To those of you considering MS, or other standalone EFI systems.
02-05-2010, 02:00 AM
#1
Nordschleife Master
Thread Starter
To those of you considering MS, or other standalone EFI systems.
I have installed MS II V 3.57 onto an 86 Koenig 928 that has an 89 engine in it.
I had a few problems with the install.
One was the Cayenne COP units requiring 18 milliamps in the +5V logic level signal to them.
After I got that sorted I could idle the car, but trying to rev the car would result in a sync loss, and the tachometer in the tuning software would flicker between 1200 and 0. When I say flicker I mean, on off, on, off.
I spent a great deal of time and emails with Matt of DIYautotune.com whom I got the unit from trying to sort out the problem.
After testing and trying many many different things we could not figure it out.
Turning a resistor pot for the input voltage to increase would make the problem worse, and the input signal choppy. The opposite of what he was suspecting should happen.
He was suspect of noise and interference in the signal from the VR sensor to the MS brain. But I assured him that the wiring was top quality, and all connections were soldered and heatshrunk.
I ended up chatting with an old 924 friend who had done a couple of installs himself and he had stumbled upon 1 other person whom had had similar problems awhile ago.
What the problem was is that the VR sensor was too strong and generated too much voltage. This was due to the tight clearance between the VR sensor and the trigger wheel.
I undid the bolt clamping it down and pulled the sensor out roughly 1/4" give or take and the problem completely dissappeared. This will also increase the life of the VR sensor due to the lighter pulses it will make.
So if you do a standalone EFI system consider adding a 1/8-1/4" spacer to elevate the sensor more than stock to help generate a slightly softer signal if your going to make a proper harness!
Now as soon as I get that bearing carrier moved back and the 315/25ZR19 tire from tirerack, I can have fun tuning the car!
I had a few problems with the install.
One was the Cayenne COP units requiring 18 milliamps in the +5V logic level signal to them.
After I got that sorted I could idle the car, but trying to rev the car would result in a sync loss, and the tachometer in the tuning software would flicker between 1200 and 0. When I say flicker I mean, on off, on, off.
I spent a great deal of time and emails with Matt of DIYautotune.com whom I got the unit from trying to sort out the problem.
After testing and trying many many different things we could not figure it out.
Turning a resistor pot for the input voltage to increase would make the problem worse, and the input signal choppy. The opposite of what he was suspecting should happen.
He was suspect of noise and interference in the signal from the VR sensor to the MS brain. But I assured him that the wiring was top quality, and all connections were soldered and heatshrunk.
I ended up chatting with an old 924 friend who had done a couple of installs himself and he had stumbled upon 1 other person whom had had similar problems awhile ago.
What the problem was is that the VR sensor was too strong and generated too much voltage. This was due to the tight clearance between the VR sensor and the trigger wheel.
I undid the bolt clamping it down and pulled the sensor out roughly 1/4" give or take and the problem completely dissappeared. This will also increase the life of the VR sensor due to the lighter pulses it will make.
So if you do a standalone EFI system consider adding a 1/8-1/4" spacer to elevate the sensor more than stock to help generate a slightly softer signal if your going to make a proper harness!
Now as soon as I get that bearing carrier moved back and the 315/25ZR19 tire from tirerack, I can have fun tuning the car!
02-05-2010, 02:05 AM
#2
Administrator - "Tyson"
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Awesome progress Colin.
It's an awesome feeling when you find the smoking gun and she fires right up.
It's an awesome feeling when you find the smoking gun and she fires right up.
