1998 Ford Ranger DTC Code P1309

THETOOLMAN

MEMBER
1998 FORD RANGER
6 CYL
4WD
MANUAL
135,590 MILES

I am working on a 1998 Ford Ranger XLT it has a 4.0L V 6 with 135,590 miles on it. It is a Five speed Manual transmission. I recently replaced the fuel synchronize shaft and the cam shaft sensor. When I removed the old sensor it was completely destroyed in pieces. I also removed the shaft to visually inspect it. It was damaged as well. I went to a junk yard and got a shaft from a 98 ford ranger 4.0 L. I put it in and it ran great. By the way I also replaced the plugs and wires and the EGR DPFE sensor. I noticed that the plugs on the 4, 5, 6 and six were in bad shape the center electrode was almost gone as if the engine had ran real lean on that side. The other side 1, 2, 3 were the opposite they were black and appeared as though it had run rich on that side. I changed the air filter the oil and Oil filter. I cleared the codes and test drove the vehicle it ran fine. No light nothing at all. Customer arrives picks up the truck and is gone maybe 5 min. Comes in and says the Check Engine light is on. I check it and get the P1309 Misfire Monitor Disabled. Cleared the code drove it for about 30 mins. NO Light. I kill the ignition start it back up drive it down the road about a mile and here comes the light. I have noticed that right after I clear the code it doesn't set on the 1st start but it will on the 2nd. Confused! Any help would be greatly appreciated.

2 Replies

SCHRIMPIEMAN

MECHANIC
166 POSTS

First, thanks for the detailed description. It helps a lot. I realize your post is almost a week ago; I hope this reply helps in your diagnostics (on time). I was just brousing around and came upon your post.

The issue you most likely have is the cam sensor being out of synch with the crank. You'll need to find the correct angle to which the cam needs to be set in relation to the engine block and crankshaft being BTDC or ATDC for piston #1.

For detailed info on P1309, go to motorcraft. Com homepage. Near the top middle it says Technical Resources; then in new window that pops up, choose OBDII Theory and Operation. You're given a list of choices. Choose your "98 model year OBD System Operation.

You'll have a *. Pdf file.
Lucky for you, Page 6 of 60 specifically indicates your fault code under "High Data Rate System". Your cam vs crank signals are out of synch. Also, the PCM needs to see the engine temperature rise to normal operating temp before all monitors can run, so make sure your Coolant Temp Sensor is accurate and functional. (Not the temp indicator on the gauge, mind you. You need to investigate the other sensor which the PCM uses to measure engine temp. It usually has 2 wires going to it.)

If you need details on how to set the cam sensor, let me know.

If you are confident about your cam/crank synch, you'll likely need a new camshaft chain and tensioners. Any excess slack in the cam-chain will thow off the timing for synch.

. Enjoy.