New 7.3 IDI Owner Here

[PNW_noob]

Hey Everyone,
Yesterday (10/13/24 I purchased my first diesel rig;
- 1992 E-350 ambulance (seller said it was a 1994 but title says 1992)
- 67k miles
- E4OD auto transmission (I think)
For my very first trip I had to take it over the Snoqualmie Pass here in WA state (3k mile elevation, curvy, ~5% grade)
Overall the ambulance runs well but toward the summit began blowing a little blue smoke.
On the way down I encountered traffic and got the infamous *flashing overdrive* light (this is the light located at the end of the transmission selector stalk)
I wasn't in a position to stop the vehicle and decided to push on (I know many recommend against doing this)
When I had the opportunity I pulled off and located what I thought might be the "EEC TEST" plug (under the steering column inside the cab)
Installed the jumper wire but got no codes with KOEO (trouble lamp illuminates momentarily with key-on)
I completed the trip with no apparent issues

Next step is to pull the codes and begin diagnosis;
- Does anyone know where the EEC TEST connector is on a 1992 e350 ambulance (the connector i found looks slightly different than what I've found online)
- The connector I found is beige not black
- The "extra" loose single connector that others are jumping to is not present and it looks like they updated the connector by integrating the loose single wire connector (OR I'm totally looking at the wrong connector)

Anyway, thanks for sharing all your knowledge and I'll slowly post updates as I dig into this project.

Thanks!

 

[nelstomlinson]

I've been struggling with intermittent flashing "OFF" in my '94 E-350. I spent big bucks on an aftermarket transmission controller, and learned that the vehicle speed signal was dropping out, sending the OEM controller into limp mode, and causing the aftermarket to shift to first gear. I changed out the PSOM (speedometer) and the problem hasn't recurred. I suspect the original PSOM puts out a weak, distorted signal that's barely clean enough, and occasionally isn't quite clean enough.

What are your plans for the machine?

 

[XOLATEM]

Does anyone know where the EEC TEST connector is on a 1992 e350 ambulance

I am not sure I can be any help from having a fuzzy memory...but...I would look under the hood on the exteme left or right.

If there are two (different colors but same configuration) it is possible that one is for the ABS and the other for the TCM.

If it has never been accessed the connector may have a cover over it.

Other folks on here probably know more...I would rattle @Cubey 's cage and see what he has to say...

@franklin2 is good for that stuff and so is @trackspeeder

 

[Cubey]

This was posted recently on Facebook. I can't confirm or refute the two comments I showed below, but nobody else had an answer.

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[franklin2]

Here's a link.

https://www.thedieselstop.com/threads/1992-e350-diagnostic-port.541546/

 

[PNW_noob]

@nelstomlinson, Thanks for sharing your experience with the PSOM (Programmable Speedometer/Odometer Module) I'll take a look at the system.
@XOLATEM, Thanks, I did finally locate the EEC plug (forward of the driver side battery, attached to the body, black cover with red plug)
@Cubey, Thanks for sharing those photos, your top right photo shows the plug that i mistook for the EEC connector.
@franklin2, Thanks for the link but I'm a pretty visual person and i couldn't quite locate it with the info in that link.

Ultimately I had to remove the driver side battery, and battery support, feel very dumb for 20min. until I located it. (if it was a snake it defiantly would have bit me)

I got a code "15" which I think is a "keep-alive" data issue, the rig has a battery cut-off switch that kills power (I think it sitting with this switch open may have drained the power?)
I think I'll have to drive it again then pull codes when the issue re-presents.

Thanks everyone!
-Scott

 

[PNW_noob]

What are your plans for the machine?

Going to make a camper out of it.

 

[klook]

I have the same ambulance, mine started flashing after I had it awhile and now it does not light at all. Still works to operate overdrive. Mine would start flashing randomly at idle or when I let off the pedal completely. At this same time my tachometer stopped working unless I push reset on the center console and will work fine when I am above certain rpm's. If I let off and coast or come to a stop it does not work. There are a lot if integrated systems in these things. When my voltage got real low from not plugging it in overnight(twice)and I hit the glow plugs and then the starter. I lost marker lights and highbeams and I don't know what else. I had to pull the fuse on the large computer board in the back compartment behind the drivers seat to reset it it. I know the headlights have a wig wag mode that goes thru that controller....I decided that even though I have the schematics from Horton, the builder, I could not get it all out. Or it was not worth getting it all out.

Mine is a work truck

 

[XOLATEM]

I did finally locate the EEC plug (forward of the driver side battery, attached to the body, black cover with red plug)

So...that's where the little son-of-a-nugget-eater is tucked away....

Now we all know...good for future reference...

Thanks for doing the heavy lifting (no pun intended...moving the battery...you know...) on that so we all can benefit from it.

I got a code "15" which I think is a "keep-alive" data issue, the rig has a battery cut-off switch that kills power

Yeah...we (the transmission rebuilder community) were told about that soon after the E4OD came into existence because the issue kept surfacing...
I believe what we were told to do was to run a fused wire to the TCM so that the memory in the controller did not have to start from zero every time you fire the puppy up...
I would monitor the draw and see how long it can set before battery drain becomes an issue.

mine started flashing

my tachometer stopped working

Try replacing the RPM sensor on your IP drive gear cover...might clear up your flashing light...or...at least eliminate one thing that could cause it...

lost marker lights and highbeams and I don't know what else.

I would clean all of the grounds and see if that helps...

@nelstomlinson, Thanks for sharing your experience

@Cubey, Thanks for sharing those photos,

@franklin2, Thanks for the link

I am a firm believer in the world running well when positive feedback and gratittude is freely and appropriately given....Good job @PNW_noob.


This is why I mentioned @Max Mini a few months ago....still waiting for a modicum of appreciation...the way everyone jumped when she wailed...you would think at least a little feedback would have been forthcoming...

I am very grateful to have found this site and have learned a ton of good info that I will use for the rest of my humble existence...

Thank you very much, guys and gals...

Just my .02

 

[PNW_noob]

I have the same ambulance, mine started flashing after I had it awhile and now it does not light at all. Still works to operate overdrive. Mine would start flashing randomly at idle or when I let off the pedal completely. At this same time my tachometer stopped working unless I push reset on the center console and will work fine when I am above certain rpm's. If I let off and coast or come to a stop it does not work. There are a lot if integrated systems in these things. When my voltage got real low from not plugging it in overnight(twice)and I hit the glow plugs and then the starter. I lost marker lights and highbeams and I don't know what else. I had to pull the fuse on the large computer board in the back compartment behind the drivers seat to reset it it. I know the headlights have a wig wag mode that goes thru that controller....I decided that even though I have the schematics from Horton, the builder, I could not get it all out. Or it was not worth getting it all out.

Mine is a work truck

@klook how did you go about identifying who the builder was?

 

[PNW_noob]

@XOLATEM Thanks, I'll try adding a wire to the TCM (Transmission Control Module?)

And I totally agree with your "positive feedback" comment, forums only work when there are meaningful responses.

 

[klook]

@klook how did you go about identifying who the builder was?

It says HORTON on a couple of badges on it and it is on several decals and build specs sheets all over the rig.

 

[klook]

I contacted them and they sent me the complete electrical schematics for it.

 

[PNW_noob]

I contacted them and they sent me the complete electrical schematics for it.

@klook that's awesome.
I'll look for some badges on mine, currently there is nothing obvious.

 

[nelstomlinson]

Good luck with the transmission issues. Show us some pics of your progress on the camper part, too, please.