So I went about replacing the stock AC/Delco battery in my '99 Coupe with a new Optima Redtop; although all the accessories, etc., were fine, there was a zero-crank condition when attempting to start the motor. I figured the 5 year old battery had finally just run down enough to where it didn't have the CCA to crank the motor anymore; fair enough, 5 years is a good battery life.

I swap the batteries and go about re-attaching the cables. I had a bit of a problem with the positive - kind of a snug/short fit on the cable. As I'm holding it against the terminal and screwing it in all of a sudden the lead to the starter breaks off from the terminal end. Crap. So now I'm thinking maybe the battery was still good and the starter lead had been broken but just hadn't separated from the end connecter (yet). No matter, I have a new battery anyway but now a larger issue - battery cable replacement. On other cars it's never been very fun but usually just a pain in the rear, not a technical challenge.

I consult the service manual for the procedure and am surprised to find that part of the procedure is to remove one of the O2 sensors from the exhaust manifold - after jacking the car! Looking at the procedure around the O2 sensors I'm further perplexed by (a) admonitions not to disconnect the pigtail that connects the sensor upstream and (b) advice that it may be difficult to remove the sensor if the engine temp is below 120 degrees F.

My first response is WTF put a pigtail on a cable if you don't want it disconnected but I answer myself that perhaps it's an ease of manufacturing issue. OK. But I now have a car I can't start and my odds of getting the engine temp anywhere near 120 F in April in Chicago are slim and none.

I have not yet visited the dealer to obtain a new positive cable harness (which I'm certain will be very reasonably priced :rolleyes: ) so haven't seen the starter end of this cable in any detail to understand the connection specifics. I also have the LGM Long tube headers so I imagine the O2 sensor mounting point is somewhat different than the original stock exhaust manifold mounting point.

All that said - my question is to anybody that has had to replace/reinstall a positive battery cable on a C5 - is it really necessary to do the disconnect the O2 sensor portion? If so, has anyone just disconnected and reconnected the pigtail? I'm in an awfully cramped 1 car garage and the thought of having to jack the car up and deal with all this is in no way attractive. Any advice/tips/tricks would be most welcome. Thanks to all for any assistance.

 

Hi Karl!

I Know you are tight on space, but do yourself a HUGE favor and jack the car up (can you push it out to the driveway?). Jacking is a mild pain in the butt - you need to get a good look at what you are working with. The O2 sensor is a little bit of a pain to get to, depending on the headers you have, but there is no real good way to get a good look at your work area from the top - you may not have to remove the O2 Sensor. If you do, they come out easy enough usually, I would only do it on a stone cold car though. The hardest part is getting to the O2 to get it out in the first palce.

Also, it sounds like there may be corrosion that weakened the cable - you will want to be able to look for this to prevent other trouble

Just my .02 cents worth.

 

Plug for Gene @ Fred Beans here.

Before you visit your local dealer give Gene a call (hes a forum sponsor). He gets me parts delivered to my door, for less than jobber+sales tax at my local dealer.
If you don't have a hook-up to buy jobber, you will pay even more (GM retail is painfull)

BTW, I'm sure the admonitions to not mess with the pig tail has to do with the O2 sensor leads themselves.
You would just need to unplug the sensor lead from the main engine harness before removing the sensor, standard

 

Have an inclined driveway and other issues, car is stuck in garage unless it's towed out. :(

Yeah, there appeared to be some corrosion coming directly from the positive battery terminal; there was a small amount of fluid in the battery tray as well. I'm pretty sure that's my source. This would be consistent with some of the other posts discussing how the positive connection pulls/stresses the terminal on the battery with resultant leakage (fortunately minor in my case, but enough to probably be my culprit).

I can jack the car if I need to, just really trying to avoid it. Once I take a closer look, who knows, maybe I catch a break and the LG Headers O2 sensor mount is more convenient to access from above (hey, a guy can dream, right?) :lol:

 

Update - looks like I am not as bad off as I thought. After pulling the terminal bolt out of the cable-end and inspecting the connector, I can see that corrosion was indeed the culprit. The starter cable does not need to be replaced as it had just corroded the very end and fallen out of the crimp to the connector. I should be able to just get a new connector and clean, strip, and crimp the ends of the fusebox and starter cables onto the new connector and be good to go.

Oh yeah - and there's no way in heck I could have accessed the other end of the starter cable without jacking the car or having Cirque du Soleil-like contortionist abilities, so I'm pretty happy!