2002 F250 diesel - discovery and build thread.

[sgtsandman]

Thank you for confirmation. I just never saw it work properly. So I don't know what normal should be.

The dome light should come on when you open the door.

The lights coming on after the engine is shut off and shuttng off after a couple minutes is called courtesy lights, I believe.

They are nice to have but can be a catch 22 if you get complacent. There has been a time or two I left a map light on or the dome lights and found them to be still on a little while later. Thankfully, the 2019 is advanced enough that the battery saver system will kill them before they drain the start battery down too far.

I don't know if your truck or out work truck is that advanced since the system isn't working correctly.

I do know that the courtesy function for the radio doesn't work. A couple people killed the battery because they assumed the radio would shut itself off when the door was opened and it didn't. Of course, there is a nice sign on the dash right above the radio warning about that but that requires people paying attention and reading the sign for that approach to work.

 

[racsan]

On my ranger the door switch for the drivers side doesn’t work, so have to turn it on manually. I dont know how many times Ive forgot to turn it back off but fortunately I had put l.e.d. bulbs in so the current draw was minimal and I didn’t have a dead battery the next day.

 

[Curious Hound]

The check engine light came on last week. So I continued digging into electrical gremlins on this thing. I didn't like the info I was getting from the Torque Pro app on my phone. So I tried Forscan. I haventyet gotten Forscan working in my computer. But I did put Forscan Lite on my phone. And what a huge difference that makes.

I started with a pretty big laundry list of fault codes. After recording all those, I reset all codes to see what would come back. The short story is that I have 3 things that I am concerned with right now.

1. Instrument cluster is reporting a communications error with one or more other modules.

2. MAP sensor circuit low.

3. ECT is erratic

Not sure what to do about the communications issue. I have several reasons to believe there may be a problem with the microprocessor in the instrument cluster.

The MAP sensor is brand new. But not Motorcraft. It seems to pick a random reading and hover there, within a few 10ths of a psi. Might be around 1psi, might be around 7psi, might be 10 or 11 psi. Every once on a while, it works. But that is becoming less and less frequent. I just back-probed it. I am getting a solid 5 volts from the PCM. The signal wire, while I was testing, got about 1.2volts or 3.8volts depending whether I measured to the 5v wire or the 0volt wire. Disconnecting the hose and blowing into the sensor to give it a high pressure made no difference. Homing out the sensor, it reads in the thousands of ohms. But I don't know what it should be.

The ECT reads erratic until the truck warms up. No fault code. Just something zi see watching realtime data in Forscan. Sometimes really low, sometimes really high, like 500degrees on a cold engine. Instrument cluster reads fine all the time. My wiring book seems to show that with the diesel, the PCM is looking at transmission oil temp instead of Engine coolant. Doesn't quite make sense to me. But that's what the book shows. Transmission fluid is full, so that temp sensor should be in contact with fluid and reading it.

So, I think I’ll get a Motorcraft MAP sensor on the way and also an ECT sensor and maybe trans fluid temp sensor. The temperature sensors should be cheap.

Not sure about the communications bus issue. I'd like to try a different cluster. I also have intermittent ABS fault codes - ABS output power circuit failure and both left and right front inlet valve coil circuit failures. Is the module bad? Or is this a symptom of the communications bus issue? I unplugged the connector on the module yesterday, cleaned it with contact cleaner and put it back. No change. There is at least one other module at my local junk yard. But I hesitate to buy that for an unknown intermittent problem. Money trees don't grow in SC. Plus I have to learn how to bleed it after replacement.

I hope to drive this to Pennsylvania in about a week. Need to get the MAP sensor here before then.

 

[Curious Hound]

Oh, yeah. After fiddling around under the dash yesterday, I'm getting a fuel pump circuit fault. Previous owners had bypassed the original relay and installed a separate one hanging loose under the dash. Have to look at that again (first time was shortly after I bought the truck. ). I had gotten sidetracked yesterday and pulled the central junction box out and was unplugging and cleaning the connectors on the back of it. No good deed goes unpunished.

 

[scotts90ranger]

If your instrument cluster is anything like my '97 F350 I would pull the cluster then put some dielectric grease in the terminals for the speed sensor or just that whole connector... I did that and after a bit the speedo started working just fine instead of reading 0mph all the time...

