1995 7.3 missing - Ford Powerstroke Diesel Forum
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post #1 of 11 Old 10-16-2011, 08:22 AM Thread Starter
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1995 7.3 missing

I'm having a problem with my 95 PSD where it seems to be missing a bit. Still lots of power, no smoke, no codes. It was just missing on acceleration and pulling at first but now it's pretty much all the time. I took it to the Ford dealer they scanned it and did diagnostics including an injector self test (which I assume is a buzz test). They wanted to do a compression test for $700 so I brought the truck home and did my own compression test and all of the cylinders but one had over 400 pounds. Cylinder six has about 360. I put a tablespoon of oil in the cylinder and the compression shot right up to over 410. According to my book all is within tolerance compression-wise but I'm wondering if this could still be causing the unbalance in my engine. I've read somewhere that an injector shooting too much fuel into a cylinder can wash it down and cause this loss of compression but I would've guessed I would see some smoke if that were the case.

Another thing I've noticed my DC voltage drops pretty low when I turn on the key and down to 10.5 V when I turn the ignition. It takes a little while but after it started the voltage goes up to a nice healthy level. It does shake pretty bad when I first start up.

So far I have replaced all the glow plugs, cam position sensor, fuel pump, fuel filter, air filter, alternator, battery, thermostat(the truck was never warming up into the normal range and now it is). The glow plug relay seems to be working. I pulled the pressure sensor connector and it did not seem to have any profound effect. It does need a water pump as I can feel the fan rocks back and forth a bit.

When I first opened the valve cover on the driver side I found number eight glow plug had broken open and the innards were shorted against the head. The glow plug was not screwed in all the way and I thought I'd found my problem but fixing this really didn't help. I replaced the valve cover gasket and VC wiring harnesses on that side as they were melted a bit at the glow plug connection. I did not replace the incoming side of the VC harness as there was only slight melting on the glow plug connection. They did come with my valve cover gasket. I assume you have to snip off the old one and use crimp connectors to splice it into the old wiring harness. Didn't want to do that if I didn't have to.

This is my first diesel truck and I really like it. It's in perfect condition except for this one thing and I'd sure like to get it running smoothly again. Would appreciate any suggestions or things to try, but being in 1995 model it's probably not worth throwing too many dollars at.
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post #2 of 11 Old 10-16-2011, 08:38 AM
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try unplugging it with the valver vover off while its running(injector). Test all of them this way. I have had bad injectors pass the tests but cause misses and vibrations. They get weak. Maybe when u unplug one the engine rpm wont change as much. Try or actually, have you replaced the O rings on the injectors?

2008 6.4 f250 lariat 4wd
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post #3 of 11 Old 10-16-2011, 08:46 AM Thread Starter
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I did try unplugging each of the injectors one at a time last night. All of them seem to drop the RPMs to some degree but it's hard to tell exactly how much. Perhaps I can get someone to look at the tac while I do this.I will try again after a bit and see if I can tell how Affect each injector has. I have not messed with the injectors yet as I don't know how to do that. I'll have to bust out the book on that one.
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post #4 of 11 Old 10-16-2011, 09:19 AM
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Run it with th valvecovers off and watch the oil coming out of the injector oil deflector spouts. The discharge should be pretty even between them all. If there's one that's discharging less, you may need to remove the injector solenoid (4 torx screws on top) and see if the poppet screw underneath the solenoid is loose. I had this happen multiple times on the #7 injector on my 94. If it is loose, it takes a #8 linehead bit to tighten it, although a 4mm socket that has been ground down can work in a pinch (even the linehead bit doesn't fit perfectly). Cheers!

1997 F250 SC 4x4, E4OD, 4.10 LS, Basically Stock, Relocated Block Heater Plug, External Trans Filter, Tru-Cool Max, I/C Mounted but not Plumbed

SOLD - 1994 F350 CC DRW 2WD PSD, 5 Speed, 4.10 LS, SBC Con-O, Baldwin Filter, Tymar HPX Hose, DPPI DP, Bilsteins, $12 AIC, Coolant Filter, Explorer Overhead Console, A-Pillar w/ISSPRO Black Ice, EV Boost, and EV Pyro, Modified Pedestal, Gutted EBPV.
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post #5 of 11 Old 10-16-2011, 03:32 PM Thread Starter
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some of the injectors are shooting like a bullet and some just oozing and one not at all that i can see. how tight should the 4mm screw be?
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post #6 of 11 Old 10-16-2011, 06:45 PM
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I just tightened mine as good as I could get it (just snugged down, the linehead bit and 4mm socket will only let it get so tight before losing grip). If one were so inclined (I myself never got to it), you could order allen-head cap screws from Mylex to replace the factory ones. If you're down that far, you can also measure the clearances on each injector for the armature plate (that's the plate that the screw goes through). The clearance under the plate should not be less than 0.0015" (more like 0.004"). If they're less than the minimum the injevtors probably need to be rebuilt. Cheers!

1997 F250 SC 4x4, E4OD, 4.10 LS, Basically Stock, Relocated Block Heater Plug, External Trans Filter, Tru-Cool Max, I/C Mounted but not Plumbed

SOLD - 1994 F350 CC DRW 2WD PSD, 5 Speed, 4.10 LS, SBC Con-O, Baldwin Filter, Tymar HPX Hose, DPPI DP, Bilsteins, $12 AIC, Coolant Filter, Explorer Overhead Console, A-Pillar w/ISSPRO Black Ice, EV Boost, and EV Pyro, Modified Pedestal, Gutted EBPV.
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post #7 of 11 Old 10-17-2011, 08:12 PM Thread Starter
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All poppets tight, 50-55 lb fuel pressure, clean screen in fpr. I think I'm whooped. I have a friend with a 97' 350 dually with 33k miles he wants to sell. It's starting to look better than dumping money into this 95. It's a shame too as this truck is near perfect except for the miss.

Last edited by Blackbox; 10-17-2011 at 08:13 PM. Reason: spelling
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post #8 of 11 Old 01-21-2014, 07:29 AM
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Blackbox, did you ever figure out the problem/Fix? I have an 01 with the same kind of issue.

Thanks, Michael
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post #9 of 11 Old 01-21-2014, 09:18 AM
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following as well similar problem on my 97.

I replaced inj orings, cps, decent FP, decent HPOP pressure, no codes, chip on and off but more when chip is on higher levels. Passed buzz and cyl contribution test

Leads me to think Weak HPOP, FP or weak injectors.

1997 F350 4x4 PSD Crewcab Longbed, ZF Swapped South Bend 1944-5OFE, 4" Exhaust No Muff, TS Chip and Stacked D-Fuser, Cold Air, Terminator Gauge, 36" Goodyear's. Soon to come E-Fuel and 17* HPOP!
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post #10 of 11 Old 07-31-2014, 04:19 PM
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did anyone every figure out a solution to this issue? I am having the same symptoms with my 96
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hard start , low compression 1 cyl , low voltage , missing , runs rough

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