Anyone know why I would have 12 volts at wire 13 (test point for ect) on the ecu instead of the max 5.5 volts?
Can anyone tell me if this indicates a bad ecu? From what I have read, a bad ecu would show no voltage as there would be a break in the circuit... Anyone??
Also, since the ect is "double" sensor where is the other test point (wire) at the ecu?

 

Maybe start with yr and model,
then why you are testing the ECT.
How is the car running.?

 

Sorry i was thinking I was still on the other forum.
I am working on a 1990 740 Turbo.
Throwing codes 123 and 224 both pointing back to the ect.
Car is a little hard to start. Hesitating upon acceleration. Check engine light on. Cuts out and then corrects itself.
ECT replaced twice. No obvious vacuum leaks.
Thanks for replying.

 

123 is bad grounds from ECT ,....on the intake manifold.
Remove and clean/file both sides, manifold and ground washer.
Do them all, theres a few, might as well do the whole lot.

If that fails , take a look at the ECT plug itself, they have failed like any other connector.
I like to pinch the plug terminals closed so they are tight when the blades (prongs) on the ECT slide in.

That will fix it.

 

Thanks, I am going out to try these things in about 2 minutes. I have removed and sprayed clean the ground points on the intake, but maybe that isnt enough. I'll give it a shot.
Mark

 

A bit of fine sandpaper...or a file.

If that doesn't fix it , check theecu end connection w/ your meter,
...this might help.

https://blarf.homeip.net/greenbook/TP32043_1

if that isn't the problem it might be a bad wire between the 2.

 

Thanks Jonesg
I took the intake back off, removed the sensor again and throughly cleaned the contact surface there with steel wool attached to my 1/4 ratchet & extentions. (still pretty hard to reach)
I also cleaned the two ground points where the four brown wires ground to the intake with a file. Are there other ground points? Is there point that I am missing? Is there a point where the intake is specifically grounded to the engine block or head? - Since I am asking this, you can summise that there is no change in running condition.