Troubleshooting Advice

[jeffs]

Unfortunately I couldn't get an MBE cable (they are currently on backorder), so I'm pulling the data with an AIM SOLO DL.  Oil temp, air temp, oil pressure and air pressure all looked reasonable during these runs.  That said I could very well have a bad cable/connection as much as a bad sensor and will do some poking around.    

[MV8]

That's good! Easier to find when it happens more often. Zero experience with your system.

 

I would remove, wire brush, and reinstall the engine/trans to chassis, batt, and ecu grounds, and reseat sensor and ign connectors and fuses. I'd also monitor/log operating voltage and ohm the plug wires while flexing back and forth. Flex/wiggle the harness and near terminations while running to find poor crimps/splices.

 

Again, not familiar with your systems, but the amplifier for the timing pickup on many vehicles can fail by thermal expansion which breaks a contact, which reconnects when the assembly cools. They often are mounted to a heat sink buttered with thermal compound like a processor on a motherboard. This compound can get washed away from pressure washing under the bonnet or just dry up with age.

Lead acid batteries develop conductive sediment in the bottom with age and use that can partially short the battery internally if tilted or from hard cornering and cause the alternator to fully load the engine to try and maintain voltage.

Edited May 4, 2022 by MV8

[ashyers]

jeffs,

I'd take a very careful look at your coolant temp sensor and it's connector. If it's Bosch and you can find the P/N you can look up the temp vs resistance curve and check it out with an ohmmeter. If it's inexpensive it may be worth just swapping it out.

 

Readings like you describe will cause havoc and may have killed your O2 sensor if the ECU kept dumping in fuel every time it was told the engine was at a very low temperature.

 

Andy