Injuneer

The number in the knock count field doesn't mean anything. It's a 'counter'.... starts at zero, and increments up periodically. It can add 3,000 counts at cold start, which has no significance. It will increment up to ~64,000 and reset to zero and start all over again. You could see 50,000 counts at startup, and that would simply be the reading when the engine was shut down, plus any counts added due to startup.

The important thing is how fast it changes. It will typically stay at a fixed value, until the PCM detects an event. But even then, increasing knock count does not always produce knock retard, and you can get knock retard when their is no change in knock counts.

You will never hear "ping" (that's actually pre-ignition, knock or detonation is a second flame front occurring after the spark has already ignited the mixture) if the knock detection/retard system is working correctly. The knock sensor "hears" the knock way before it would become audible to the driver, and retards the timing to eliminate the knock.

I can't send the .pdf until Monday because I send it from "work". The .pdf does not address knock counts, because all my testing was done way back in the 90's using my Scanmaster LT1, and it does not report knock counts. I haven't used the stock PCM to run the engine since 2000. Over the intervening 18 years or so, I've probably reviewed over 1,000 data logs for people, so I was able to get a handle on knock count.

One of the best things you can do is download a free copy of the 94 factory manual (should be the same as 95 with respect to PCM) and look at section 6E3-A, which has a full technical description of all the PCM parameters and sensor values, and the detailed charts for each of the DTC codes. For your 95, use Rob/Shoebox's 1995 PCM wiring diagrams, a few minor differences, mainly some changes on what a couple of the fuses supply power to.

LINK: 4TH GEN SERVICE MANUALS

Chet1185

I just downloaded the app. When I try and open it, it says application failed to initialize properly (0xc0000135). Do I need to install anything else? I'm running windows XP.

GaryDoug

First, did you extract all files from the zip file and place them in the same folder?

Second, do you have Microsoft .Net Framework 4.0 or later installed? If not, you can download it for free from Microsoft.com.

Chet1185

Sorry, I don't know what that means....lol

I will look into the Microsoft.net framework.

Chet1185

OK, I got the APP to work but won't connect. I downloaded the drivers from ALDLcable. In the APP it has COM3 and COM4 but won't connect on either.

horridohutch

https://www.mediafire.com/folder/5gw...4kzs/Documents

My first data log using the scan 94/95, nothing wrong (that I know of) just started out in the garage got onto freeway and ran my usual route when I go for a quick run. Near the end I took off from a stop and the rpm gets up about 4550. Nothing too radical. So how do the numbers look?

Injuneer

I'll try and look at it tomorrow.

horridohutch

The DTC was for my AIR pump, fixed it but had not figured out how to clear it at that point.

Thanks Fred!

Injuneer

The first thing I noticed is that the tune does not appear to let it operate in long term fuel correction cells 16, 17 or 18. 16 is the normal idle cell, but yours idles in Cell 4, and it's pulling some fuel out (LTFT's below 128 - 116L/119R). Cell 17 is usually a "decel" cell, but yours does not switch to 17 on decel, and 18 is the open loop load cell. You started the log with the system in closed loop, but it is normal to see Cell 18 pop up under some conditions in closed loop.

I would think this has to be something in the tune. The cells are defined by a grid of MAP on one axis and RPM on the other. Yours is idling within the normal parameters for Cell 16, and the things that might cause it to not operate in that cell (TPS%, MPH) do not appear to be outside the normal limits.

Can't think of a downside to all this, but first time I've seen this.

Fan 1 (low speed) is on all the time, apparently because the AC Request flag is set. But the AC Clutch Status and AC Clutch Relay show "0" at all times. AC Temp shows on the 45* range.

Peak RPM shows as maximum of 6,068 RPM at 205.02 seconds during a WOT pull.

z28cam1993

Just curious Gary. Will your program work for diagnosing when my car just idles?

Injuneer

Yes. It will pull stored and active codes, you can watch all the sensor and PCM parameters, from startup through the transition to closed loop. The analysis of data will be limited to the idle conditions. But faulty sensors, incorrect operating data will be seen. And don't waste your time revving the engine as it idles, because it won't show much of anything.

z28cam1993

That's a perfect answer. Thank you

robss96dcm

Is there a pid for ac pressure sensor volts? I see you have it for psi. A lot of us use this input for a wb o2.

Thanks for all the hard work you put in to this, it looks like its shaping to be a very good app.

GaryDoug

They don't really call them PID's, since the values are obtained all at once in one long line of data, not individually like an OBD2 PCM. But yes, voltage is one way to convert the reading.
Given than N is the 8-bit value returned from the pcm, either of the following formulas can be used to convert it to something useful:
VOLTS = 5N/255
PSI = 1.833N - 14.95
I chose psi because I thought it would be more useful. An option could be added to report it as volts, I suppose.

robss96dcm

That would be great if you could. Its for mostly when someone records the data during a run or a dynopull.