944/1 Bucking Issue - Fixed
08-17-2013, 11:18 PM
#1
Instructor
Thread Starter
944/1 Bucking Issue - Fixed
Well okay I fixed this a long time ago, but figured I would share.
So the issue is, while driving anywhere, the car randomly bucks/surges, bogs some, and may die. Just happens randomly.
It seems silly, but heres what convinced me - I have two 84 944's, BOTH had this problem, and BOTH were resolved with the same simple fix.
It seems that on many cars the AFM harness is run as in the picture below (highlighted in red). The best explanation I have is that is strains the wires or plug in a way that eventually stops making connection.
The solution - remember, this solved the issue on BOTH of my cars - Run the harness on the other side of the timing case vent hose (or whatever you want to call it). This puts the wires straight into the plug, instead of with the funky 90 degree bend.
So the issue is, while driving anywhere, the car randomly bucks/surges, bogs some, and may die. Just happens randomly.
It seems silly, but heres what convinced me - I have two 84 944's, BOTH had this problem, and BOTH were resolved with the same simple fix.
It seems that on many cars the AFM harness is run as in the picture below (highlighted in red). The best explanation I have is that is strains the wires or plug in a way that eventually stops making connection.
The solution - remember, this solved the issue on BOTH of my cars - Run the harness on the other side of the timing case vent hose (or whatever you want to call it). This puts the wires straight into the plug, instead of with the funky 90 degree bend.
08-17-2013, 11:52 PM
#2
Good catch! Porsche put out a TSB on that very thing in '87 IIRC. Seems that they discovered the problem after the cars had been through a couple of services that the mechanics were either using improper procedure or routing the wiring incorrectly. Early days of the DME!
08-18-2013, 02:13 PM
#3
Rennlist Member
Trying this now, I've been having bucking/jerking (see my post recent thread).
If this doesn't fix it, I'll be getting a new ignition switch and hoping it's that.
If this doesn't fix it, I'll be getting a new ignition switch and hoping it's that.
08-18-2013, 02:48 PM
#4
Race Car
Bucking and surging is also common of a bad Tps or fuel delivery issue just in case the Op method doesn't assist you.
08-18-2013, 03:16 PM
#5
Rennlist Member
That's where it's supposed to be anyway.
More important, make sure the wires are secured to the wire mount on the AFM to keep them from moving. I still unplug / plug in my AFM about once a year to make a fresh connection.
More important, make sure the wires are secured to the wire mount on the AFM to keep them from moving. I still unplug / plug in my AFM about once a year to make a fresh connection.