Hey there folks.

My main aim here is to compile a little collection of Vag-Com trickery for the favorit/felicia.

It seems to crop up a fair bit in thread about how to do the basic settings for throttles bodies and immobilisers etc so perhaps those more knowledgeable among us could post some stuff here then it could be put into a pretty thread to be stickied?!

One thing I would like to know is can engine RPM etc be monitored via vag-com on the felly?

Phil

RPM yes. I used it a lot diagnosing the issues with the mpi before I was advised to do the valve clearances.

How do I do it? I'm guessing I need to know the exact address/value thingamy to view the readings from it?

I imagine it will be different on the SPi to the MPi though although not sure if they use roughly the same ECU.

Phil

On the mpi I just went into engine, then measuring blocks and went through each measuring block until it showed rpm.

ah right... will give that a whirl then!

Trying to diagnose if the faulty rev counter is the ECU's fault or not.

Phil

Well that was easy! It was the first measurement block.

Had all sorts of other stuff in there too like throttle body angle, engine load, voltage, temperature etc. There was also a reading of "inj. timing" which was reading around 1.7ms. Guessing this is to due with the ignition advance etc.

The RPM was displaying fine so it's either the output of this signal from the ECU that's not right or something else!?

Also another cool little bit is in the ABS measurement block it displays the speed for each wheel in KM/H.

Phil

handy stuff. Using the abs wheel speed log and logging, you can do 0-60 times and all sorts

Oh yeh! good tip! Only thing is that the vag-com cable streched across to the passenger seat gets in the way a bit! lol

Perhaps I could move it slightly!? hehe

Silly really that the speedo is cable driven when there is an electronic speed signal that could have been used! (in ABS fitted cars at least )

Phil

Yeah, I dont have ABS ... Infact my motor has nothing really. No leccy anything, no ABS, no powersteering etc etc.

Hehe. Suppose it is just a stop gap/charlie mobile!

Mine doesn't have power steering... about the only thing it doesn't have!

Another really useful bit of info that the ABS control unit contained was whether the brake pedal was pressed or not... :P Suppose that could be used to diganose a faulty brake light switch though!

Had all sorts of other stuff in there too like throttle body angle, engine load, voltage, temperature etc. There was also a reading of "inj. timing" which was reading around 1.7ms. Guessing this is to due with the ignition advance etc.

That will more than likely be the injector pulsewidth, how long the injector is triggered for, i.e. how much fuel is being put in.

The RPM was displaying fine so it's either the output of this signal from the ECU that's not right or something else!?

Doesn't really tell you much; if the RPM wasn't reading fine then the engine wouldn't be running properly, or at all, as the fuelling and spark timing would be all wrong.

I've had a couple of rev counters that didn't work, never had an ECU output go wrong (yet!)

ok phil, i think it's a good idea putting up commonly used daignostics procedures, but the only slight problem with this is they sometimes vary depending on which ecu you have, they sometimes use different channel/block arrangements per manufacturer.. i've really only ever fiddled with the magneti-marelli 1av system on the 1.6 engine.

also dont read too much into the speed readings from the wheel sensors, they are often grossly inaccurate, all the abs computer is doing is looking for a differential in speeds bewteen the front and rear wheels

as an aside note to this, it might be a good idea to do one of those checklist things like you used to get in the back of a haynes manual. how many times do you see somebody ask the same question that is asked and answered in a thread a couple below. i'd be happy to write up a quide for engine non-starters etc on the petrol models if it could be made a sticky

Edited 11 November, 200916 yr by TeflonTom

as an aside note to this, it might be a good idea to do one of those checklist things like you used to get in the back of a haynes manual. how many times do you see somebody ask the same question that is asked and answered in a thread a couple below. i'd be happy to write up a quide for engine non-starters etc on the petrol models if it could be made a sticky

Aye cracking plan.

There could also be a list of common failures and problems too.

If we can collect all the info together then stick it in a thread then a mod can sticky it.

About the difference in ECU's then that fair enough. Suppose the info could be listed specific to a certain ECU. Are there many different ones? Surely only about 4; SPi, MPi, 1.6, and 1.9D (if it even has one?!)

Phil

I'm happy to be "sponsor mod" as I have a vested interest. I'll create a sticky.

Done

Thanks Danny! Jobs a good 'un!