MAP sensors don't read well on ohms since they're a digital thing, they take power and ground and spit out a voltage relative to pressure, if the ground side of the ECT is common with the MAP which it probably is the MAP can cause issues with the ECT... I could have sworn the ECT was reading the engine oil temp not trans but I've been wrong before, I think that's by the oil cooler on the drivers side rear of the oil cooler by the block heater? I don't remember what's down there...

 

[Curious Hound]

If your instrument cluster is anything like my '97 F350 I would pull the cluster then put some dielectric grease in the terminals for the speed sensor or just that whole connector... I did that and after a bit the speedo started working just fine instead of reading 0mph all the time...

MAP sensors don't read well on ohms since they're a digital thing, they take power and ground and spit out a voltage relative to pressure, if the ground side of the ECT is common with the MAP which it probably is the MAP can cause issues with the ECT... I could have sworn the ECT was reading the engine oil temp not trans but I've been wrong before, I think that's by the oil cooler on the drivers side rear of the oil cooler by the block heater? I don't remember what's down there...

My engine oil temp is on the HPOP reservoir. Speedometer is reading fine. But pulling the cluster and checking connections is one of my next steps. The MAP sensor is analog. It is a 3 wire device. 0 volts on one end of a resistor and 5 volts on the other end. Pressure on the device moves the "center tap" to vary the voltage signal sent back to the PCM by the third wire. My voltage readings are consistent with that. It just isn't reacting to pressure changes.

By the way, thanks for the comments. I'm open to any help. I don't always think of everything. The common grounds thing has passed through my brain. But in this case, the drawings don't support it. Too many other things sharing those grounds are working perfectly.

Here is the page showing the ECT being used if manual transmission and trans fluid temp being used if automatic. Of course, there could be a misprint in the book, too. It wouldn't surprise me.

 

[Curious Hound]

Motorcraft MAP sensor should be here Tuesday.

 

[Curious Hound]

So, the truck has been acting much better with the new MAP sensor. Awesome difference. But, the real kicker came today, on my trip to Pennsylvania.

I have mentioned an issue with my brake pedal switch. We'll, the pedal doesn't firmly return to the full untouched position. I have known this. It's just barely off, by maybe 1/8". The brake lights work fine. But the other set of contacts that are supposed to deactivate cruise control never make it to their natural state. So, while driving along at 75mph, this morning, I tried pulling the pedal up with my toe and holding g it to see if I could get cruise control working. No dice. But when I did that, I heard and felt the torque converter lock up. Ding, ding, ding, ding!!!!! That's the key to my lousy gas mileage! I've been driving around with a slipping slush box torque converter. My mileage lately has been less than 14mpg.

So, when I stopped to use the rest room almost 200 miles into the trip, I bought a pack of small bungee cords and did a "trail-side field modification" to make the pedal retract completely. As a result, when I bought fuel at the 444 mile point in my trip, my mileage calculated to 17.5mpg. Can't wait to calculate again after another 3/4 tank all with the bungee cord doing its magic. Might be closer to 19mpg. And today was cruising a spirited 75-80mph most of the way up I-85, I-77 and I-81. This truck loves to run 80mph.

I love my $4 fix. The MAP sensor probably helped, too.

 

[RobbieD]

So, the truck has been acting much better with the new MAP sensor. Awesome difference. But, the real kicker came today, on my trip to Pennsylvania.

I have mentioned an issue with my brake pedal switch. We'll, the pedal doesn't firmly return to the full untouched position. I have known this. It's just barely off, by maybe 1/8". The brake lights work fine. But the other set of contacts that are supposed to deactivate cruise control never make it to their natural state. So, while driving along at 75mph, this morning, I tried pulling the pedal up with my toe and holding g it to see if I could get cruise control working. No dice. But when I did that, I heard and felt the torque converter lock up. Ding, ding, ding, ding!!!!! That's the key to my lousy gas mileage! I've been driving around with a slipping slush box torque converter. My mileage lately has been less than 14mpg.

