Where's the power in my V10... Am I missing something?
#16
02-21-2018, 09:21 AM
Possibly a partially plugged fuel filter or catalytic converter? Double check that a caliper piston isn’t sticking.
Other than that a 3.73 equipped V-10 X even with 285 tires should be able to hold speed up a grade. And yes the V-10 loves to rev. Mine routinely sees 4K rpm going up the big mountains towing my 9200lb trailer.
Other than that a 3.73 equipped V-10 X even with 285 tires should be able to hold speed up a grade. And yes the V-10 loves to rev. Mine routinely sees 4K rpm going up the big mountains towing my 9200lb trailer.
What happens to the cat is that the 02 sensors go bad, dump raw fuel into the cats, creates extra heat in the cat, which melts the honeycomb, cat now blocked. Engine runs poorly.
Remember the old potato up the exhaust trick? Same thing
#17
02-21-2018, 10:04 AM
I've owned my 2000 6.8L since July, so still fairly new to this beast too. I was "underwhelmed" by the big V10 until I did some reading. Being a very low mileage unit (75k), the internals should have been in pretty good condition and not worn out yet. I've had no issues with blown plugs or missing yet, so I can rule out any of those problems. However, mine is riding on 35in tires and has the 3.73 gearing, so I'm not going to be winning any towing or efficiency contests. The 5Star tuner helped the shift points noticeably, but did little to add HP to my butt-o-meter. I hope to pick up some extra pulling power when I take the lift and big tires off this thing. Eventually, I'll also have better towing gears installed. My trailers don't weigh that much, but I do notice them when towing up a decent grade. Also, I'm in Montana and live at about 6000ft, so my elevation plays into what power is available.
I say all of this because I don't want you to feel like you are necessarily alone. I can't speak to the shaking sensation that you're experiencing, but as to the overall power, I haven't been super impressed. My dad's 99 F250 has the 5.4L, 4.30 gears, and rides on stock sized tires. That thing will get up and move compared to the Excursion. I have a sneaky suspicion the tires and gearing are really playing into this.
I say all of this because I don't want you to feel like you are necessarily alone. I can't speak to the shaking sensation that you're experiencing, but as to the overall power, I haven't been super impressed. My dad's 99 F250 has the 5.4L, 4.30 gears, and rides on stock sized tires. That thing will get up and move compared to the Excursion. I have a sneaky suspicion the tires and gearing are really playing into this.
#18
02-21-2018, 01:31 PM
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Thanks for the good info. I'll do O2 sensors, fuel filter and get a spare COP and start rotating it around and see if that helps with the vibration. I was assuming that if there is a misfire or a bad COP I would be getting a code. Is this not the case?
I have a fuel pressure gauge. Might as well throw that on and see what I'm getting after I replace fuel filter. What kind of reading should I expect?
Regarding the catalytic converter, how do I know if it's clogged other than visible exhaust. I see exhaust coming out on cold mornings when I start it but that's not much of a gauge. I live in an emissions county here in the front range of CO and it passed emissions test in January.
I have a fuel pressure gauge. Might as well throw that on and see what I'm getting after I replace fuel filter. What kind of reading should I expect?
Regarding the catalytic converter, how do I know if it's clogged other than visible exhaust. I see exhaust coming out on cold mornings when I start it but that's not much of a gauge. I live in an emissions county here in the front range of CO and it passed emissions test in January.
#19
02-21-2018, 01:39 PM
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He didn't happen to mention that he was also getting 18 MPG while doing the Ike Gauntlet did he? 
Between that looong steep grade and the high elevation (which robs NA engine power) I seriously doubt that claim as being totally accurate. Of course, there is no mention of what this 30' trailer weight was either, but I would think the claim may be a bit "optimistic". I've never towed that far West, but from my understanding, that grade is a well known test for towing abilities. And I'm pretty sure if his story is accurate that he isn't running the same tire size and gear ratio as you are, deeper gears make these V-10s completely different animals. And 4K in a mod motor is not "screaming", it's designed to rev up there where the best power lives, different flavor from the PSD for sure.
What kind of shape is that K&N filter in? They need proper cleaning care and oiling to be as efficient as they can, which in my opinion isn't as efficient as a street driven air filter should be. K&Ns are fine for track cars, but I wouldn't run one on the street, they pass too many particles in my opinion. If oiled too heavily the K&N can foul the MAF sensor and cause some performance issues, a good MAF cleaning is quick and easy. Is the "Cold Air Intake" properly installed with no air leaks and is it drawing hot under hood air vs the stock air box's cold air? Hot intake air is better for efficiency but bad for power output.
