Some of you may remember back in November when my truck had a glitch that took out my fuel pump and pcm communications. Took 2 weeks to get my truck running. THe post was "Major Electrical Issue" . So drove to lake today. 100yds from parking lot, truck dies. Turn over nothing. Again all gauges dead, no pcm communication. Heres the Killer. Buddy tows me to the lot with his GMC Sonoma. BooHoo, hope no one got pictures. Pop hood, immediately unplug the EBP Sensor. Pump fires back up, communications back, truck runs great. Thank the gods. Plug back in truck dies. SO drove all the way home with it unplugged, wondering if its hurting anything. It actually ran fantastic. Couldn't notice it was unplugged. NOW, why is my truck eating these up. I still have to pull the tube and look at it, but last time it wasn't coked up. I'll clean it again anyway. What cause this to keep happening. There not cheap, and now I need to carry a spare and replace every couple of months it looks like.

 

Have you inspected the harness (wires and connectors) for the EBP sensor? I cannot remember, was the sensor you bought OEM or aftermarket?

It almost sounds like your harness has a bare spot in it somewhere and when it makes contact it is causing problems.

 

The sensor was from Napa. The thing is, its a totally unusual failure. In 99% of this sensor failures, you just get bad mileage, and maybe a bit of power loss. But for some reason when mine fails, it continuously sends the 5v reference signal, which is what tells the PCM theres a problem, and it shuts all the stuff off and won't communicate. Now it happened twice??????? So if it was shorting out, the signal would be lost, not sent. I think the sensors are sticking some how. I have to pull it still to see if its coked up. I cleaned the tube but not the sensor since I got new. I think its continuously pushing the diaphragm sending that signal because it may be coked up. I will look this time instead of just throwing it away. That said, how can I stop this?

 

Can't say for sure that the NAPA jobber is the problem but the word here is genuine Ford sensors only. I cheaped out once with a water sensor, which didn't work when I got it. Ford only for me from now on. I know they're obscenely expensive but...

 

So got it apart and as suspected, the sensor is toast, tube is real clean still, and sensor was as well. All I could find is that on one of the 3 terminals on the plug side, one of the side by side ones was green and gunked up with green corrosion. I cleaned that up, maybe it shorted there. The post on the sensor was green too. SO off to Napa to see if warranty applys on this one.

 

Your explanation of the 5 volt reference above is somewhat incorrect. There are 10 sensors on the 7.3 and 8 are on the reference voltage / Signal return.

Any one or more could be suspect and not the EBPS. Which is a not testable other than using OHM for variance because it senses pressure variations. Anywhere in the circuit or shared ground (feeds are not shared) could cause the issue. Unplugging one at a time will identify the bad circuit or device.

If you found "green stuff" then you have located high resistance and not a bad sensor.

These rigs are getting older everyday and need additional preventive maintenance to keep them up.

 

Ok, went to Napa. Had a 36mnth warranty on the sensor. So its back in action. I cleaned up that green goop and put some electrical grease on there to protect it. Hopefully it holds on this time. I'm hoping it was a bad connection cooking the sensors.

 

The sensor was definitely gone, since the new one works fine now. After 2 weeks diagnosing this issue with others on this site, it was determined the only way to put the pcm into no communication off this sensor was to send the 5v signal continuously. Can the resistance cause this, I don't know. But since the green goop was all I could find wrong, I,m assuming it was the reason this happened. Why green goop. I have no idea. I figure maybe bad connection there like a battery does. So cleaned it up, gooped it up and seems to be connecting fine now. That said. I cleaned it first, started the truck and plugged the old sensor back in and it quit immediately. Unplugged it and started right up. So the sensor did fail, what ever causes it.

 

36 month on electrical sensors? Never heard of that, that's good. But lots of us had this sensor go out and never had the engine shut off that I've read. First I've seen this.

 

[QUOTE=Bonanza35;15982385]36 month on electrical sensors? Never heard of that, that's good. But lots of us had this sensor go out and never had the engine shut off that I've read. First I've seen this.[/QUOTE

THis is my point. It only fails this way about 1% of the time. Vary rare. The whole reason I wish I knew why. It does make sense that a short or the resistance cooked the sensor in the on position. Heat will do that. Resistance causes heat. I have 36mnths on this new one. So we will see how it lasts now that I cleaned up the plug. At first, the Napa girl said" oh no, electrical parts have no warranty". I said "F" you, its only 5mnths old! I paid 141 bucks for that thing. So she punches it in, and totally surprised says i'm lucky it has a 36mnth warranty. Gee, it better be for that kind of coin!

