Just use the one pigtail (the wire in the same position as your stock connector). Color is irrelevant. De-pin, clip or tape up the other wires.

 

Did you check your battery voltage at idle, directly at the battery terminals? The battery may be fine, but you may be losing voltage to the PCM, or have bad grounds for the PCM. What does your dash voltage gauge read at idle?

DIAGNOSE FIRST - REPLACE PARTS LAST.

 

I replaced the harness because the clip was broke so it was a loose connection, but now the freaking thing won't start...just audible clicking sounds. I went back over and made sure everything was plugged in. ?

I cut the wires on the new pigtail that didn't match up with the wire I needed from the old one. This is very annoying. I'm going to recharge the battery and come back out tomorrow.

 

Ok, battery is charged and the car starts no problem. Checked the voltage at the battery while idling and it was around 13.5 or so, the gauge in the dash however read around 15 or so soon after start up and gradually fell back down to around the readings I was getting off the battery with the meter and the reading it was giving on FreeScan of 13.2 and it stayed around 13.2 or so.

I did a google search for possible relations to low MAP readings, and a few topics came up relating the low MAP reading to bad timing, ever heard of that comparison?

I started looking at data on FreeScan and again the MAP bar was only around .3 or so again. So once again I pulled the fuse for the pcm and left it out for about 10 minutes. I also reset the IAC actuator and BLM's again. Since the voltage is where it should be now I'm going to do another scan, a shorter log this time

I'm going to check a few more things; PCM ground, power at PCM connector etc..

 

Here's the scan. I checked to make sure the PCM was grounded good and it was. I also took the PCM out and checked for burnt or corroded terminals or wires and it all looked good. I performed the scan, much shorter in length this time. After I stopped the file for the log, I unplugged the MAP sensor and within seconds the idle came down to the 800 range but still fluctuated from around 800-1200rpm back and forth quickly but still relatively stable, just a lot of quick jumping/bouncing of the tach. The IAC steps came down to 30 initially and peaked at 39 while at idle. Although the data log will not show this as I said, I stopped the csv logging before I did this. Could this mean yet again I have another faulty MAP? I have once before checked the signal voltage from this sensor and it was good, also I am still getting the 5V reference.

Here's the data log on Freescan: http://www.mediafire.com/download.php?ilrczycx0fr3rwl

Here's a data log on DataMaster: http://www.mediafire.com/download.php?vn1z1xqszq0n5su

On the datamaster log I unplugged the MAP sensor and it idled down along with steps, then plugged it back in after a short while. Once it began to receive info from MAP the idle and steps stayed the same as it was while unplugged.

 

I put an old MAP sensor on that was replaced awhile back, and the readings were the same. So it's not my actual sensor...now what would I look for?

 

You have DTC 24 for the VSS and DTC 34 for low MAP reading. I'm assuming that's from when you unplugged the MAP. It starts reading 10kPa at record 798 in the DM log. Did you reconnect it around record 1360? At that point the MAP readings start to look more rational, and the engine is idling at the programmed speed, with more normal IAC counts.

Does the engine now idle correctly when you restart it?

The system voltage is now a healthy 13.5V.

The erratic 5,000+RPM spikes are still there. Never saw anything like that.

 

No, when I restart it goes back to the erratic surging and fluctuating idle. If I unplug the MAP it comes down to normal ranges, then I'll plug it back in and it stays at the normal range. IDK if I can somehow upload this file to the thread, I used winflash to read the tune file and have it saved on my computer. Is there a way you could look at it and see if something is wrong or would it just show the same info we've been talking about? IDK the differences in these files yet. I tried uploading the file to mediafire so I could share but it won't let me. Maybe I could send it in an email attachment to you if you would like?

Also, what would I do about the dtc 24? This is also the first time I've noticed this code in all my scans.

 

I could really use a stock '94 z28 m6 bin file if anyone has them. I found them on a website but they are zip files and idk how to rework them so I can use them.