Go over everything under the hood again to check for any possible vacuum leaks.
In my experience the custom tunes really don't make a very big improvement in engine output BUT, they DO make some very nice improvements in the trans shift strategy which makes the seat of the pants feel much better. The application of the available power is handles better with the better shift points and pressures. This is more evident with higher loads on the drivetrain, like heavy towing where there are pretty significant gains.
That shaking sure does sound like a miss to me, and a miss (maybe a part time one) would explain the power being down a good bit too. Maybe pick up a new Denso COP and start trying it on different cylinders to see if the shaking goes away. And new O2 sensors (2 for most rigs, 3 for Cali spec) are pretty cheap and easy to do.
Between that looong steep grade and the high elevation (which robs NA engine power) I seriously doubt that claim as being totally accurate. Of course, there is no mention of what this 30' trailer weight was either, but I would think the claim may be a bit "optimistic". I've never towed that far West, but from my understanding, that grade is a well known test for towing abilities. And I'm pretty sure if his story is accurate that he isn't running the same tire size and gear ratio as you are, deeper gears make these V-10s completely different animals. And 4K in a mod motor is not "screaming", it's designed to rev up there where the best power lives, different flavor from the PSD for sure.What kind of shape is that K&N filter in? They need proper cleaning care and oiling to be as efficient as they can, which in my opinion isn't as efficient as a street driven air filter should be. K&Ns are fine for track cars, but I wouldn't run one on the street, they pass too many particles in my opinion. If oiled too heavily the K&N can foul the MAF sensor and cause some performance issues, a good MAF cleaning is quick and easy. Is the "Cold Air Intake" properly installed with no air leaks and is it drawing hot under hood air vs the stock air box's cold air? Hot intake air is better for efficiency but bad for power output.
Go over everything under the hood again to check for any possible vacuum leaks.
In my experience the custom tunes really don't make a very big improvement in engine output BUT, they DO make some very nice improvements in the trans shift strategy which makes the seat of the pants feel much better. The application of the available power is handles better with the better shift points and pressures. This is more evident with higher loads on the drivetrain, like heavy towing where there are pretty significant gains.
That shaking sure does sound like a miss to me, and a miss (maybe a part time one) would explain the power being down a good bit too. Maybe pick up a new Denso COP and start trying it on different cylinders to see if the shaking goes away. And new O2 sensors (2 for most rigs, 3 for Cali spec) are pretty cheap and easy to do.
I think the revving is something I'll have to get used to.
I'm also not a fan of the K&N filters, I removed the one on my diesel truck as soon as I bought it. I've heard nightmare stories about letting grit into the turbo on those trucks. This truck came with a spare so that one can be cleaned, dried and oiled while one is in the truck so I have serviced it. Maybe I'll just replace it with a nice big dry filter.
#20
02-21-2018, 01:53 PM
I've owned my 2000 6.8L since July, so still fairly new to this beast too. I was "underwhelmed" by the big V10 until I did some reading. Being a very low mileage unit (75k), the internals should have been in pretty good condition and not worn out yet. I've had no issues with blown plugs or missing yet, so I can rule out any of those problems. However, mine is riding on 35in tires and has the 3.73 gearing, so I'm not going to be winning any towing or efficiency contests. The 5Star tuner helped the shift points noticeably, but did little to add HP to my butt-o-meter. I hope to pick up some extra pulling power when I take the lift and big tires off this thing. Eventually, I'll also have better towing gears installed. My trailers don't weigh that much, but I do notice them when towing up a decent grade. Also, I'm in Montana and live at about 6000ft, so my elevation plays into what power is available.
I say all of this because I don't want you to feel like you are necessarily alone. I can't speak to the shaking sensation that you're experiencing, but as to the overall power, I haven't been super impressed. My dad's 99 F250 has the 5.4L, 4.30 gears, and rides on stock sized tires. That thing will get up and move compared to the Excursion. I have a sneaky suspicion the tires and gearing are really playing into this.
I say all of this because I don't want you to feel like you are necessarily alone. I can't speak to the shaking sensation that you're experiencing, but as to the overall power, I haven't been super impressed. My dad's 99 F250 has the 5.4L, 4.30 gears, and rides on stock sized tires. That thing will get up and move compared to the Excursion. I have a sneaky suspicion the tires and gearing are really playing into this.
