Best part number/item for thermostat gasket?

Thanks for confirming my thoughts. This will make the troubleshooting effort make 100% sense now. From here it's divide and conquer - should be simple. "Should" except its likely something broken or melted buried under tubing and harnesses.
 
For this kind of troubleshooting I find the EVTM's to be frustrating. They try to tell you what you need to know but they don't tell you what you will actually find in the vehicle. I find I use the actual vehicle wiring diagrams 99% of the time. They tell you exactly how many connectors there are in the system, what they look like, and where they go. Well, electrically where they go. Physically you still have to find them. But to me the big thing is they tell you exactly what else might be connected into a particular circuit and what definitely isn't.
 
Dave - which actual diagrams are you referring to? Is there something better than the EVTM? I've got tons of books for this car...
 
Well I FINALLY got this solved. Nice day here in Denver today so I rolled the old girl out into the driveway and tool the PCM out so I could do some Ohming out. Found a bad pin in the main harness at the back of the firewall going into the PCM. I had 4 K Ohms from the sensor return to the PCM unless I wiggled the harness a bit. Thought it was a bad wire but the contact is a little sloppy. I pinched it together a bit and the code cleared. Drove it for 15 minutes and it came back. Planning to get some Arctic Silver conductive paste to put in the contact unless someone else has a better idea. I have no idea what pin extraction tool would be needed to pull the pin to make it tighter. If anyone does know what tool I could use besides a small screwdriver I'd love to hear.
 
Remind me, are you working with pins/male on the connector side, and contacts/barrels/female on the ECU side, or?

Arctic Silver conductive paste

About Arctic Silver...it is 'thermally' conductive.

"Arctic Silver 5 was formulated to conduct heat, not electricity. ... While it is not electrically conductive, the compound is very slightly capacitive and could potentially cause problems if it bridges two close-proximity electrical paths".
 
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I am working on the female side of the harness that goes to the ECT. I was hoping since the compound has silver in it that it was conductive. I guess I'm gonna have to find something else.
 
De-pinning tools are low cost and many to choose from via eBay, but the last ones I bought came in direct from China and would take a couple weeks to receive, but...they won't help re-size female side contacts, only help release the contact from the connector, so...

Just clean the pins, then spray with CDC electronic contact spray, don't coat them with anything else (the clamping force on the female contact is too low; di-electric manufs. don't recommend using it on low pressure contacts)...I've gotten out of the habit and just use CDC contact spray now.

Gently burnish as best you can, then do the same on the terminal/male side, then apply di-electric grease on the connector shell halves where they mate as a seal. On the female side, just squeeze it down against a small diameter object, like a toothpick, so you don’t inadvertently crush it. Best solve when the contact is too far gone is to replace the wire end with a new contact.

Did you open the harness side connector near the relays on the pass. side firewall, inside the engine bay, where the top left side engine harness connects to the body harness that leads to the PCM?

Those are prone to corrosion and can inhibit signals/ref/return. I’d expect corrosion to raise resistance/lower volts, and a loose pin/contact, if clean, to cause an intermittent path, not necessarily high resistance. In other words i’d blame corrosion, first, and more likely, as opposed to a faulty connection, where there would be 0 resistance because of a break in the path. Not sure a loose pin would raise resistance….?
 
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I did not open the clamshell on the PCM. I was able to verify that the 4.4K Ohm of bad resistance lives in the connector itself (in the engine bay)

I'll be looking for that contact cleaner. 100% worst case I will bypass the connector for that single wire.
 
Another trick that can help after everything is cleaned and di electricted is to VERY slightly bend the corresponding male pin on other side of connector so that it "presses" against one side of female connector barrel. Be careful not to overdo it tho.

Adam
 
So I fixed it. I remembered I had a silver paste pen that I've used to jumper bios and other video card "fun". I used a 1mm bead of it and shoved it inside the pin. I did use dielectric grease around the connector. Drove it for an hour - no code. I did wrap the wire with a very small blue zip tie behind the connector shell in case I get the code again and I have to do a more elegant/permanent fix.

Thanks for all the help on this one. I must be getting old as I used to chase wires on an electronic warfare plane in the Navy when I was a kid. Maybe I just wanted the easy button.
 
I was able to verify that the 4.4K Ohm of bad resistance lives in the connector itself (in the engine bay)

That's where I've been finding corrosion. Two connectors were hiding it in that location. Others were clean. Typically it's on wires that are constant hot, even when key off, I believe. Same with ABS always hot wiring/connectors.


Walmart, Home Depot, Autozone, Amazon, eBay etc. all sell CRC electronic contact spray. Can labeling may differ as it seems CRC has updated it's branding lately. Not inexpensive, but worth it, I think. Verified results on my SC.
 
Does the 5V come directly from the PCM? I appears to in the EVTM. Wondering if it goes through the IRCM first... tearing it down now.

I think I went over this with someone here in the last few months....let me search and see what I can find. Might depend on year.
 
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