So, when I stopped to use the rest room almost 200 miles into the trip, I bought a pack of small bungee cords and did a "trail-side field modification" to make the pedal retract completely. As a result, when I bought fuel at the 444 mile point in my trip, my mileage calculated to 17.5mpg. Can't wait to calculate again after another 3/4 tank all with the bungee cord doing its magic. Might be closer to 19mpg. And today was cruising a spirited 75-80mph most of the way up I-85, I-77 and I-81. This truck loves to run 80mph.

I love my $4 fix. The MAP sensor probably helped, too.

Good idea with the bungee!

Necessity is truly the mother of invention . . .

I think that you might appreciate this story.

One afternoon at the transmission plant I just retired from, a pneumatic cylinder in an automation cell blew the rod end cap and the cylinder wouldn't return. Line down. MRO didn't have a replacement in stock. So one of the Equipment Service guys rigged rubber bands to pull the cylinder back when not advanced. The damn thing worked and cell ran fine through the end of night shift, and was still working that way when the line restarted the next morning.

When that ES shift came back in, the head of ES and the techs were standing at the cell watching it run, still with the rubber band technology, and the head of ES was reaming the guy for making such a hack repair (remember, no replacement cylinder in stock). About that time, the plant manager walks up, pumps the ES tech's hand, and says "GREAT job! You kept the line running!".

Nothing more was said about the "hack job".

 

[Curious Hound]

So, I've been wanting to build a safer, more suitable dog bed for Livvy. No matter how I stuff things under her, she finds places for her legs to poke through by the door when she falls. So, 1/3 of the back seat was easy to remove. But, that reminded me that I needed a better way to store my bottle jack. So, I modified the original jack bracket behind the seat. Then, built a sub-frame for the dog bed. I think it's going to work well.

Built a cage onto the OEM jack bracket.

Nice, neat and snug

Sub-frame for the dog bed. Bolted in where parts of the seat were assembled.

Nice access for storage underneath.

Next, will be a slightly larger frame on top of this, that will follow the contours if the door, fit snug to the front seat and slightly overlap the middle part of the back seat. It will have a layer of expanded metal to support a soft, padded dog bed that she already owns.

 

[RobbieD]

Nice work. That's gonna be a great place for the relief driver to sack out.

 

[Curious Hound]

Just a few details left.

This is the bed she normally has in the truck. For long trips, I can put her bigger, softer bed here.

 

[Uncle Gump]

Sure looks like she approves...

 

[JoshT]

You've probably moved past this already, but...

The 2000 F-250 in my sig is a manual transmission. Back after I got it I started digging into why it would never warm up according to the temp gauge on the dash. Turns out the the reported engine coolant temperature isn't from a coolant temp gauge. That is actually a reading calculated and sent by the PCM based on the engine oil temperature. In other words the gauge in the dash is a fake, so are the readings displayed by Forscan or any other OBD based ECT gauge. Things might be different for your automatic, but it;s something to look into and consider.

Also FWIW, 19 MPG averaged over a tank is about what I'm getting out of mine as well. Your auto should be doing the same or possibly better with no load. Sounds like your trail fix got something straightened out.

 

[Curious Hound]

You've probably moved past this already, but...

The 2000 F-250 in my sig is a manual transmission. Back after I got it I started digging into why it would never warm up according to the temp gauge on the dash. Turns out the the reported engine coolant temperature isn't from a coolant temp gauge. That is actually a reading calculated and sent by the PCM based on the engine oil temperature. In other words the gauge in the dash is a fake, so are the readings displayed by Forscan or any other OBD based ECT gauge. Things might be different for your automatic, but it;s something to look into and consider.

Also FWIW, 19 MPG averaged over a tank is about what I'm getting out of mine as well. Your auto should be doing the same or possibly better with no load. Sounds like your trail fix got something straightened out.

Thank you. Between Forscan and the wiring diagrams, I figured out that there is something funky about engine coolant temperature. Just don't have the exact details worked out in my head. I think I'm having some issues with the transmission not always shifting consistently. That is probable the remainder of my fuel economy issues, other than the fact that this thing has 278,000 miles on it now and has ingested dirt in the past. I'll be slowly working through things to yry to improve it. But, I'm relatively happy with how it's running now. Is it perfect like a brand new truck?no. Not at all. But for what it is, I think I'm pretty close to getting the max it can provide.