Hey guys,

When I log battery voltage in ECMLink the value is generally 0.7-0.8V lower than what I read across the posts with a multimeter, is this normal? Let me know if you see the same kind of drop in your logs. Thanks!

I would expect to see a lower value although 0.7-0.8V seems a little much. Did you do test this with the car running?

I only noticed this yesterday with the car sitting, I saw 12.5V at the battery and 11.8V while logging in link. I believe that the same drop occurs with the car running but I will confirm in the next day or two and get back. Could this indicate something along the lines of a bad ECU ground? My battery cables are brand new and the connections have been meticulously checked as I had starting issues last year.

There was a thread a (really) long time ago (can't remember if it was on here or one of the other DSM sites) about voltage at the ECU, alternator, battery, etc. comparing and discussing them.

I'm curious to see what your results are with the car running.

I don't have Link in my Laser otherwise I'd test my car out and see what I get. (The Talon is put away right now)

I need to go get dog food, I can check when I do that and let you guys know.

I usually never see less than 13.5v in a log during a WOT pull, and 13.9-14.1v at idle. Perhaps cleaning up the current grounds, and perhaps even add a few more may help bring up that voltage. I know if my voltage was that low I wouldn't be doing any spirited driving until my issue was resolved. I'm so paranoid when it comes to voltage, that I have the factory boost gauge set to monitor battery voltage.

Thanks for the help Salomon and Brian.

Where do the ground pins (13 and 26 IIRC) on the ECU run to? Kevin would you simply recommend cleaning up these connections? As I said my battery and engine grounds have been checked and are in good shape.

Iirc Ive added an additional 4-5 grounds around the engine bay, and it certainly helped raise my voltage. I also resanded(made sure no paint or rust) all the factory grounds to ensure a solid connection.

The alt is grounded by the block, so I always run a ground wire on the pivot bolt to the chassis to ensure a solid ground.

Kevin has some good suggestions.

This seems to have made small improvements (at least) for a number of people that I've read about doing it, so it's definitely worth a try. Would start with the alternator personally, and go from there. It's definitely one of the more critical items given that your entire electrical system relies on it.

Hmm, I've been pulling and reinstalling the battery a lot lately so I may have just had a loose terminal when I noticed this issue in that particular log. I just stopped by my parents where the car is stored and threw the battery back in to check. I only saw a 0.1V drop between the terminals and what Link was logging which seems much more reasonable. The battery is on the trickle charger for the night so I'll take some more readings on a full charge tomorrow and with the car running, thanks for the help guys.

Sorry Chris, seems I forgot to plug in my laptop, will let you know tomorrow.