Prob with my '96 VR6 - please help!

[Draco]

gman It's great to hear that you got your problem fixed.. Mine has the same problem only intermittently and only on accelerating from coasting (Or changing gears). I'll have to look into this as well.. I too had the mounts, drivetrain, etc cgecked... How much did the repair set you back?

I always thought that it was a sensor or something as one day it's purrfect and the next, it's like I've just started to drive manual.. It's embarasing at times when i have a passenger... And of course the scanner tool didn't show anything up

As for cleaning the injectors, you could always try a bottle of Nulon Total Fuel System Cleaner (TFSC)..

[gman]

throttle body cleanup

gday draco and everyone else,

just got back from the snowy mountains - driving the vr6 through the mt kosciuszko national park's quiet, banked, winding roads was just brilliant - gave me a chance to enjoy the car far more than the usual city traffic grind allows. the little car has such great grip and power!

i think the bill for the throttle cleaning came to $160, i thought this was quite reasonably priced, given that they had to spend time to troubleshoot the problem to determine what it was..

its amazing - no one was able to diagnose the problem - i thought i was up for thousands of dollars of gearbox or drivetrain repairs..

it made a big, big improvement to the driving experience in the car so was well worth the effort.

the guys at wolfsburg told me that the throttle body is actually not meant to be opened and cleaned - they said it is meant to be a 'sealed system', but they managed to open it and clean it anyway..

since having the problem fixed i bought a throttle body from golf loon (just in case the problem re-appears). having received the throttle body i don't really understand how it is a 'sealed system' as the wolfsburg guys said..

hang on i'll attach a pic of the throttle body i bought from golf loon - anyone know why i was told its a sealed system?

gman.

[deemoE36]

i had similar problem, happened when engine is down low in rpm and i try to accelerate
checked spark plugs and they were in there since the car was built, bought new ones and that was the end of that...i would recommend checking them before taking it to the mechanic, cus they can take ur money while only replacing the plugs and telling you that it was something huge

[gman]

hey deemo that's good advice, thanks for that. i am fairly confident that these guys are genuine though, the car has had a good service history with the plugs replaced just a year ago.

any ideas about the throttle body being sealed though??

[Draco]

Great to hear that you had a great time with your VR6, I'm still amazed at the torque this puts out and I've had it for 3.5 years now..

The only think I can see that could be sealed is the Throttlebody Position Sensor.

Thanks for the pix...

[Golf Loon]

I think they say they are sealed cos a layman can bugger up the settings easily.

[h100vw]

The only sealed bit is the position sensor. They would normally be sealed to stop the **** getting in causing failures.

There would normally be a throttle closed and wide open resistance to allow the ECU to know when to idle and when you are after full steam. The resistance in between giving the load to the ECU.

What often happens is that after years of driving round at the posted speed limits, the tracks in the TPS getting dirty at certain places which correspond to the throttle required to maintain particular road speeds.

When you open or close the throttle past this position the ECU would get an inaccurate signal, maybe one which tells it to cut the fuel as it should be at tickover, this would also kill the timng too. Big loss of power would happen until you get back to a place where the signal is again valid. I see this quite often at work on various aircraft instruments and sensors. In the workshop we can strip and clean the offending parts before testing and certifying them. We usually clean them up with brasso and a squirt of contact oil for lubrication and to stop oxidation.

The way to check it would be to find the varying resistance on probably 2 pins of the TPS and monitor this resistance with a meter while opening the Throttle very, very slowly looking for sudden jumps in resistance or open circuits. I would expect the TPS to run from close to zero to maybe 2-300 OHMS over the full range of movement.

If you get problems again it may be a case of repalcing the TPS with the one from the spare TB. You still need to set the TPS correctly so the ECU knows where it's at.

In more modern Dubs this would be a TB adaptation.

Gavin