I have a 2002 7.3 and ran codes on it yesterday. It did a test called the rotational vel - I have no idea what it measures, but it gave me results:

#1 = 2.4
#5 = .6
#8 = 3.3

Can anyone tell me what this means?

We are having issues with this motor and are trying to figure out what is going on. The stealership charged me $150 and basically screwed me and was not helpful in the least! Then called me a liar!

Anyway - would love to find out what this is.

Thanks!

 

Cylinder rotation velocity is the percent of rpm drop when the cylinder fires at idle. %0 is ideal, when I check mine 7 out of 8 cylinders are >%1. My #8 cylinder is 2.5-3.5 percent, and is making a slight miss.

 

as far as I know it measures the rotational velocity of each cylinder as it fires. I believe a higher number is bad. so from your numbers I think 1 and 8 are weak cylinders.

here is some info. check this link in the contribution test section toward the end of the section it talks about rotational velocity
http://www.itpdiesel.com/store.php?diags=1

 

So - if 1 & 8 are weak - could that be anything? Injectors/harness, etc.? or does it mean the motor is junk?

Am thinking of pulling it apart and doing a compression check then having the injectors all gone through.

We are just learning about the diesels and really appreciate the help guys!

 

[QUOTE=tjbeggs]

here is some info. check this link in the contribution test section toward the end of the section it talks about rotational velocity
http://www.itpdiesel.com/store.php?diags=1[/QUOTE]

Thanks for pointing me here - this helps a lot! Also explains some of the acronyms that we didn't know!

 

the best thing to do is to post what problems you are having and let us help you out! there are a ton of great minds around here than can point you in the right direction

The weakness could be just about anything at this point. could be injector, fuel, compression, or it could be normal and there is another issue.

One thing I am thinking of right now is on the superduty 7.3 don't the fuel lines feed one end of the head and each ehad is fed from different ends. I think the drivers side is feed from the rear and the passenger side from the front. And I think if I remember the cylinder numbering that would put 1 and 8 at the end of the fuel supply chain. Somebody correct me if my assumptions are wrong but maybe you have a fuel supply issue.

 

2002 7.3l Excursion with 70,000 miles on it. When pulling a 27' enclosed sled trailer, the truck just doesn't have much power - it struggles to do 50 up a hill. No chip in it - dealer says it has had one before. BAD fuel mileage (under 10)

We had an independent shop do a cylinder balance test and it came up with cylinder 1 not contributing. So we call Ford to see about remaining warranty - they say the truck is still under warranty according to them until September. So we figure we'll take it to them to get it done under warranty.

The Ford dealer did a cylinder balance test and came up with 1 & 8 not contributing, so he did a crankcase pressure test and says it shows 4.5" instead of the 2" which is spec. We asked if this would all be under warranty, because he wants another $600 to do a compression test. He says since there is a K&N-type filter on it, and he can tell at one time it was chipped, he " just wasn't sure" but would be happy to do the compression test to find out what is going on. <of course he will - then it won't be warranteed and we'll be stuck with the bill>. Someone had suggested the EBP valve, so we asked them to look at that (which he did not do).

We got the tools to do a compression test from a friend who owns a shop and were getting ready to pull it apart and run the compression test and discovered that the EBPV was not hooked up at all! So before we did compression or any of that, we spent the time (excruciatingly long) to get that hooked back up and just took it for a test drive. Runs better! Here's the scenarios:

Day 1 - hooked up the scan tool, ran the cylinder contribution tests 4 times - nothing coded. Passed buzz test. However, we would only get about 7 lb of boost pulling a hill. PRetty guttless.

Day 2 - after re-attaching the EBPV, did cylinder contribution test 4 times - twice coded cylinder 1, twice coded nothing. Today though - were getting 16-18 lb boost and ran much better pulling the hill.

Did clear codes in between each test and made sure we were warmed up and stopped when did the tests. You can almost hear a miss in it.

Lastnight scanned again, coded cylinder 1. Rotation vel showed #1 = 2.4, #5 = .6, #8 = 2.4

With it coding off and on, not sure where to go from here.

Questions are:

1. Would the EBPV closed have caused excessive backpressure into the crankcase to cause the reading the dealer got?
2. Harness under valve covers?
3. Do the compression test?
4. Replace injectors or have them gone through and larger nozzels put on?

Sorry so long - but it's been a long road!

We are new to this diesel thing, so we appreciate the help!

 

Answers

1. yes EBPV closed could cause excessive CC pressure but if it were all the way closed you would have a hard time getting 30mph empty
2. Unlikely its a UVC harness as it passed the buzz test
3. With a K+N filter a compression test would be a good start. They are bad news on Diesels.
4. With 70k on the clock the injector should be good unless they had bad fuel run though them. That would be my last step in the process

From the sounds of it you had a good gain in hooking the EBPV up. Was the rod on the bottom side unhooked or was the electrical connector just unhooked? Does the impeller of the turbo look sand blasted at all or is the edges or corner rounded off? they should be straight and sharp. If they look damaged that filter has allowed too much dirt through.

