Ok, so I had a friend run a contribution balance test?(and every other test) from his snap- on scanner on my PSD and it only came up with one code, P0284 Cylinder 8. I dont remember the full phrasing, but it was an injector code. Also, when running the injector buzz-test, the last injector did sound slightly "dull" compared to the others, I'm assuming this one was 8. I might have a bit of a rough idle, cant tell really, I'm not used to working on diesels. I have been chasing a fuel mileage issue, about 12 mpg average, with no towing, leadfoot, large tires, aftermarket parts, or any other conditions to justify poor mileage. So, where do I go from here? Pull the injector? Have it tested? I'm not sure.

 

Sorry for the bump...I was just hoping to get an answer tonight, I was about to buy a bunch of other parts tomorrow, which might empty my budget for fixing this depending on what I need to do. Anyone got an idea? Thanks in advance!

 

P0284 is a common code you will get with the gray CPS that Ford installed as part of the recall. There is a Service Letter from Ford letting techs know that there are "Phantom Codes" including P0284. I have tested this many times on different trucks. They will all get the code and if I throw an OEM black CPS into the truck, the code goes away and the truck idles smoother.

#8 should not buzz any differently than the others. It may be a little different sound due to locations, but should sound close to the same.

 

The soft buzz is a little bit of a concern but without an matching SES light I would be inclined to ignore that code unless you have some symptoms such as shaking while in top gear and accelerating between 45 and 60 mph.

A 20% drop in mileage does point to a bad injector though....
I think that maybe the next thing to do is pull the valve covers and observe the oil discharge from each injector at idle to make sure they all are firing. Another buzz test on a stone cold engine might be a good idea also...

Do you smell any raw diesel fuel in the engine compartment?

 

Ok, so dont worry about the code. The last injector was noticeably different, me and my tech buddy both noticed it immediately, we tested it again and it did the same thing. The test was done on a warm engine, although hes moving in the next few days and another buzz test wont happen. There is no smell of diesel in the engine bay. I have no shaking or any other problem like that. Only other problem I have is what I suspect is a boost leak or clogged ebp valve, I only produce 2 lbs of boost at 65 mph with no load, and peak boost is 15 lbs( it will flash 16 for a split second). So, all I have to do is pull off the drivers side valve cover and observe the engine running? Doesn't sound very difficult. Anything I should know before doing this?

 

What date on driver valve cover say?

Just want make sure it early 98 or 99.

You sound you had boost leak. They are horrible if you deaf and can't find leak. Did it pour black smoke more than it supposed? I mean in Stock tune.

When I had boost leak It would pour black made you think it been tune or air filter clog. Now I only able pour little haze smoke after fix boost leak.

Stock 7.3L on mine is 2000 with 220k I can hit 20 psi no turbo surge after fix Intake spider boots twice.


On that #8 injector Mine did same thing. Ignore that one. Had him do on your 7.3L when it is cold let say warm little before scanner able do test without pop error say Oil temp not meet demand. When I did on 7.3L. Cold it show 3 bad injectors at 110oF on oil temp. At 180oF It show none bad injectors.

 

Do you have an early or late '99 model?
For 99.5-03 models....some engines were shipped with an AE coded injector in the #8 spot instead of the normal AD units. The difference is in the length of the intensifier piston so I would expect both types to sound the same during a buzz test (since all that is actuated is the poppet valve...). The fact that #8 does sound noticeably different is a bit hard to ignore. A rogue code on #8 is quite normal but I think the sound of the buzz should match the other injectors.

Pulling the VC on either side is pretty easy, the gaskets are re-usable but the o-rings in the CCV doghouse on the driver's side like to swell and are almost impossible to re-install. Unless you have a nice assortment of replacement o-rings in your toolbox then I'd recommend that you leave the doghouse on the VC and pull the assembly off together (that way you don't have to mess with the CCV o-rings...). Take a look at the wiring harness under the valve cover and see if it's connected nice and solid and do the 50 cent mod if you haven't done so yet. Don't forget to check the center common terminal to make sure it's not burnt. Also check the connectors on the injector solenoids and make sure they are nice and positive. Then start the engine and watch the oil discharge. If all looks good then button it up and see if it drives any better. With luck, your issue might just be a slightly loose connector.

If you haven't done the 50 cent mod then you might want to check the other side as well. That valve cover is real easy to get off, you don't have to remove the A/C or anything like that. The two lower bolts can be accessed through the wheel well on the 1999/2000 models (not sure about the later years...).

I see about 2 1/2 lbs of boost at 65 mph also. Peak is around 17-18 lbs in stock tune so your numbers aren't too abnormal IMO. Might as well check the up-pipes for exhaust leaks, look for soot residue around the pipes and on the firewall insulation. That insulation should be nice and shiny reflective aluminum, if it's all black then you might have leaking up pipes. My truck has 285k miles and the OEM up-pipes are just now starting to leak, I can see a little line of black soot shooting down one of the up pipes from the collector flange. It's about 2" long and 1/2" wide so I am fixing to replace those gaskets this coming weekend. Should be a miserable job.

 

I need to add this to my sig. Its an E99. Ill check all that stuff out later this afternoon. Thanks!

 

I have a 01 f350 it has a rough idle. Also upon accelerating the RPMs go up and down at random times. The cylinder contribution test shows code p0284. Should I replace the number 8 injector.

 

The cylinder 8 contribution fault is as common as dirt - on perfectly good number 8 injectors. The original black CPSs from the factory weren't as likely to do this - but all the subsequent CPSs pop this and the #3 cylinder code. More tests are needed to verify an actual problem, but air in fuel is a common cause of loping. Search "Hutch mod".

The jumpy tach makes me want to say the CPS is in question. A new OEM CPS from Riffraff Diesel and about 10 minutes time is an easy, inexpensive, and safe thing to try for a next step. If this has no measurable effect, put the used one in the glove box and keep it as a spare - we all carry one.

 

You might be right about the CPS unit. Mine was putting out the code for the cylinder 3 also until I put fuel injector cleaner in the tank. Right now it puts out a cylinder 8. I'll try that thanks for the help.

 

I just put a new fuel filter in the 7.3 today and it ran better. So I think it's the injector.what do you guy's think?

 

I have all those symptoms with the shaking at acceleration 40-60 and rough idle as well as the code about #8 cylinder. Is it a bad injector?