Hi All,

I finally get a way ahead for my tune and this happens... It was just pouring down rain like someone pulled the plug on the swimming pool and the A/F gauges went to max rich. The car sounded like a truck. After the car slowed down I noticed it was really just idling. I gave it more and more gas but the RPM didn't change at all. I finally had to park it because I knew I wouldn't be able to make it to the top of the approaching hill.

After stopping and trying to figure out my options, I decided to try to start the car to see if the problem would just go away (wishing). The car started a couple of times and immediately died. Then it wouldn't start at all. When the tow truck came, I gave it another shot. I hear a real funny (not) noise from the throttle body. After getting it to the shop and removing the intake tube, I could see that, every time the ignition was tuned off, the throttle would vibrate open/closed for a couple of seconds. I was able to repeat this at will and I didn't even have to start the car (it wouldn't start anyway) to make it happen - just key on, key off. It moved so fast it made a kind of buzzing sound.

Has this happened to anyone before?

 

OK, it looks like you are all stumped on this one, so I'll give you an update...

Water

Apparently some water found its way through the firewall harness boot behind the battery and down the harness into the E-Manage Ultimate wiring. Nasty stuff. The harness is all unwrapped and drying, but it looks like that was the problem and the throttle is no longer flopping around. There must still be some moisture in there because the ECU is only registering 85% throttle when the pedal is to the floor, so it's not going to get wrapped up until that's fixed.

 

isn't the 85% throttle normal? I vaguely remember that WOT doesn't equate to 100% throttle on the g35

 

That passenger side grommet is notorious for leaking once it's been cut to pass something through it. Did you use it for sensors and stuff?

 

Yes, there were quite a few passengers added to the road through the firewall - sensor wires, EDFC, Amp... I got some Auto/Marine sealer and slimed it up last night. I'll give it a water test tonight and see how it goes.

 

That suck's...had this happen to me as well, very uneasy feeling to know that water has gotten on your computer harness, wiring, utec, etc.

Good luck man

 

I had a closer look at how all of this fits together... The design has all the water coming down off the window on the passenger side going through a hole in the plastic fitting at the bottom - directly dead center onto that grommet. So, I made a cover out of aluminum that causes the water going through that opening to fall beside the grommet instead of on top of it. I'm waiting for some heavy rain to see how it works. (I shouldn't have to wait long in Victoria)

 

Yeah a lot of water goes down that side. Funny thing is the driver side grommet feels like it's double insulated, I was running some power wire thru there and it's nowhere as easy to slide stuff in and out of that one. Hope it solves the problem.