I have a thread in the 6.8l section of the forum but am getting desperate and see theres more viewers in this sub section.... https://www.ford-trucks.com/forums/1...ower-loss.html

I have an 02 super duty E350 with the 6.8. Tried everything and keep getting the p0340 fault. Lack of power, idles good for a while then stumbled acts like it will die.

Have tried everything. New plugs,coils,fuel filter, o2s,pcv,iac,cam sensor, cam sensor connector,alternator,cleaned maf, checked cat, cleaned pcm connector, fuel pressure good.

Sometimes takes a couple tries to start, idles good but randomly stumbles and studders, drives good but completely falls on its face and acts like cats are clogged with no power if I give it wide open throttle.

More details in linked thread but anyone have any other ideas?

 

Sure sounds like you've tossed some parts at it without success. What is the mileage on the vehicle in question? Based on the fact that we are working on a 14 year old vehicle with some mileage, my money is on your timing chain guide(s) are either broken, and/or the timing chain(s) have jumped time by a tooth to a tooth and a half. And don't think for a minute that I don't have any appreciation for how intrusive this is going to be, on an E-Series van to access. I've ran into more than my share of stubborn P0340s with unsuccessful repair attempts by other shops or techs through the years I've been wrenching. ALL, ended up being base engine valve timing being the cause. Good luck.

 

170k

When I bought it, it barely drove. Had to drive 30 miles on highway to get it home and it took forever to get it to 60mph. I was hoping it was a bad coil or two and/or a clogged cat.

After all the parts I threw at it... It does drive way better now. I could drive it daily at cruising speeds. Its just got a studder/stumble every couple revolutions at idle and if I give it full pedal it falls on its face and goes nowhere like when you have a clogged catalytic converter.
My cat is good, flashlight tested fine

If my timing chain jumped a tooth wouldnt it run like total crap? Or would its symptoms be similar to what I have going on? I guess if the chain slipped, that would throw off the cam sensor readings right? So that would make sense for why I have the cam sensor code. I just wouldnt think it would drive fine at cruise speeds but I dont know...thats just my assumption.

 

You will be amazed at how relatively well one of these engines will run with valve timing off by a tooth or two. Based on the fact that you have a hard P0340 fault (as in a fault code that won't "go away" when you clear it) by what you've described, I maintain my position that you likely have a valve timing issue. I realize it sucks having to pull the engine front cover off (pulled more than my fair share off a lot of 4.6/5.4/6.8 engines in my time) to correct this problem, but how much longer do you intend on farting around with it? How many more parts are you going to throw at it? Yes, I get that pulling the valve covers off this engine is going to be a pain (especially the driver side one with that balance shaft) to get to the front cover, but I don't think you have any other options at this point. You do know how to time these engines right? If not, I will gladly walk you through it.

 

I was a chevy guy my whole life and only got into fords the last several years after getting a 4.6 vic interceptor and gained respect for the modular ford motors.... that car is still going strong at over 300k miles. Ive only had to replace the intake ,plugs and coils, and other minor work. since that car ive got another interceptor - a 2010 which ive only had to do maintenance on,and a navigator with the 5.4 that ive only done maintenance on, so I havnt dug real deep into these mod motors.

Im mechanicaly able to do it and willing to.... just want to be sure thats indeed the problem before I dig in. Most of my experiences are on older pushrod/carburated chevy short blocks so this will be a whole new thing for me but sure I could do it being patient and careful.

How hard of a job would you say this would be? Its in a van so probably need to remove radiator etc..... (need to replace radiator anyway)

Is there any way to diagnose it as off timing without tearing into it? Would hate to get into it and find out thats not the problem

 

Well, if this vehicle were on MY doorstep, based on the information provided so far, the first thing I would be doing, would be what's called a "relative compression test" which would be to connect IDS (Ford dealership scan tool) and crank the engine over (with fuel and ignition disabled by the tool). I will bet you the result will be five of the ten cylinders in the "green" zone while the other five will be in the "yellow". For clarity, this would indicate the five in the "green" zone getting good compression while the other five in the "yellow" would be indicated low. At this point is where you would be getting a quote for the labour to remove the engine front cover, along with removal and replacement of all the timing drive components as needed to correct the condition.

In answer to your question regarding radiator removal, yes according to the Ford workshop manual, radiator removal is necessary to gain access to the front cover. As are removal of both valve covers. You will also need to remove the fan clutch and shroud as well. The harder part of the job will be to remove the power steering pump (three 10mm bolts if I recall correctly) since it is bolted to both the engine block and the front cover.

As far as how to time the engine goes, once you have the engine front cover removed, you will manually turn the engine over until you see the crankshaft sprocket timing mark directly at the six o'clock position, while the timing mark on the passenger side camshaft sprocket is at the 11 o'clock position and the driver side camshaft is at the 12 to 1 o'clock position. When installing new chains, you literally fold the chain in half and mark the marks end to end to line them up. There are 61 chain links in each chain according to the workshop manual. If you choose to go in this far, I would be very happy to walk you through it. You time a 4.6, 5.4 or 6.8L the exact same way.

 

Any update to this saga?

 

Ill be testing the cam sensor plug this weekend, if that doesnt help I will be digging in to see if the timming chain has slipped.

Im sure ill have plenty pics and questions lol.

I really appreciate your help!

 

I'm going to move this to the E-series forum. Lots of folks down there have experience with working on these in the van chassis. I don't have anything helpful to add other than good luck!

 

Almost everything has a 'cam/crank' correlation spec built into the program, so when the timing chain and gears wear out the correlation of the two Sensors go out of spec and you get a never ending P0340..............

 

Makes sense... but I had a leaking cowl area that let rain water drizzle on the main harness. It corroded out my voltage regulator, i soldered on a new cam sensor connector to be safe and found the wires oxidized so thought it may be worth a shot.

 

Most people don't think about it, but todays cars and trucks are only good as their wire harnesses..........lol

 

I have to change the brakes and oil in the ol ladys navigator today. After that I plan to start tearing down the 6.8 to access the timing system.
Ive tried researching my fault code and issues to exhaustion and still not sure what the issue is. So many people with same issue never posted back their findings I guess they gave up or never got to the bottom of it.

Before I proceed and spend another couple hundred on chains and guides,gaskets etc....and spend a bunch of time doing this, would you say with a good amount of certainty that my issue is probably timing related?
I know noone can guarantee anything or know for sure without physicaly diagnosing the vehicle but just want to have some confidence im heading down the right path.

I think im going to skip running new wires for the CPS to the PCM.... if I unplug the cam sensor it pings the CEL instantly so it must be getting a reading.

Im ready for this dang van to run right so I can move ahead with the conversion project of making a camper van out of it.

Anyway.....i got the beer cold and ready to tear into it....just looking for confirmation I guess lol

 

M-chan68 is a Ford master tech, and he's told you how he would proceed. I think that's about the best confirmation you're going to get over the internet.

Let us know how it goes.

 

Sorry... I didnt read his sig previously. Thanks and ill be digging in