Having gone from 32" tires and 3.73s to the same tires (for a while anyway) and 4.88s and feeling what a huge improvement the gears made I can't imagine how much of a dog it must be with 35" and those 3.73s! When you drop it and go back to shorter tires and more gear it will be like a completely different truck!
#21
02-21-2018, 02:17 PM
Not always, the miss has to register enough misses to finally set a code, if its intermitted you might not be hitting that threshold.
Regarding the catalytic converter, how do I know if it's clogged other than visible exhaust. I see exhaust coming out on cold mornings when I start it but that's not much of a gauge. I live in an emissions county here in the front range of CO and it passed emissions test in January.
for a quick check you could just take one of the O2 sensors out and go for a test drive and run it where and how it currently is acting up. If the extra open port resolves the issue then I would assume the cat is clogged. It will be loud and smelly so keep the test drive as short as needed.
Yep, any radical change in how a motor behaves will require some time to adjust to it, my old sportbike liked to shift at 11,000 RPMs, that was fun but things happen quickly at those revs!
I'm also not a fan of the K&N filters, I removed the one on my diesel truck as soon as I bought it. I've heard nightmare stories about letting grit into the turbo on those trucks. This truck came with a spare so that one can be cleaned, dried and oiled while one is in the truck so I have serviced it. Maybe I'll just replace it with a nice big dry filter.
I've used K&N filters and others like them on various race cars, where their freer flowing design holds some benefit and the engines see much shorter service lives than a street driven car/truck. For a street car/truck I trust a good paper filter to protect the engine for the long life and miles it was designed for.
#22
02-21-2018, 02:32 PM
Something definitely seems wrong. A V10 with 3.73s (not towing) should be able to hold overdrive and speed on mild highway grades. It should be very rare if it can't hold overdrive at 70, due to a large hill. The 285s will definitely hurt performance overall, but it shouldn't be that significant. Yes, the Tritons love to rev, but it shouldn't NEED to that much without a load.
To confirm, it ran relatively ok when you first bought it, correct?
Personally I'd start with the COPs, and with that mileage, I'd consider just replacing all of them. With such a significant performance issue, I would be surprised if just one was bad. I'm wondering, did you check the coil's springs when you put them on? I wonder if some aren't making a good contact.
With the truck in park in your driveway, will it rev up to 1500/2000 or so RPM and hold it without the truck shaking? Curious if the vibrating is still there with no load or the trans moving.
To confirm, it ran relatively ok when you first bought it, correct?
Personally I'd start with the COPs, and with that mileage, I'd consider just replacing all of them. With such a significant performance issue, I would be surprised if just one was bad. I'm wondering, did you check the coil's springs when you put them on? I wonder if some aren't making a good contact.
With the truck in park in your driveway, will it rev up to 1500/2000 or so RPM and hold it without the truck shaking? Curious if the vibrating is still there with no load or the trans moving.
#23
02-21-2018, 02:40 PM
The part that stuck out to me in the first post was you mentioning it "screaming at 4,500 rpm" This engine is designed to do just that. I have no issue holding 65-70 towing my travel trailer up the largest grades here in AK. I floor it and let the truck do the work, most of the time that is in second gear at 4500+ RPM thanks to my 3.73 gears.
Don't fear the revs!
Don't fear the revs!
#25
02-21-2018, 05:29 PM
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Something definitely seems wrong. A V10 with 3.73s (not towing) should be able to hold overdrive and speed on mild highway grades. It should be very rare if it can't hold overdrive at 70, due to a large hill. The 285s will definitely hurt performance overall, but it shouldn't be that significant. Yes, the Tritons love to rev, but it shouldn't NEED to that much without a load.
To confirm, it ran relatively ok when you first bought it, correct?
Personally I'd start with the COPs, and with that mileage, I'd consider just replacing all of them. With such a significant performance issue, I would be surprised if just one was bad. I'm wondering, did you check the coil's springs when you put them on? I wonder if some aren't making a good contact.
With the truck in park in your driveway, will it rev up to 1500/2000 or so RPM and hold it without the truck shaking? Curious if the vibrating is still there with no load or the trans moving.
To confirm, it ran relatively ok when you first bought it, correct?
Personally I'd start with the COPs, and with that mileage, I'd consider just replacing all of them. With such a significant performance issue, I would be surprised if just one was bad. I'm wondering, did you check the coil's springs when you put them on? I wonder if some aren't making a good contact.
With the truck in park in your driveway, will it rev up to 1500/2000 or so RPM and hold it without the truck shaking? Curious if the vibrating is still there with no load or the trans moving.
