Hello all,

I am doing the Engine Running test and I am getting 4 trouble codes back from my 1992 F-150 5.0L:

12 - Cannot control RPM during ER Self-Test high RPM check.
73 - TPS senor did not exceed 25% rotation during Dynamic Response Test (user error).
25 - Knock not sensed during dynamic test.
52 - Power steering pressure switch always open or closed.

Can someone explain to me what part is usually associated with these errors?

Also, I recently removed the throttle body and TPS thinking it was bad, but it was not. Could I be getting the 73 from a possible error in reinstalling it? The Haynes manual is very very confusing when it's telling you to reinstall the TPS. I also think it might be due to me not pressing the throttle in enough.

And for the number 25 code... I have a 1992 and the Haynes manual says my model is not installed with a power steering pressure sensor. Do they leave this code in ALL F150 computers anyway?

 

What is your curb idle at normal op. temp.? Did you rev the engine once during the KOER test? Did you turn the steering wheel to the left & right? Do you have idle surge? Did you do the test at normal op. temp.?

 

Okay, so I pressed the throttle WIDE open this time and it knocked out codes 73 and 25. Which is good...

Now I just have 12 and 52.




Curb idle: ~800-1000RPM

Rev. engine once during KOER: Yes

Steering wheel turn: No because my vehicle is not equipped with a power steering pressure sensor.

Idle surge: What is that?

Test at normal op. temp.: Yes. I let it run for a good 3-5 minutes.

 

Also, besides codes 12 and 52 for KOER, I am getting 33 for KOEO which is:

EGR valve opening not detected.

When I run a test on my EGR sensor, it gets the required 5,000 Ohms with no vacuum being applied. But when I apply 10 inches of Mercury it is supposed to drop to about 100 Ohms, but instead stays are around 3500-4000 Ohms.

Does this mean a bad valve?

 

http://www.fordfuelinjection.com/ Wander around this link for info about component & sensor function & test methods. your norm. op. temp. idle should be 650-700 RPM. surging idle means it wanders up & down/ not constant. Any known drivability issues? Check closely for Vac leaks! See IAC (IAB) function/ cleaning & test of, on link. Have to make a home depot run. I'll check back later. Removal, cleaning EGR valve & mounting portways & inspecting it's diaphragm for leaks is a good thing to do with that #33code. then we can move on to testing the EGR regulator. Or before I guess. Remove the vac hose from the EGR valve at warm idle. There should be no Vac present at the hose. Raise idle to 2K. you should have full vac at the hose. WOT= no vac again.

 

Sorry I haven't posted an update. I've just been so happy my engine is running again.
Sometimes I can't start it at all. And all I do is go under the hood, unhook the vacuum hose from the EGR valve, plug it back in, and the truck starts right up. This makes me think the diaphragm is getting stuck. I will follow your instructions and take that baby off and clean it. Will report back with updates.