The Diesel Stop banner
1 - 20 of 45 Posts

·
Registered
Joined
·
998 Posts
Discussion Starter · #1 ·
Well been away awhile trying to make some moola in this horrible season I'm having. Now my truck died. Heres what happened. Leaving walmart in parking lot driving slow of course. Suddenly just stops running. Died so smooth I didn't realize it immediately. Dead on side of lot. Still cranks over but does not start. I have stock oil gauge and a mechanical one. Notice when cranking I have no oil pressure. Check oil, full. Change CPS just in case. Tow home. Have infinity dash daq so try to run codes. It keeps saying can't communicate turn on key, which it is on. Try several times will not link. Try to load new program. Cannot connect still. Get my lap top and plug in AE. Finds usb port but cannot connect. So can't get codes if any, no connection for some reason. Notice that when trying key on and off my glow plug light no longer goes out, just stays on. At home now battery charger on, start cranking to get some oil pressure. Dash gauge reads normal after a few seconds, mechanical gauge reads nothing then creeps up to about 10psi max. So appear to have oil pressure problem. Pull plug on top of hpop put rubber hose on and crank. Oil flows out but not blast out. THen notice mechanical fuel pressure gauge on the prv under the hood reads 0 as well. Turn key on, climb under, fuel pump not working. Unplug, check with tester, no power in wires or plug near pump. Hot wire pump, pump works and pressure gauge goes to normal 65psi. So pump works. Still no start. So I'm stumped. First off, I seem to have lost low pressure oil, but have some pressure. But one gauge says ok, other not ok. Fuel pump works but is not getting power. AE, and infinite ( which is AE) Both cannot connect to the computer. Dash daq reads no gauges except pyros which are independent on there own. So I'm thinking I may have a dead computer?? I did check as many fuses as I thought were related to it, found no dead fuses. No communication makes me think dead computer, and also because fuel pump isn't getting power either. And also cause of the odd gauge activity like the glow plug light staying on, and the dash gauge working but not the mechanical. The mechanical never used to read until the motor started unless you cranked a real long time. So I suspect I have pressure. Although when it did read it read low. I'm out of ideas. Any suggestions?
 

·
Premium Member
Joined
·
4,341 Posts
Absolut,

I wondered where you have been.

Would the fuel pump symptom be tied in with the Fuel Shut-Off Switch by the passenger side kick panel?

You have so many things going haywire that its probably not that simple, eh?
 

·
Premium Member
Joined
·
15,098 Posts
Definitely an electrical issue. Likely a failed PCM if you've checked all the power sources and swapped out the PCM relay. Stop worrying about oil pressure for now. 10 PSI is plenty to start the motor. On a hot motor, that's normal for cranking speed. Even running it would only be about 25. The dash "idiot gauge" pops up to normal above 7 psi.

Recheck every fuse with a multimeter. Then, pull the PCM and check for power on all the appropriate pins - 7_3L_wiring_diagram_handy.jpg

After that, you're going to have to try swapping PCM's with a buddy to see if you can get it to start.
 

·
Registered
Joined
·
998 Posts
Discussion Starter · #4 ·
thanks guys. pcm swap is not possible unless I do the full pull. I have dp tuner programs for single shots and its related to the pcm serial number so I can't load programs on another pcm. talking to jody to see what I can do. All fuses are fine. I don't know were the pcm relay is, there is no click under the hood at all when I turn on key. Others said they here a click, and I think I used to. Lol. Cant figure out why its not communicating. Codes could help here. OBII port has power and powers the infinity, but will not allow communication. Its happened before, but only for the infinity and it was the feps cable for it that went. Truck never died for that though, and I only lost the infinity. As said, only way to make fuel pump go is to jumper it. No power at all at the plug on the frame. No glow plugs, light stays on, no one home. Im stumped. I heard of an IDM that causes the pcm to fail and shut down communication. Any thoughts on that? were is the IDM, and can I test it? Also what power and grounds should I check?
 

·
Premium Member
Joined
·
15,098 Posts
The idm is under the driver wheel well liner. I don't think that's it. You can still do a PCM swap just for a test. It will still start even if programmed for splits- just will run badly.
 

