Ok, I've been checking my logs so I can get the hang of tuning and reading my own information. I'm using TunerPro RT and the tables within the EE_manual.adx file I have for my vehicle which I downloaded off their site. I'm using these tables to attempt to match up my data logs and see any inconsistencies and my logs are CRAZY.

For instance, I'm currently checking my IAC steps as they are suppose to relate to coolant temp. According to the tables in TunerPro, my IAC steps are suppose to be at 32 in relation to 80 degrees C. On my data log, my IAC steps fluctuate between 82 at the lowest all the way up to 101 at times all within the 80 degrees C temp.

Either the file from TunerPro is wrong, doubtful, or I have some serious problems still. Like I said, currently going over my logs and trying to learn as I go. Any additional feedback to help me get the hang of this stuff is appreciated. Thanks.

 

Injuneer has some info on his site all about scanner readings.

http://www.injuneer.com/ScanMast.html

 

Thanks for the resource, however it helps me realize how far off a lot of my numbers are and my problems.

This is the latest data log I just finished. During this one I reset the IAC actuator, the steps began to drop and the rpm's would lower too but then they would just shoot right back up. I was once again just idle in the garage.

Codes 42(EST grounded or short) and 48(MAF failure) appear on this scan, but I unplugged the MAF for a short while during the scan.

The BLM's also get up as high as 155/147 while in blm cell 16(idle cell).

http://www.mediafire.com/download.php?aectmeo92tk4cwp

 

You can clear the codes by pulling the "PCM BAT" fuse for 30 seconds. On your 94, that fuse is on the panel at the end of the dash.

I'll take a look at your file.

Wow..... huge file. This is going to take a while.

 

Thanks Injuneer, I pulled the pcm fuse and also reset the blm's and idle actuator before the scan. Actually, reset them a few times just to see what it actually did and how the numbers changed to enlighten myself ha. I have yet another scan done after I reset these if you want it too...so far I think this makes 4 data logs on the site.

or 5? lol
http://www.mediafire.com/download.php?4lv8fhn4b2i3dzb

 

Yea, sorry...they're all quite big. How long should I typically let them run then?

What's good about the second log on this thread is that eventually it began to idle properly, the steps came down as well as rpm's and the other numbers began to fall in appropriate ranges...but it didn't last long. Another awesomely huge file though, I walked away for a bit. You probably won't want to look at the second one ha

 

Anyone else feel like helping out and checking these?

 

Appears you just let it idle the whole time.

When you view the log in DataMaster, are you getting a red "DATA ERROR" flag (window in upper right corner)? Every few seconds, there are two records that show in excess of 5,000 RPM (sometimes as high as 6375RPM), with the idle speed in the frames on either side of those two records. Something is screwed up. High voltage interference with the Opti cam position sensor signals? Problem with the cam position sensor signals themselves?????

I have to try and figure out why the BLM's are moving all over the place, ramping up slowly from 135 to 155 and then slowly dropping back down. Never saw anything like that before.

Looking at the end of the log:

Even though its idling at 1,700RPM, and the programmed idle is 800 RPM, the IAC valve is not being commanded to change, with a commanded position staying at 107 counts. The PCM should be pulling the counts down to close the idle air passage and reduce idle speed.

The MAP reading is exceptionally low (0.26bar vs a barometer of 0.99bar).

Your system voltage is way too low. I did a MAX and a MIN in Excel, and the entire log the system voltage varied from 10.5V to 11.2V. Alternator does not seem to be charging adequately. You should be seing anything in the range of 12.0 - 13.2V.

 

I let it idle in the garage through the whole scans, I have only one scan where I took it for a short drive. I can't stand to drive it much anymore due to the shuddering and shaking.

I haven't ran a scan in datamaster only freescan so far, only have the trial 20 scans and haven't purchased the software.

I had a terrible intake manifold leak previously, the entire front end was caked in oil and some coolant. I figured it has gotten into the opti and fouled the sensor possibly. Seem like the logical explanation to you?

In regards to the iac valve, would the problem lie within the pcm itself as for not pulling the counts? Or could I have some sort of funky vacuum problem still that may effect it that way?

I also noticed the map readings, they stay consistently low in that range in all my scans. Would that also mean I could still have a vacuum leak since the pressure isn't where it is suppose to be? I can't recall if higher or lower voltage means vacuum loss or if it's the other way around. What are the actual ranges those two voltage readings should be in while relating to each other? Also, the clip for the harness broke on the MAP pigtail, however the harness still fits snug and isn't loose so it shouldn't be the problem.

