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Discussion Starter · #1 ·
I have a 1999 F250 Super Duty power stroke 7.3 turbo 330,000 miles.
Six months ago I started having problems starting my truck with the ignition. Put key in turn to start and some times it
would start like normal or may have to turn switch on off back and forth several times before it would start. may have to shift to neutral and it would start. At one point in time while on one of those times of on off with the switch truck having to
be jump I lost the wait to start light and no fuel pump. I found that the two bolts holding shift lever were loose. I fixed them
truck set all winter. I have new ignition switch, new neutral safety switch, new cam shaft sensor, one new battery the other one is good, new PCM relay in fuse box under hood, new #30 30amp fuse and last a new remanufactured PCM. I've checked every fuse by eye sight and with meter 6 - 8 times no blown fuses. I've disconnected 42 pin on drivers side to see if wait to start light would come back on 3 times no luck. I"ve disconnected plug to PCM to make sure no pins had been damaged all are good. Not sure what to do next so any help would be appreciated. Also the connection on the fuel heater is disconnected.
 

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You've obviously done your homework, checked the "usual" culprits, but the PCM is Not running (no WTS, no energizing the fuel pump).

The earlier problems of not cranking on the starter, the NSSW misalignment, ign sw and all, I would think are unrelated.

So now, what is it that keeps the PCM from booting-up? In most cases this is about Power to it (fuses, connections, shorted engine sensor) but you're aware of that and checked a lot of it. This could also involve Grounds allowing that power to flow and you can get much more in depth by confirming that there is the power, and good ground connections, coming into the PCM at the PCM's connector.

But, the most obvious answer might be the PCM itself...

As an afterthought,,,, you don't have any tuning, a connection on the board or anything, in the PCM do you?
 

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Discussion Starter · #3 ·
No I have no chip installed. I was wondering it PCM was properly programmed from oriellys? When I went to order it I took vin # and mileage info with me I offered it to the guy he said that it wasn't needed. When I pick it up he told me it was all programmed ready to go. In the box was a info sheet saying "F"- Flash programming required. Should I take it back?
 

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Somehow,,, I missed the "and last a new remanufactured PCM " (I gotta work on that reading comprehension thing more...) ;)

So you've changed the PCM? Our PCMs are Less complicated in that they don't require Flashing, but More complicated because they are more than just engine management (the "P" stands for Powertrain) and while you need a "match" to the old one it means that it's compatibility has more to do with how the truck's powertrain is configured (at least year-to-year).

What you want to go by is the 4digit Alpha/Numeric White sticker on the side, and while an exact match isn't always necessary, you want to be sure that your new one is compatible.

That being said, I believe (and somebody please correct me if I'm Wrong here) that you should, at least expect to see the return of a WTS light...

O'Reilly's would not have been my first choice, did you already turn-in the core? (depending on what the core charge was, it would give you the ability to send-it-out for testing).

Might be time to go to the PCMs connector and look for a missing source maybe...
 

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Discussion Starter · #5 ·
Yes I already turned it in. When I ordered the new PCM I took the old one in at that time and it called for a 402 and that's what he order. On the PCM connector are you referring to as far as source the power input pins #55, #97? And also when checking those with meter do I need to use a ground pin in the connector?
 

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No, not any "402", that's part of the general part #, this is Alpha/Num, my '02's reads VDH4 but, again, that has to do with it's configuration and unless that was Really out-of-whack, I would think you should still get a WTS.

Yes, 55-97-71 might be others too, you have a pinout?

And yes again, maybe take one of them and go to the Grounds to confirm it flows thru it...
 

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Discussion Starter · #7 ·
I've to go with my son he's closing on a home. I'll check those pins for power and will get back to you probably be this evening before I get back to do it. Would the key ingnition have anything to do with getting wtsl and power to fuel pump? Or dose that all come from PCM?
 

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06 6.0 drw 635 rwhp (retired) 08 KR build in progress
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Check power and ground at pcm, I like to use an incandescent test light as multimeter draws no current so it’s harder to spot a ground voltage drop or weak power supply. If those check out then resistance test the communication lines between pcm and obd2 port. Have you checked out the idm yet?
 

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Discussion Starter · #9 ·
On the plug in that gos to the PCM I tested pin 55 with pin 77 had nothing. Pin 71 with 77 key on and key off had nothing. Pin 97 with 77 key on and key off had nothing. I only have meter if I need to use something different you tell me what to get I try and get it. I have not check the idm. What do I need to do to check it out?
I'm not educated very much in diesel mechanics just enough to get thing messed up as you can tell. But I learn fast and listen well may have to have it explained in simple mans explanation you tell me what needs to be done I'll get it done. Thanks for both of your help.
 

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06 6.0 drw 635 rwhp (retired) 08 KR build in progress
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71 red should be hot from pcm power relay check fuses 24 27 and 19 for power those fuses should have power at all times. Pin 55 comes from fuse 2 and that fuse should be hot at all times as well. On the idm pin 14 should have power as well. You can use a multimeter or test light either one. Pin 97 on pcm should also get power from pcm relay. 103 and 51 should be ground
 

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If I remember right, the PCM turns that relay on itself -- via the key power signal -- so no power will come from the relay power path when testing with the PCM disconnected

EDIT: After looking at the diagrams, this is not correct -- the relay is operated by the key power
I was thinking of the IDM relay
 

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Discussion Starter · #12 ·
It's raining out right now here so it will be tomorrow after I finish up a job I'm on. As soon as I get them checked I'll let you know what I find.
 

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Would love to have an actual wiring diagram for the '99 trucks, all I have is the pinpoint manual -- sucks to chase wires in that
 

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These are for '99 ?
I have for '97, but Ford changes pinouts for the years so hard to know if what I have is relevant to this thread
 

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You may have already checked these (just got a chance to look at the diagrams), but is there power on fuse 30 in the fuse box, with the key on ? -- PCM power relay input

Also terminals 86 and 30 of the PCM and IDM relay socket with the key on

Referring to engine performance circuit 1 of 3 diagram that was posted by @Racer71
 

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06 6.0 drw 635 rwhp (retired) 08 KR build in progress
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Check power at pcm by backprobing the appropriate pins, I use T pins available at fabric stores but you can use a paper clip or something small to go into backside of connector.
 
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