·
Registered
Joined
·
998 Posts
Discussion Starter · #6 ·
found the IDM fuse and relay. fuse good, relay clicks once when I turn on key. Didn't find the PCM relay, but the power train one next to the idm relay in the fuse panel under dash clicks as well. Noticed this time the dash gauges all cycle and zero out when I turn on the key. Doesn't that mean the pcm is functioning? I think my oil pressure is ok. Only power or ground issue I can see is the batterys themselves. They have always corroded up and get green both positive and negative. I changed the cable clamps recently, and they are already green. Used the dielectric grease stuff too. Don't know why that happens. there tight and everything else works, so I suspect there ok. Il clean them anyway to be sure. Pulled the PCM plug under the hood, and it looks clean and brand new. No corrosion. Im totally stumped. I rely on those codes so much. Now I can't get them. Need a ground and positive check list to see if I have a bad connection. that's all I can think of. I am apprehensive to try a new pcm without programing. so Im waiting to talk to Jody to try that. Originally he said never do that, then when I got my new injectors and was having issues, full force owner told me to try the stock tune. Blew the engine, ten feet outside my driveway. And that's why I ended up doing a full build. Injector miss fired and boom that was it. A check list would help for now. At least I can eliminate the wireing possibility. Not sure why my pcm would go if it did.
 

·
Registered
Joined
·
998 Posts
Discussion Starter · #7 ·
Well looking all night. havnt found anything really. Started cleaning all the grounds attached to the fenders and rad mounts, remounting clean with a ground attached to each one, then straight to ground on battery. That should kill any chance of bad ground. Cleaning all the batterys tomorrow. One odd thing I discovered because its dark now. After playing around and testing, I was locking up and shut the key off. Because it was dark I noticed that the first three digits of the odometer are partially lit up. Like half of each number and the decimal point. Not even eather. One number might have piece of top, half the bottom. the other just the middle???? THat can't be pcm related can it. I think something under the dash might be shorting and maybe messing the pcm up? Anyway. Another odd symptom. Rest of the dash seems to work fine, other than the oil gauge has the only reading since it wont start. But all the gauges do the cycle and zero out. Lights and chimes all seem to go right except glow plug light which just stays lit. Almost certain theyre not turning on and the lights just lit. Il have to test tomorrow. too dark. Still can't get it to communicate so testing has been limited to wires and grounds and fuses. Got a loner truck so at least I can get fuel to my hoe. Any ideas appreciated thanks.
 

·
Registered
Joined
·
998 Posts
Discussion Starter · #8 ·
Grounds all seem fine and fixed up anyway. Jody figures my PCM fried. Said I could get new one from car-parts.com, but isn't that a lovely web site. My god it was frustrating, and I never found it. There list of parts in the search engine was in the thousands I'd say, and PCM or power control module was not on the list. Trying a few wreckers around here. Might have one for an automatic. So still looking for a PCM to buy. Jody said I need to find out what fried it, he said its usually the fuel bowl heater, or a short in the harness. So looking for a harness too. I can't see myself dismantelling that monstrosity to trace wires. I'd rather buy a new one. And a PCM. Any way to test the fuel bowl heater??? Might just unplug it. ****ty in the winter, but its a 100 here now. lol . He also said I could get a stock recovery to get my vin onto the new PCM so I can load my programs. Any one want to explain what that is? Doesn't it come pre programed stock? And please tell me I can just take the PCM to were ever to get it done. I don't want another 150 tow bill as well to get it to ford or something. Then hope it starts when I re assemble in there driveway. OMG
 

·
Premium Member
Joined
·
15,098 Posts
I suspect the part about needing the VIN number corrected has to do with your fancy Infinity DX. I don't think the F5 or F6 would have required that. Did he have any input on trying a loaner PCM just to verify it would fire up? Hate for you to have to buy one only to find out that wasn't really the issue. You might have to send it to Jody to get it programmed to work with the Infinity as I'm pretty sure Ford will have to have your truck to do their programming. Jody can burn the PCM directly - Ford uses a tool that plugs in through the OBD port.
 

·
Registered
Joined
·
998 Posts
Discussion Starter · #10 ·
sucks about having to take truck to ford. there a long ways away. The infinity is a programmer, not a chip, so yes I had to provide the vin of the pcm to get the programs. It blanks the pcm then installs Jody's programs on there. So no codes, but have to shut off and wait 2min to load a new program. Chips just piggy back, that's why they toss all the codes and engine light. Still looking for a PCM, new or used. Any chance you have a wiring diagram that shows all the pins on the PCM, and were they go. Harness seems hard to find new as well. Used is a crap shoot, could end up with worse than I may have. Since I have the loner truck I have some time to trace wires IF I had a diagram. My rebuild manual doesn't show that for some reason. It does only cover High performance build, not stock so maybe that's why. Need a PCM, and a diagram???????
 

