Well, I wanted to make sure I did the basics before posting. 2002 Ex with the 7.3. Runs fine and all, but absolutely no *****. My 3/4 ton Hemi Dodge pulled my 24' enclosed...well, lets say it was no contest.
So I figured either this diesel is a POS and never ran the way it should have OR something has GOT to be wrong. The latter is where I am at. No diesel should be outpulled(ease) against a gas engine!

1.Wasted time but feel better...dropped the lovely 44 gallon monster fuel tank and cleaned it out thoroughly. Pulled the pickup apart and cleaned the little debris out...just like new! And my Ex lost 50 pounds after cleaning all the dirt and silt off the frame rails and inside the skid around the tank. Shouldn't say waste of time...diagnostically eliminates the tank as culprit.

2. Replaced fuel filter to be safe. Old looked like new as previous owner said he just did it. Guess he didn't lie.

3. Fixed the airbox lid and installed new air filter. Lid is airtight now.

4. Wiring that lays on valve cover: wires had rubs but nothing to the copper. Made a sheath out of 5/8 heater hose and zipties to hold in place. Lucky on that one.

5. Fuel pressure is at 62 psi at idle. 60 psi sitting in garage @ 2000 rpm. Load testing dropped to 50 psi at lowest reading, averaging @ 52 after rebounding a little, holding steady speed and rpm.

6. Boost pressure is at 1.5 psi at idle. 6 psi lite throttle/easy driving. At WOT and out of OD pressure is at 16-17 psi.

No codes at all.

Best description: Floor it, it downshifts, boost builds, acts like its going to do something themn falls flat. Like driving the old 6.2s in the old chevys without turbos. Towing @ 7000 lbs gross, I'd floor the old Hemi and it would carry it up my "test" local steep long hill, dropping only from 55 to 50, but guzzling the gas to do it. The Ex? 60 mph running start...10 mph by the top, floored. Yeah somethings wrong.

Only thing I found was a wet ICP sensor. Oil filled, grommet is sponged out as well as the wiring insulation having also swelled.

Truck driver now, previous trans tech for 10 years so between the mechanics and the understanding of a diesel engine, I should be ok with where we go on this. I am not throwing parts at it...never do unless I'm out of options anyways...thats the sign of a bad mechanic.

$189 for the sensor at NAPA. Seen them on Ebay with the plug for like $40-$50. Anyone ever use these aftermarkets?
Besides that, whats the next common step. One at a time please!

Thanks in advance!

 

I would start with some data capture tools. Something like this:

https://www.scantool.net/scan-tools/...bdlink-mx.html


along with an app like Torque Pro would be a good start if you have an android phone or tablet.

Then read the threads on this forum about autoenginuity and torque.

Once you're set up you can then do so tests on your test hill (without the trailer) to see whats going on.

 

What gear are you in, and what is your RPM, when you find yourself at 10 mph approaching the top of the grade?

 

PERFORMANCE DIAGNOSTIC TESTS

Tools: Tools: Fuel Filter Cap Removal Tool / Flash Light / White Bond Paper / Stop or Wrist Watch w/Second Hand Sweep / DVOM / Vacuum Pressure Test Gauge Bar #014-00761 19-0002 / Fuel Port Adaptor and Pressure Gauge 0-160 PSIG

Step #1: Visual Engine/Chassis Inspection

Tools: Flash Light

Fuel Oil Coolant Electrical Hoses Leaks Check

Step #2 Check for:

a. Contaminates
b. Correct Grade and Viscosity
c. Miles/Hours on oil
d. Correct level.

