Car cranks but will not start

Hi,

If you know the coil and PCM are good, then we have a wiring issue between the two. Power is supplied to the coil via one circuit. The ground path is then provided via the PCM. So, if 2 of the plugs are firing, we know there is power. If two aren't firing at all, then there is no ground provided via the PCM and the two that are not working correctly at best have a poor connection.

If you look at the first pic below, it shows how power goes to the coil. Keep in mind, two cylinders at a time get spark, 1 & 4, 3 & 6, and 2 & 5. This pic shows where power enters the coil.

Next, I attached a pic of the PCM connectors. Now for cylinders 1 and 4 to fire, the white wire (pin 3 at the PCM) has to provide a ground path. So, check the connector and wire for damage or corrosion.

The same thing applies for cylinders 3 and 6, but it will be pin 2 and the wire is red. Note that these two pins are side by side. I suspect there is an issue at the connector. Make sure the pins are not damaged, corroded, or pushed back into the connector.

Pin 3 powers cylinders 1 and 4

Pin 2 powers 3 and 6

pin 11 powers 2 and 5

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I hope this helps. Let me know what you find or if you have other questions.

Take care,
Joe

Hi Joe,

The plug that goes to the coil pack. I took a look at it for damage it looks good.I tested the plug through the top and bottom of the plug. There is power on green. red, black , white no power. I took a look at the PCM plug that had red and white wires going to it. The pug looks fine. When I tried a rebuilt PCM nothing changed. I ordered it on line the quality of the unit didn't look that great. I put the original one back in a sent the other back. The mounting brackets on the PCM to the car i took to bear metal to make a good ground. Is it possible that i have two bad PCM's? Where should i go from here?
Thanks, Alan Soderstrom

The green should have power. That is supplied to the PCM. The other 3 wires are grounds, so no power should be there. You replaced the crank and cam shaft sensors. Okay, is it possible for you to have gotten a bad PCM, sure it is. However, lets back track a bit. I want you to remove the crankshaft position sensor connector and check for ground and power from the PCM. Note that you will not have anything from the signal wire unless the engine is cranked.

Take a look at the pic below. Check pin 1 for 5v and pin 2 for continuity to ground.

Let me know what you find.

Joe