Another E4OD flashing OD light thread

[Greenie]

Any codes? Have you tested for AC ripple? Set engine speed at 1,500 RPM and set a multimeter to AC. Measure at the battery terminal. Anything more than .50 VAC will cause electrical issues. Good solid grounds and a throttle position sensor that sweeps without any hiccups.

 

[trackspeeder]

Unfortunately, I’m still not trouble free. With everything I have done so far, the tranny has never shifted and felt better than it does right now. But I am still getting the limp mode once in a while. Still hot on the trail to solve this mystery.


Does anyone know what exactly what parameters the computer compares to go into limp mode?
I’m thinking I need to systematically look into every sensor the computer watches to throw the limp mode command.
I’ve been told it compares engine speed to vehicle speed. I know the VSS is in the rear differential and that signal goes to the PSOM and from there, I believe the computer. But where exactly is the engine speed being monitored from? And where all does that signal go?

The TCM uses the tach sensor for RPM. VSS for speed. TRS for gear selection and MAP for altitude.

Tach sensor signal goes to the TCM.

 

[XOLATEM]

Have you checked your BARO sensor..? It uses a frequency signal...

1993 7.3 Turbo, E40D, MAP/BARO?

Howdy fellers, I've got a noggin scratcher going here. Can the BARO sensor cause transmission shifting problems on an E4OD, in an IDI truck? Truck info- 1993 F-350 single rear wheel,4x4, Centurion, 7.3, Factory/ATS turbo. ( 4 Door 1 ton Bronco) 521k on truck, 371k ish on trans. Truck sees...

www.powerstrokenation.com

 

[charredsteak]

Ok. I’ve got a pretty nice scanner. Not one of the cheapies. I’ve had it for years. Usually works fine for me. I’ve ran the codes on this truck twice in the past week. Both times comes back 011. Which means all good. No trouble codes found. I’m not sure what else to do to get the codes.

Innova 3145 was my go to, but if it's reading codes it should be working. Would definitely plug into it once it starts acting up, keep your code reader in the truck or something. Pretty sure EEC doesn't hold on to codes for very long like an OBD system would

 

[Cant Write]

I’m still thinking with you being in the rust belt, the harness is compromised somewhere causing your intermittent completely random limp mode.

What about that thread @XOLATEM posted.

Great job sticking with it and what you have done so far!!

 

[94NAIDI]

Ok. So the little two wire sensor I took a picture of in my previous post with some oil on the wires is the only source for engine speed the computer compares to vehicle speed to determine transmission slippage.

My truck is extremely slow. Meaning, she is really sluggish. I have no other experience to compare if this is normal 7.3 IDI performance or not.

But is it possible that my truck is so slow that the computer thinks there is a mismatch due to lack of power?

I really think my injection pump timing is off causing my truck to be sluggish. Any chance that could make the computer think there’s an issue in the torque converter?

 

[94NAIDI]

Unfortunately I am still chasing this issue. It went away for a while but now is back. I have ordered an engine speed sensor as well as a TPS both Motorcraft brand. I’ll install those and see if anything changes.

 

[Diesilee]

Anything new on this? All of us E4OD owners want to know!

 

[94NAIDI]

I have not updated in a while because the issue is so random. But I did end up replacing the engine speed sensor as well as the throttle position sensor. Or whatever they called it in 94. This did help, I think. I aligned my TPS for 1.18 volts at closed throttle. It did not want to get to the recommended 1.2 volts. After doing these two replacements, the truck has been much better, but not completely fixed. What I mean by this is the truck will now go weeks without ever going into limp mode. I have even taken it on 3 hour trips with no issues. I was convinced the problem was solved, but then the OD light started blinking for about 10 miles the other day and eventually fixed itself on the same trip. This has happened twice in the past month. Which is way down in frequency compared to what it used to be. I drive this truck many miles every day. Obviously all of the things listed in this thread have helped the problem. But not completely solved it. I am starting to think that the TPS was a big part though. Since it is better now than it has ever been since replacing it. I did get the black TPS. I have heard the grey ones are better. I may order a grey TPS as soon as I figure out the correct P/N for them and see how that does. But for now, the frequency of it messing up is so low that I am pretty happy with it. I will eventually get this resolved. But as you can see in this thread, it is a long trial and error process.

 

[Ohiogoldfever]

Thanks for keeping this up to date. My 92 has a hard shifting issue I’m trying to work through. I’ll be referring to this thread a few times I’m sure.