Help 7.3 missing, no codes, did buzz and contribution tests

[Probuilder]

I have the FU chip and burner in a early 99 7.3 F 250- With DAC2 PCM.
I installed the chip and everything worked great for about 2 months.
I decided to reprogram different tunes on the chip, and change the order of them. When I reinstalled the chip everything seemed ok but I didn't try the 1200 rpm Hi Idle tune, until I was jumping hooking up my 18' car trailer, tune used to get he truck warmed up a little faster.
Once I switched the chip back to Heavy tow, the truck started missing on idle and all the way up through the rpms. EGT's were about 400 degrees higher than normal, running 1200 degrees running down the road @ 60mph on flat ground.
When I reprogrammed the 6 pos chip I didn't put the stock tune on it. I shut the truck off and reprogrammed the chip again, and just removed the one program and reburnt the stock program on the chip.
Now I have tried to remove the chip, while in stock setting, and then check for codes, I come up with nothing, no codes at all.
So I took the truck to a ford garage, after completely removing the chip from the PCM, they can't come up with any codes that are stored either and no pending codes.

Ford garage did a contribution test, #3 and #8 are only contributing 80% but the buzz test is perfect.
They told me that it was because of the chip tuning??????? That something was loaded wrong????? Is Ford right? I know the PCM is a DAC2 and we are installing DAC3 tunes to the chip????????

What do I need to do to get this truck back to stock, and running right?
I need to use this truck to pull my 34' and 16K goose neck construction trailer Tomorrow.

[907DAVE]

Do you have the "new" gray CPS?

Many people are experiencing issues with this CPS causing 3&8 CCT codes.

[F-127]

There isn't a problem with DAC3 tunes for DAC2 PCM.

Has it ever acted up without the chip?
Once it started missing, did it continue to miss until the chip was removed and run fine immediately afterwords?
Were all the files from the same family when you reburned the chip, ex. All VOAA7P6 tunes, and not a VOAA7P6 and something else?

My first gut reaction when reading the title of your thread was valve cover gasket(the connection though it). It could have happened to fail at the moment you flipped the switch. The connections on the valve cover gasket can be tempermental, running on all 8, miss for a while, then work perfectly again. There are two plugins, one for each bank, going into each valve cover. Maybe try putting some slight pressure on the plugin to see if either develops a miss, or if it acts up on you, try again to see if it clears up. I've done two valve cover gaskets in the past few weeks.

I see Dave posted about the CPS while I was typing this which is another good possibilty.

[Power Hungry]

Troy,

The files you're using have been on the server for some time with about a dozen people running it without issue, so I'd say we're pretty good with eliminating that as a problem. This leaves either a physical chip problem (most likely PCM connection), or something else wrong with the vehicle.

The chip connection is easy enough to verify. Just pull the chip (keep keys in your POCKET!), brush the contacts with little Scotch Brite, and reinsert. In many cases, that clears up any drivability problems.

Outside of that, there could be a variety of mechanical/electrical issues that could be causing you some trouble. Some popular ones are:

CPS
UVC Harness (This one is good for poor drivability along with high EGTs)
Injector O-Rings, copper washers, or cups leaking (Also high EGTs... happened to me recently!)
IPR (May cause drivability issues , but generally not higher EGTs)

One simple trick to isolate injector related issues is to remove the UVC connector on each side (1 at a time, of course) and see if there's a noticeable change in engine drivability. Usually this is related to very extreme cases where the engine is missing badly and has no power. If the engine is running smoothly at idle, then this is probably not the case and is usually something much less serious, although it might be a bit more difficult to track down.

If you can get us any more feedback on how the truck idles, runs at low speed, if it's missing and how severe, or any scan tool information at all, that would be helpful.

Give me a shout if you have questions and we'll see if we can get your truck figured out.

Take care.

[Probuilder]

Ok, Sorry should have given you more info.

Things that I have already tried:
1: changed out the CPS, no change after swapping that out.
2: changed the UVC's on both sides, still no change.
3:Unhooked the IPC- no change/ but has a small amount of oil inside the plug in.
4: Unhooked the MAT- no change
5: unhooked the IAT- no change
6: When I pulled the chip out it runs the same as with the chip in and on stock setting.
I have to turn the chip up to at least Daily Driver to get any power out of the truck.
7: unplugged one side at a time (UVC's) major change in the way the truck runs.
8: The truck has a Gray CPS in it now but I just swapped that out with a new Black one- still no change.

Now for more info on the way the truck runs:
It feels like it is missing on 1 or 2 cylinders only, No major knocking on one side or the other, of the motor. The motor will shake when idling, and all the way up through the rpm range. Loss of power through the whole rpm range, but seems to get a lot better when at 2200 and above, but might just be the power band of the motor.
No the truck has never acted up without the chip, until now.

9: Ok, when I pull the chip out of the truck, no matter what tune it is turned to, does that return the truck back to stock?
10: Or does the PCM still have the tune programmed into it?
11: This truck has never had an update done to it, the PCM, could that be a problem?
12: how do I check the IPR? Can I just unplug it, like the IPC and it go to Default?
I don't have a scanner that will read the truck codes, that is why I took it to Ford Garage. All I have for a scan tool is a Actron CP9180. It will come up with a lot of codes, but can't do the contribution tests or buzz test.
Ford garage came up with no codes present, except the one that tells them it had a tuner in it, so they told me.
13: How much do I have to spend on an AutoEnginuity software to diagnos these problems with the 7.3 motor/ truck. I already have a laptop computer.

Thanks for all the help, Troy You can call me at 319-432-4648

[Probuilder]

No the truck has never acted up without the chip, until now.
- It sounds like isolated cylinder miss. When running the Buzz Test, did you hear any cylinders that sounded different? Meaning... did any injectors sound "dull" or "softer" than others? When I had an injector issue with our truck, I was able to isolate which injector was the issue by doing a buzz test and listening for an injector that didn't sound the same as the rest.

The buzz test sounds equal on all cylinders, but the contribution test showed that the #3 & #8 cylinder showed about 80%???????? Not sure what that means, but that is what the Ford Stealers said. But, I am not sure as I didn't hear it myself, and the Dealer may just be trying to sell me a new truck.


Ford garage came up with no codes present, except the one that tells them it had a tuner in it, so they told me.
- Ford equipment doesn't tell them you have "tuner" on it. That's garbage. As for codes, driveability issues rarely set codes and you'll really need to be able to log PIDS such as ICP, IPR %, PWM, EOT, and maybe a few others in order to come to a conclusion as to which direction to look.
Will the AE Software scanner do these tests?

13: How much do I have to spend on an AutoEnginuity software to diagnos these problems with the 7.3 motor/ truck. I already have a laptop computer.
- Corey can help you with pricing on A/E.
That would be great, I found the Ford kit on Sinister Diesel for $379.95 is that a good deal.

Thanks for all the help, Troy You can call me at 319-432-4648
- I'm tied up at the moment but will be happy to give you a shout this afternoon when I'm back on the road.
A phone call would be greatly appreciated. Even though it sounds like it isn't a problem with your chip or program. Your customer service is above and beyond what I expected!!!!!

[Probuilder]

Groovy Chick,
What service ticket?

[Probuilder]

Bill,
you wanted me to start an online support ticket for this problem, but I can't seem to log in to the support system. I don't know what my user ID and password are.