Advice on troubleshooting 7.3L IDI

[daimoku]

Hey guys, I've been lurking for a while, but finally registered. Used the great info here as a reference while shopping for my first diesel. I finally took the plunge last week and bought a '94 F250 7.3L IDI with 95k on it. The transmission was shifting rough and the OD light was blinking so I had a transmission shop pull the codes prior to purchasing the truck. Here are the codes:

• 23 TP/FIPL Sensor Out of Range

• 14 Profile Ignition Pickup (PIP) Erratic

• 99 Idle Not Learned / EPC Circuit Fault

I have an analog multimeter so I used that to adjust the TPS (tested okay, no dead spots). I went ahead and ordered an el cheapo digital multimeter so I can fine-tune the setting. I've done some research on the error code 14 and 99, but I haven't found much info.

Here is the info I found for error code 14:

• I read that the tach sensor may be the culprit. To test this you can do the key on, engine off self test and key on engine running tests to test for a signal from the tach.

Here is the info on error code 99:

• "Code 99= electronic pressure control circuit control failure (E4OD). Once again check fuses and wiring to the transmission. This is assuming you have the E4OD. I also have a listing for this code as idle not learned, but is more likely the transmission code. That would probably be an EPC circuit failure. If this circuit fails line pressure should go to full at all times. The full line pressure puts a good deal of extra load on the engine, and will usually effect the idle. It is especially noticeable if your engine is already in need of a tuneup. You will need to check the electronic pressure control solenoid and its wiring.
  
  Either of these could be causing the EPC code.
  ISC needs to learn (Let idle for 2 minutes, Erase memory and retest)"

Do you guys have any other advice regarding the error codes? I'm going to perform all the regular maintenance stuff, but I wanted to get these issues squared away first. Thanks in advance for your help!

[strokin94]

Here is a thread that may help you. Flashing O/D light

[daimoku]

Thanks for the reply. I read that thread, but I don't think the transmission is to the point it needs a rebuild yet. I've been driving my old vehicle until the F250 runs like it should.

I'm trying to adjust the TPS/FIPL within specs. I can get the throttle closed, engine off to 0.9V or 1.0V, but the wide open throttle voltage reads ~6.4V. Is there a way bring down the wide open throttle voltage or should I just replace the TPS/FIPLS? I tested it and there are no dead spots.

[daimoku]

Forgot to adjust the max travel screw! duh haha I'm going to try it tomorrow and I'll post back with the results.

[daimoku]

Alright, got the TPS and max travel screw adjusted so I'm at 1.0VDC closed throttle and 3.8VDC WOT. Transmission shifts smoooooth now! Still going to throw a new transmission filter and fluid in there. Who knows when it was done last.

The OD light still blinks, but only when I let off the accelerator. I'll try to grab the codes again tomorrow, but I imagine it's still the code 99 which is EPC circuit fault or idle not learned. All I have been able to find regarding that code is to check fuses, wiring to the tranny, EPC solenoid and EPC solenoid wiring. Any other ideas? Thank you!

[daimoku]

Checked fuses and found 3 fuses blown in the engine compartment fusebox. Not sure what they go to because I don't have the manual. Anyhow, checked the codes and no more error 99. Error 14 is still there though. I'm going to check the RPM sensor as I hear that's a part that commonly causes this error. If anyone else has ideas, shoot.

[daimoku]

In case anyone is actually reading this thread...I tested the RPM sensor today and it is dead. Test infinite resistance which of course means no power is passing through. Going to order a new one tomorrow. I suspect that will take care of the Code 14.


Can anyone tell me if the Stancor 586-902 or 586-903 glow plug relays will work in a '94 F250 IDI (non-turbo)? I've read where they work in the '96 F250 powerstrokes, but nothing about earlier models. Here's a pic of the failing relay:

[daimoku]

Alright, well don't everybody jump in here at once haha....

I bought a new RPM sensor today at the Ford dealership...$80.
Ford only part: Engine RPM sensor E5TZ-17B384-A

Here's how to check yours:
1. Remove 2-wire connector end.
2. Hook meter leads to pins on sensor. It doesn't matter which way you hook up the red or black leads.
3. Set scale to AC/ 0 to 40-volt scale..
4. Start engine in park. Raise rpm while watching DVOM.
5. Voltage must increase or RPM sensor is bad.
That took care of the error 14 I was experiencing.

I also went ahead and bought the Western Snowplow relay because the dealership wanted $160 for a replacement GPR! It works, but it fits tight. For those interested, the P/N is 56131K and it cost $14 with tax. Anyhow, all is well for now. Still have a few leaks to take care of and whatnot, but the biggest concerns are resolved

[Black&Gold]

WOW MAN! you have done a great deal of trouble shooting and research! here is to you It is not often you come across someone willing to do the research and trouble shooting as you did. oh and welcome to the org, we can definitely use the likes of you

[codyh]

tps and max travel screw? I have a 93 idi that shifts rough. Would love to get it shifting better. Also won't always downshift when it needs to. Sounds like you know what your doing. Any help would be great.