I got back from Atlanta at about 1 this morning, drove the Vette home from SFO and it was fine. This afternoon I ran a couple of errands and decided to take the car to the local car wash since I was too tired to do it myself. this is one where they vacuum it out, pre-wash, then run it through the machine and hand-dry it.

As soon as I got about a mile from the car wash I noticed the engine was shaking as I pulled away from the traffic light and was severely down on power. I thought maybe something got a little wet and I'd let it dry out since it was about 95 today.

Let it sit in the carport at home with the hood open for about an hour, then ran over to Target for my wife. On the way there the car was running worse, then the CEL came on. As I got into the turn lane I noticed the coolant temp was at 230, so I kept on driving - getting out of traffic so I could keep up some speed and get it to cool off since the fans weren't cutting it.

Checked codes after it had a while to cool off and got a bunch of codes - some of them related to the battery. I also noticed that the DIC voltage was steady at 13.7 - ever since I got the car it's always run at 14.7 so it was down 1 volt.

I ended up at O'Reilly's, checked the battery and it tested out as needing to be replaced. Swapped it out with a new 850 CCA unit, it fired right up, the CEL went off and it's charging at 14.3 volts. It's running better, but still not right.

I'm still getting these codes:

B2282 H
B2283 H
B2284 H
B2285 H

U1255 H
U1064 H
U1016 H
U1096 H

These are all from the left and right door control modules. I'm confused how door modules are giving the engine a miss/stumble effect. Before the battery replacement, there was a code for engine mis-fire, but now it's not there even though it still has a stumble.

Sorry about all the rambling, but I'm trying to give all the info I can.

 

Since you just swapped batteries I would clear all of those H-suffix codes and see if any of them come back. I'm thinking they probably won't and I agree that they shouldn't have any impact on the way the motor runs.

What is the condition of your spark plugs and plug wires?

 

Marc

With the weird symptoms that your having and U series DTCs ,, I would like you to try this before you get too deep into spending any cash:


Pop out BOTH door accordion tubes. Fish out the door connectors from the hole in the A Pillar.





The POWER connector can have issues with deformed female pins:



Most C5s have this issue so,,,,, even IF,,, its not your issue, its to your advantage to examine and address this possible issue.

Give that a try and see if it helps.

Bill

 

About 15k miles on the GMPP wires and iridium plugs.

I'll take a look at clearing the codes.

 

Bill, thanks for the pics and tips. I'll check that tomorrow morning.

 

That's a pretty recent plug and wire swap. I'd suggest checking to make sure you don't have a plug wire rubbing part of your exhaust manifold. I've seen plug wires last for a little more than 15k like that but eventually the heat will penetrate through the boot and damage the wire itself which causes a missfire. I'm guessing you've been pretty gentle on the throttle since this started right? That might be why you haven't gotten another missfire code

I've seen plug wires rubbing headers twice on C5's and once on a C6. It was cylinder 7 all three times and they were all acting exactly like you're describing. They would only throw a missfire CEL on hard acceleration; they would just run a little rough under light load.

 

The charging issue is resolved now, everything back to normal there.

This morning I found the rough-running issue. I parked at the bank to use the ATM and left it running with the A/C on since it's already 80 here. When I came back around to the drivers side, I could hear the tell-tale "snap" sound of a spark. Sure enough, I could see the spark arcing from the wire of the 3rd cylinder back on the drivers side to the header. The amazing thing is that the wire is about 1/2" from the header.

I came back home and I'm letting it cool off so I can insulate it till I can replace it.

 

I thought so... Do you have LT headers?

 

Good call!

 

Nope, B&B shorty headers and the wires don't touch the headers anywhere. From the wire at the point it split to the header is a good 1/2".

When I got the wire off I was really surprised to see that it was split open to the core. I used some RTV to seal it as best I could just so I could drive to the store and pick up a new set of wires.

I expected more than 6 months use out of the GMPP wires

 

Just installed the new MSD wires and went for a test drive. Everything is back to normal

Thanks for the quick replies everyone!

Bill, I'll take a look at those door connectors this weekend.