***EDIT***

Injuneer since you've been helping me through this, this would most likely pertain to you but if anyone else wants to chime in go ahead.

I used winflash to pull/read the pcm tune on my car and WOW was it confusing. I searched for quite some time until a came across a forum called "Monodax" and eventually found a stock '94 m6 camaro tune. I opened this file in tunerpro rt and looked at the numbers on it, and they were way different then the file I pulled off mine. My file the numbers such as idle rpm's in relation to coolent temp jump all over the place with no logical relation to each other, more like random. On the file I got from Monodax the numbers have smooth transitions and actually make sense. So somewhere my pcm might have been corrupted or something else may have effected it. I've done nothing like this since I got the vehicle and it only started acting up after some terrible over heating issues I had when first getting the car. That lead me to believe, and Injuneer mentioned, that the PCM itself could be fried or corrupt. I'll still try this tune and see what differences it makes.

Another thing noted, if the PCM is "fried" how would it be able to log all the data and communicate with my computer? Wouldn't those basic functions be ruined if the pcm was in fact trashed or however it may be put?

I am going to wait until tomorrow to upload this tune and see how it does. I have my CRAPPY file still saved on my computer just in case this new tune somehow doesn't work or makes something worse I'll put the old one back on. I really hope this will be my solution. If this doesn't work, I'll be hunting down a new pcm. Wish this tuning newbie luck!

 

Managed to upload the bin files to mediafire I'll post links in case you're curious as to what I pulled from my pcm before flashing.

BIN file I pulled: http://www.mediafire.com/download.php?kmia5fvaji8tc85

BIN file I uploaded: http://www.mediafire.com/download.php?68qy6qwiei2eyvk

Also, if the one I uploaded isn't the correct one let me know.

 

I don't tune stock LT1 PCM's, so there's no way I can review your file. I switched to an aftermarket ECU 11 years ago.

 

Here's a data log after I flashed the pcm with the new stock tune. The BLM's still climb and the rpm's still have random fluctuation and spikes.

http://www.mediafire.com/download.php?k30xo2rh9z2xrio

There was a code 24 for when I pulled the MAP for a short few, and then there is a 42 for EST grounded...still

I also can't figure out which readings are for the MAF sensor. Injuneers page says it's expressed in gps or ppm....? I'm trying to see if it is possibly bad.

 

DTC 24 is for the VSS (vehicle speed) sensor, not the MAP.

Your MAF units in the logs I've looked at are grams/second. They are high because your RPM is high. The faster the engine turns, the more air is pulls in. Get the RPM back where it belongs and the mass airflow will come down where it belongs, the injector pulse width will come down where it belongs, the ignition advance will come down where it belongs. The stuff that is out of range is mostly due to the high RPM.

The fact the problem largely goes away when you unhook and rehook the MAP sensor is telling us something. The MAP readings in the range of 30kPA and below aren't way out of range, but it does return to what appears to be more normal 32-33kPa when the idle problem goes away.

Let's try this. The MAP sensor shares a ground and 5V reference supply with the IAT sensor, the A/C Evap temp sensor and the AC pressure sensor. Unhook all of those sensors, and see it things get any better. I'm not sure where the connection is for the A/C Evap temp sensor (the sensor is in the firewall air box), so if you can't find that, just unhook the other two sensors.

 

I unplugged the IAT and the ac pressure sensor, I looked up where the other sensor is located and it says int the passenger compartment but I went ahead and just left it alone. It didn't effect anything, still acting up like it has been. The rpm's did come down quicker though, but it was very spurratic and fluctuating massively when it got below 1200 or so and shot right back up to 1700rpm range.

I also tried figuring out that est ground problem. I pulled the icm/coil off and cleaned off the ends of the wires where they attach to the stud. I also took the ground strap off the frame and checked it. Put it all back on. I have another friend of my grandfathers who is the service shop manager at Jaggers chevy. Since they are mainly a GM service shop and dealership they should be able to help on somethings as well, he's letting me bring it in tomorrow for more scans and whatever else they may want to do.