 

Thanks Tim for all your insight - that helps a lot -

1. yes EBPV closed could cause excessive CC pressure but if it were all the way closed you would have a hard time getting 30mph empty We did have a tough time getting it to go when we first started it - it would barely do 30 mph for quite awhile. Ford dealer told us there is no way the EBP could have anything to do with the CC pressure! Also argued with me that the EBP was the issue with barely being able to move the rig!
2. Unlikely its a UVC harness as it passed the buzz test
3. With a K+N filter a compression test would be a good start. They are bad news on Diesels. Not a K&N, but that type of filter. There is no dirt in the tube going to the filter and no visible issues - but if they are bad news, maybe we need change that out - do you have a recommendation for a filter or just go stock? We are for sure going to do the compression test as we want to know that the motor is okay before we put some $$ into.
4. With 70k on the clock the injector should be good unless they had bad fuel run though them. That would be my last step in the process Okay - maybe we'll tear it apart and just do the compression test first. Then if that turns out okay - look at injectors, etc.

From the sounds of it you had a good gain in hooking the EBPV up. Was the rod on the bottom side unhooked or was the electrical connector just unhooked? The rod on the bottom was unhooked.
Does the impeller of the turbo look sand blasted at all or is the edges or corner rounded off? Impeller looks good - nice and straight and sharp. they should be straight and sharp. If they look damaged that filter has allowed too much dirt through.

What about this Roational vel test that we did lastnight - it showed #1 = 2.4, #5 = .6, #8 = 2.4 does that tell us there are issues with 1, 5, & 8? All the others came up 0%.

The other problem is we don't have any idea what this thing had before we bought it - whether it was chipped, etc. So no idea how hard those 70,000 miles were.

Thanks again-

 

there are a few oil type filters that are designed for diesel that from what I hear do good. if your turbo doesn't look sand blasted and the tubing is clean either dirt isn't a problems or the turbo impeller has been replaced recently. The best thing to do is to buy a 6637 air filter from napa and do what is called the Kwik filter. Search that kwik filter and you will find all the info you need. or you can check out the pics link in my signature and see a version of that setup (same filter, different tubing) that I use on my truck. though my truck is older it all works the same.

go ahead and check the compression and go from there I would say. also run the Rotational vel test again just see what happens. try it with the engine cold (after 3 minutes of running or so then after its fully up to temp.

 

0 is ideally what you want. Ignore 5 its not enuff to worry about. the 2.4 is not enuff to set a contribution code, but if you can read live rotational velocities if you bump the throttle I would expect those to increase above 3% when returning to idle. 3 things can effect contribution - fuel delivery (injectors), compression (rings, vlaves, ect), and timing.

With an 02 you should have the LL injector in #8 but 1 and 8 still have to deal with the dead end fuel rails and air in the fuel can cause problems when the injectors compress the fuel for injection as well as damaging the injectors themselves. I agree with TJ since you have the equipment go ahead and do the comp test to rule that out but before tearing into the injectors take a look at the intank mods to deal with air in the fuel.

 

I agree. Since this is an unknown engine I would do the compression test before I went any further. No sense in that if a slug is down. A bit of good news is that the valve cover gaskets are reusable unless they've been abused.

While you have the VCs off, I recommend checking the UVC wiring isde there and torque checking the valvetrain just to be sure. See this post for more info on that.

Wiring:https://www.ford-trucks.com/forums/2...or-wiring.html

Rockers:https://www.ford-trucks.com/forums/5...dastals-2.html

Both of those courtesy of our former SuperModerator Kwikkordead.

 

GREAT information guys - thanks! Gonna do the compression test and see what we got.

 

What I've read about the Ford spec for the crankcase pressure test is that the CCV is sealed off and the engine is run at WOT for 30 seconds with a special oil cap installed which has a small vent in it to allow blow by to pressurize the crankcase, and the resulting crankcase pressure to bleed of at a calibrated rate. When done in this manner, the Ford spec for a good engine is a maximum crankcase pressure of less than 4.0", not the 2" number you were given?

This is not correct. I have a crankcase pressure gauge installed on my truck, and if I apply my exhaust brake at idle it increases crankcase pressure by about 0.3" H2O, and this is with a CCV mod that is venting the crankcase to the atmosphere. If the dealer ran the crankcase pressure test as I've seen it described with the CCV sealed off, a closed EBP valve will have a more dramatic effect for increasing crankcase pressure.

 

Wow - thanks for that information - that is the kind of stuff I need because I am gathering information to take to the manager of our local Ford dealer to attempt to get my $150 back. They jacked me around on several issues that are bull and, of course, they will never admit it. So I am putting together printouts and copies of things that prove the tech wrong.

They screwed me on it and I didn't even enjoy myself!

We are doing our compression test today, so should know a little more later. Hope it's good news.

T