7.3L Power Stroke Engine and DrivetrainDiscussion of the 7.3L Power Stroke diesel engine and drivetrain in the 1999-Up Super Duty trucks and Excursions. No gas engine discussion allowed except on transmissions and drivetrain that pertain to all models. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.
New to the forum here, but not to the ford diesel world. My truck is listed below in my sig and I apologize in advance for the long post!
'02 7.3L with 140k on the clock. Around 120k, I lost 3 injectors, had them replaced and life went on.
Recently, I've been seeing my CEL flicker on and off. Finally, it stayed on constantly. The truck runs PERFECT...no starting issues, smooth idle, plenty of power. Here is what is odd about the CEL...it will stay on at idle and during accelleration. However, when the TC is locked and I let off the go-pedal...it will shut off and remain that way until I step on it again (does not matter how hard) or the TC unlocks. This happens with my chip on/off, installed/uninstalled.
So, here is what I have done to try and pinpoint the problem.
1. Checked to ensure my chip is properly seated on the PCM.
2. Inspected all wires that go from the PCM & IDM to the main valve cover harness.
3. Checked all wiring harnesses that go to the transmission (thinking one might have been chafed)...but they seemed fine.
4. Had the codes pulled.
First Code was P1316...which I know all it means is that codes have been stored in the IDM. So I ran an injector buzz test, cylinder contribution test, glow plug relay etc. First time I did it, I got P1277 (Injector 7 high to low short) and P0284 and P0269 (cylinder 8 & 3 contribution faults).
Knowing that the UVC's are notorious for causing troubles, I decided that for $40 a piece from the IH dealer, it was not going to hurt anything to replace them. The ones I took off did not look messed up, but I wasnt about to put them back on. Jody at DP Tuner also pointed out that the grey CPS that was installed by Ford under the recall could be the culprit as well, so I replaced it with a BW one from O'rileys today. Still have the CEL illuminated.
This evening, I went and pulled codes/ran tests again, and consistenly got P1277. So my question is, what is wrong and why does the CEL shut off when I let off the gas...all while the truck still runs great?
Sorry for the long post, but im really looking forward to hearing your responses because it sounds like there is a great deal of info on here!
Jourdan
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Jourdan
2002 F250 Lariat 4x4, 7.3L
DIY Intake, Zoodad, 4 inch exhaust turbo to tip, DP Tuner F5 (no start, stock, high idle, 60hp tow, 80hp econo, 120 hp race), Isspro Gauges: egt, boost, tranny (thank you girlfriend!:hail), Dieselsite Coolant Filter, AIH Delete, HPX Line, in-tank & pre-pump mods, FPR shimmed to 70 psi, Hawk Brake Pads and Powerslot Rotors, Dieselsite WW, Rhino Bedliner, 285/75 Goodyear Wrangler Silent Armors, Trailer Tow Mirrors, Bilstein Shocks, 203* T-Stat, Dieselsite Billet T-Stat Housing, Door Seal Mod, Fumoto Oil Drain Valve, Passport 9500i hardwired in w/ smartcord, A toolbox full of goodies and a few other things here and there:sly
DIY Intake, Zoodad, 4 inch exhaust turbo to tip, DP Tuner F5 (no start, stock, high idle, 60hp tow, 80hp econo, 120 hp race), Isspro Gauges: egt, boost, tranny (thank you girlfriend!:hail), Dieselsite Coolant Filter, AIH Delete, HPX Line, in-tank & pre-pump mods, FPR shimmed to 70 psi, Hawk Brake Pads and Powerslot Rotors, Dieselsite WW, Rhino Bedliner, 285/75 Goodyear Wrangler Silent Armors, Trailer Tow Mirrors, Bilstein Shocks, 203* T-Stat, Dieselsite Billet T-Stat Housing, Door Seal Mod, Fumoto Oil Drain Valve, Passport 9500i hardwired in w/ smartcord, A toolbox full of goodies and a few other things here and there:sly
DIY Intake, Zoodad, 4 inch exhaust turbo to tip, DP Tuner F5 (no start, stock, high idle, 60hp tow, 80hp econo, 120 hp race), Isspro Gauges: egt, boost, tranny (thank you girlfriend!:hail), Dieselsite Coolant Filter, AIH Delete, HPX Line, in-tank & pre-pump mods, FPR shimmed to 70 psi, Hawk Brake Pads and Powerslot Rotors, Dieselsite WW, Rhino Bedliner, 285/75 Goodyear Wrangler Silent Armors, Trailer Tow Mirrors, Bilstein Shocks, 203* T-Stat, Dieselsite Billet T-Stat Housing, Door Seal Mod, Fumoto Oil Drain Valve, Passport 9500i hardwired in w/ smartcord, A toolbox full of goodies and a few other things here and there:sly
It may be that the solenoid on that particular injector is internally shorted and it only shows up on load (longer firing time for the injectors).
I'd suggest checking the resistance across each injector solenoid. Measure between the center pin on each VC connector and each of the 2 pins closest on either side of the center pin. I'm guessing that you'll find #7 quite a bit different than the others. A normal solenoid should measure less than 5 ohms, but significantly lower than that (say below 2 ohms) would indicate a problem.
