Lots of data errors
Thread Starter
Pro
Joined: Oct 2004
Posts: 628
Likes: 6
Update
Originally Posted by Blower91
Have you made sure you set up Datamaster for Corvette and not F-car? Just a thought...
Last night I made sure that the MSD unit was well grounded (Took the earthing bolt out of the frame, sanded it all down and then tightened).
Big discovery of the night was a large relay that sits under the PCM under the hood. It is glued to the brake booster and has it's 'control' wires tapped into the PCM harness. It's ground wire was sitting at 48 ohms relative to battery negative, it was bolted to the mounting point for the PCM bracket (i.e. the edge of the hood locator). I took it apart and cleaned up the connectors, put it back, now at 0 ohms. I have no idea what this relay controls - I didn't have time to trace the positive wire. I'm hopeful that this may be it, I will test at the weekend (I'll be in Mexico city for the rest of the week. Joy.).
Another option is that the MSD unit has a 'stereo suppression' option that I will check to see if it is installed.
The saga continues...
Melting Slicks
Joined: Apr 2003
Posts: 2,150
Likes: 6
From: NS
Originally Posted by djxib
I have tried two different laptops - both Dell. Both have IR disabled, both are running Windows XP. Maybe that's my problem. Who knows..
Instructor
Joined: May 2003
Posts: 109
Likes: 0
From: st louis mo
Originally Posted by djxib
Yeah, I've checked that a few times.
Last night I made sure that the MSD unit was well grounded (Took the earthing bolt out of the frame, sanded it all down and then tightened).
Big discovery of the night was a large relay that sits under the PCM under the hood. It is glued to the brake booster and has it's 'control' wires tapped into the PCM harness. It's ground wire was sitting at 48 ohms relative to battery negative, it was bolted to the mounting point for the PCM bracket (i.e. the edge of the hood locator). I took it apart and cleaned up the connectors, put it back, now at 0 ohms. I have no idea what this relay controls - I didn't have time to trace the positive wire. I'm hopeful that this may be it, I will test at the weekend (I'll be in Mexico city for the rest of the week. Joy.).
Another option is that the MSD unit has a 'stereo suppression' option that I will check to see if it is installed.
The saga continues...
Last night I made sure that the MSD unit was well grounded (Took the earthing bolt out of the frame, sanded it all down and then tightened).
Big discovery of the night was a large relay that sits under the PCM under the hood. It is glued to the brake booster and has it's 'control' wires tapped into the PCM harness. It's ground wire was sitting at 48 ohms relative to battery negative, it was bolted to the mounting point for the PCM bracket (i.e. the edge of the hood locator). I took it apart and cleaned up the connectors, put it back, now at 0 ohms. I have no idea what this relay controls - I didn't have time to trace the positive wire. I'm hopeful that this may be it, I will test at the weekend (I'll be in Mexico city for the rest of the week. Joy.).
Another option is that the MSD unit has a 'stereo suppression' option that I will check to see if it is installed.
The saga continues...
Racer
Joined: Jul 2002
Posts: 313
Likes: 1
From: Dallas Tx
Originally Posted by djxib
Hey Scott94C4 - do you mean that you hooked up the body of the MSD unit to the battery ground?
Thanks,
Andy.
Thanks,
Andy.
That solved my data errors.
Originally I had the MSD's ground wire to the frame ground strap. No amount of cleaning or sanding would give it a good enough connection to stop the data errors.
Try running the MSD ground wire to the battery when you get back. It just might work...
Last edited by Scott94C4; Apr 20, 2005 at 03:16 PM.
Thread Starter
Pro
Joined: Oct 2004
Posts: 628
Likes: 6
Finally!!!!!!
I know what the problem is. I made up some wires with croc clips and ran them straight from the battery to the 12v supply lead for the obd1 cable. NO MORE DATA ERRORS. 
Tried again with the lighter socket and get data errors. Tried the supply that feeds the button for the rear hatch (it's a vert) - get data errors. I think there is a common ground for all these 'always on' supplies so that's the problem.
I'm a bit tired from the Mexico trip, so I'm thinking about putting a permanent solution in place for WOT runs. I think I will dismantle the dash and clean up the lighter ground; if this is no good I'll run wires straight to the battery (via a fuse) from the lighter socket.
Thanks for staying with me; the encouragement on this forum is great. Cheers!
Tried again with the lighter socket and get data errors. Tried the supply that feeds the button for the rear hatch (it's a vert) - get data errors. I think there is a common ground for all these 'always on' supplies so that's the problem.
I'm a bit tired from the Mexico trip, so I'm thinking about putting a permanent solution in place for WOT runs. I think I will dismantle the dash and clean up the lighter ground; if this is no good I'll run wires straight to the battery (via a fuse) from the lighter socket.
Thanks for staying with me; the encouragement on this forum is great. Cheers!
Instructor
Joined: May 2003
Posts: 109
Likes: 0
From: st louis mo
Originally Posted by djxib
I know what the problem is. I made up some wires with croc clips and ran them straight from the battery to the 12v supply lead for the obd1 cable. NO MORE DATA ERRORS.
Tried again with the lighter socket and get data errors. Tried the supply that feeds the button for the rear hatch (it's a vert) - get data errors. I think there is a common ground for all these 'always on' supplies so that's the problem.
I'm a bit tired from the Mexico trip, so I'm thinking about putting a permanent solution in place for WOT runs. I think I will dismantle the dash and clean up the lighter ground; if this is no good I'll run wires straight to the battery (via a fuse) from the lighter socket.
Thanks for staying with me; the encouragement on this forum is great. Cheers!
Tried again with the lighter socket and get data errors. Tried the supply that feeds the button for the rear hatch (it's a vert) - get data errors. I think there is a common ground for all these 'always on' supplies so that's the problem.
I'm a bit tired from the Mexico trip, so I'm thinking about putting a permanent solution in place for WOT runs. I think I will dismantle the dash and clean up the lighter ground; if this is no good I'll run wires straight to the battery (via a fuse) from the lighter socket.
Thanks for staying with me; the encouragement on this forum is great. Cheers!
Thread Starter
Pro
Joined: Oct 2004
Posts: 628
Likes: 6
Originally Posted by kvu
So your cable requires an external 12v power supply and you was using the lighter socket? This helped your WOT runs? If the answer is yes and yes, then my friend's car has a different problem....
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
