Engine speed sensor?

[spink]

Yeah I saw that after I posted, just thinking that may have been the code, I just saw speed sensor, and got on the phone, need to check it tomorrow.

Will have a quick rundown...

When I picked it up, it was doing it straight away, I changed the recirc valve for a forge one and it made it a fair bit better, but you could still feel it holding back but it wasn't violently cutting out. Did the exhaust, first test drive, put my foot down in first, shot up to 2 bar, then cut but softly. So went back, plugged it into the computer, and it said overboost and speed sensor.

Changed the speed sensor, and now its cutting out violently almost kangeroo'ing!

I've had a look about, and everyone suggests checking for boost leaks which I'll do tomorrow, but if theres anything else I can do to check/rule out? I've got another speed sensor on the way tomorrow, in case the new one was faulty. Will check the codes again tomorrow.

A friend of mine is due to take the car and I wanted to enjoy this lovely 5 cylinder note before I hand it over!

http://www.youtube.com/watch?v=qiiIR3AhopU

Did u clear the codes in vagcom after fitting the new sensor?i forgot to last week and had the kangaroo effect until doing so.

[Evilgoat76]

I've had G28 showing up on a non running engine, see my Dead S2 post. It was a red herring that cost me a lot of time and aggro.

Pull it by all means and check for swarf and crap stuck to it.
S2central might confirm this or otherwise, but I dont think the sensors are interchangeable.

[philj]

I didn't clear it to be honest, have done now, went out for a rally, boosted to 2.0 fine, changed and it did the boost cut, put it back on the computer, and its still giving these 2 faukt codes...

00513 G28 speed sensor, no signal

00544 Max boost pressure exceeded no plausable something...

Going to put the old sensor in, and check the wiring, have a look for boost leaks although another garage with the computer is convinced its something to do with a sensor...

[philj]

Right, this is getting very irritating!

Changed the speed sensor for another new one, cleared the codes, went for a rally, first boost went up to 2.0, changed gear and bam boost cut again.

So, put the old sensor back in, cleared the codes, same again.

So checked continuity between the wiring to the sensor and the ecu pin, and its fine, even the earth, and the G4 sender is fine.

Checked the pipe after the MAF for leaks, and its fine...

What can I do next? All out of ideas!

[haaran]

Have you tried the simple, but somewhat effective, MAF plug unplugging/plugging back in a few times technique?

Worth a try!

[philj]

Hmmm, I'll give it a go, we have removed the maf and cleaned it twice! Re-did all the pipes up.

Just a thought, but would the exhaust and decat have any effect on this? Only seemed to be doing it after the exhaust thinking about it, although it wasn't running properly before, just didn't violently cut!

[philj]

http://forums.audiworld.com/showthread.php?t=2162872

This suggets that if the crank sensor actually had no signal the car wouldn't start at all? Hence the small red fishy thing

Still doesnt solve the overboosting problem, is there anyway of adjusting the wastegate? Going to replace all the jubilees in that area tomorrow.

[Gazjen]

It won't start without G28 sensor unplug it and have a go

I think your barking up the wrong tree with the G28 sensor

[philj]

Fair enough, any ideas what I should be looking at next?

Will make something to pressurise the system tomorrow.

[Gazjen]

That's the next thing to do I think look for leaks

Have you tried disconnecting the MFTS?

I had a strange miss fire thing on mine that happened when it had been stood for a couple of days. If I drove it for about 50 miles it went away. Now it doesn't do it at all.

What about coil packs?

[philj]

Cheers, coilpacks have been changed in the last 40k along with the ECU according to its history. As per everyone screaming boost leak (more in everyones elses searches) there was a tiny hole in the intercooler... Havent fixed it yet, but is that enough to cause the overboost to cut in?

[philj]

Right, fixed the boost leak, cleaned the n75, it was a large split in the pipe from the cooler, so we made another pipe, and it was pretty quick for a while, went to 1.7bar on the digi gauge most of the time. Few times it went to 2.1 and was bloody quick! Back off, cruise along for a bit, foot down again and the overboost cut in, went and got the code cleared, same as above. And now everytime it gets anywhere near 1.5 it cuts out again!

Pain in the c*nt!!

[philj]

Unplugged the air flow meter (possibly a stupid question, but is that the mfts?) and it ran sound (most rampant so far!) getting full boost, then suddenly the digi gauge reads 1.0 and its slow! Any thoughts?

Anybody got spare afm?

[HMS-S6]

If you unplug some of the sensors it will automatically drop the boost levels down. And no the mfts is the 4 (?) pin sensor under the inlet manifold.

[spink]

Unplugged the air flow meter (possibly a stupid question, but is that the mfts?) and it ran sound (most rampant so far!) getting full boost, then suddenly the digi gauge reads 1.0 and its slow! Any thoughts?

Anybody got spare afm?

no the mtfs is the big fat sensor screwed into the water rail under the inlet manifold,common for those to go bad.

Sounds like your air flow meter is duff,where abouts in the world are you?