Tools: White Bond paper

Step #3 Intake/Exhaust Restriction

Tools: Flash Light

a. Inspect air filter and ducts
b. exhaust system
c. Inspect exhaust back pressure device

Step #4 Intake Restriction

Tools: Vacuum Pressure Test Gauge Bar #014-00761 19-0002

a. Check filter minder or measure at WOT with magnehelic gauge.
b. Spec: Magnehelic-2"- 2.5" / Filter Minder / H20

Step #5 Perform KOEO On Demand Test

Tools: OBD-II On-Board Diagnostics, Phase 2 Vehicle Media Communications Unit (Scanner)

a. DTCs set during this test are current faults.
b. Note: IDM DTCs displayed here could be current or historical faults

Step # 6 Retrieve Continuous Trouble Codes

Tools: Bi-Directional Scan Tool

Note: IDM DTCs are cleared when codes are cleared

Step #7 KOEO Injector Electrical Self-Test

Tools: OBD-II On-Board Diagnostics, Phase 2 Vehicle Media Communications Unit (Scanner)

All injectors will momentarily buzz, then individual injectors will “Buzz” in sequence 1 through 8.

Step #8 Fuel Pressure Tests

Tools: Fuel Port Adaptor and Pressure Gauge 0-160 PSIG / DVOM

8a. Fuel Pressure at the right head
a. Verify that fuel is in the tank and the pump is being powered.
b. Measure fuel pressure at the front of right cylinder head Road Test- engine at full load condition Spec. Measurement / Head 0-160 PSI / WOT 45 PSIG min.
c. If fuel pressure fails low, go to step 8c.
d. If pressure is above min. spec, go to step 8b. 8b. Fuel Pressure at the left head
e. Measure fuel pressure at the front of right cylinder head Road Test- engine at full load condition Spec. Measurement / Head 0-160 PSI / WOT 45 PSIG min.
f. CAUTION: Secure hose away from turbo and exhaust
g. If fuel pressure is below min. spec, replace left check valve > If fuel pressure is above min. spec, Go to step 9.

8c. Electric Fuel Pump Pressure
a. Measure at fuel outlet from electric fuel pump: 45-80 PSIG > Road Test- engine at full load condition 45-80 PSIG
b. If fuel pressure fails low, go to step 8d.
c. If pressure is above min. spec, replace right check valve.

8d. Electric Fuel Pump Inlet Restriction
a. If fuel line is restricted above 6 Hg, check for: blockage between pump and fuel tank.
b. If fuel line is not restricted, inspect regulator valve condition and for debris, If OK replace pump
c. WOT under load Spec: > 42 psig

Step #9 Perform KOER On Demand Test

Step #10 Injection Control Pressure Tests

Tools: Bi-Directional Scan Tool / Stop or Wrist Watch w/Second Hand Sweep

10a. Injection Control Pressure Tests (Oil Aeration - Poor idle quality)

a. All acc. Off
b. Monitor ICP and RPM with Bi-Directional Scan Tool Hold engine speed at 3400 RPM for 3 minutes
c. Spec: ICP: 1800 PSI MAX @ 3,400 RPM

10b. Low Idle Stability (ICP Pressure)

a. Check at low idle, EOT above 180 F
b. Monitor ICP and RPM with the Bi-Directional Scan Tool 400 – 600 PSIG @ 670 RPM’s If engine RPM is unstable, disconnect the ICP sensor, If RPM is still unstable, change IPR and re-test.
c. If RPM smooth’s out, the ICP sensor is at fault. Note: ICP will default to 725 PSI when disconnected

Step #11 Crankcase Pressure Test

Tools: Vacuum Pressure Test Gauge Bar #014-00761 19-0002

a. Verify engine is at normal operating temp
b. Measure at oil fill with adapter and orifice tool P.N. 5631 & 014-00743 installed.
c. Block breather tube on left valve cover
d. Measure at WOT no load Spec < 3 H20

12. Cylinder Contribution Test

Tools: OBD-II On-Board Diagnostics, Phase 2 Vehicle Media
Communications Unit (Scanner) / Stop or Wrist Watch w/Second Hand Sweep

a. Verify that EOT is above 70 F
b. Turn A/C and all accessories off
c. Select Cylinder Contribution from the test menu
d. NOTE: The test will run at idle speed for about 120 sec. and no engine change will be felt during the test

