My first E4OD…what is the issue?

[steve phillips]

I have all the info aggiediesel101 mentioned virus free, yours for sending an email. I have more electrical information pinouts for solenoids and torque converter. yours for an email address or personal address i will burn it all to flash drive and send to you. I can tell you for sure if your brake light and light at back of cab arent working your tranny wont work right. If your overdrive light on gearshift is not working you have most likely , a burnt out bulb or damaged wiring, this will have to be fixed. on a 90 model truck, the ecm relay is most likely under the dash not mounted. It will be just hanging loose, it is the 1 you cant figure out what it does. It supplies all the power to the trans. will cause all sorts of problems, no codes thrown.

 

[OldIron82]

Well, I’ll let everyone know what the code say after I split apart the brand new scanner and fix the prong that is halfway pushed inside the body.

Junk

 

[BeastMaster]

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1. Here goes. With the selector in DRIVE:

…2nd, 3rd, and 4th… When you let off the throttle, the transmission neutrals out and when you get back on the throttle it reengages at the rpm it was at before you let off.

2. If you are sitting at a stop and get on the throttle and get up to highway speed it will shift flawlessly 1-2-3-4 but once you let off, the engine unhooks and is neutral until you get back on the throttle and bring the RPMs back to where you let off at.

3. Selector in 2: engine stays with transmission no matter what. Selector in 1… engine stays with trans no matter what.

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The E4OD controller is Designed to do this.

It's called the "Coast Clutch". It's an improvement for fuel economy. It's a sprag clutch. Once you get the hang of it, you can use the engine to get up to speed, then coast up to stoplights, saving you the fuel consumption of running your Diesel at unnecessarily high rpms ( higher than needed fuel injection rate ).

How Does A Sprag Clutch Work? | GMN Bearing USA

Sprag clutches, also known as one-way bearings, are critical devices in many industrial applications. Learn more about how a sprag clutch works here!

www.gmnbt.com

If you really want engine braking, use 1 or 2, or press the toggle button on the end the gear selector lever to use gear 3 and lockout OD for things like going down a long downhill grade so you can save wear on your brakes.

Next, trace back your brake switch wiring... My own experience was a misbehaving parking brake.

 

[OldIron82]

I thought it was Designed to do this.

The Coast Clutch.

What? This is normal operation for this transmission?
It feels so very wrong to me. You let off the throttle it is not hooked to the engine at all. When you get back on the throttle, if you slowly increase, it does not do anything until you get to the RPM it let go at and then it hooks up abruptly. I don’t want to run it that way because I’m terrified that it might be slipping and destroying itself.

 

[Black dawg]

Does the tach return all the way down to idle speed when you let off at at speed?

 

[BeastMaster]

Yes. Normal operation will disengage the engine from the drive train upon backing off the fuel. The sprag clutch disengages when the engine is placed in a situation where it would brake the vehicle. This decision can be overridden by the driver.

I edited my previous post to clarify what is going on here and why, with a link to how the coast clutch works.

I really like that clutch being there, now that I know what it is, why it's there, and what I expect it to do.

I often edit my posts if I think I was unclear on something ( happens quite frequently ) as I am trying to share some experience I have had and often fail to realize others have not experienced it yet. I'm quite sensitive to this as I find myself in the same boat all too often. The biggest point I can share is "why".

 

[OldIron82]

I have all the info aggiediesel101 mentioned virus free, yours for sending an email. I have more electrical information pinouts for solenoids and torque converter. yours for an email address or personal address i will burn it all to flash drive and send to you. I can tell you for sure if your brake light and light at back of cab arent working your tranny wont work right. If your overdrive light on gearshift is not working you have most likely , a burnt out bulb or damaged wiring, this will have to be fixed. on a 90 model truck, the ecm relay is most likely under the dash not mounted. It will be just hanging loose, it is the 1 you cant figure out what it does. It supplies all the power to the trans. will cause all sorts of problems, no codes throw

Does the tach return all the way down to idle speed when you let off at at speed?

Does the tach return all the way down to idle speed when you let off at at speed?

Yes correct

 

[OldIron82]

Yes that’s correct.
Completely back to idle RPM.
I have a class a CDL and I’ve driven big trucks since 2007. I’m not a fan of automatics at all. I always prefer a Non-synchronized manual. However, the automatics I have driven, none of them acted like that and this is big massive, heavy weight moving vehicles.
So if this is something that is unique to the E4 OD in this era of trucks, it’s just completely foreign to me and feel feels like there is something wrong.
I can get used to it if it is normal operation, but man it just feels weird.

 

[BeastMaster]

Well, no wonder you were concerned!

As a professional CDL, you are well aware of the massive amount of kinetic energy stored in a moving vehicle and concerned that energy may be misrouted into destruction of the transmission, maybe like having that thing shift back into gear 1 while you are going 60mph!

Well, that is what that sprag is all about. You are freewheeling until everything is in order to transfer energy from the engine to accelerate.

Should you choose the OD lockout button on the gearshift lever, the little LED on the lever will illuminate and the computer will lock up the coast clutch appropriately ( it's called the "coast clutch solenoid" ). There exists another solenoid that will lock up the torque converter which is also under control of the powertrain control module, aka transmission control module. That's the E part of E4OD.

 

[aggiediesel01]

I’ve never driven an ‘90-‘91 E4OD but I have driven and rebuilt the E4ODs in a ‘92 and my current ‘97. Both were rebuilt to the ‘97+ spec updates. Neither of them go into neutral when the accelerator is released. As I mentioned earlier however, the torque converter does unlock and re-lock when driving at speed and letting off the accelerator and then accelerating again. If that unlock/lockup is overly harsh or there’s something wrong with the converter…..maybe it’s slipping excessively and behaves like it’s going into neutral?

 

[Black dawg]

Should not return to idle.

 

[OldIron82]

Well, I used the OBD one scanner and the code I did get was 23 which is the FIPL.
So I’m going to get a voltmeter on that thing and see what it looks like and tomorrow probably just changed it out no matter what.

I have a feeling that is not the whole problem however and if it is, hallelujah.

I will report back tomorrow.

Thank you, everyone for your time and insight

 

[BeastMaster]

I am leaving a placeholder here for a later reply to your post. I have just been through this FIPL thing and I need some time to make a proper reply by editing this.

Quickie edit: Just to get you something now, here is a cut and paste from one of my notes apps:

TPS :: Cold Low 1.33 V High 4.32 V FIPL Hot/Run Low 1.15 V High 4.32 V

The Wes Paul likes it in the 1.25 - 1.38 range
Dirtleg likes 1.35 - 4.22

09/20/2024 Late Shifts, TCC erratic.
Was 1.33C/1.15H/4.32W
Adj to 1.28C/1.01H/4.17W

Tach :: VRS 53 pulses / rev
ALT :: Idle 180Hz Top 440 Hz
VRS. :: Idle

C is Cold, H is Hot, W is Wide Open



Quote

 

[OldIron82]

OK, I don’t have much more time to spend on this tonight, but I will say I did get a voltmeter on the truck and I have 5 volts solid at the lowest wire key on engine off.

The center wire is a hot mess.

0.50 V low 3.23 V High

I don’t have the damn torx fitting I need so I will get one and start with this tomorrow. Thank God, I didn’t drive this very far, I would say I could start here.

I have no idea how far the previous owner drove it like this, hopefully the damage is not already done. I know a bad or improperly adjusted FIPL is a mortal sin.

Oh the tachometer says 600RPM at idle

 

[Black dawg]

I usually start at 1.2 at idle.