Rage

No, the PCM/ECM555 does not output knock retard or injector pulse width,......

What about recording the eight individual injector signal outputs external from the ECU that physically actuate the eight injectors. I am told that the Merc PCM555 responds to perceived "knock events" on a cylinder by cylinder basis so if cylinder #5 for example is receiving an increased injector pulse width for a "knock event" it should stand out from the other seven ???

stevesxm

can't imagine that system can id individual cylinder to correct... would need 8 knock sensors... have to presume that on motors that have two, it MIGHT do just one bank but not even certain about that.... my guess would be what it does for one it does for all...

Pat McPherson

I was reading on the Whipple web page yesterday that they replace the computer and wiring harness with their package for the 525.
I guess they can't reprogram the PCM555 either...

Rage

Dustin Whipple, for a fee, can and does reprogram the PCM555 under his arrangement with Mercury. He also advised that the Mercury PCM555 does monitour and respond to engine knock on a cylinder by cylinder basis. I suspect that since the ECU knows when it is firing each individual cylinder it can easily figure out which is the offending cylinder from the two knock sensors, one per bank.

Any thoughts on my preceding question about recording the actual electrical voltage pulse width that the ECU sends to actuate the individual injectors for use in identifying ECU recognized "knock events"?

Dave_N

Seems to me that it would be easier to monitor two knock sensor circuits than eight injector circuits. Either way, you still need the means (equipment) to do it.

Dave

Rage

Dave,

Maybe I am wrong but I believe that the knock sensors emit signals triggered by engine vibrations wether they are from an engine knock or engine vibrations from the various other sources. It is my belief that the ECU is programed to filter out the non knock event vibrations and respond to the true knock events. To monitour the raw knock sensor output directly without a means to determine what is or is not a knock event would not seem to be helpful.

If you are saying that the knock sensor is itself calibrated to only detect a knock, exclude all other vibrations and only send a signal to the ECU when a bonifide knock has occured, please confirm this.

I tried the hose thing to locate engine noise sources before. I couold never make it work.

Thanks!

John_at_J&S

We make an individual cylinder knock controller, and it has an analog output to indicate the amount of knock retard.

This output is normally used to drive a bargraph display, but it can also be data logged. The range is 0-1.3v, in ten steps, 0.13v/step.

The voltage can change with each spark event, reflecting the amount of knock retard for each cylinder, as they fire.

The unit can drive a coil directly, or trigger an MSD/Crane, etc.

MnHowardCat

I believe that Tyler Crockett can also do re-programing
I booked some time next month to reprogram and dyno my engines
Don

Rage

MnHowardCat,

I am very interested in any details regarding the performance of the PCM555 in reponding to knock events. Anything you would care to share would be appreciated.

Thanks