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Check engine light after rebuild

Old 01-12-2018
Thread Starter
Join Date: Jul 2017
Location: Paxton, NE
Posts: 29
Check engine light after rebuild

The rebuild went well. No check engine light on start-up. I forgot to order a new camshaft synchronizer and position sensor, so the old one went back in. After about 700 the check engine light came on. Auto parts store code check said "misfire on number 6." Cleared it and carried on but the light came back on is less than 100 miles, this time with another auto parts store code check the dreaded P1309 showed up. Bought and installed a high quality synchronizer and sensor. Still had intermittent check engine light, always checked as P1309. Took it to a shop this week had it scanned and mech said it was "way off," had him set it correctly. He said there a few other codes that might cause the check engine light to come on. Sure enough less than half a mile from the shop the check engine light came on. At home I disconnected the positive battery cable. Next start-up no light, but at about 75 miles the light came back on. I did forget to mention that the engine seemed to run fine through all this. After searching online I assumed that the computer had not been reset. Here is the dilemma, recommendations seem diverse. Some disconnect the positive cable, some the negative, some disconnect the negative and jumper the positive to the disconnected negative cable. So does anyone out there have a procedure for resetting the computer that has worked? This is a 2000 Ranger XLT, 3.0 flex fuel, 2 wd, auto tranny.
Thank you for reading this.
Old 01-12-2018
Join Date: Jul 2016
Location: BC Canada
Posts: 1,582
Disconnect the ground cable from the battery and jumper it to the positive battery terminal.
You may leave the positive cable connected to the battery, it won't matter.

What you're doing by jumping the cables together is draining the capacitors on the PCM.
This may or may not reset the computer.

For best results, leave it for at least 1/2 hour, some like to leave it over night, but I think that's a bit excessive.

After which the truck may have a wondering idle, that will go away with 2 or 3 driving cycles.
The PCM will have to re-learn your driving habits too.

Also check your ground wire at the back of the head on the drivers side, make sure it's clean and tight.
The post on the fire wall that it connects too should also be inspected.
Ford painted it green, so you may have to remove it and clean the green paint off to get a good ground for the PCM.
There is also another ground wire that comes out of the main wiring harness from the PCM, make sure that connection good as well.

Here's some more info in the cam synchronizer.
You can check it yourself to verify that the mechanic did it right.
It's pretty easy, turn the engine so #1 is at TDC on compression (make sure it's on the compression stroke, not the exhaust stoke), number 1 being the front left cylinder when you're looking at the windshield.
The tooth in the synchronizer should not be quite in the center of the window of the synchronizer casting if everything is correct.
Some put the tooth in the middle, but for your year, it is not, it's just slightly off.
The proper alignment tool doesn't set it in the center.


Last edited by Jeff R 1; 01-12-2018 at 11:34 PM.
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