Ok, I know you have a couple threads on this, but let’s cover a few easy things, and have it all in one place.
1. Does the tachometer work, and appear to be fairly accurate? Meaning, at idle is indicating the 600-700 RPM it should, it’s not reading zero until you give it some throttle.
2. Does the speedometer work and appear to be accurate? On this and the tach I’m not looking for “surgically correct”, but if you’re going 10 is shows about 10, not won’t move, or shows 50.
3. When you first started the engine, and the light is off, it’s truly off, not dimly glowing? I don’t think this is the issue since it will blink and stay bright solid, but want to check. Very dim all the time is a power supply to the TECA (Transmission Electronic Control Assembly).
4. Do ALL your brake lights work correctly? All 3 bulbs, the stop/turn/tail and the high mount in the back of the cab? They are not LED bulbs either? They don’t do anything “funny” electrically? Like make other lights light up when they aren’t supposed to. That TECA passes a small contol current through the brake light circuit, and any issues there can cause limp mode.
5. The FIPL (Fuel Injection Pump Lever (throttle position sensor)) on the drivers side of the pump is plugged in? Have you check the voltage from it? Center pin should be smooth from idle to WOT. It has a specific range, but right now I wanna make sure it just works.
6. Have you inspected the electrical connector on the passenger side of the transmission to the solenoid pack? It’s behind a heat shield (yess it needs to be there, the exhaust is very close and can melt an unprotected plug. Make sure there is no transmission fluid in the connector. If so, that can cause this.
I’d say more than likely it’s an electrical problem, since it starts as soon as you move, and that you can get the OD OFF to,work until you move.
The E4OD need a good tach signal (from the tach sensor on the IP gear cover), a good speed signal (from the VSS (vehicle speed sensor) on a brick, a pickup in the speedometer cable, on an OBS in the rear differential), a good throttle position signal (From the FIPL), the gear selection (From the MPLS (“neutral safety switch”) on the drivers side of the transmission) and it must be able to “communicate” wither the solenoid pack in the transmission.
There are some other things, but if those “basic” things don’t work right, then it can cause limp mode.
I would drive it least as possible, as limp mode is a get it off the road safely thing. I understand you need to get it to the shop, but I would make it as direcr and “short” as possible.
PERFECT!!!
I have some answers right now. I will check some things, and have other answers, later.
First, thank you very much for going to the trouble!!
And thank you Steve Phillips for sending me all the info!
1. tachometer actually appears to be pretty dead on. Yes, 600 to 700 at normal, warmed up, idle.
2. No way I can be positive about the speedometer. I have never had it over 20. But it does appear to be ok.
3. a.) If I disconnect the batteries when I come in for the night. Then when I start it in the morning, the light is completely off. No dim glow. Pushing it, turns the light on, solid. Then any driving causes it to blink.
I was disconnecting the batteries, because there was a parasitic drain. I think that drain was caused by the electric trailer brake assembly. Which I have now removed, and suddenly my 'wait to start' light, and my dome light, both work.
b.) If the batteries are left connected, then when I start it again in the morning, the off light is still on. Solid. (unless I turn it off.) But starts to blink again, when I begin to drive.
4. I have not checked the light over the cab. But the regular brake lights do work. No LEDs. (Backup lights are LED, though.) The brake light on the dash comes on, and stays on, most of the time. Only a time or two where I have seen it go out.
The brake pedal is sticky. It stays down, further than it should. Never returns all the way to the top. Even when I pull it up with my toe. And this DOES effect the brakes. The truck moves a lot more freely, when I pull that pedal up. That is going to be looked at by the shop, next week. I'll probably have them do a complete brake job. I hate brake work.
5. FIPL is connected. And it does work. I don't think the voltage goes as high as it is supposed to. Basically, I couldn't get the range I needed. Go low, it won't go high. Go high, it won't go low. I'll probably just have the shop replace, and adjust that, next week. If I don't replace it myself before then.
6. No. I have never looked at that. I will get to that as soon as I am able. And I will report back what I find.
And that synopsis is exactly the sort of 'comprehensive understanding' I was hoping for. Thank you!
Also, I was having the same thought, when I started this. It would be good to have all the information in one place.
Now I have work to do, a plan to get it done, and a whole lot less confusion about what I am doing. It'll probably be a few days. I have to take care of other things in life. But this may get-er-fixed, even if I have to buy parts. Or at least I may better know what to have the shop look at.