john walkers workshop

i removed the oxy sensor's green wire from the computer plug at terminal 28 and so far the engine runs fine, other than the check engine light is on because of no oxy sensor in the system. good suggestion. so somewhere in the loom, that wire must be shorted to B+, just like the hammer said. simply unplugging the oxy sensor itself did not do anything. the hammer readings tend to be so general, they can mean several things. now the hammer does not read short to B+, only HO2S not present. i'm going to run a separate wire from computer to sensor just for test purposes now.

Indycam

Hiya john walkers workshop
Can I put that one in my success list ? Toot Toot Toot .
That earns me a good deed beer . Maybe two .

john walkers workshop

appreciate that. now to find the real reason. i'm thinking it's not in that wire, but in the black/green power wire that goes from DME relay term 7, to fuse 34, to plug under seat, to oxy sensor. maybe both wires fused together for some reason.

Indycam

Hiya john walkers workshop
I googled your workshop , nice site , nice photos . If I'm ever up in your neck of the woods ...

Red rooster

Hey Indycam,
Look back through the thread .

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Did you see the same O2 fault with the lamda probe disconected ?
Did you look at actual values and check lamda operation?

Looks like the Hammer could be telling you whats wrong !

Geoff
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Gets kind of frustrating that even with a Hammer, a simple problem like this just goes on. You deserve the beers for stating the obvious.

Happy 2006 .

Geoff

Lorenfb

As inferred in my above post, the most likely problem source is RFI from the
many ignition elements, e.g. spark plugs, spark plug connectors, spark plug
wires, and an improperly inserted spark plug connector. This IS the most common
DME electrical problem which affects the 964. Why has this been ignored, as any
Rennlist search will indicate such based on the data provided?

Yes, it's possible that a harness breakdown is feeding a plus voltage into the O2
wire, but this would be a very rare case. A simple test for this would be to measure
the O2 wire input to the DME at the O2 sensor connector with the engine not running
and then running using a DMV set to D.C. volts. If the voltage is about .45 to .55 in
either case, then it's unlikely that a harness problem exists.

Also, as was mentioned, one needs to disconnect one of the two ignition modules
separately to try and isolate the possible RFI source to either the upper or lower
ignition system.