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.
truck started missing badly eventually died and would not start. mechanic said the idm was bad. I changed it. Started ran fine for 15 miles and then began missing again (injectors on driver side of motor not firing at all). It came and went, sometimes running fine and others it would start missing. The only pattern I can detect is that it would start or stop doing it at idle most of the time.
Yesterday: Sitting at taco bell idling and it died. Won't start again. I'm thinking a wiring issue. Any advice? Buying idms is getting expensive.
__________________ 2000 F250 CC PSD 4x4 Long Bed, 8" All Suspension Lift, 40x13.5x17 GoodYear MTR's, Dynatrac Upgrades Front & Rear, 4.56 Gears, Warn Premium Hubs, Custom Leather Seats, Frontier and Ranch Hand Bumpers, EBPV Delete, Straight Pipe Exit in front of Rear Wheels, Regulated Fuel Return, Gauges, DIY Tymar, Zoodad Mod, CCV Mod, Limo Tint, Hide away Gooseneck hitch, blah, blah, blah
SOLD99 F250, CC, 4x4, LWB, 6" lift, 37's, Ranch Hand bumpers, tool box, top bed plates, blah feakin' blah....
If you can get a buzz test and a injector contribution test done.
The buzz test will provide any codes stored in the IDM, and provide fault codes for individual injectors. The contirbution test will provide information about the preformance of each cylinder/injector helping to pinpoint bad injectors.
If all the injectors on one side are not firing, you could have a problem with the "low voltage" injector circuit. This circuit is common to all injectors on one side of the engine. Individual injectors each have a "high voltage" circuit. Don't use a test light on these the "high voltage" is about 115 volts.
You need a code scanner similar to AE to make all the tests.
If you really have a bad IDM (doubtful), Dtech (DIPACO DIESEL PARTS) sells rebuilt ones for about $199.
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2001 F250 SC 4X4 Blue PSD Auto, Cody Gooseneck Hitch, Rancho Shocks and Steering Stabilzer, Tekonsha Prodigy Controller, Garmin Streetpilot 2610 GPS, Walker BTM, 285/75R/16E, Western Diesel Trans-Pyro-Boost, Pillar Mount, Painless fuse panel, In-tank and Pre-pump mods, Slotted Rear Rotors, Slotted and Cross Drilled Front Rotors, Fumoto Valve, Zoodad Mod, Transfer Flow 46 gal tank, Mag-Hytec Differential Cover, Electric Tailgate Lock, IAH Deleted, Coolant Filter, DP-Tuner 80 hp PCM, CCV Mod, 203 Thermostat, Ford AIS Air Filter
IDM codes like P1316 are commonly thrown when the UVCH connector comes loose. That's the Under Valve Cover Harness. It's a flat 9 pin connector located on each head. There's a plug on the inside of the valve cover that has been known to come loose, which could explain why you've lost those injectors. If you know which side is the problem I'd pull that valve cover and take a look. You can make a shim to keep it from coming unplugged again, or you can get an updated wiring harness. The harness is cheaper from International than from Ford.
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Chris
2002 F350 6 spd 3.73LS XLT Heated Seats 270,000 & counting.
UVCH harness bad or keep in mind that 1 shorted injector can and will keep it from running . it will throw all kinds of IDM codes too . last injector i seen go bad was at 2.4 ohms the rest were at 2.9 ohms.
Thanks guys. I'm going swap pcm with my 01 excursion to see if perhaps its that's it.
I was thinking about the uvch since I recently changed injectors. The pcm does not currently show any codes...only when it's missing. Right now it has no codes and won't start. Gonna mess w/ it tonight. If I can't get it fixed, I'm buying 2 uvch's.
__________________ 2000 F250 CC PSD 4x4 Long Bed, 8" All Suspension Lift, 40x13.5x17 GoodYear MTR's, Dynatrac Upgrades Front & Rear, 4.56 Gears, Warn Premium Hubs, Custom Leather Seats, Frontier and Ranch Hand Bumpers, EBPV Delete, Straight Pipe Exit in front of Rear Wheels, Regulated Fuel Return, Gauges, DIY Tymar, Zoodad Mod, CCV Mod, Limo Tint, Hide away Gooseneck hitch, blah, blah, blah
SOLD99 F250, CC, 4x4, LWB, 6" lift, 37's, Ranch Hand bumpers, tool box, top bed plates, blah feakin' blah....