13. Exhaust Restriction

Tools: OBD-II On-Board Diagnostics, Phase 2 Vehicle Media Communications Unit (Scanner) / Stop or Wrist Watch w/Second Hand Sweep

a. Visually inspect exhaust system for damage
b. Verify EBP device is open at WOT in park or neutral
c. Monitor EBP with the Bi-Directional Scan Tool with the engine temperature at 170°F minimum at 3400 RPM
d. Spec: 34 PSI Max @ 3,400 RPM

14. Boost Pressure Test

Tools: OBD-II On-Board Diagnostics, Phase 2 Vehicle Media Communications Unit (Scanner) / Vacuum Pressure Test Gauge Bar #014-00761 19-0002

a. Verify that MAP hose is not damaged, plugged or pinched
b. Verify that intercooler hoses or intake are not leaking.
c. Verify that the green Wastegate hose is not plugged.
d. Monitor MGP (manifold gauge pressure) and RPM
e. Road Test - select appropriate gear to obtain desired engine speed and full load on engine (best accomplished climbing hill or truck fully loaded).
e. Spec: MGP 15 PSIG Min

Hope this helps,
Tom

 

No control over gear choice. Just left it in auto and started with taking it out of OD. Truck kept kicking down just fine in line with power loss. The tranny was shifting perfectly. I'd love to tell you where my rpms were but when a truck falls on its face THAT bad, rpms weren't being held high very long. My concern was getting to the top of hill! Hard to see the rpms through pissed and embarrassed eyes. Ever been scared you and your toys were going to start rolling backwards? 60 to 10 in 5 seconds compared to a hemi gas engine that only drops to 50 in about the same time frame and holds the rest of the hill. Even without the trailer, it struggles to climb hills, kicking down to 3rd every time even on slight inclines. Cruise control is a joke as the vehicle speed fluctuates so bad from the power loss...you know how pissed you get when the guy in front of you can't hold a speed to save his own life? Set at 55 and it drops to 45, kicks down, takes forever to get back to 55, then passes it and finally starts easing off at 60ish.

Still leaning towards fuel delivery in some way. If it were a big truck, I'd swear it was an injector. Reminds me of when Mack 427/460s would drop injectors from companies cutting the fuel back to far against Mack TSBs.

 

That is plenty, Tom! Now to memorize all the acronyms...

 

Pulling codes would be nice. However here's something to ponder before investing a ton of money and trying to run all sorts of diagnostics.... if the check engine light doesn't come on and the fuel and boost are normal as posted, that leads me to think that there just might be a transmission issue here rather than an engine problem.

A 7.3L wouldn't make that kind of boost if the injection pressure was dropping or if it was loosing fuel or if there was an issue with the injectors firing. Yet it can't pull a small load uphill without losing speed at 16-17 psi of boost (that's plenty to pull 7,000 lbs up a hill at speed). Motor doing the work, but no go anywhere. Anyone see the missing link?

.......Unless of course the check engine light just doesn't illuminate anymore and we're missing something here.

To the OP... do you see black smoke out the tailpipe when this is happening? Does the transmission temp get hot?

 

I tried to post on this yesterday, but my iPhony was a fail. I strongly suspect ICP - be it injector O-rings, sensor, or something else. Step one: Unplug the ICP and leave it off. While ignoring the SES light laser-beaming to the "I'm gunna die" button in your brain, go for a test drive.

ICP sensor choice - OEM, baby. Riffraff Diesel has reasonable prices.

 

got a 1999 f250 7.3 ltr dies while worm, replace icp, an harness, ipr, cam sensor, an still same results runs then get warm about 20 miles dies for 4 hrs cools off then restarts runs short range an dies, when raining dies as well same conditions happen, it popped a cam code up on the supper chip reader an thats all it ever shows up no other codes i have change the ford sensors about 30 times in last 2 yrs. even after market ones.. i use electrical grease as well, an change out the pig tail as well there as well. same results. any help.

