Starting problems? Get grounded!

Here is a hint from a lesson learned on my '74 911. In keeping our 20+ year old cars on the road things in general will just run a whole lot better with good solid grounds. This is more or less common knowledge with the obvious examples of the battery ground cable and the transaxle to chassis strap often mentioned. On my car these are both new parts.

Last weekend I solved an intermittent starting problem caused by a less famous ground. On the left side of the engine compartment hidden behind the fuel filter and pump is a ground bolt. On my car it has 6 wires coming to it attached on three lugs. I found it recently during the hours spent with my head stuck in the engine bay while swapping out my air box. Already a believer in good grounding I disassembled, inspected, and polished the contact points. I noticed that of the three lugs two were machine crimped factory original and the third a hand crimped replacement part. A close inspection of the hand crimped joint, including a good tug to make sure it's tight, satisfied me it was good to go. The car ran fine after getting the air box back in.

A few weeks later she developed an intermittent starting problem. Engine would crank but there was no ignition, it would not even try to fire. On two occasions the car started after sitting overnight so I spent time inspecting the distributor cap, rotor, ignition wiring, and CDI module, all the usual suspects. After the third no-start incident I was resolved to start the shotgun approach of throwing money at the problem starting with the distributor cap, rotor, and CDI module. But first I slept on it, a luxury I enjoyed because my 911 had the good sense to refuse to start while sitting in her garage. Saturday morning I awoke thinking about that hand crimped ground lug. It is right by the CDI box. So for one last try before bringing on the new parts I removed the two clamps holding the fuel filter and pump. Swung them out of the way and disassembled the nut and lugs from hidden ground. The hand crimped lug still felt tight. Using a hot soldering iron and electronic solder (NEVER ACID FLUX PLUMBING SOLDER!!!) I soldered the hand-crimped lug. With it nice and hot I worked plenty of solder in the joint as the flux bubbled and smoked away floating the non-conductive gunk out of the joint. After re-assembly she not only started but did so the instant the motor cranked. In the two years I have owned the car even after tune ups it always cranked for a couple of seconds before firing. Now it starts almost instantly.

Electronics and computers are my business so I know exactly what happened in 20/20 hindsight. A factory crimped electrical connection and hand-crimped connections are deceptively similar but in fact completely different animals. The ideal electrical connection is called a 'gas tight joint'. The 'gas' referred to the air around us. Just like it turns a copper roof green given the chance it will oxidize the copper in our Porsche's wiring. In factory crimped electrical connections the connector is chosen to exactly match the wire used and the crimping is done on a precise powered tool. The tool crimps the joint so hard the metal from the wire and connector are cold-welded to each other. Thus the air cannot get in and degrade the interface between wire and lug. When we hand crimp we typically use a connector lug which is 'close enough' to the wire size and squeeze it on with a $5 hand tool. And this works for awhile but after a year or two the air can do its oxidizing thing until your number is up and the Porsche will not be starting today. When a hand-crimped joint is soldered the solder flux scrubs oxides off the metal and the solder fills the spaces between the copper of the wire and lug with a gas tight conductive metal. The moral of the story is for reliable electrical repairs use precision crimping parts and tools or go for the 'belts and suspenders' approach of hand-crimp plus solder.

I think you raised some good points Norm. If there is one thing I hate to see, its those red or blue crimp-on connectors dangling from the end of a wire (usually with a few frayed strands hanging off of them).

One thing I've observed about soldering connectors on. Many connectors that I've seen fail have been soldered, and they fail due to wire fatitgue just at the point where the solder ends. Any movement seems to eventually do them in. My favorite approach is to crimp a connector on the wire and use shrink tubing firstly over the crimp and wire, then, if it is a spade connector, put shrink tubing over the whole connector. The result looks much like the original connector. I've had very few problems using that approach.

I have an interesting story to relay about rebuilt starters, grounding, and a car that just won't start. A few years ago, the starter failed on my "other" car, a BMW 2002. I happily went out and bought a rebuilt Bosch starter, spent about half an hour installing it, and turned the ignition with high hopes. But- nothing. I tried all the usual tests, the starter was getting 12v, all the connectors looked good, I resoldered a few, but still no start. What I did notice was a brown wire burning itself up when I tried to start the car. Well, I figured brown must be ground on a german car, and that the starter wasn't getting it's proper ground. It turns out that when they rebuild the starters, they paint them. To make a long story short, they painted the mounting lugs in front, through which the unit grounds itself. I scraped the paint from these, and the unit works perfectly. Moral of the story- a car won't start without a grounded starter, and one should always check rebuilt parts for boneheaded oversights.

Just a note on soldering wires. The FAA will not allow any soldered connecters on any plane. They have a problem with planes falling out of the air. Solder always adds resistance to a connection. Always use crimp connecters of good quality. The hardware store has lots of junk. Also look for a decent crimping tool. If it is only mashing the connector from the sides it is probably substandard. (surplus aviation parts are great)

Yep, in my '74 914 2.0, I avoided these problems by just changing ALL of the ground straps and starter/battery wires with brand new, heavy duty stuff. I changed the ground strap for the battery negative to the chassis, the ground strap off of the transmission, and the long wire from the battery positive to the starter. Cost about $30 total, and has solved all starting problems.

My brother had a starting problem on his '93 Ford Explorer (total POC, but that's another story!). It turned out that corrosion in the crimped on connector at the battery positive post (the wire that runs from the battery positive to the starter) was the culprit. It was difficult to spot, because from the outside the connector and the wire looked fine. You had to take it apart to see the corrosion. I was surprised to see this on a car that is relatively "new" (its 6 years newer than my newest car!].