ECU: testing circuits & interpreting results '76 280Z

[Jennys280Z]

The problem was the plug or else the plug wire. Immediately my baby fired up and idled up to 1000+RPMs in that sweet silky smoothness I remember! Then settled back to 800 after a minute of warming up. I tapped the gas pedal a few times and I was so happy it wasn't chug-a-chug-a anymore! That was a fun drive; running better than ever maybe!!! :love:

Thanks everyone for all your help! :kiss: I'm going to have waking dreams about my car before bed tonight!!!

[Jennys280Z]

So the dead cylinder explains all the symptoms I experienced, why my fuel gauge went down so fast yet didn't blow any black smoke from rich condition (just the uncombusted gasoline fouling the oil through the rings plus mostly just shooting out the tailpipe!)

Yup, I changed the oil before driving it any more than that one time. Treated the dirty parts of the engine (front cover and oil pan) to a foaming degreaser too! Now it's so clean I can eat off of it again! Yay!

[Zed Head]

Hey Jennys280Z, does your car actually run like it used to now, and run well? I'm curious since your AFM resistance readings were the same as mine, which was definitely bad.

Just trying to learn something. Thanks.

[grantf]

double post

Edited February 24, 2010 by grantf

[grantf]

This was a great story. I love happy endings (well not endings....). Anyhow this is a good example of being stuck to the wrong diagnoses (it's happened to me all to many times).It seems best to me to start with the simple things first and eliminate them, it saves time and money. Still this was a good read and I learned a little about my 280, thanks.

Edited February 24, 2010 by grantf

[Jennys280Z]

Hey Jennys280Z, does your car actually run like it used to now, and run well? I'm curious since your AFM resistance readings were the same as mine, which was definitely bad.

Just trying to learn something. Thanks.

Hi Zed Head! I'm sorry I was away for so long. Where did the month go? Ugggh! Yep my Z's still running really good! The AFM is fine as I suspected then that it might be. Or at the very least, I was never ready to concede that it was defective. And it's not, despite those readings. Sure they were high, but apparently not too high. Actually when you told me you had the exact same readings, it encouraged me that my AFM might NOT be defective rather than the reverse. I was going to keep it to the bitter end in any case, and the decision worked out for me. Your help was sooo appreciated, thanks again!

And gosh, how lucky was I that cylinder one was dead? I wouldn't have even thought of checking the other cylinders with my timing light and I admit I really lucked out on my diagnosis there!

P.S. The resistance readings in the EFI Bible were for 1975, and I have a 1976. Not sure this would make any difference but I never know.

[Jennys280Z]

This was a great story. I love happy endings (well not endings....). Anyhow this is a good example of being stuck to the wrong diagnoses (it's happened to me all to many times).It seems best to me to start with the simple things first and eliminate them, it saves time and money. Still this was a good read and I learned a little about my 280, thanks.

Awww I'm so happy to hear that grantf! I learned a lot too! There's an old saying "necessity is the mother of invention" and even though I didn't invent anything, the need I felt to fix my Z made me read my manuals slowly and repeatedly until I actually understood them! And that's a great point, to start with the simple things first. Honestly though, I was still figuring out what the simple things were and thanks!

Edited March 24, 2010 by Jennys280Z
xo