I've got a P117 code, which indicates the head temp sensor is bad. I'm going to try cleaning the connector, but I may have to replace it. The car runs okay on the freeway, but is barely drivable in stop and go, so I don't know if I can get it to my mechanic. If I end up changing it myself, do you get to it from the top or from the bottom?

BTW, it ran fine at the track as long as I was at WOT. However, it's hard to do that constantly on the street, so I guess I better fix it.

 

#3 cylinder is accesible. You need to borrow or make a tool out of a deep well socket. There is a rubber cover over top of the engine tin and the wire comes out of the cover. Remove the driver side wheel. Pop the cover off on the vertical surface. You need to cut a channel in a deep well socket ( I believe it is a 13mm, but please check) that allows the wire to exit the socket. Break it free then turn the entire connector/wire with the grommet attached easy around until it is out of the head (don't twist the wire around anymore than you need to). The wire should have a white slightly transparent cover over it.

 

Thanks! That's great info. I owe you a beer.

 

I may do a cycling tour out in Bryce this year in August. Will PM then for that beer.

 

I cut the 14 mm deep socket with a cutoff wheel, then smoothed the notch with a metal bit.
Mike

 

Here are a few shots from replacing my CHT in a 964 (similar to the 993).








Marc

 

It was typical: 15 minutes to get to it and 2 hours figuring out how to actually remove it.

The turbo complicates things because the turbo intake is exactly in the way. It's a convoluted plastic pipe. I took off the rubber couplers at both ends and it was almost possible to pull it out but not quite, not without removing the muffler and turbo. So I just moved it as far out of the way as possible.

I took off the heater duct, both the rubber and the metal pipe. Since the sensor was bad I cut its wires as close as I could to the sensor. But then another interesting problem became evident. There was a structure in the way (maybe this is only on the turbo?) that prevented a deep socket from being able to go on the sensor. On the other hand, I could get a regular socket on it, but the metal jacket surrounding the wires for the first 3/8" or so meant I couldn't get the ratchet in the socket. If I first put the socket on the ratchet, I couldn't get it on the hex of the sensor very much and, as mine was very tight, I started to round the hex (which could have turned out very badly, pulling the engine, deciding to do a few other things like replacing the clutch, fixing a synchro and, hey, why not re-gear, not driving all summer and spending $10K).

I had to get rid of the metal jacket, but I couldn't cut it with wire cutters. So I took a hacksaw blade, just the blade, and wrapped a cloth around it and resigned myself to a couple hundred awkward 1" strokes. This cut it half way through and then I could break it off with pliers. Now I could get the socket/ratchet on it and, pulling like crazy, it finally broke free.

I'll get the new sensor in a couple of days and if I'm lucky I'll be able to fish it through the hole without removing the intercooler and blower. After all the work this better fix it or I'll... well, I guess I'll try something else.

 

I'm currently in the middle of this job and I'm really struggling to get the upper grommet out (the one w/ the CHT and flywheel sensor wire).

I'm trying to get to it from the bottom using a flat screwdriver and my hand, but I can't get it to budge enough to work it out of the engine tin.

 

Pushing it through into the engine rather than pulling it out???