OMP

I got my 200 turbo automatic back together.

I did replace the final drive by the one it should have had ( 3,08). New rebuilt Torque converter, new cranckshaft seals, few colant hoses here and ther, new oil, final drive oil, ATF, filter, etc,etc,etc...

However, I am having this noise that sounds exactly like a pinging noise.

Idle speed is perfect. The car starts fine. TDC sensor and engine speed sensor are alright ( check them as Bentley says)...

Problem is that from 1900 rpm or so, there is a sound that is pretty much like a pinging noise.

Sensors are OK (TDC and speed), the rest of them are almost new ( air intake, MFTS, temperature sensors for ECU ( 2 small ones), knock sensor, there are no vaccum leaks, turbo pressure is perfect ( also replaced the WG diaphragm).....BUT the car does have some difficulty when getting into high rpm's....it takes quite a while for the engine to push from 4500 rpm's on...

I have tried everything and it still does it.....

My final conclusion is that maybe the ECU is not working OK...

Can the ECU make the engine "work" without taking care of the timing advance? Is it fairly common to see these go?
Can this be happening to me?

ECU is the MAC-11C unit.

Thanks

V8QinNJ

if the pressure transducer in the ECU is bad then it could cause these symptoms.

I'd check the vacuum hose to the ECU first.

Katman

>Can the ECU make the engine "work" without taking care of the timing advance?

Yes, it can.. (sort of!)

Check to make sure that the small hose from the intake manifold to the ECU is good, and holds pressure/vaccum.

Also, along that hose (just before teh ECU) is a small plastic thing that looks like an inline fuel filter. (It's supposed to trap any moisture that may be headign towards teh ECC pressure sensor).

Make sure that it isn't broken, or cracked from old age.

In otherwords, if the ECU pressure sensor can't tell what's going on, it may think you have no boost, when in fact you have lots of boost. ECU won't back off the ignition timing, and you have a good chance of doing damage.

(Which is exactly haow I blew out my head gasket between cylinders! Once the gasket goes there, it's pretty easy for combustion gases to flame cut a slot in your head!)

So.. Check the integrity of line to the ECU, and drive really easy if you think that you are having an ECU problems..

OMP

Ok. Thanks a lot guys.
I'll check the hose, the filter ( ETKA describes it as fuel condenser, PN: 055 131 527), and the unions of them all....

Where is this filter located?. Is it in the interior of the car near the ECU or in the engine bay?

For what I saw yesterday, the green vaccum line goes under the carpet towards the shifter/console....How is it routed?

I'll check those see if there is something bad...

If not, I have an ECU already located in case it went....

Thanks a lot. I'll keep you posted.

BTW, I am running on 95 octane gas, which is the standard over here in Europe....

audi_marv

Could the pinging be a result of the car not getting enuff fuel at the higher rpm's ?
Check your codes for ECU faults....

Also....in Europe shouldn't you be running 98 RON, or is that the equivalent to N. American 95 octane ?

Katman

"Filter" thing is located near the ECU, at the right side of the dash/kick panel. ECU vaccum line ususally goes from the ecu (bundled into the red wiring harness, just after the filter) ,and comes out of the wiring harness again under the hood.

I don't think the ECU reference hose goes anywhere near the center console..?

OMP

OK. Done the vaccum/pressure line going from the intake to the ECU. It holds pressure by blowing into it and the filter looks pretty new. No craks and not at all dirty.

I bought an ECU from an Audi with 90000 milles. I should have it in a couple of days. I only hope this can be the cause, because I can not hink of anything else.

However, how about the fuel thing? Could it ba that there is not enough fuel getting into the engine? For what I know, this shouldn't really affect the timing, wouldn't it?

I don't drive the car on a daily basis. In fact, the car hasn't done much milleage in the last 4 to 5 years. I have being putting it together and I'll drive it on a daily basis when done with this issue, since the rest it's already done....

Thanks.
i'll keep you posted...

Katman

>Could it ba that there is not enough fuel getting into the engine?
Sure. Fuel filters have been known to clog. Especially if you don't know if/when they have been last changed! Fuel pump can go bad, and can be eclectical problems delivering power to the fuel pump.

>For what I know, this shouldn't really affect the timing, wouldn't it?
Noo, not as such. But it you *are* running lean, mixture can 'preignite' easier than proper mixture, so giving the 'symptoms' of wrong timing.
As the ECU controls timing, it *can't* be wrong (unless you somehow moved the reference pin on the flywheel! :-)

If you can do a 'fuel flow' test (see how much fuel flows in a set amount of time) as per teh Bently, or better yet, a running fuel pressure test, that should give you and idea if you have a fuel delivery problem or not.

Remember too, that bad electical feed to the pump, or a bad pump can cause fuel delivery problems too..