starting problems S2 3b

[nielsl]

ow thanks! I will try this tomorrow

[K Simmonds]

You've got all info you need there from John...

I've just checked my old 3B sensor, it was showing 5k Ohm's at close to 0C and 1.8k Ohm's at around 21C... if I hold it in my hand so it warms up the resistance keeps dropping.

[nielsl]

I mesured the sensor and at 0C its 6,3k ohm, now it's 10degrees and its 3,9k ohm. Don't think thats bad but for the safety I ordered a new one. It's only 20euro's for a genuine bosch.

Does the sensor needs to be installed in the head, or is it also good to put it in the connector?

But I think it won't help. What's the first that i need to test, if I have ignition and fuel?

[steve briance]

Fault codes.

You never know, the car may save you from guessing which part to buy next...

The ecu saves fault codes so even if it is working when you test, it should tell you what has gone wrong in the past. This really should be the next thing you do.

[nielsl]

My neighbour who works in an audi garage read it out with VCDS and there are 2 faults.
514 G4 sensor no signal and 513 G28 sensor no signal.
I found that the G28 sensor gives a fault when the engine is not starting. Then here it's the G4 that is the problem.

I searched on the internet and I can mesure this sensor out. And mabye disassemble the sensor and look if there's no iron sticking on it or the pin on the flywheel that's gone.

What are you thinking I can start with it best?

[simons2]

If the pin was missing then it wouldn’t start at all

[nielsl]

I've pushed him today back in my garage and tomorrow I will try if he wants to start. It's now 3 weeks that he wanted to start.

Maybe it was luck that he started inside my garage

[nielsl]

Inside my garage he starts perfect. Can the g4 sensor go bad when it's a little bit colder?

I disassembled the g4 and there was a little bit of iron sticking on it. Can this be the reason?

[steve briance]

This is exactly what happens with my cq20v with 7a engine. Subzero sometimes gives no start, then without doing anything, when it warms up again, no problems.

http://www.s2central.com/ds_G4.html

Difficult to test properly as this site says but mine read around 1000ohms and was clean. I tried a spare i had and the problem persisted so, im thinking it might be wiring or connector issue...

My theory is cold = ice where it shouldn't be forcing open what should have continuity. Pure guess and my next move would be to run fresh wires to the ecu... We don't get that much cold here so im in no rush to tackle that.

[nielsl]

yes but when it's 10degrees outside he also dont want to start.

I just drove with the car and first he drove good, but when the engine was warm and I kicked the gaspedal fully in, I suddenly had no power and the engine was shocking enormous and there was black smoke out of the exhaust. Pffff i don't now it anymore....

It's the same i had when I cleaned the enginebay with the pressure washer a couple months ago. But then after some km's it was over.

Now at stationairy the engine runs good, but I have no power...

[K Simmonds]

Check the small bore pipe work to the fuel pressure regulator.

[newsh]

You need to check static timing of the distributor against the flywheel and you need to do a proper boost leak test.

The 3B does some weird stuff if the timing is not spot on, including blowing clouds of black smoke out the back, I've had this on mine.

A leak in the inlet tract somewhere could be sucking in unmetered air and making it too lean to start when cold. The same leak will make it run very rich on boost as metered air doesn't reach the engine.

[nielsl]

I think I found it! Today he started outside but not very well and he ran bad stationary. Then I went for a drive, again no power and shocking a lot.

Then I opened the hood and the ignition cable from the coil to the distributer was giving sparks to the tension bar in the engine bay. I guess that's also the reason that he don't wanted to start outside, because it was there a bit more moist than inside my garage.

I put the cable a bit further of the tension bar and now he pull's like before. Hope tomorrow he starts fine again.

Can you buy that cable separately? Or beter a complete set of cables?

[newsh]

Good find!
Kit has some HT cables I believe, send him a message.