It ran OK when I got it, it was smooth at all rpm's but lacking power. All the springs were replaced with the boots when I did the spark plug job. I should have mentioned that in the first post. The vibe started after I did the spark plugs and exhaust work. (all done at once, I had it taken apart in the shop for several days) I was attributing the vibe to the new Y pipe, thinking that maybe the restriction in the factory pipes where the T is was to provide more back pressure and prevent the thumping that I'm getting? Anyone else installed that SPD y pipe and had similar experience? Hopefully it is something silly like a spring not seated on a spark plug or a wire connector not all the way engaged. I'll check all those and report back.
I thought I'd start with 2 new COP's and rotate them through and see what happens. I feel like they are something I should have a spare or two of in my tool bag that lives in the back of the car.
#26
02-21-2018, 08:20 PM
Fleet Mechanic
... I was attributing the vibe to the new Y pipe, thinking that maybe the restriction in the factory pipes where the T is was to provide more back pressure and prevent the thumping that I'm getting? Anyone else installed that SPD y pipe and had similar experience? ...
Can't tell if high speed load conditions are better and the MPG is no different.
Our Exped a few years ago started having trouble pulling a steep grade near our house.
The lack of power kept getting worse and it was a clogged cat.
It would rev fine unloaded and would accelerate fine up to 65 MPH as long as it was done slowly.
I would check for misfires under load with Forscan and an OBDII bluetooth adapter.
I've seen new testers are available ($30 - ebay) that measure exhaust back pressure with a gauge temporarily installed in an O2 port.
#27
02-21-2018, 09:09 PM
Laughing Gas
Cleaning the MAF sensor makes a noticeable change in how our EX runs. I agree with the clogged Cat idea. Definitely change the O2 sensors. I like NTK. I have never bought a BWD product that worked correctly, but oddly I have great results with Standard Motor Products parts (they make BWD). I think your rough running is a COP problem now that they've been removed and replaced.
Something is definitely wrong with your EX. Our 6.8 is awesome. I'm sure with these guys help, you'll figure out the problem. When you get your EX running well, buy a set of Banks headers. They make enough difference to feel it. Good luck.
Something is definitely wrong with your EX. Our 6.8 is awesome. I'm sure with these guys help, you'll figure out the problem. When you get your EX running well, buy a set of Banks headers. They make enough difference to feel it. Good luck.
#28
02-22-2018, 09:08 AM
If you have the 5Star tuner, it has a code reader built into it and can clear codes when needed. As for the K&N, mine had one when I bought it and it got tossed immediately in favor of a WIX paper filter. I had one of those on a 68 Mustang with built 289. The foam literally disintegrated every time the throttle was mashed. I could see it flaking off right in front of my eyes. For the money they charge for those things, they sure are junk. That was 25yrs ago, maybe their quality is better by now.....but I don't trust them.
#29
02-22-2018, 12:25 PM
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After installing the SPD y-pipe on Excur it smoothed out idle a bit and at low speeds it feels like it has more pull - no thumping.
Can't tell if high speed load conditions are better and the MPG is no different.
Our Exped a few years ago started having trouble pulling a steep grade near our house.
The lack of power kept getting worse and it was a clogged cat.
It would rev fine unloaded and would accelerate fine up to 65 MPH as long as it was done slowly.
I would check for misfires under load with Forscan and an OBDII bluetooth adapter.
I've seen new testers are available ($30 - ebay) that measure exhaust back pressure with a gauge temporarily installed in an O2 port.
Can't tell if high speed load conditions are better and the MPG is no different.
Our Exped a few years ago started having trouble pulling a steep grade near our house.
The lack of power kept getting worse and it was a clogged cat.
It would rev fine unloaded and would accelerate fine up to 65 MPH as long as it was done slowly.
I would check for misfires under load with Forscan and an OBDII bluetooth adapter.
I've seen new testers are available ($30 - ebay) that measure exhaust back pressure with a gauge temporarily installed in an O2 port.
#30
02-22-2018, 01:56 PM
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for a quick check you could just take one of the O2 sensors out and go for a test drive and run it where and how it currently is acting up. If the extra open port resolves the issue then I would assume the cat is clogged. It will be loud and smelly so keep the test drive as short as needed.
I just ordered new O2 sensors, 2 coil packs and a fuel filter. All motorcraft items. today I'm going to remove all COP's one at a time and re install and reconnect wire to make sure it's not just a bad connection or spring not seated correctly somewhere.