·
Registered
Joined
·
998 Posts
Discussion Starter · #11 ·
Ouch. Best quote so far on a pcm with the same number as mine brand new, was 577!!!!!!!!!!!!!!!!!!!! That's American too, so about 700 to my door. Most others. 176. How come mines always more expensive. Not fair. lol. Just in case some ones helping me find one, the number is 2C3F-12A650-DD. Thanks if ya find one.
 

·
Registered
Joined
·
998 Posts
Discussion Starter · #12 ·
Anyone? Still looking for a PCM and a pin diagram of the PCM so I can trace the wires to find what baked my PCM.
 

·
Premium Member
Joined
·
15,098 Posts
Are you looking for something more than the one I posted up at the top?
 

·
Registered
Joined
·
998 Posts
Discussion Starter · #14 ·
Actually I have that drawing and it helps on the plug side, but My pcm has 4 rows of pins and they are not numbered. So being a none electrical guy I cant figure out which holes to probe on the harness. Looking at my pcm at the pins, if I turn and orient it so its facing up as it does say on the pin part, Then is pin 1 , top left corner, then count all the way across top row to other side, top right corner being 26, then 27 would be below 1. Right? That's what confuses me on the pins in the diagram. there in a straight line unlike what I see. But yes the harness side is great. That post should confuse everyone. lol . Finally got car-parts.com to show me where my part is. Sent for a couple quotes. Hope to find one soon. Found another post you put out that had an IDM test and trouble shoot. Still havnt found the actual IDM, just the relays under the dash. Looked under the fender like some one said. Don't see anything there. My PCM harness turns upward and goes across the top of the fire wall to the other side. Most of it anyway. Rest goes to 4 huge plugs on the fender inside engine compartment. Cant find that IDM though. Looks like a big plug too so its gotta be there visible some were. Working a lot, so testing hear and there as I can, so weekend will have better results I hope. Thanks for the diagrams,
 

·
Premium Member
Joined
·
3,754 Posts
IIRC the IDM is on your drivers side fender well , you'll have to take out the plastic well liner, you'll find it there.
 

·
Premium Member
Joined
·
15,098 Posts
Like that nut in post #5 said, huh?
 

·
Premium Member
Joined
·
3,754 Posts

·
Registered
Joined
·
998 Posts
Discussion Starter · #18 ·
Ok, found a PCM, finally. Wrecker in Prince George is shipping it down today. That being said, I still need to find out what burned it up. Jody said it is the harness or the fuel bowl heater 90% of the time. Not knowing which pins and wires to test, I am just doing all 104 of them. I started with the fuel bowl first of course. So far, everything tests good in the harness and wires. Does anyone know if you can test the fuel bowl heater itself? Or do I just throw another part at it and replace it? Winter is a ways away, so I'm hoping just unplugging it will be ok for now, if it was the issue. I have about 90 more wires to test, so going to be awhile until I try putting that PCM in. If anyone can narrow down my testing by telling me which pins could be involved, eliminating the rest, that would sure save me some time. Thanks for all the help so far.
 

·
Registered
Joined
·
998 Posts
Discussion Starter · #19 ·
Got my new PCM, its a DE instead of DD, but that won't matter. Haven't put it in yet, waiting for Jody to send my recovery program. Hope to get it today as well. Looks like my issue may have been the fuel bowl heater. I'm unplugging it for now and ordering the bowl delete kit. All the wiring test good, but the plug for the fuel heater was darkened and black inside. Turns out when I did my build I figured I was being proactive and I dielectric greased all the plugs and connections. Turns out that stuff is crap, and it can conduct causing temporary shorts and especially bad grounds. So I have some plug cleaning to do. And I got the blue spray stuff for the batteries instead of the grease too. Its probably causing all the corrosion I can't stop on the batteries. The stuff actually does the opposite of what its supposed too. EEEk!
 

·
Premium Member
Joined
·
4,341 Posts
So grease is better for the battery terminals than the spray protectant?
 
1 - 20 of 45 Posts
Top