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sprinkles08, Chrysler/Dodge/Jeep master tech
Category: Dodge
Satisfied Customers: 22996
Experience:  ASE Master and Advanced Certified, Chrysler/Dodge/Jeep Master Certified, Trans and Hybrid Specialist
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Dodge ram 1500: 99 ram 1500, I had a p1391 code come up. A

Customer Question

99 ram 1500, I had a p1391 code come up. A lot. So I changed the whole front of my motor timing chain pump hoses figured do it all. Along with 1391 I had bucking usually 3rd gear 3000-3750 rpms (nv3500) however I haven't gotten the code since replacing chain but did get the bucking today in 4th gear at 3300ish rpms. It's done it since I bought it.
Submitted: 2 years ago.
Category: Dodge
Expert:  sprinkles08 replied 2 years ago.
Hello and welcome to JustAnswer!
The bucking could be the coil or a secondary ignition issue but if it had set a P1391 previously then there is a good chance the problem is still related to that. P1391 sets when there is an intermittent signal from the cam or crank sensor or their out of sync enough that it can't determine which sensor to believe.
The most common cause of this would be the crank sensor but it could also be a cam/crank sync issue. If the distributor has been moved, the drive gear is worn, etc then it will cause cam/crank sync to be off. The first thing that should be done at this point is et cam/crank sync. Was it done after the timing chain was replaced?
Customer: replied 2 years ago.
After timing chain took it for a test drive only bucked once. (Which it has done for 2 years now. And have replaced ignition system after ignition system multiple times.) however mo matter how hard she runs now I can't get a code to Pop up. And distributor hasn't been removed. I'm kinda stumped with this
Expert:  sprinkles08 replied 2 years ago.
Has cam/crank sync been set?
Customer: replied 2 years ago.
Expert:  sprinkles08 replied 2 years ago.
How was it done?
Customer: replied 2 years ago.
Not sure stealership checked it all out.
Expert:  sprinkles08 replied 2 years ago.
Neither of us have a way of knowing if it was done in that case.
Do you have a scan tool?
Customer: replied 2 years ago.
I have some software called pcm scan
Expert:  sprinkles08 replied 2 years ago.
Does it show cam/crank sync degrees?
Customer: replied 2 years ago.
Not that I'm aware. However tonight I drove her hard recreated every time the code would pop up and nothing. She's running better and couldn't get a buck.
Expert:  sprinkles08 replied 2 years ago.
Do you have a digital voltmeter?
Customer: replied 2 years ago.
Hey sorry I was at work. And yes I do
Customer: replied 2 years ago.
And I'm also gonna try another scan tool. For cam crank sync degrees, what would I be looking for with that?
Expert:  sprinkles08 replied 2 years ago.
Take a look at it at idle and let me know what you see.
Customer: replied 2 years ago.
Alright so I can't find anyone with a scanner that'll show ckp and cmp sync degrees. However it showed ckp count witch was like 15 over 240 and sorry it took so long I've been busy at work. If you know what brand scanner can get me the info I need?
Expert:  sprinkles08 replied 2 years ago.
I can describe a procedure to use with a voltmeter if a scan tool isn't available. I'm going to be offline for the next couple hours and will reply as soon as I am able.
Customer: replied 2 years ago.
Ok that'll work
Expert:  sprinkles08 replied 2 years ago.
I'll get back to you as quickly as I can!
Expert:  sprinkles08 replied 2 years ago.
Turn the engine clockwise by hand with a ratchet until the slot on the crank damper lines up to the zero mark on the timing cover. Ensure the number 1 cylinder is on the compression stroke, you can see if the rotor is pointing toward number 1 if it's in question.
If you go past the zero mark then back the crank up 20-30 degrees and then turn clockwise to line the mark up again.
Set up to backprobe on the tan/yellow wire at the pickup plate connector and turn the key on. Loosen the distributor hold down clamp and turn the distributor counterclockwise about ten degrees. Watch the voltmeter while slowly turning it back clockwise while watching the meter. When the meter switches between 0 and 5v stop turning immediately. If you miss the mark back up ten degrees or so and come in again. Set it as close to the switch point as you possibly can and lock the distributor back down.