The other thing to check is where the engine harness connector goes across the driver's side valve cover. The Engineers (not so wisely) put the high voltage injector circuits on the bottom of the bundle where they'd be the first to chafe and short out. Maybe some electrical tape will fix your problem.
Injector #7 was indeed one of the ones replaced. Do you have a process that i can go by to ohm out each of the injectors? Do you do this with the motor off and basically put a volt meter in between the male and female side of the connector on top of the valve cover?
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Jourdan
2002 F250 Lariat 4x4, 7.3L
DIY Intake, Zoodad, 4 inch exhaust turbo to tip, DP Tuner F5 (no start, stock, high idle, 60hp tow, 80hp econo, 120 hp race), Isspro Gauges: egt, boost, tranny (thank you girlfriend!:hail), Dieselsite Coolant Filter, AIH Delete, HPX Line, in-tank & pre-pump mods, FPR shimmed to 70 psi, Hawk Brake Pads and Powerslot Rotors, Dieselsite WW, Rhino Bedliner, 285/75 Goodyear Wrangler Silent Armors, Trailer Tow Mirrors, Bilstein Shocks, 203* T-Stat, Dieselsite Billet T-Stat Housing, Door Seal Mod, Fumoto Oil Drain Valve, Passport 9500i hardwired in w/ smartcord, A toolbox full of goodies and a few other things here and there:sly
Id like to know what are the Ohm readings coming in to the harness out of the injectors myself. Maybe someone will post something that I could Learn from as well.
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2001 F-250 7.3 - 4 Door Platinum Edition / Triple Pod-Auto Meter Pyro-tranny & Boost gauges / Bully Dog Pup programmer / Stock Straight pipe
so when I ohm it out and find things out...will it point to a bad injector?
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Jourdan
2002 F250 Lariat 4x4, 7.3L
DIY Intake, Zoodad, 4 inch exhaust turbo to tip, DP Tuner F5 (no start, stock, high idle, 60hp tow, 80hp econo, 120 hp race), Isspro Gauges: egt, boost, tranny (thank you girlfriend!:hail), Dieselsite Coolant Filter, AIH Delete, HPX Line, in-tank & pre-pump mods, FPR shimmed to 70 psi, Hawk Brake Pads and Powerslot Rotors, Dieselsite WW, Rhino Bedliner, 285/75 Goodyear Wrangler Silent Armors, Trailer Tow Mirrors, Bilstein Shocks, 203* T-Stat, Dieselsite Billet T-Stat Housing, Door Seal Mod, Fumoto Oil Drain Valve, Passport 9500i hardwired in w/ smartcord, A toolbox full of goodies and a few other things here and there:sly
Injector #7 was indeed one of the ones replaced. Do you have a process that i can go by to ohm out each of the injectors? Do you do this with the motor off and basically put a volt meter in between the male and female side of the connector on top of the valve cover?
Whenever checking resistance with an ohmmeter, ALWAYS denergize the circuit. If you tried it with the engine running, you'd smoke your meter and possibly kill yourself. The injector circuits run in excess of 100V.
To check your injector solenoids, disconnect the harness connected to the outside of the valve cover gasket. You'll see 9 pins on the gasket itself arranged like this:
G-G-I-I-C-I-I-G-G
G = glow plug
I = Injector return
C = Injector common feed
Put your meter on C and each of the I pins in turn. What you're doing is measuring the resistance of the valve cover, the UVC harness and the injector solenoid.
Last night, I was trying to put one end on the pin, and the other end of the meter on the the harness itself and coudlnt get any kind of reading at all!
So I want to put one end on the center pin, and then proceed to put the other end on each pin for the injectors and get a reading from there correct?
How can I test to see if the harness is bad? I just wonder if that could be my issue as well...
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Jourdan
2002 F250 Lariat 4x4, 7.3L
DIY Intake, Zoodad, 4 inch exhaust turbo to tip, DP Tuner F5 (no start, stock, high idle, 60hp tow, 80hp econo, 120 hp race), Isspro Gauges: egt, boost, tranny (thank you girlfriend!:hail), Dieselsite Coolant Filter, AIH Delete, HPX Line, in-tank & pre-pump mods, FPR shimmed to 70 psi, Hawk Brake Pads and Powerslot Rotors, Dieselsite WW, Rhino Bedliner, 285/75 Goodyear Wrangler Silent Armors, Trailer Tow Mirrors, Bilstein Shocks, 203* T-Stat, Dieselsite Billet T-Stat Housing, Door Seal Mod, Fumoto Oil Drain Valve, Passport 9500i hardwired in w/ smartcord, A toolbox full of goodies and a few other things here and there:sly
So I want to put one end on the center pin, and then proceed to put the other end on each pin for the injectors and get a reading from there correct?
You got it.
Quote:
Originally Posted by TXF-250
How can I test to see if the harness is bad? I just wonder if that could be my issue as well...
