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2000 f250 7.3 Very odd issues Crank no start Has new batteries 240rpm cranking After going over all fuses and relays and verifying that they work I finally hooked up a friends Autel Ultra. The scanner will sometimes enter the pcm and sometimes wont. I found it will usually work right after i turn the key, but then sometime later it will not have any communication with pcm. it goes back and forth and sometimes when turning key back on it wont communicate. I hooked up my breakout box and verified grounds and voltage. Im not sure if im getting a bad connection but when hooking up to a random body ground I get about 20ohm resistance on both ground pins on the DLC. If i connect a jumper from battery to lead and then test i still have about 1.6 ohms I thought maybe there is a ground issue but then I discovered that the brake booster was leaking powersteering fluid onto the pcm. I pulled it out and the connector was full of fluid. I took everything apart and cleaned with contact cleaner. I was busy so It sat for a week in front of a fan to dry. cleaned the female plug for it as well and let it dry. I did have some gunk built up on the male pcm pins that resembled corrosion but i think it was just fluid that had gunked up. I cleaned it all the best I could. Plug it back in and still weird communication issues and crank no start.
After suspecting the autel of having an issue, instead of the pcm, I hooked my laptop up with forscan. As far as I can tell I no longer have communication issues and every time i tried accessing the pcm it worked fine. Switch back and autel doing same thing where it has no comm with the pcm randomly. I feel like maybe the pcm is compromised but not 100%.
Back to Forscan - Everything reading fine. Only codes i can get are from unplugging the ICP.
I did just notice that if the ICP is plugged in, the service engine light goes immediately off. If it is unplugged it stays on like it should. does this mean short in icp/wiring/pcm? Fuel heater unplugged for all of this.
LIVE DATA - With icp plugged in The ICP goes straight to 14,xxx kpa/psi and the IPR almost immediately goes to 46%. With the icp unplugged the icp goes to 15,5xx and ipr goes straight to 41%
Note - Buzz test produces no noise at all but also shows no codes with it. None of the KOEO demand tests produce any codes at all. While cranking and testing over and over I get absolutely no new codes in the pcm.
Not sure if i have several issues or just one weird one causing multiple problems.
Fuse for fuel heater is replaced? Oil level normal?
I'd focus on the buzz test. Injectors are not getting the command to fire. Typically PCM or IDM and all related wiring. Any wear on the bottom of the 42 pin harness?
Should have clarified, the fuse was never blown, I had just unhooked the heater in case it was causing some issue.
Oil level normal on stick and in reservoir.
No wear at all everything looks good there.
Does the fuel pump come on when the key is first turned to run? Do you have B+ voltage at pin 30 of the IDM relay? Continuity between pin 85 and ground? When the key is in run to you have B+ voltage at pin 87? If Forscan is connecting every time without issue then I would ignore the other scanner issue and not consider it a symptom. I agree the buzz test is the best starting point here. If it's not able to communicate with the injectors then the truck will never run. If the correct power is going in and out of the relay then the next step would be to test the IDM and harness. Here's a link for the procedure from the tech section.
Yes fuel pump comes on like normal.
I had just a short amount of time after work to test it.
Have b+ at pin 30
KOEO with relay in i do have b+ at pin 87
Does the fuel pump come on when the key is first turned to run? Do you have B+ voltage at pin 30 of the IDM relay? Continuity between pin 85 and ground? When the key is in run to you have B+ voltage at pin 87? If Forscan is connecting every time without issue then I would ignore the other scanner issue and not consider it a symptom. I agree the buzz test is the best starting point here. If it's not able to communicate with the injectors then the truck will never run. If the correct power is going in and out of the relay then the next step would be to test the IDM and harness. Here's a link for the procedure from the tech section.
Google has royally confused me. I found an incorrect diagram that showed be the pin towards the rear of the truck in the fuse box was pin 85.
After searching more i realize that the pin to the front is pin 85.
pin 85 towards the front is OPEN.
Where does the ground come from for this? I couldnt find a good diagram.
Ok i think i found an accurate diagram. Pin 85 on the relay comes from pcm connector pin #80. is that correct? Does this mean the pcm is faulty if its not sending that ground signal?
If its pin #80 I can test in morning to make sure its not a bad wire.
According to this diagram from the tech section it goes to pin 80 of the PCM, listed as IDM enable out. So it would appear the PCM is responsible for providing ground to the relay that powers the IDM. I'm not real familiar w/ what parameters have to be met for the PCM to trigger that signal. I'll have to investigate that one. When you checked resistance was that w/ the key on or off? I'm thinking the key would need to be on but the 86 pin would have to be disconnected. You'll never get an accurate reading if the circuit is energized but the PCM can't trigger the ok is it isn't powered up.
I just saw the earlier post that pin 87 is showing B+. That means the relay is activated and the IDM should have power. So next up would be pulling the inner fender to access the IDM for testing.
I just saw the earlier post that pin 87 is showing B+. That means the relay is activated and the IDM should have power. So next up would be pulling the inner fender to access the IDM for testing.
According to this diagram from the tech section it goes to pin 80 of the PCM, listed as IDM enable out. So it would appear the PCM is responsible for providing ground to the relay that powers the IDM. I'm not real familiar w/ what parameters have to be met for the PCM to trigger that signal. I'll have to investigate that one. When you checked resistance was that w/ the key on or off? I'm thinking the key would need to be on but the 86 pin would have to be disconnected. You'll never get an accurate reading if the circuit is energized but the PCM can't trigger the ok is it isn't powered up.
I just saw the earlier post that pin 87 is showing B+. That means the relay is activated and the IDM should have power. So next up would be pulling the inner fender to access the IDM for testing.
Ok against my better judgement i went and fought the mosquitos.
23 & 22 - 3.1ohm
23 & 7 - 3.7
23 & 19 - 3.5
23 & 9 - 3.5
The rest were open like theyre supposed to be.
I found the diagram for the Connector over the valve cover. What should resistance be from the IDM connector to that connecter?
The rest were open like theyre supposed to be.
I found the diagram for the Connector over the valve cover. What should resistance be from the IDM connector to that connecter?
Less than half an ohm if you're talking just the wire and terminal connections.
Will go over the harness tomorrow when I get off work.
1- would having an electrical issue on just 2 of the cylinders cause a no start condition? I mean in reference to the two Cylinders that were way out of spec.
2- why would the icp being plugged in make the check engine light not stay on (KOEO) like its supposed to?
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