2006 Ford F150 P0300

HI Chris, My experience with the P0316 is that there is either coolant or fuel leaking into the cylinders causing the engine to misfire on startup. It may also be leakdown of the fuel into tank after the ignition is turned off. Check fuel regulator for leaks at vacuum line if it has one. You could also check for PCM updates as there may be an inherent problem with a cold start that is addressed…

Thanks for the reply Michael. I will look into those thing and see if I come up with anything. There is a TSB 5-25-5 for a p0300 with spark knock. When they changed the engine they put in new motorcraft plugs so I can look into seeing if it needs a reflash.

Thanks.

"My experience with the P0316 is that there....." Out here it just means they waited two months, after the coil died, to bother coming to a shop, Mike. :-)

I would suggest pulling a spark plug and seeing what brand is in there. There are many aftermarket plug designs for these 3V 5.4s and they just don’t work as well as the recommended PZT-2F motorcraft plugs. If there is anything other than the specified motorcraft plugs, you would not be wrong with recommending replacement as a starting point. I would also make sure the PCM is up to date with the…

I pulled a plug and it was a PZK14F on the side of the plug which I checked with aftermarket and that is what they listed. I called ford and they said it is a SP-546. I ordered a plug from a aftermarket store and the plug box has the part number the dealer gave me on it also so I would assume it is the same plug. But I will look into the latest calibration.

Chris, also check the routing of the CKP sensor wires, I have seen aftermarket add ons, or wires routed too close to alt. causing issues. Are the coil packs OE Motorcraft? Maybe check alternator for ac ripple,

Thanks for the reply I will look into the routing of the harness. All of the coils look to be OE not sure how many miles they have on them as the truck does have 270k on it. I will look into the alternator as well it had crossed my mind I just never did it. It does appear that it has been recently replaced.

Chris, since the engine runs fine, it seems like a probable PCM logic fault.

2 weird Ford misfire codes I've seen lately: first from the harmonic balancer being wobbly - felt like a vibration, PCM registered misfires. Second was resetting KAM. Somehow, PCM got confused. Also, test drive warmed up, at 45-50, up a long incline, TCC engaged, high gear, medium throttle. If there is some "bucking", this is ignition misfire (usually coils).

Thanks Robert for the info!

I’ve reprogrammed a lot from that era with the P0300 and P0316. If you don’t actually feel a miss a flash usually fixes it

Chris, this is a GIF of the known good cmp, ckp, for the guys who don't use the Pico If the engine continues to misfire on cold start, first connect the scope, set at 500 ms/div, to 4 COPs, then start the cold engine, so that you can try to capture some misfires. If you did not capture any misfires, you will have to connect the scope to the other 4 COPs, that were not scoped the first time…

Just so we are clear, did it stop counting misfires now?

Yes sorry I was not clear about that. Rpms raise off idle and driving down the road there were zero counted misfires now.

Thanks man. This actually makes a good study. One of those "you just cant trust electronics when a mechanical fault is present" tales.

This is an awesome example of how not being afraid to ask for help can save time. Great job by everyone involved. Except the engine installer. I would be sure to explain to the customer the damper being loose COULD have damaged the crank gear and/or the crankshaft. You won't know until a few thousand miles down the road. Would recommend the vehicle be returned in 500-1000 miles to re-check the…

They are lucky this isn't the smaller Ford engine that bends valves when the balancer is loose. (2.5?)

Thanks for the post and some good ideas. I did recommend that the customer come back to recheck torque.

Hi Chris, That crank bolt is a one-time use fastener (possibly torque to yield). I see nothing in your post indicating that it was replaced (the post actually reads more like you just tightened the one on the vehicle.) If this is the case, I strongly recommend that you replace that bolt; otherwise it may come loose again (it may also have already been re-used by whoever was in there before you…

Thanks for the info. I did just torque it down at the time to make sure that did fix my issue. When he stops back in to double check it I will replace the bolt. Thanks

WHAT A PHENOMENAL CASE STUDY!!! There are soooo many things that could cause this...everything that is listed and some!!!! Always think outside the box! ....do we know what caused the loose bolt.....Is this another known but kept quiet issue to be on the look out for?

I don’t know 100 percent but it just had a engine put in it about 2 months ago. Was it left loose from the install possibly but no way of knowing. It could also be due to the fact that maybe the bolt was reused but when I torqued the bolt it did press the crank pulley in about 1/4-1/2 inch. Now that I think about it the bolt did look relatively nice and new so maybe it was changed. Not sure…

Thank you for responding....I will be on the look out for this to see if it is something of a concern and I will DEFINITELY replace as needed in the future! Great post!

The p0316 could be key here. Keep it over night and your scan tool should have a cylinder contribution graph.....have it misfire and watch the graph.....what amazes me about Ford is it takes 1000s of misfires to set a mil but just a few for a p0316 AND no cylinder named in the code

Ken---He found the problem. {Quote}Chris Winkler Diagnostician Bryans Road Sunoco in Bryans Road, Maryland Thanks everyone for the info it let me be a little opened minded before jumped into reflashing the PCM which it still might need will have to check. I looked at the alternator harness and it was laying on the harness coming up from the crank sensor but this did not make a difference…