpm and oscillate betweent 1100 and 1400. any ideas could it still be the tps is knackerd?
cheers.

[Flat on my back]

.

Best way to check the 'track' in the TPS is with an AVO, rather than a digi. meter. This will show the increasing/decreasing resistance of the track and show if there are any 'bad' spots.

Hope that all makes sense.

[jonnaz]

Whats an AVO is iit an oscillascope? the hunting when the throttle is lightly pressed stopps for a few minuts when i disconect the isv then reconect it but it dosent take long for the car to act up again. is it a good idea to just replace the tps? dignostcs always throws the isv code out might just repace both.

[twoqu]

Difficult call to make!
Take a look at this:

http://www.s2-audi.co.uk/workshop/3b_ignition/3bi.pdf

The diagnostics measuring blocks has a load of ISV values.
Worth a look.

[Flat on my back]

.

Ita a moving coil meter...works by passing a small current trought the part you are testing so that a full cicruit is made. If at any point there is a break or 'flat' spot in the resistance being measuered you will see it in the movement of the needle.

http://www.richardsradios.co.uk/avo8.html

[jonnaz]

right now im really confused. the problem is not caused by the isv or the tps as new ones have been fitted and no change. the car only acts up when wam, runs and drives perfect on cold start. so what could it be o2 sensor MAF? anyone got any other ideas. its begining to p***s me off.

[jonnaz]

i have tried everything i can think of the car is still surging on light throttle the only code i get 533 isv code, however the isv is brand new, its not the tps or maf as have tried a fully functioning ones on the car, have ran the car without lambada sensor connected no change. everything was working fine before engine was taken oout f the car. anyone got any sugestions?

[UrS4boy]

right now im really confused. the problem is not caused by the isv or the tps as new ones have been fitted and no change. the car only acts up when wam, runs and drives perfect on cold start. so what could it be o2 sensor MAF? anyone got any other ideas. its begining to p***s me off.

If the problem occurs AFTER the engine is warm, it could be the coolant temp sender which for an ABY (or AAN) is the G62 sender. I am not sure if that signal is from the MFTS in a 3B. What I am thinking is the coolant sender is telling the ECU that the coolant is still cold when in fact it is warm/hot. As a result, the ECU will be trying to enrich the mixture in one circuit while the O2 lambda sensor is getting rich exhaust and tells the ECU to back off the fuel for Fk's sake. The ECU does this but then the G62 (equivalent) says but it's cold, turn up the fuel. And so on and so on = surging.

Have a look at this post:

http://forums.quattroworld.com/s4s6/msgs/20985.phtml

HTH

[jonnaz]

that would make sense i will give it a shot and do some testing i have tried running with the lambda unplugged previously and problem still occoured. i see what i can come up with and have a fiddle around thanks for sugestion.

[jonnaz]

im still having this surging problem when the throttles is lighty touched roughly at 1100 rpm and it is doing my head in. following sensors have been changed. knock sensors, mfts, tps, lambda. also the isv has been changed, all vac pipes on the inletmanifold are new and the maf is working correctly. if the maf is disconnected and then reconnected the engine does not surge for a few minutes however after this time it starts again when the throttle is touched lightly.

the clocks in the car have been changed as the original ones no longer worked could this cause a rouge signal or could the ecu be knackered?

the code that is throwen out by the diagnostics is 533 isv limtationa exceeded or something.

any ideas fellas?

[phillheth]

did you ever get this sorted, I'm having a similar problem

[jonnaz]

no still doing it it is really anoying. have you tried everything in the thread to fix it? most people solve it by cleaning the isv from what i have read. i have started another thread after finding the shaft for the butterfly in the nthrottle body is leaking air out which may be causing. im still trying to fix it tho

does your car begin to surge/hunt at 1100 rpm?

link to boost leak thread.

http://www.s2forum.com/forum/showthread.php?t=47756

[philS2]

Did you change the ECU coolant temp sensor?

[jonnaz]

Did you change the ECU coolant temp sensor?

no the g 62 has not been changed but has been tested and seems to be ok. im probs should change it tho. mfts has been changed.