Help understadning my CJ7 SBC datalog

[dave w]

Perhaps a picture of the EXTREMELY UNUSUAL Knock (sawtooth pattern) will be helpful?

dave w

Knock.jpg

[dave w]

Perhaps a picture of the EXTREMELY UNUSUAL Knock Accumulation will be helpful?

dave w

Knock.AccumulatorJPG.JPG

[tayto]

i would focus on the injector that's not firing personally. 4 cylinders not firing might be what knock sensor is detecting.

[Dlxman]

Hello All, I have had the injectors ultrasonically cleaned and replaced. Still runs poorly after warm-up. The data log from 8/26 is attached. I also have no idea why the sawtooth pattern exists. Could this be a bad ground?
Checking the spray pattern with a timing light (cyl 1), I could only see the one injector spraying (again), but do both injectors fire simultaneously, or do they alternate? I could see fuel hitting the port of the throttlebody on the injector that appears not to be firing.
I have two new matched injectors on the way, but wont ship until after Sept 1.

Thank you once again for your support and suggestions. I'm not one to give up or afraid of hard work!!

[dave w]

I have only looked at the first data log posted in this thread. It seems odd to me the engine would be running rich with only one injector working.

Perhaps a quick timing light test of unplugging one injector at a time would be a worthwhile experiment?
Ignition key off ... unplug one injector ... start the engine and check spray pattern with timing light ... repeat test on other injector.

Seems one of the logical outcomes of the above test might be . . . if one injector is not working ... the engine won't start?

Sawtooth knock pattern, possibly measure the resistance of the knock sensor. Remove the electrical connector from the knock sensor and measure from where the were the electrical connector was plugged into (center of knock sensor) to ground.

dave w

[tayto]

you should see them both firing. sounds like 1 still isn't firing. did you try my tapping trick on the injector housing while the engine is running? swap the injector connectors and see if the "working" injector is still firing. could possibly be a connection at injector or ECM, or the ECM itself (failed driver). it's possible 1 injector is bad even though they cleaned them.

[Dlxman]

I did try tapping the injector housing as suggested, and also originally swapped the connectors as noted in a previous reply. Neither one produced gas out of one injector. The new matched injectors ship Sept 1, so hopefully I can get the by Friday. I did replace the ECM through original diagnosis by the manuals. This did not change anything, so I now put the old ECM (6 years old) back in. Hoping it is the injector.

Also, commenting on Dave's post, I do not have a knock sensor. The *.adx file I got from the sight had it in there, so I am going to remove that and a few things I do not have. this should clean up the data log a bit.