TheTrooper73

I know this has come up in the threads before, because I read some info from google when my DIC first indicated an issue, but I wanted some feedback.

I have a 2007 (Z51 for those that care) with a Vortech SC (here's the thread for all that: http://forums.corvetteforum.com/c6-f...post1576940804.

I just got back in the saddle (coming home from 2 years deployed) and for the last 10 days or so my battery voltage drops every so often to about 12.5-13 or so when idling in a parking place or at a red light. I read a few forums here about battery, alternator, plugs, etc...and the first two fit my bill since it had been in pseudo-storage for two years.

I took it to the dealer and had them run the diagnostics and pay particular attention to the battery and alternator (since it sat most of the time in my bro's garage). For the first 2 hours the voltage never dropped, so they kept running it at my insistence and it started doing it--but there were no 'bad reads' from the computer.

Everything came back "clean" but the dealer printed out a TSB about certain high performance spark plugs causing this exact thing. I also saw this on a few threads here as well (still amazes me the amount of knowledge here).

Anyway, just throwing it out there to you guys to ask if any of you had these problems after dropping in the SuperCharger, and/or if I NEED to change the plugs back out or if dropping to 12.5/13 and hearing the DIC ding at me is really that big of a deal.

If I do need to change them, should I just go back to OEM, or is there an aftermarket that won't "clash." I have NGK now. I'm also not a gearhead, and basically know jack **** about cars--so nothing too techy for support.

BLUF: do I NEED to change the plugs, and if so, to what? I'm kind of inclinced not to if there's no reason, but if it will/could cause any other issues, I will swap them out ASAP.

Thanks.

eboggs_jkvl

I read the same things you did on the plugs. I had TR6s in the car but I was not having trouble. I decided to pull the TR6s out and I went with the stock plug the ZR1 uses.

.040 gap AC 41-104


Elmer

5 Liter Eater

I had this problem and for me it was the lug on the starter where the alternator connects to was loose. I have a thread on it.

eboggs_jkvl

I remember that. These damn systems are just plain too touchy on the possible electrical gremlins running around.

Elmer

dgrant3830

I'm one of those that the spark plug did in fact cause a problem for the charging system on my '07 Coupe. I removed and replaced the stock plugs with laser cut NGK's. Started having issues with the charging system. I replaced the battery and alternator with no effect on the problem. Then another forum member, Sgt Rod, told me about the plugs as he too had this happen to him and went through a similar nightmare with his and it turned out it was the plugs for his. Even though I was having a really hard time believing this being a possible cause, I trusted him and put in new stock plugs. The problem went away!

Turns out, the PCM monitors the alternator frequency via the rotation at the horn/sense fuse. It checks to see how fast the alternator is turning in order to determine how much charging can be done as opposed to how much is needed....or something like that

Motorhead-47

huh?....any link to a more detailed technical explanation by chance? I'm not saying you aren't close but I'd like to get the full scoop if you have any further intel. I have two A&A V2 buds (TheTrooper73 and Tally Ho) with the same issue and would like to help them put this to rest for good.

1fastbob

I think what is going on is that the off breed plugs generate electrical noise that messes with the computer causing the alternator voltage regulator to wrongfully lower the output of the alternator. This causes insufficent charging of the battery and causes starting problems.

Bob

dgrant3830

There is a whole disertation on this in the maintenance manual. I don't remember the exact detail but gave the basics of what I remember. Yes, noise generated by "some" plugs, will cause the PCM to not tell the alternator to charge properly.

Bill Dearborn

Here is the Service Bulletin along with the DTC that usually gets set when the plugs cause a problem. The bulletin indicates the problem is with Pulse Type plugs so as long as you avoid them you should be OK.


Bill

dgrant3830

Mine happened with NGK plugs, no clue if they are related to pulse type plugs, but my problem was solved when I changed back to AC Delcos