Hi, I have 01 F550 6spd 4x4. sounds rhythmic, smooth at idle but just over 1200 is a pattern surge but doesn't sound like one cylinder, cel is off, ICP and pigtail changed as it was leaking , no change. From what I've read duty on ICP and IPR should be about same % I've included the codes I've gotten, I have the epc disconnected right now as I thought it was a wastegate issue, checking the ICP plug next,anything I've missed? It had a cyl 8 contribution at idle which I hear is common? Will changing CPS help that one? Think it's a grey one. There's no water in bowl I replaced filter, since replaced ICP, pigtail, and bleeding fuel bowl and new filter the codes are gone but still misses, will be checking uvch, injector buzz test showed no faults. Old diesel guy said to flood with Stanadyne fuel treat? Thx for reading

 

Check for burnt pins and pig tails or loose connectors on the uvch.

 

Make sure that alternator is up to snuff. (Code 1105). One bad diode leaking AC can introduce all kinds of non related quirky faults in certain sensors that are effected by EMI.

 

Hmm good point a bad diode could cause some a/c action, it does have the dual alts

 

All codes cleared except p1139, so ran to temp and did cylinder contributions and comes up with #8, injector buzz test is good. Had spare cps, but it's a grey one too but same code for #8 cyl. Time to pull injector?

 

Isn't #8 the cylinder that is most affected by cackle and with stock fuel system has a problem with producing the same power as the other cylinders due to fluctuation in rail pressure?

 

The #6 split shot injector exposes the rail to a high pressure mini spike when #6 spills fuel between its pilot and main shots. Since #8 is filling and getting ready to fire right after #6, the high pressure spit back through the #6 spill port directly next door to #8 puts a pulse in the fuel rail that could impinge on the fill of #8.

 

And the fix for that is??

 

With a 2001, you may already have Ford & International's collaborative fix, which is to install a special injector in #8 with a longer lead time surrounding the pilot injection, which is controlled only in manufacturing by where the annular ring on the plunger is machined, and sadly, is not able to be dynamically controlled by the PCM. However, a different PCM program is needed with the long lead injector, in order to avoid false readings in the cylinder contribution test. Because model year 2001 (which were built in calendar year 2000 and 2001) was a transitional time period when the long lead injector #8 began to be used, it is hard to guess by model year alone whether or not you have one.

It isn't that big of a deal, whether you have one or don't. My previous post was just in answer to Larry's (retiredsparky's) question regarding the cackle and idle knock in #8. The diversion isn't necessarily a thread hijack, because it helps you to know that #8 can give false readings on a CCT if the calibration doesn't match the *8 injector. As these trucks get older, and parts get swapped around to keep them running, and owners get swapped around as they are bought and sold, and different mechanics poke around to get 'er done... never mind aftermarket tunes, programs, and rebuilt injectors along the way... it can get hodge podgy.

As far as Stanadyne fuel treatment (I had to go back and re read your OP), I too, use it religiously. Stanadyne was the original fuel injection pump manufacturer for the 7.3L IDI before Navistar and CAT introduced HEUI. Furthermore, Stanadyne is the only diesel fuel treatment manufacturer that is specifically identified and recommended by Ford in various Broadcast Messages and TSBs, other than Ford/Motorcraft branded fuel treatments. Stanadyne makes a variety of formulas, and Ford hasn't recommended all of them, but Ford has recommended the Performance Formula and the Lubricity Formula (formerly called something else, like "Lubricity Additive" or similar). I use the Performance Formula, blue label. It offers the best balance of cetane improvers, lubricity enhancers, anti gelling properties, water demulsifiers, injector cleaner, and corrosion preventatives. And it contains NO alcohol, which is important. Both the driver and the truck need to stay sober on the road.

 

Ok so don't worry about the#8 contribution? I have an 01 F450 customers truck and it runs very smooth, also I have an 01 E350 dame drivetrain as I'm mid 4x4 6sod swap and it too runs mint. I have an IDM and PCM for an 03 E350 7.3 could I plug and play? I know you can go up in idm for years but not back. But don't know about PCM. Also could swap the injector. I also just bought another F350 7.3 psd as driving parts truck lol I have issues 😜Right now it still knocks, runs rough/ miss and no power