Like the other guys said, check wiring harnesses before dumping more money in IDM's. You probably didn't need to replace the one you did (not much consolation, I know). Can the mechanic tell you what codes he came up with. He should have recorded them. If he didn't pull the IDM codes before telling you the IDM was bad, then he's a parts-swapper, not a mechanic. But in his defense, other things can make the IDM show bad.
A low-ohm injector has been know to kill one side. You should see less than 5 ohms (per Ford) across each injector (can be checked without pulling VC's), and others have reported that an injector showing less than 3 ohms or so had killed the bank it was in. That would make the range for a good injector 3-5 ohms, not just below 5 ohms.
Also check the main harness for shorts to the valve cover. The injector circuits are on the bottom of the harness, so are the first ones to chafe thru and short out.
Mechanic said that I wasn't getting any high voltage to either side of the motor and that it "was most likely the idm." What doesn't make any sense to me is why when I did replace the idm it started last time. I've checked the wiring harness and can't find anything.
Do I just test resistance to the injectors with the key in the "on" position or does it have to be running?
__________________ 2000 F250 CC PSD 4x4 Long Bed, 8" All Suspension Lift, 40x13.5x17 GoodYear MTR's, Dynatrac Upgrades Front & Rear, 4.56 Gears, Warn Premium Hubs, Custom Leather Seats, Frontier and Ranch Hand Bumpers, EBPV Delete, Straight Pipe Exit in front of Rear Wheels, Regulated Fuel Return, Gauges, DIY Tymar, Zoodad Mod, CCV Mod, Limo Tint, Hide away Gooseneck hitch, blah, blah, blah
SOLD99 F250, CC, 4x4, LWB, 6" lift, 37's, Ranch Hand bumpers, tool box, top bed plates, blah feakin' blah....
???
If you tested across each injector coil individually, then you should get 3-5 ohms, not 0.03 ohms. The injectors have to be disconnected from the rest of the harness to test, but you can do that by pulling the 9-pin connector on the outside of each valve cover gasket. The pins will be:
G-G-I-I-C-I-I-G-G
G = glow plug, I = injector return, C = injector common
the position on the plug corresponds to the position on the bank for injectors and GP's
Test between C and each of the I's.
Quote:
Originally Posted by cpope
uvch were loose and I pushed them back on and put superglue on the connectors. Truck still will not start.
Must be something else than UVCH, then. Did you verify that the pins were in good shape on the VC gasket?
Quote:
Originally Posted by cpope
Is it possible that the uvch caused the idm to go bad?
Possibly, but not likely.
Quote:
Originally Posted by cpope
Is there any way to check/fix the idm once out of the truck?
Not without some sophisticated testing equipment. I've checked voltages on a powered-up IDM on the bench, and get only about 1.5 volts on the output pins unless triggered (and I'm not smart enough to figure out how to trigger them). The coil powering the injectors does output 110+ volts, but that's not accessible from the outside.
Unless your guy pulled codes, saying that "it wasn't getting high voltage" doesn't mean much. The IDM does it's own diagnostics and reports problems to the PCM and scan tool when the proper test is run.
P1261-P1268
High to low side short cyl. # 1-8
Short circuit, shorted injector, failed IDM
P1271-P1278
High to low side open cyl. # 1-8
Open circuit, open injector, failed IDM
P1291
High side # 1 (right) short to grd. or B+
Short circuit, faulty IDM
P1292
High side # 2 (left) short to grd. or B+
Short circuit, faulty IDM
P1293
High side open bank No. 1 (right)
Open circuit, faulty IDM
P1294
High side open bank No. 2 (left)
Open circuit, faulty IDM
P1295
Multiple faults on bank No. 1 (right)
Miswired connector or harness, short to ground
P1296
Multiple faults on bank No. 2 (left)
Miswired connector or harness, short to ground
P1297
High sides shorted together
Shorted wires, faulty IDM
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