S2 Checkup

[Rusty]

Right, the old girl wasn't quite as good as she should be so I decided to check over all the things I could think of... basically a lumpy idle and not as fast as she should be.

Water level checked and is fine, detected a small leak, fixed
Oil level is fine - oil could do with replacing really
Boost leak tested to 0.5bar using hand pump, tiny leak detected and fixed
Removed and cleaned injectors
Removed and cleaned ISV
MAF swapped for spare, might clean and re-fit original
Visual inspection of vacuum hoses, fine

Anything else anyone can think of other than a VAGcomming

[Rusty]

I think a check over of the temperature sensor resistances is next... any links?

[GazzaG60]

do you have and AF gauge. not wideband fitted.

do youm get good fluctuation on it on cruise.

any hesitation when gonig WOT.

lambda

have you tried unplugginging the isv and then getting her running you may have to rev her a few times to get it idling then it should be ok. if its smooth then id say isv. on the corrados they were prone to leak boost. also they had code to bleed boost if certain criteria was met. check valves and reroutes were the order of the day.

[mcandmar]

What about recirc valve, i was amazed how much better our S4 ran with a new one. Nothing to do with WOT or full boost, just day to day low rev driving was much better.

[S2central.net]

Andy - I'll dig out graphs to check IAT and ECT sensors - if they are saying its cold then the ECU will overfuel and could upset idle amongst other things...

Worth checking MAF output voltage - and maybe logging that on a run too... Its such a critical sensor.

You got your injectors all ASNU cleaned already ?


Paul

[Rusty]

Recirc valve is Forge, all cleaned and greased a few miles ago.

Injectors haven't been properly cleaned, only had carb cleaner dripped through them... not sure that'll do anything.

The water temperature on the dash looks fine, it's the ECU sensors that I need to check. What's the one on the back of the head? Is that the ECU one?

[S2central.net]

Thats waht I said ... IAT on the manifold for air temp and ECT at rear of head for water temp - real ****** to get at with a multimeter. I have the data here - actually the graphs might be posted already in the past.

[Rusty]

I'm certain they're all on SJM actually. Been busy buying a patio today Will have a look now.

[Rusty]

On S2central

IAT should be about 500 Ohms at 25 degC
Coolant about 300 Ohms at operating temperature (90 degC), 3 kOhms at 25 degC.

On the water amnifold there is the MFTS and after run swithc, correct? What does MFTS cover, dash and ... ?

Cheers

[Rusty]

Measured with the engine cooling from 90 degC about 1 hour ago

IAT 526 Ohms, corresponds to 30 degC = OK
Water Temp 676 Ohms = 60 degC = OK

Both seem spot on there.

Another boost leak test didn't show anything although I can't get much pressure. Need to get to the local garage and get it on the tyre air hose

I think the injectors are the next source of investigation.

[Rusty]

Anything else to check tomorrow? Might try a spare DV if I get stuck although the Forge one sounds fine and was serviced not many miles ago with no problems since.