Reading Diagnostic Codes - '91 XLT; Need Help Deciphering! | Ford Explorer - Ford Ranger Forums - Serious Explorations

  • Register Today It's free! This box and some ads will disappear once registered!

  • Holiday Special! - 2 for 1 Elite Explorer sale!

    Right now you can purchase an Elite Explorer membership for $20 and receive a two year membership! If you have an existing Elite membership contact me by PM and I will upgrade your account manually.

    Click Here to start your membership and get rid of the ads!

Reading Diagnostic Codes - '91 XLT; Need Help Deciphering!

Thallarsen

Well-Known Member
Joined
February 21, 2000
Messages
126
Reaction score
7
City, State
Potomac, Maryland
Year, Model & Trim Level
'99 5.0 Limited AWD
I've got some pretty serious missing/stumbling on acceleration; and some feedback is leading to fuel pressure regulator:
My earlier post about missing/stumbling
I'm now at the point of reading the stored codes (got an Actron reader from Autozone) Both the reader's instructions and my Haynes manual say that the codes could either be two digit or three digit numbers, but they don't say specific years. The Actron's instructions mention that the first set of codes are the KOEO codes "which are sent twice (so you can double check your code list)". Then there is a separator code followed by the Continuous Memory Codes, which are also sent twice. The Haynes has no mention of the codes being sent twice.
How can I find out how many digits my PCM is returning?
On the KOEO read, I'm getting the following:

Flash (1 sec. pause) Flash (1 sec. pause) Flash
(3 sec. pause)
Flash (1 sec. pause) Flash (1 sec. pause) Flash
(5 second pause) Flash (5 second pause)
Flash (1 sec. pause) Flash (1 sec. pause) Flash
(3 sec. pause)
Flash (1 sec. pause) Flash (1 sec. pause) Flash

Based on my little experience with this thing, I'm interpreting either 111 with a 'separator code' of 1; then 111, which would mean everything's fine.....assuming I'm on a 3 digit read.....BUT, if it's a two digit read, then it would be more like 33;with a 'separator code' of 1; then 33. That would mean EGR not opening or not seated.
Does a '91 have an EGR?
In the Haynes manual, it refers to 33 as a code for continuous memory & engine running; and not KOEO.
I'm kinda stumped here.

J.P.
'91 XLT
 




Jason_25

Elite Explorer<br>ECX Member
Joined
November 26, 2000
Messages
5,339
Reaction score
5
City, State
New Bern, NC
Year, Model & Trim Level
'95 Explorer "Expedition"
Pretty primitive huh? I got tired of dealing with the mess and I bought a scan tool for OBD I and now I don't have to decpiher the morse code :D

It will help you out to know that the 91 explorer does NOT have EGR. Also, it sounds to me like the computer is giving you the all clear.

Good luck with it.
 




Runnin'OnEmpty

Explorer Addict
Joined
July 20, 2002
Messages
2,036
Reaction score
52
City, State
Southeast USA
Year, Model & Trim Level
2000 Sport
JP, I also think the code is a 111/System pass.

My gut feeling is you have a bad TPS (throttle position sensor). These things are basically potentiometers, and they wear out in the mid voltage range. If you have a multimeter, they are easy to check. Your Haynes manual has the procedure.

When you test the signal wire, the voltage reading from idle to full throttle should be smooth. If it is the least bit erratic, the TPS is bad.
 




Thallarsen

Well-Known Member
Joined
February 21, 2000
Messages
126
Reaction score
7
City, State
Potomac, Maryland
Year, Model & Trim Level
'99 5.0 Limited AWD
Jason 25 & Runnin' On Empty

Thanks for your input. Every little bit helps. I'll be checking the TPS as the next step. It certainly can't hurt to check it.....If it's okay, it'll be just another component that gets an 'all clear' in the list of sensors, valves, lines, connections, wires, etc. that I need to check.
Eventually, I'll come up with the problem (probably something as basic as a bad plug, or something like that).
Thanks again.

J.P.
 




Top