I have the AJ6 enginnering mid section pipes, no CATs and the rear boxes are Eisenmann from a 7 series BMW i used to have, i had to turn them upside down to make it fit so the twin pipes are on top of each other as a result, its very noisy !

 

Success (or something that looks like it)...

Now all the memories come flooding back.

On that ill-fated day when the cat left me stranded, I immediately tried to do anything to get it going. Remembering that a bad CTS could foul things up, or keep it from starting at all, I pulled both the wires out of the CST and shorted them out. After the fact, I remembered that I had run it with that connection shorted out before with no problems, so I didn't bother to reconnect them when troubleshooting what I though was a fuel or ignition amp problem. What I didn't remember was that when it did run well with the leads shorted out it was in the heat of summer, which is when the sensor would have expected a resistance of about 1,000 ohms. But since my incident of being stranded it's been late winter/early spring, with temperatures in the 40's and 50's, when the sensor wanted to see 4,000 to 6,000 ohms...and of course it was seeing zero ohms, which works well if its a couple hundred degrees out.

Anyway, so I just went down and untwisted the wires going to the CTS, jumpered a 3.3K ohm resistor across them, which would be what it wants for temps in the 60's F...and it started right up!

Of course I've claimed success before and been bitten, but this solution is one that makes sense, so I'm optimistic.

I'll run it up again this evening, let it get nice and warm and make sure the issue has disappeared. Then I'll wire up the CTS again.

FWIW, I don't regret anything I've done to it during this process. It now has a new fuel filter, new fuel pump, new coil, new ignition modules to spare, the fuel sump is now clean...all stuff I don't know that I would even have gotten motivated to do without something like this to push me into it.

Thanks to all for ideas and input!

John
1987 XJ-S V12

 

good news.

 

We may have both been chasing the same problem, hopefully we've both resolved them. Cheers!

 

Just an after-action report.

It seems to be holding up well. Drove it around last night with no issues at all.

Part of my new "emergency" kit is a pair of test leads (with with alligator clips at both ends) and 1K and 3K resistors + wire strippers. If the CTS does go bad away from home cutting the wires to the CTS and jumpering a resistor(s) of the appropriate value will get you back running again.

Thanks to all!

John,
1987 XJ-S V12

 

Great to hear you've got it sorted. Here's a link to the original equipment Lucas CTS for a song.

http://m.autopartswarehouse.com/sear...132+4294962447