Cascade Crew

scott in wa. · Posted: Tue Nov 29, 2005 7:02 am Post subject: Bad ECM?

1987 z28
My coolant temp sensor is reading -39. deg
I check the voltage at the sensor with the ignition on and its correct (yellow wire)
I checked the ground wire a as well and is good. Its a brand new sensor.

I ran the car, hooked up my lap top viewed the values and tapped on the ECM.
AND
Bam,...I lost my o2 sensor, taped again, it came back on, then my BLM's went red, then taped again, car runs like crap, so you get the idea.
the coolant sensor never came up but allot of the other values and how the car ran changed with each tap.

So, Iam think about getting a rebuilt ECM.
My question is, Can I get this bench tested? where? before I replace it?

Oh, I was able to data log with tunerpro r/t sweet. New version is out now

what a pain in the a$$

thanks
Scott

Twilightoptics · Posted: Tue Nov 29, 2005 11:05 am Post subject:

Hmmm... sounds like something might just be loose too. Not sure. Maybe Brandon will chime in.

Rebuilt units are about $120 from napa with exchange. Remember to take your chip stuff out! LOL

Did you check the resistance on the wires opposed to the voltage? Make sure they aren't shorting out? Did you get all the ground wires that bolt to the back of the cylinder heads when you put everything back together?

scott in wa. · Posted: Tue Nov 29, 2005 6:05 pm Post subject: ecm

Went and bought a rebuilt ecm at Autozone today. $81.00 out the door.
gave them mine, ($140.00 core)

Plugged it in started it up, and coolant sensor is working now.
So is everything else.
data logged for a few minutes,

No codes, good.

The other ecm was registering codes, but they weren't showing up on the service light, blinking light.

Didn't go into closed loop, but I didn't run it very long, its SNOWING......
Things seem to be looking better, at this very moment.

I would like to get a good data log in open loop then send the file to you guys to look at.
Any volunteers?
I could use some advice

Iam using 6e
and tunerpro r/t

thanks
Scott

Twilightoptics · Posted: Tue Nov 29, 2005 10:17 pm Post subject:

In all actuallity logs are really hard to read. Best thing you can do is take short log sensor readings at say idle..... and then again cruising at a steady speed and load.

And a short one of you accelerating moderately. And then one with a WOT blast (if you can)

Glad the ECM helped! That coolant will make a huge difference. But you have to start tuning ALL over again. So that last bin I sent you, don't use it because it richened things up LOL.