240 Another K-jet question

Car in question is an 84 242Ti. Trying to get it back on the road...

I have something (CIS) driving the dwell to full rich on this car.

Hooked a dwell meter up to the test point, and I do have the Frequency Valve relay closing on the drivers fender. Frequency valve is buzzing away happily on initial start. But when starting the car, the dwell is going to full (and I mean FULL) rich! The dwell meter starts at 100 and immediately starts falling, going to 0 in the span of 5-7 seconds. Or vice versa, depending on which way the meter is hooked up.

I can't get the dwell/frequency valve into the correct range (42-46%) to get the car to run reliably. It will start, but since it goes full rich, it REALLY doesn't like it, to the point of stalling out.

Any ideas about what could drive the CIS computer to do this? I've tried a different CIS box, within success. Disconnecting the O2 sensor also make no difference.

Any help would be appreciated...

Step 1: Measure fuel pressures.

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http://forums.turbobricks.com/showthread.php?t=289775

Rotted wire insulation causing an enrichment sensor wire to be shorted to ground? (lambda box pins 7 or 11). See the greenbooks or bentley for sensor/wiring diagnostics.

There are two enrichment terminals to provide extra fuel when cold running and the other is for under boost. If either of those gets grounded at the wrong time it can cause high dwell reading and excess fuel. Terminal 7 goes to the boost switch on the firewall. Blue switch with hose from the manifold. When it grounds the wire at about 2.9 psi it makes the engine rich for boost. The terminal 11 is used with the thermal valve on the head. In the manifold there is a vacuum hose that goes to a dark green thermal valve on the head. The other hose on the valve goes to a pressure switch on the firewall. It is a round disc with the vacuum hose on one side an a two pin terminal and wiring on the other side. When cold the engine makes a vacuum variation under acceleration. This grounds just for a moment terminal 11 on the lambda controller. Gives extra fuel when cold and the thermal valve closes during warmup shutting off this feature.

Look over your engine wiring harness and make sure these wires aren't grounding out to other decayed wiring.

Wiring harness has been replaced, but I suppose that other wires could have the bad insulation and therefore be grounding out.

I'll try to find some time time to take another look at it later today...