So, I had just changed my oil and everything was fine. I was on the highway, had stopped a couple times for errands, and the engine cuts out and dies. It will still crank over just like usual, but won't catch and start.

I had it towed home and checked the fuel pressure at the rail, and it was at spec--40 psi. So I started troubleshoot ignition problems--no spark. I can see nothing wrong at first. So I took at the ignition control unit and had that tested at the parts place. Seemed like maybe it was bad, so I replaced that. Still no go.

So, I'm tracing out the wires and find that there is a wire about to break apart at the connector from the crankshaft position sensor to the harness. There is a connector with 4 wires and another connector with 1 wire that goes into the CPS harness. The wire in fact breaks apart as I go to disconnect it. I trace the broken wire up into the CPS harness, and the insulation, such as it is, has crumbled away into a powder. I tried to use a jump wire to patch it and start it, but it didn't work.

So, I replaced the crankshaft position sensor. (While I was in there I put in a timing belt which I had intended to replace anyway.) Got it back together, and I'm about to connect the connectors, when the OTHER end of the single wire connector breaks apart in my hand. It, too, no longer has insulation. So, I try to patch it up, as much as I can without going deep into the harness, and try to start the truck. Just as before, it turns over just fine but doesn't start.

I want to be able to eliminate this and move on to the next thing (whatever THAT is--any ideas?) but I don't feel like I can until I know where this wire goes, why it has different insulation, etc.

I did a post-mortem on the old CPS. This single wire goes into the sensor harness, then around 4 inches from the sensor itself, it just winds around the 4 other wires. That's it. It had some fabric electrical tape around it, and was in a plastic harness protector.

The wire on the engine harness seemed to be taped to another wire, a black wire. I could not, however, tell if this black wire had been connected to anything or what its purpose was. I can chase it about 5 inches until it goes into the engine harness, and from there I didn't want to open that up, besides which it is really cramped in there and difficult to get to.

WTF is this wire, and if not this wire, what else could the problem be?

 

Test the coil pack.

 

Do you have the specs--my book says "not available."

 

Primary and Secondary Circuit Tests

1.

Turn the ignition switch OFF, disconnect the battery, then detach the wiring harness connector from the ignition coil to be tested.
2.

Check for dirt, corrosion or damage on the terminals.

PRIMARY RESISTANCE


1.

Use an ohmmeter to measure the resistance between the following terminals on the ignition coil, and note the resistance:


2.3L engines

*

B+ to Coil 1
*

B+ to Coil 2

or,

*

B+ to Coil 3
*

B+ to Coil 4

The resistance between all of these terminals should have been between 0.3-1.0 ohms. If the resistance was more or less than this value, the coil should be replaced with a new one.

SECONDARY RESISTANCE

1.

Measure, using the ohmmeter, and note the resistance between each corresponding coil terminal and the two spark plug wire towers on the ignition coil. The coil terminals and plug wires towers are grouped as follows:


2.3L engines-right-hand coil pack

*

Terminal 1 (coil 2)-spark plugs 2 and 3
*

Terminal 3 (coil 1)-spark plugs 1 and 4


2.3L engines-left-hand coil pack

*

Terminal 1 (coil 4)-spark plugs 2 and 3
*

Terminal 3 (coil 3)-spark plugs 1 and 4

If the resistance for all of the readings was between 6,500-11,500 ohms, the ignition coils are OK. If any of the readings was less than 6,500 ohms or more than 11,500 ohms, replace the corresponding coil pack.

On 2.3L engines, if one coil pack is found to be defective, the other pack does not need to be replaced.

 

Thanks. Very helpful.

So, primary resistance in all four coils is in range at 0.8. However, secondary resistance in all four coils is infinite. What are the chances that all four secondary resistance circuits all failed at the same time?

 

OK, so I must be checking secondary resistance incorrectly. I went the parts store and checked the secondary resistance on a new one and it is also infinite. I checked the resistance between the first terminal and each plug on the same half of the coil pack, and then the resistance on the last (third) terminal and each plug on the same half of the coil pack.

So, am I doin it rong?

 

Ignore 2ndary coil i get the same reading on my truck?

 

Thanks. I did end up swapping out the driver's side coil just in case but no change. I am going to refocus my efforts on the wire from the crank position sensor and post back when I am successful. Hopefully.