As for the alternator, I've recently started hearing a "whining" sound coming from it. At least mostly sure it is the alternator. Also, the pigtail harness clip on it too broke yet it doesn't fit as snug. I know I need to get that changed.

I told you my car was being FUNKY.

And just in case you get a fire up there and feel like looking at the data log on post 5, you can see on it the idle steps actually did come down to 30 and the idle set at 800 or in the range for a short amount of time. Yet the map voltage is still in the same low range as before. You could compare the numbers in that area to the rest of the data logs inconsistencies. However it too is a huge file, bigger then the one you looked at. You could just scroll down, way down lol, until you see the readings like I mentioned. Wouldn't blame you if you didn't want another huge file on your hands.

 

SO, some suggestions.
1. Get your alt checked at AutoZone or someplace. Replace if needed. The computer needs a stable voltage supply to run correctly.
2. Repair the alt pigtail so that the connection is a very good one.
3. Make shorter data logs. 3-5 minutes, it makes the haystack smaller for that needle you are looking for.

 

If voltage is really below 12v, you need to fix that before doing any more logs, IMHO.

 

I'm going to take the alternator over to advance auto tomorrow to have them check it, and also see about getting another harness connector.

 

Rob/Shoebox hit the nail on the head. This data log is unlike anything I have ever seen before. First, check the battery voltage. See if it matches, or is at least within 1V of the voltage being indicated by the data log. I see numbers in the 10's. The PCM is either unable to function correctly at this low voltage, or the PCM is corrupt.

First, solve the voltage problem. If the problems persist, borrow a PCM (I'm assuming you have a stock tune), and install it and see if things get any better.

The engine is idiling high because the IAC valve is open too far. The MAF reading (AFGS) tracks the IAC counts.... counts go up, AFGS goes up. Counts go down, AFGS goes down.

This is totally a problem with the PCM. The IAC valve appears to be doing exactly what the PCM is telling it to do. But there is no logical reason for the PCM to ramp the IAC counts up to 160, then randomly ramp them down, when the engine is way above the programmed idle speed at all times.

Check your MAF. At record 7145 it appears to have failed, indicating an air flow of 471 G/S. That's what you see when you have an open circuit. The reading stays at that value until recod 7450, when the MAF sensor starts working again. During the apparent failure nothing changes, so it appears the PCM was able to maintain the engine operation with speed-density mode.

There are weird readings all over the place. I already mentioned the periodic appearance of RPM as high as 6375RPM, with no change in the TPS position (closed). The spark advance also increases with the RPM error, but nothing else changes.

The O2's sensors seem to be possessed as well. They seem to be reading normally, and either just before, or just after the unexplained high RPM readings, the O2 sensors drop to near 0.0xx volts, and then stay there for an extended period of time, then gradually return to normal.

In record 7142, for no apparent reason at all, the left injector pulse width jumps to 39ms. But nothing else changes. If it really went this high, there would be a rich spike in the left O2 reading. While this is happening on the left bank, the right bank injector pulse width stays at 4ms.

System enters closed loop as it's supposed to (at 206 seconds operating time). But whil running in open loop, the O2's are slowly drifting up and down over a very wide range, and that shouldn't happen.

Fix the voltage. It's not really worth the time it takes to look at the logs until you do this.

PS: Pardon all the typos. I normally correct, but this is a long post, and my boss doesn't like it when he sees me on the internet while I'm supposed to be working.

And... are there different versions fo Freescan? Is it possible you are using the wrong version? I don't know the answer to that, because I have never used Freescan.

 

Freescan has different vehicle options on the control screen, I have selected the correct version which says "GM 1994 Camaro Z28-Impala SS-Corvette (LT1).

I had advance check the alternator today and it was working just fine. They gave me the pigtail they said I would need and that would fit but this is where I get confused. The harness currently on mine only has one wire, the red wire. The new harness they gave me that is suppose to work has 3, red-black-green. Yet the red wires do not match up on the same terminals as each other. I'll put pics. Idk if this matters as long as I make sure to connect the red wires. Do I need the other two for something? Or is this totally the wrong pigtail I was given...?

Old pigtail


New pigtail

 

Obvisously there are several issues as mentioned, but I also see you have a Holley TB. The iac counts an idle will be all over the place since the aftermarket tb does not utilize the idle air passages of the intake.