Ok. Heres the deal. I finally received my AutoTap today for my obdII 96 TransAm. I mainly ordered this because I have been trying to track down a detonation problem that is audiable from about 1700rpm to around 2400rpm. Anyhow, I hooked everything up logged some stuff I thoought woud be important to log and went for about a 20 min drive.

Now Im home looking through my recording and noticed something very strange. Every other record within the log is the same...messed up record. Ill give an exaple of what Im looking at right now.

Ex...lets say record number 1000 looks like this:

Calculated engine load... 12.5%
Engine coolent temp... 196*f
Engine Speed... 1618rpm
Intake Air temp... 27 f
Mass air flow rate... 3.884lb/min
Throttle position angle... 10.9%
Vehicle Speed... 65mph
Ingnition timing...-39deg
knock retard...0degree
knock sensor counter...4097
Manifold Absolute Pressure...13 in Hg

That would be the so called normal record. Does that even look alright to you!?! The knock sensor counter seems to be going crazy. What does that mean?

Now This is the record that appears after every other one. This would be record number 1001.

Calculated engine load... 0%
Engine coolent temp... 196*f
Engine Speed... 1618rpm
Intake Air temp... -40 f <---WTF did that temp come from
Mass air flow rate... 0lb/min
Throttle position angle... 0%
Vehicle Speed... 65mph
Ingnition timing...-64deg <--WTH that a lot of advance
knock retard...0degree
Manifold Absolute Pressure...0Hg

Then the following record would look somewhat like the above and would be number 1002...but the the one that would follow that would be this same messed up one number 1003. It keep that patter up through the whloe log. When this happens almost all reading go to 0. Example is the MAP reading, throttle position angle, engine load and mass air flow rate. All those 0 out when this happens. Every other record is this messed up one. What would/could be causing this?

 

No, thats not going crazy at all. I would see at least about 2000 counts just on starting the car, there is probably no instance at all of a "1" count, it is much higher RESOLUTION than that. So, to actually trigger timing getting pulled, may well be an 8,000 count or so SINGLE EVENT.

Now, what is somewhat abnormal is watching your knock counter roll over, but I have gone past that 100k point when tuning my own car.

 

Do you have a scanmaster hooked up to the PCM? If you do, I think that and the computer has to compete for data from the PCM and that could be a reason of why you were getting erroneous data for every other record.

 

Well, i wish i had scanmaster so that could be the problem. Well, either way I am going to fix it. I just ordered LT 1 edit, new IAT, MAP and O2 sensors 3 days ago. I figured that since all those sensors are fairly cheap...that it would be worth a shot. Then, if nothing else..Ill have LT 1 edit, which I have wanted for a while anyways. I am broke as hell now...but am determined to fix my broken beast. Ill keep you all updated when I find out what the problem is.

 

ablackcamaro, correct, dont want those things hooked up in unison.

I too went on a sensor buying craze once, generally its a waste of money. If you aren't getting a SES for something out of range, or seeing something very strange, consider it preventative maintenance not a fix.

So your saying the car is not driving well right now? I didn't realize that from your post, if I missed it, my fault...

How are the BLMs when fully warmed up, etc?

Are you converting to OBD I or sticking with OBD II?

 

Yes...my car is NOT running good at all right now. It has been running like a 14sec car since the detonation problem a few months. That is why I have only driven it for 2 tank fulls of gas in the past four months. Thats why Im so determined to fix it. I took the expensive and maybe regretful rout of staying with OBD II. Pennsylvania is pretty strict on emissions/inspection...at lest where Im from. I have not been able to do any logging since first posting because we have had nonstop snow for the past 4-5 days. As soon as it stops..I will make some good logs and be back with that info for you to look at. I really appreciate you guys tring to help me out! I didnt think I was even going to get any responses. Thanks.

Also...I have a splice/tap going into my TPS sensor for my TPS activated nitrous switch, and a splice into a O2 sensor for a Air/fuel meter(<--I know basically useless, but did not know that when I bought it). Do you think either of these splices could be causing the computer problems? I did NOT get any codes/warnings on autotap saying that there was any problem with them.

 

the strange readings are probably cable glitches or something.

i wonder if TTS datamater work with OBD2 computers..b/c then i could actually watch an entire run. with autotap..do you have files that are saved that you could send? .bin files? if so i MIGHT be able to read them with datamaster.

adding information like fuel trim reading is very important in determining how the car is acting.

 

I dont know if datamaster and autotap are compatable or not. I just got autotap a few days ago and was only able to log that one run before we started getting all this snow. I was not too sure of what to log soo I just logged a lot of things...but not nearly everything. Autotap does have files that I can save to view a later times. I am new to this stuff(but not computers..my BS degree courses in Computer Information Mangement will be done April)...but I think I would have to send you my Config file(to view my graphs/gauges/etc..) and my .atl(whatever the autotap log file extension is) which would contain my actual log info. Someone correct me if im wrong. Will it work with your stuff???....I have no idea. If your willing to try to look at it...I get the files off my laptop tomorrow and email them too ya. If they work, then great...tell me what you see. If not, well then...it was worth a shot. Thanks for your help. Ill get send you the files sometime tomorrow afternoon. Later

 

Ok, I have the files ready to email to ya after I post this. There are two of them...if they even work, this is what youll have to do: First, load the file named "n2oconfiggood.atc"...that is the config file that has all my graphs, gauges....things to look at. Then if/once that is loaded load/play the log file name "11.atl" That is the actual log file with all the info. Then heres what to do if you can actually view it. fastforward/skip to the END of the log. Then go back one record at a time. You will see the F*C*&) up records im talking about. Let me know if you get it and if you areable to view it. Also, If anyone else has autotap to view my log, I would really appreciate your input also. Thanks

 

Just so you know, upon start up the pcm runs a quick test on all sensors including the knock sensor, that's why you see a high count right away. This is normal.

I too have wondered why my knocks were high upon start up. This is what I've read in the GM books.