Hooked a scanner up, weird numbers????

[Bossman429]

So I finally got around to hooking up a scanner, and monitoring some of the numbers my SMEC is seeing while running and such. A few caught me off guard:

Coolant temp: showed 14,000 ( it was a 5 digit # I don't think I saw a decimal) degrees F :confused: with engine off key on, and with engine on. Makes me think that the Coolant temp sensor is going haywire. At least I hope the coolant wasn't really that hot.:nod: I'd have a molten piece of TII. Ambient air temp sensor read about 161 F, temp gauge in car runs near the minimum line on the gauge. A infared temp gun on the CTS reads 160 F when the engine is warmed up.
Do these cars have 2 Coolant temp sensors? One for the ECM, and another for the gauge, or do they both run off of the CTS in the head? My GMs have two CTS's, that's why I ask.

Desired RPM: was only 5 RPM! Is this normal? I almost wonder if this has something to do with the CTS temp being WAY up there.

Knock retard: 3 cylinders were 0, except cylinder 2 which was 32 degrees with the enigne off? Starting, and revving the engine changed nothing. Seems odd to me, do TD's have a knock sensor on each cylinder? :bowl:

Thanks for the input

[GLHNSLHT2]

what type of scanner? what year smec and code?

[Turbodave]

There are two temp sensors, the one by the thermostat is the input for the computer, if it was really as messed up as you say it is the fan should be running all the time.

The other temp sensor is is on the front of the head over near the #2 cylinder, just a 1 wire sensor that is the input for the gauge on the dash.

It sounds like the scanner is either thinking it's a different car, or isn't reading something correctly.

[Bossman429]

It's a Snap On "Red Brick" scanner.
I don't recall what the SMEC code was, all I remember is that it might have been 54XX. It's a 1989 ECM.

When I unplugged the CTS on the t-stat to adjust the base timing, the fan came on, so the CTS must not be completely bad, or probably a scanner issue. Still made me raise an eyebrow.

[GLHNSLHT2]

sounds like a scanner issue, did it Auto-ID to the right year and smec?

[Bossman429]

I entered the VIN info (3rd, 5th, 8th, 10th digit) into the scanner. It listed an SMEC code to choose, but only listed one, I think.
I didn't know what the code should have been, where can I check? SMEC case?

[turbovanman²]

What cal are you running. You have to play with different engine codes to trick it. I have the same problem and just played around until the data was correct as I am running a TU cal.

[Bossman429]

It's a Mopar Cal for all I know. It's not an aftermarket.

[turbovanman²]

It's a Mopar Cal for all I know. It's not an aftermarket.


Still play around, I know on my 89 van with the stock cal, it came up with different cals on the screen, if you picked the wrong one, my data was like yours.

[ssheen]

When the scanner is told the wrong car it is scanning the data will be all messed up.