To do that, you'll need to disconnect the other end and put your meter on each end of each wire in the harness. You'll have to match wire colors with pins on each end. That's called a continuity test to see if that particular wire is intact from connector to connector.
To check for shorts between other wires is a bit more involved as there are lots of combinations. Again, with both ends disconnected, check with one meter probe on the pin you want to test, and the other probe on all the rest of the pins in sequence. While you have the meter in place (hopefully reading infinite ohms) wiggle the harness along it's entire length and watch for the meter to go to zero ohms. That indicates that the insulation between the two wires has chafed and the conductors are making contact. - But I wouldn't try that test unless you've got some indication that it's occuring, as it's fairly unlikely.
The other test is to check for short to ground. Meter probe on wire being tested, other meter probe on a ground, and again wiggle the harness bundle.
well i went out there and attempted this...one of two things is going on
either i dont know how to use a volt meter (which in this situation is likely) or the injector harnesses are ok
On my volt meter i have 2 settings to test resistence: one is "RX1K" and the other is "RX10" On the RX1K setting (I think) when I go through this process, it just pegs out on the analog meter ive got. When I switch it to RX10 setting and go through the same process, I cannot get any reading at all.
And again, this is with putting one terminal on the center pin, and then taking the other terminal and touching each of the injector pins. Am I doing this wrong/not using the volt meter right?
Sorry for being such a newb with this, but electircal stuff is not my cup of tea! Thanks!
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Jourdan
2002 F250 Lariat 4x4, 7.3L
DIY Intake, Zoodad, 4 inch exhaust turbo to tip, DP Tuner F5 (no start, stock, high idle, 60hp tow, 80hp econo, 120 hp race), Isspro Gauges: egt, boost, tranny (thank you girlfriend!:hail), Dieselsite Coolant Filter, AIH Delete, HPX Line, in-tank & pre-pump mods, FPR shimmed to 70 psi, Hawk Brake Pads and Powerslot Rotors, Dieselsite WW, Rhino Bedliner, 285/75 Goodyear Wrangler Silent Armors, Trailer Tow Mirrors, Bilstein Shocks, 203* T-Stat, Dieselsite Billet T-Stat Housing, Door Seal Mod, Fumoto Oil Drain Valve, Passport 9500i hardwired in w/ smartcord, A toolbox full of goodies and a few other things here and there:sly
You're doing it right, but your meter probalby isn't the best one to use. If yours only has the two resistance ranges, it's probably straddling the range you need, which is about 0-10 ohms.
You can get a digital multimeter for less than $30 from Sears. Craftsman Multimeter
Or a professional quality Fluke meter for about $150.
ok finally got a good check set and heres what i found. I pulled the harness and ohmed out each of the injectors...all of them read 3.6 ohms.
Is this about normal? Seems like my issue is not injector related right? What do you guys think?
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Jourdan
2002 F250 Lariat 4x4, 7.3L
DIY Intake, Zoodad, 4 inch exhaust turbo to tip, DP Tuner F5 (no start, stock, high idle, 60hp tow, 80hp econo, 120 hp race), Isspro Gauges: egt, boost, tranny (thank you girlfriend!:hail), Dieselsite Coolant Filter, AIH Delete, HPX Line, in-tank & pre-pump mods, FPR shimmed to 70 psi, Hawk Brake Pads and Powerslot Rotors, Dieselsite WW, Rhino Bedliner, 285/75 Goodyear Wrangler Silent Armors, Trailer Tow Mirrors, Bilstein Shocks, 203* T-Stat, Dieselsite Billet T-Stat Housing, Door Seal Mod, Fumoto Oil Drain Valve, Passport 9500i hardwired in w/ smartcord, A toolbox full of goodies and a few other things here and there:sly
Your results tell me that the injector solenoids are OK. The spec is less than 5 ohms, and some guys have reported less than 2 ohms will cause a problem. You're right in the middle of the accepted range, IMO. That and they're all the same.
Now you need to check continuity back toward the IDM.
Well thats good news to hear (I guess?). How does one go about checking continuity back to the IDM?
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Jourdan
2002 F250 Lariat 4x4, 7.3L
DIY Intake, Zoodad, 4 inch exhaust turbo to tip, DP Tuner F5 (no start, stock, high idle, 60hp tow, 80hp econo, 120 hp race), Isspro Gauges: egt, boost, tranny (thank you girlfriend!:hail), Dieselsite Coolant Filter, AIH Delete, HPX Line, in-tank & pre-pump mods, FPR shimmed to 70 psi, Hawk Brake Pads and Powerslot Rotors, Dieselsite WW, Rhino Bedliner, 285/75 Goodyear Wrangler Silent Armors, Trailer Tow Mirrors, Bilstein Shocks, 203* T-Stat, Dieselsite Billet T-Stat Housing, Door Seal Mod, Fumoto Oil Drain Valve, Passport 9500i hardwired in w/ smartcord, A toolbox full of goodies and a few other things here and there:sly
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), AIS, 
The injector circuits run in excess of 100V.
Linear Mode
