Hi, everyone names Derek. got an 87 trans am with a heads/cam lt1 and t56 that a previous owner swapped in and its having some serious bucking issues only at WOT. The datalog shows some weird things like voltage being at 0 sometimes and only 50 rpms with a 50% tps reading. Registered here to try and get some help with it!
welcome! we have a lot of lt1 guys here. if it's obd-i, get all the stuff in my signature and take some logs, we'll figure 'er out
Thank you! Ive already got some logs with tunerpro. I didnt see anything in your program that displayed voltage. I feel that seeing the voltage in this case. Ill post my tunerpro log for now and ill go get a log for $EEHack.Originally Posted by steveo
1:46-1:51 is where things start getting strange in Tunerpro.
add user parameter, type 'voltage' in the search field.I didnt see anything in your program that displayed voltage.
...or go to the main tab instead of the dash
...or go to graphing and click 'select element' and type 'voltage' in the search field
most of the tunerpro adx files out there for the lt1 don't verify checksum, so you could just have bullshit data in that area
[QUOTE=steveo;58783]add user parameter, type 'voltage' in the search field.
...or go to the main tab instead of the dash
...or go to graphing and click 'select element' and type 'voltage' in the search field
most of the tunerpro adx files out there for the lt1 don't verify checksum, so you could just have bullshit data in that area[/QUOTE
Its not letting me attach the EEHack log. Am i doing something wrong? I apologize for being a noob.
Last edited by Dukes164; 04-03-2016 at 03:37 AM.
.eehack files aren't directly allowed (maybe they should be?)
just zip it, or change the file extension to .bin and mention to change it back to .eehack once downloaded.
They should be!
Anyway the fun starts at #465. Volts drop to .8 at #468. Seems like I was wide open for a lot longer then the log suggests.
do some graphing, click 'view points' and zoom in on that area. you'll see there's actually a data dropout at that point.
general wiring fault, a loose ground maybe? that'd be my first guess.
edit: i notice a lot of WOT events have this happen. this really points to loose wiring. when an engine flexes the engine mounts to their max, maybe it's yanking on a wire. this is common for swaps when not enough slack is allowed.
Looking at the graph that makes sense. Ill check it out. It would make as sense to why I can (extremely slowly!) roll into the throttle and it will keep pulling never gotten it wide open doing that always run out of room. If you go just a hair too quick it will cut out and surge. If it was pulling on a wire that would make total sense. Supposedly this thing was running fine before it sat for awhile.
I checked all the wiring nothing seems overly tight. I could only find 3 grounds. One that goes from the block to battery, another that goes from the block to the fender, and single wire that goes from the back of the head to the PCM. That one splits into like 5 different wires. So all PCM ground are going through one wire.
wonder what's going on, then. there's almost certainly an interruption in power or ground to the ECM during WOT events. i'd keep examining wiring and see what's going on. there's nothing else in your logs indicating trouble except the complete shutdown of the computer during WOT.
Whatever it is it has something to do with load I think, It will go WOT in neutral with no problem. Think it would be worth trying a different PCM? Also fuel pressure drops and rises from 40psi to 30psi back 40psi in tune with the surging which is probably due to the PCM shutting down becuase ive replaced the pump regulator and filter. Not sure if that info is of any help but thought id add it.
Constant power is coming from the starter to pins 15 and 31 on the black connection. Ignition power is coming from the stock fuse block into an aftermarket fuse block and into Pin 30 on the black connector, and Pin 3 on the Blue connector.
Do you know if the sensor grounds are grounded by the PCM? All 4 of my PCM grounds are grounded but neither of my two sensor grounds are...
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