 

I'm a newb with Superchips. OBDII connection? Does this happen with no added electronics plugged into the PCM or OBDII port? Is your fuel filter black? Any symptoms (like smoke out the pipe) other than the stalls?

 

oldbonbon...copy/paste this to a NEW THREAD so THIS thread, dont go haywire....

 

I was a tranny tech for 10 years. It is NOT transmission related. But please read the entire original post. Im not going to give that much info and leave out the fact i got a factory smokestack going on out the back. Clean as could be. Im going back to my gut...it is a fuel delivery problem. 100% bone stock. Check engine light works but is not present. Still need to get a buzz test done, but just got back from my 10 vacation. At least I caught my first Pike and Salmon ever outta lake Michigan!

ICP is definitely next, but $200? Has anyubody had any luck with aftermarket? Its just a pressure switch like any other allowing certain voltage to read ok and outside that to affect its purpose. $40 for aftermarket with new plug/wiring...id like to stay factory but damn...

 

Since this has gone cold for a while, I had to review the thread.

The title of the thread is "Diagnosing 7.3 by the numbers". Uh... we're missing some. No Injector Control Pressure (ICP) senor reading, no Injector Pressure Regulator (IPR) command from the Powertrain Control Moudule (PCM), no boost numbers, no Exhaust Back Pressure (EBP) values, etc....

If this was a new truck under warranty, the standard answer on a forum would be "take it to the shop" - where a very early step would be to hook the truck up to a diagnostic tool and see what's going on in there. There are many hundreds of dollars worth of sensors in the truck talking and listening to the PCM. Wouldn't be nice to listen in on that conversation?

Since this is not a new truck under warranty, and it's certainly not going to improve with age - my standard answer is "get an OBDII gauge/tool". I'm not trying to waste anybody's money - quite the contrary. You have a 13-year-old diesel that's fully capable of going many more years, but not without a little attention here and there. Firing up the ol' m-w.com website, "attention" can be substituted with "observation". I don't know about you, but every time I stare at the limited needles on the dash or the block under the hood, I don't see squat.

Saying that, you have done a fantastic job of getting a fuel pressure reading. The numbers tell me your quick-disconnects on the pick-up are leaking air into the fuel intake before the pump. You may want to look into the Hutch Mod - there's a link in my signature. I have injectors that demand significantly more fuel than stock, and my OEM pump never allows the fuel pressure to dip below 55 PSI at Wide Open Throttle (WOT).

ICP sensor: Aftermarket units have been known to kill the truck for seemingly no reason. With enough repeats of the problem, we collectively learned they cut out in close proximity to strong RF signals - like radio towers. OEM sensors do not experience this problem.

 

http://www.ebay.com/itm/NEW-OEM-GENUINE-FORD-ICP-SENSOR-7-3-F6TZ-9F838-A-F6TZ9F838A-/251992451275?hash=item3aabeba8cb&vxp=mtr

 

Got the IPR out and cleaned up. New kit from NAPA 600-3609 for the orings and teflon split ring, new collar and nut. Wiring looks good. Everything was free as could be. Could still be the electronic solenoid on it...
2 things to note:
1. Really light throttle @ 35 mph very VERY slight miss, which is understandable. Its so slight you have to be looking for it. Doesn't show up on tach.
2.Alternator gets super HOT! Not from engine heat either. After 4 minutes from cold start you can not touch it...like touching a hot coal stove. Didn't know if it was normal. If anyone can try and let me know. Gas engines never got this hot, but 2 batteries and all the high draw electronics would make sense. Charging at 14.1.

I don't mean to sound snippy to anyone. Money is just really tight so for now Im going at the low cost stuff. All these little things need done anyways...used vehicle so who knows...

Ford said my fuel pressure is perfectly normal. Nothing below 60 at idle and nothing below 40 under load.