I love being the 5th Owner of My Car

[zghorner]

looking at the graph, from the point that everything starts to go haywire to the black line where everything is dead is 8 seconds. the vehicle speed is decreasing just from normal traffic driving on I40. The first sign of problems on the graph is unnoticeable while driving but obviously that's the real problem and im guessing the ECM just shuts off because everything is going crazy

 

[travisstorma]

The coolant temp sensor looks a bit suspicious to me. Notice how it drops 50 degrees at the same time everything else starts happening, then it goes right back up with no ramping.
The coolant temp is used to modify all kinds of tables in the ECM for fueling and spark timing.

ETA: Or I'd be looking for a power, ground or other electrical issue causing loss of reference voltage from the ECM.

 

[zghorner]

The coolant temp sensor looks a bit suspicious to me. Notice how it drops 50 degrees at the same time everything else starts happening, then it goes right back up with no ramping.
The coolant temp is used to modify all kinds of tables in the ECM for fueling and spark timing.

ETA: Or I'd be looking for a power, ground or other electrical issue causing loss of reference voltage from the ECM.

That's a good idea man especially since it throws a code 14 - CTS / coolant temp sensor. I replaced the sensor as well as the plug and still the same thing. Traced the wires the best I could with no damage found. Checked all my grounds and power cable and fusable links. Had the car on a rack for 30 minutes with the rear wheels elevated "driving" at 50 mph while my mechanic friend tapped and wiggled everything and we couldn't get it to act up. 5 minutes of highway driving on my way home and it dies like usual.

One thing is the CTS gets its power and ground from the ECM. If the ignition switch doesn't fix it then I will try to find a good ECM locally and see if that's the problem. I wanted to do the IGN switch first because its a $15 part and was 30 years old vs a $100 ECM.

 

[travisstorma]

I always hated fixing intermittent stuff...


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[Woody's Janitor]

Great cars and very fun to drive!

 

[zghorner]

I always hated fixing intermittent stuff...


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Yea man because it starts right back up and all levels go to normal its making it pretty difficult to diagnose. Really a bummer since I just had the motor and tranny rebuilt and need to put some miles on it before I can enjoy it for basically the first time.

 

[ronny]

zg, did those vise grips come with the car?

 

[zghorner]

zg, did those vise grips come with the car?

lol that's a b&m pro shifter [Broken External Image]

 

[oldkar]

I have wired probably 10 street rods with aftermarket wiring kits using gm wiring color codes. if youll download inst. from painless wiring youll be able to figure out where wiring goes and what it does a lot easier.

 

[ronny]

lol that's a b&m pro shifter [Broken External Image]

Ha!!!