 

This is my point. You're missing the point. Reread

 

Ok, what is the point. No pride here. Its fixed for now. Just can't figure out why it happens except the possible short at the plug. I won't know until or if it fails again. The shut down is no mystery. PCM is supposed to do that. Protects it from frying. But the reason the sensor fails that way is a mystery unless it proves to be the corrosion. So whats the point. Steer me right here??

 

Just one more note. This actually is not an uncommon issue. Happens all the time. In fact its usually a gasser that it happens too because they use back pressure to adjust more perameters. But when this first happened we spent 2 weeks trying to find the issue. No luck. Then a member sent me a you tube video of a mechanic trouble shooting the exact same issue, except on the more common failure, the map sensor. So after seeing the video. Did what he said, unplug one at a time until the fuel pump fires up. Then you have found the sensor killing the PCM. And as we see, it is true. So not uncommon, but more uncommon on our trucks and with this sensor. Our map sensors fail all the time causeing this to happen.

 

I’m trying to help you here. True I’m not an easy guy to getalong with. I get it. I was always pick last for Kick Ball. I sometimes forget.No one is saying your sensor was not bad. Or, that is doesn't run now. What I'msaying is the field could be its cause is extensive.
We can agree, something has "fried" the sensor[your phrase]. The question is not whether or not it happens every six monthsbut why it happened at all. We must identify and correct or it’s not fixed.That is the true point of trouble in the circuit. Which, has 104 wires and notjust the three you see at the sensor: Feed, Ground, and Signal. (Up front, DoNOT use a standard Test Light when troubleshooting the Circuit. PCM Damagemay occur!).
You could have a thermistor which is pulling the circuitdown resulting in overheat of that sensor due to corrosion. And, in the end,the circuit which was affected was never the issue. In order to locate an issuewhich can cause another sensor to fail, all potentiometers, pressure sensors,and Hall effects (cam, crank, and vehicle speed sensors) must be isolated tofind a short which cases spikes elsewhere. PS: Thermistors can be left pluggedin and will never cause this condition due to internal design differences. Trythis, while measuring reference voltage with the key on, at say the MAP becauseof easy access, begin unplugging the sensors one at a time and see if there arechanges in voltage by .5 or more. This will isolate a circuit, such as the onewith the green stuff (which is actually copper wire - that's why the wire orpin should be replaced). To test the PCM with the sensors all unplugged, thenyou must disconnect the PCM and measure for a short to ground on the referencecircuit. That eliminates the PCM. For instance, No short to ground, then youhave a PCM problem. (Just FYI - Make sure you check all PCM powers and groundsbefore replacing the PCM - Processors and solder can easily become dislodged. Especiallyif someone is installing a chip in HURRY. Here are some rules that don'tchange. Grounds may be shared between any inputs, Signal wires are NEVER sharedbetween sensors, the 5v reference can be shared (externally from the PCM) withpots, psi sensors, and Hall effects but never with thermistors - OUR TRUCKS. Youcan have 2, 3, 4, 5, 6, different wire combinations doing as many differentinputs. Luckily ours is limited to an easy 3.
Pressure sensors (EBP) don't "usually" go badunless something external messes with the diaphragm. Be it soot, coke, or ascrew driver. They're just a diaphragm which pulsates as a vacuum 2 stroke carburetordoes.
So the question still remains, why?

 

Ok, I get it. What you not getting is all that's been checked. The previous post "Major electrical issue" is huge, and has 2 weeks of data. Part of that was the complete dismantling of all the harnesses on the truck, testing every wire, re building, and testing again, then re installing and testing again. All that twice, with two different PCMs in case that was the issue. Also all components including PCMs and I have two IDMs as well. Every pin on the PCM, IDM, fuse box, has been checked, re checked, and every wire off of them check approximately 5 times. All grounds checked and re done for piece of mind. Everything tested perfect, except the bad sensor. ONLY thing I missed. The green goop on the plug. I test from the back of the plug and never even looked until today. I am hoping that was it. So call me proud. But I've tested everything. You are right on the sensor though. It was clean, so I assume the diaphragm was ok too. So it died an electrical death for sure. I hope it was the green goop shorting it. This is why I say my only recourse now is assume it was the goop, and see if it dies again. Because I have nothing left I can test. Its all good. If it does fail, then a whole can of worms is opened because as said, its all been tested good. What else can it be, unless something came up in the last couple months that's new and caused the same thing. Doubtful. So yes, why? we won't know until it makes it or not. The only variable known is fixed.