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Purchased a non-NOS switch, AC Delco # 212-582 to replace my defective TVS. Three ports are marked as follows: Top #1, Middle ‘D’, Bottom #2. Certainly not DCM...
Does the ‘D’ stand for distributor, which is middle, not top? Or should it be hooked up according to CSM?
Is that the TPP switch? My guess, knowing how they work inside, is you hook it up the same as the original. A 7-year old Chinese girl probably mad the mold for the plastic top and mixed up the letters.
Whichever of the other two is normally open to the distributor port goes to the ported vacuum tap on the carb. The other one goes to manifold vacuum. Yes, that's different from how the OEM valve is plumbed, but if you think about it, the port orientation on that new valve makes more sense. The actuator inside is just a spool valve that moves up and down depending on the temperature. Having the middle port be "common" simplifies that a lot. I frankly never understood why the OEM valves were so convoluted that way.
Whichever of the other two is normally open to the distributor port goes to the ported vacuum tap on the carb. The other one goes to manifold vacuum. Yes, that's different from how the OEM valve is plumbed, but if you think about it, the port orientation on that new valve makes more sense. The actuator inside is just a spool valve that moves up and down depending on the temperature. Having the middle port be "common" simplifies that a lot. I frankly never understood why the OEM valves were so convoluted that way.
I was leaning that way. if they had been labeled 1,2,3 I may have thought differently. Thank you
D is Distributor (vacuum advance can). Whichever of the other two is normally open to the distributor port goes to the ported vacuum tap on the carb. The other one goes to manifold vacuum. Yes, that's different from how the OEM valve is plumbed, but if you think about it, the port orientation on that new valve makes more sense. The actuator inside is just a spool valve that moves up and down depending on the temperature. Having the middle port be "common" simplifies that a lot. I frankly never understood why the OEM valves were so convoluted that way.
I was in a state of conundrum when I looked at this valve and reviewed the OEM style (which I removed on my '71 CS) before I elected to pass on making any statements regarding the OP's valve body. What you're saying makes so much more sense than the OEM valve. It's most likely easy to assume the part didn't come with any discernible instructions, as well I'll bet.
I was in a state of conundrum when I looked at this valve and reviewed the OEM style (which I removed on my '71 CS) before I elected to pass on making any statements regarding the OP's valve body. What you're saying makes so much more sense than the OEM valve. It's most likely easy to assume the part didn't come with any discernible instructions, as well I'll bet.
UPDATE: I hooked carb to #1, distributor to ‘D’, and manifold to #2 and the idle is much better, no more crazy vacuum advance from the bad OEM TVS unit.
My distributor weights may be sticking a bit, so I am going to get rid of the Pertronix and replace the entire unit with a different points distributor. That should get rid of any remaining unwanted ignition advance that I’m seeing.
I appreciate your piece on OBD, but I admit my comment was tongue in cheek. My last ride was a 2013 Ford Focus ST and I used to tune the ECM by updating it through the ODB II port using a hand held device from COBB.
Interesting though, how the state uses the port as well to check regulatory compliance through emissions inspections.
Interesting though, how the state uses the port as well to check regulatory compliance through emissions inspections.
That's just a testament to how much telemetry the OBD II system has. Contrary to what many people think, the old dynomometer-based exhaust sniffer tests are not accurate verifications that your car meets emissions standards. They are just spot checks at one or two RPM ranges, and based on that and the visual inspection, the state ASSUMES that your car is compliant. That's really the only practical way to do it, since a real test requires many miles of driving under a wide variety of conditions. OBD II monitors the car continuously while you drive, and matches RPM, speed, gear, temp, etc to emissions system performance to verify compliance over the entire range of operating conditions. That's why if you clear the codes on an OBD II system, you have to drive it at least 50 miles under specific conditions before you can get it tested by reading the data stream. As an example, the O2 sensor downstream of the catalyst is only there to allow the system to monitor cat performance - it has no real function in the operation of the EFI system.
December 7th, 2020, 07:46 AM
