Captain Obvious here again, with another Helpful tip.
A couple days ago I had a friend's car here, it's the 89 Nissan Maxima I Grooved 4 years ago, (that responded so dang well!) It had been having a hart-starting problem for quite some time, and my friend even needed a tow once. Turn the key and nothing.
Once it would start it would run OK, as if there was no problem. I've been into the steering column, and under the dash, and into the shift linkage in the center console. All in search of a bad connection, linkage adjustment, whatever. Last year I put a new B+ cable lug on the positive battery cable and improved it. But I never paid much heed to the Negative battery cable, besides cleaning the cable lug and batt. terminals.
Finally I was examining the Neg. cable, and saw the insulation had shrunk back in a couple places, exposing the copper wire strands. There wasn't much corrosion, or any damage to this factory original Negative cable. But I wondered if the age, and shrunken insulation might mean it wasn't up to scratch. Turns out it wasn't...
Eight bucks and a few minutes of work later, I had replaced the original Neg. cable w/ a new parts store one and added a body ground to the extra pigtail on the battery terminal end. Scuffed the cable connections to the engine and body. result...
Big Surprise Amigo!! It started right up, has continued to do so. She says that the engine is running better, and other things like power door locks work better too...
This re-inforces my opinion about Grounds. I think it's easy to get hung up thinking about the B+ 12V power to everything on a vehicle, it's kind of intuitive to do so. And forget the Ground or Negative side of things. The battery voltage needs those Ground connections to get back home to the battery, bad grounds and a bad Neg. battery cable add resistance and cause voltage drops. So simple, and So easy to miss...!
So there ya go, everyone!
Tracy G (Captain Obvious)
Gadgetman Reno, NV
Makes sense to me that the power locks work better now: battery might be fine, showing 12.7v at rest, but if the sensors and switches aren't seeing the negative/ground, they don't know what that 12.7v (or whatever) is in reference to...and stuff won't work as expected.
Now spread that lack of reference throughout the vehicle, especially one with sensors like o2 and IAT and ECT, and the computer won't be able to react appropriately...regardless if it's a 12v or 5v circuit.
Good catch, Tracy! Simple and inexpensive general maintenance keeps any vehicle running strong
Yup, so simple and obvious once you get the chance to A/B this. That batt. Neg. cable was under my nose the whole time. I now think that any battery cable that shows shrunken-back or otherwise compromised insulation is reason to be suspect. Even if the cables look ok, it's still good to clean/inspect ground connections. Connections and grounds that look "clean" can still be impeded by oxidation, which often is near invisible. I would add that it never hurts to add or improve grounding leads like: batt. negative terminal to body, alternator to body, and engine to body.
Gadgetman Reno, NV