Top speed 55mph normal for 6.9?

[Tony Stottler]

55 mph top speed on level asphalt with pedal to the metal normal with 6.9? Any way to decrease loss of speed on hill climbs?

 

[Farmer Rock]

The best way to keep up speed going uphill is to downshift.
Being that you have a 6.9 box van, I would assume you have 4.10 gears and a c6 tranny, and that you were driving empty. You should still be able to do 70 mph redline. 55 is really slow, and points to something being out of order. How many miles are on the van?



Rock

 

[Fredrickson]

Was it owned by uhaul or some commercial company before you got it?
Does it have a governor in it?

(Do you grip the steering wheel, and lean forward when it starts to slow down going up a hill? That's what I do.. )

 

[franklin2]

Do you have a tach? If you are running around 3500 rpm. yes you are hitting the governor and are not going to go any faster.

 

[Farmer Rock]

Was it owned by uhaul or some commercial company before you got it?
Does it have a governor in it?

(Do you grip the steering wheel, and lean forward when it starts to slow down going up a hill? That's what I do.. )

That is very true, it could be governed not to go faster than 55mph since it was most likely a fleet vehicle or possibly a rental vehicle.



Rock

 

[Tony Stottler]

The odometer reads 42,000 and some change. My instrument panel lens that covers the instruments on my dash is Crystal clear clean the dash has no where damage to it at all the seats were reupholstered so their brand new unrelated though. Everything that I consider when thinking about age points toward it being original 42,000 MI including two owners. This is a question I had that I haven't yet posted on the mileage. How do you tell if the odometer has rolled over once or twice on an 87 Ford E350?

 

[Tony Stottler]

I'll look up the VIN report that I looked at before buying it. To look into whether it rolled over or not.

 

[Farmer Rock]

If the miles are not exempt on the title, it would be easiest to look at that and see how many miles were on it when it was last transferred over.



Rock

 

[Fredrickson]

Carfax or AutoCheck might tell you some additional details..

 

[chris142]

M;ne will do 65 in 3 rd gear. Something is wrong with yours

 

[IDIBRONCO]

Being that you have a 6.9 box van, I would assume you have 4.10 gears and a c6 tranny, and that you were driving empty. You should still be able to do 70 mph redline. 55 is really slow, and points to something being out of order.

Maybe. Like was suggested, it may have been governed. It also doesn't take into account the built in slip in the C6 transmission or the additional wind drag from the box on the back. If it happens to be a dually and has 215/85R16 tires on it as well, that may also be adding to the slow factor. It's possible that 55 is all that you can get out of it in it's current set up. Of course there's also the possibility that the speedometer is reading slow and you're really doing 65 when the speedometer reads 55.

 

[Cubey]

Put a free GPS speedometer app on your phone to confirm your speedometer is right.

Could be a stretched throttle cable.

Did you have a head wind? That can slow an NA IDI a lot.

Check your tire pressure. Do yourself a favor and get one of these for your tires. It clamps right on the battery and has a LONG hose for reaching the rears. It fills dually tires with a heavy load on them pretty well. Do make sure the little cylinder heads are tight though. A couple bolts were a bit loose on mine (allen head bolts)
https://www.amazon.com/Slime-40026-Heavy-Direct-Inflator/dp/B005Z8HAUK

 

[Tony Stottler]

Update: hey everybody boy what a woozy of a question that oil filler spot was huh¿ Sorry about my ignorance on that one I'm a noob greenhorn to diesel. And mechanic as well. First vehicle I will have fixed the engine on myself at 40 years old and never on a diesel is kind of tough actually. But I think I got a handle on it now after a couple months. lmao.

 

[Tony Stottler]

Newest malfunction with this here Marathon is a cracked nut on the supply line that tightens down onto the top of the injector. It was running after the injectors got put in all right it's still not going over 55 so I posted that one article about 55 miles an hour thing and I discovered with help from a local injection mechanic that the throttle lever was not getting full throw due to the spring on the aftermarket throttle cable that I just put in being too long. With zip ties behind the pedal at steering column to get enough out of the pedal to give it enough full throw at the injection pump I had to remove a ring of spring.

 

[Tony Stottler]

So it's a little safe to presume that I think I'm going to get better acceleration and top speed with a full throw on the accelerator lever at the injection I just started replacing the fuel return system because I just had enough money to buy it when I cracked a nut into four that is on top of the injector it literally has like four cracks on opposite sides from tightening it down because it was leaking oh I take the that was after I replaced the o-ring that was under it that was bad. Now I'm waiting until Monday to get a word with the local injection specialists that I have had advice from here in Portland Oregon. On the availability of the part he said I could get which is the number five supply line to the injector. All these everyday parts suppliers are absolutely clueless with nothing showing up on their computers. What a day I think I'm going to go inside and kick the boots off and have a bite to eat maybe take a nap.