I own a big truck diesel shop but on occassion we get the farmer with his truck no one can figure out. This is what we have;

1999 Ford F 350 7.3, 2 wheel drive manual with A/C. Initially when thetruck came in the right bank was dead. All cylinders (right bank) failed cyl contribution tests including 4 & 8. The only codes were an exhaust back pressure code and high side open right bank. All wiring ohmed from PCM to IDM to valve cover gasket. Found an open circuit in the valve cover gasket. Installed new gasket, high side open gone. Removed exhaust at turbo and ran truck, waste gate is open and passes pin point tests for adjustments. Installed new CPS sensor, performed fuel pressure tests at the heads (65 PSI), checked oil pressure on the high side checks OK. All PCM specs for IPR etc are within spec. Compression check 400 PSI all cylinders. Removed injectors, found a few bad seals and installed new o-rings. Fired truck, cyl contribution tests shows 1,3,5,&4 failed.

We put a test PCM and IDM in the truck with no change.

Question #1 could the PCM be defueling the right bank only because of the high EPC %?

We know the injectors are firing (raw fuel out of the turbo), but it almost acts like they are firing out of time.

Question #2 Has any one evr had this happen, one bank, no codes, and scratch their heads so long their bald?????????

Any help would be appreciated....I'm sure I have left somethings out.

 

I sure sounds like wiring or clips to me. When you had the covers off, did you make sure the connectors were seated and tight? They have a rep of coming loose pretty easily, and intermittently. There is a mod to hold those clips in. It's called the "50 cent mod" because you grind two quarters down a bit, and slip them in the clips so when the covers are on the connectors can't come loose.

 

Welcome to FTE. If you're willing to put up with a bunch of questions, we'll see if we can't help you get this figured out.

Are you saying cylinders 1, 3, 5, & 7 are dead, and 4 & 8 failed the contribution test, or did you get the right bank kind of working and it fails the contribution test too?

Where did you get the CPS? Some of the aftermarket ones have been known to cause problems, the "new & improved" one from Ford has been known to cause contribution faults on 3 & 8.

No. The injectors are either on or off as far as being controlled through the IDM. The IDM can shut down an entire bank due to shorted wires like you found, or even a bad injector soleniod.

How many miles are on the injectors? Were rebuilt ones recently installed? Was there anyone else who might have tried to fix this before you got a hold of it that may have done something?

Is the bank still dead, or just running bad? I'm surprised you're not at least getting a P1316 code. (Just to rule out the obvious, but no codes also means no check engine light, right?)

Can you give us the perdel% for each cylinder? Have you tried ohming the wiring from the valve cover gasket to check the injectors? Possibly ohmed the wires from the valve cover connector back to the 42 pin connector , then on to the IDM?

If the truck is running poorly with no codes or CEL, from your description it sounds like someone just dropped in a set of reman injectors that were not rebuilt properly. That or this truck has been sitting for a very long time and a combination of bad fuel and stuck poppets has caused a problem.

Can you buzz test the injectors to see if any of them sound weak or different? Any difference in sound between cold and warm on the injector buzz? Of course with our HEUI system, did you verify clean, full oil of the proper type was in the motor?

 

400psi on that 99 engine? Wow. None of mine made that and it's a 02. Sorry, nothing to add to what has been said so far.

 

Subscribing here too.
Chris really has all the bases covered.

 

I read right past that one, Mike. Wow!!

 

OK, let me try and answer these questions,

This truck has 200,000 miles, no known work on the unit in sometime. Driver uses this to haul cattle, said he was in Iowa when the engine started acting up, drove it at least 250 miles back to our shop.

Here's a few other things I forgot to mention, injectors pass the buzz test both warm and cold. No IDM codes were found, no check engine light etc...

Here's anoter theory, could the injectors be overfueling? Before removing injectors we removed all plugs (oil/fuel) and vacuumed the cylinders before installation. Once we installed we cranked the engine for sometie to prime the injectors. Once my tech tried to crank again and it hydro locked number 1. We remoed the injector and sucked out a lot of fuel again.

Could the temp sending unit be opening the right bank as if it was cold?

The perdels are showing 0, theres also an EPV and electronic pressure control reading 0. I checked ALL DATA for parameters and couldn't find anyting on either of these.

 

hhmmm... Could it just be tired injectors??? Chris has quite a few more miles on his stock sticks, but they have had fuel with lubricity additives running through them all that time. I've heard of multiple injectors going before 200k, so it's not unheard of.

 

Right bank exhaust manifold is cold (84) whiel the truck is running, left bank is running normal temp. Thats why I was wondering about the over fueling theory, it's pumping a good amount of raw fuel through the turbo so we know its getting fuel and the injectors (at least some) are firing.

 

You've got a stuck open stick if it's pumping raw fuel out of the turbo, IMHO.

A whole bank down usually is wiring, however. Sounds like multiple things happening here.

 

We thought that 400 PSI was high ourselves, Fords matrix stops at 300 PSI for 99 and cylinder pressure is based more from a 25% decrease from others or an overall average.

 

The truck was brought to you with one dead bank, and it hauled a cattle trailer 250 miles in this condition? If the truck is mistreated this bad, then I'm guessing the injectors have been failing for some time and there is finally enough bad ones to cause some serious issues. Worn injector internals can cause an overfuel situation.

I am puzzled by some of your readings. What are you using to scan the truck? I don't understand how you can have perdels that read 0, but have 6 injectors pop codes on the CCT. On the buzz test, did you listen for issues, or just watch for codes?

I'm also interested to hear what your ICP (oil pressure readings) in each head were. What is the ICP and IPR reading at idle? How high does the IPR % go while cranking before it starts?

For future reference on the 7.3 (or any HEUI system) it's always a good idea to disable the injectors while you crank to prime the system after working on the injectors. In addition to vacuuming, I also like to turn the crank with the glow plugs removed to spray out any residual fluids that the vacuum did not get. On the 7.3, removing the IDM relay, unplugging the CPS, removing the PCM fuse, etc. will disable the injectors and allow you to crank and fill the rails with fluid.

 

We changed the engine oil and verified proper level for the high pressure side.

 

Did you check for manure in the exhaust?

 

I would say bad injectors. I had this same problem. I got a bad set.. One really good way to diagnoise bad sticks is to build something like this..

https://www.ford-trucks.com/forums/6...with-pics.html

Then you can shut off injectors and see which ones are really bad.

I am about $5k into my injector problems.. I finally went and bought a set of injectors from Clay (riffraff) and took all 8 problems out.. I got about $1800 in ford injectors in my sock drawer...

Ohh.. and an FYI on the 50 cent mod.. If you got the updated UVCH then it already has a larger clip and the 50 cent mod is not needed.

I hope this helps.

Good Luck