1988 F150 5.0 koeo codes - Ford Truck Enthusiasts Forums

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1988 F150 5.0 koeo codes

 
  #1  
Old 01-14-2019, 08:25 PM
1988f150dude
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1988 F150 5.0 koeo codes

Hello my truck has sat many years in a garage. I found it and the odometer shows 29k miles. Owner claimed original. A new battery was installed and the troubleshooting began. First off the frame mounted inline fuel pump did not operate and was tested determined bad and replaced. A couple gals of new gas added to a dry tank and the truck started and ran , not smooth but ran and idled. I even managed to put the truck in gear dive if forward and in reverse and pump the brakes to get them moving again. The truck was turned off about 8 gallons of gas put in the font tank and it went downhill from there. I have been reading many threads and posts following the repair trails of others on this site. Where I am at now. I followed kart18 through his adventure that ends with timing gears and chain. I do not believe this to be the problem but will not rule them out, I just am not ready to tear the front of the engine off and the truck conditions shows to actually have only 29k miles. I read the posts from 1988150guy his problems were similar and I have pulled the computer tested the capacitors and inspected the board it test fine. A new FPR was installed and a new fuel filter. The truck now has hard starting with rough idle that smooths out for a second or two then idles down until shutting off. If I remove the intake tubes to lean the mixture the engine will run a few seconds longer. I pulled the KOEO codes and received 21, 24, 22, 41, 11,11 . Some codes read out of self test range 0.3 to 3.5 volts. Does this mean I am not supplying the truck with proper battery voltage? Is the computer not supplying the sensor with enough voltage? I am to the point of asking for help.......
 
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Old 01-14-2019, 10:22 PM
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Looks like 21,22,and 24 are not working so indication is they need replacement. Check hook ups and vac connections before replacing. The IAC could probably be saved short term but it is not expensive so replace. 41 shows to be active when you are doing the KOER test. I don't know why that would show up in your koeo test. . Maybe someone else will chime in. 11 11 are ok modes.

Quote: Does this mean I am not supplying the truck with proper battery voltage? Is the computer not supplying the sensor with enough voltage? I am to the point of asking for help....... These codes mean the part is not performing as it should. CODES and definition. below. Sandy.


https://therangerstation.com/tech_li...gitcodes.shtml
 
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Old 01-14-2019, 10:56 PM
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Thank you
I will post an update once I have replaced the parts.
Does the computer need to be cleared of error codes manually or will proper function take care of that
 
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Old 01-14-2019, 11:05 PM
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How did you get codes Jumper,,,,, reader
 
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Old 01-15-2019, 08:26 AM
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Originally Posted by 1988f150dude View Post
I pulled the KOEO codes and received 21, 24, 22, 41, 11,11 . Some codes read out of self test range 0.3 to 3.5 volts.


If you did not warm up the engine before running the KOEO tests/Stored Code display you can falsely trigger KOEO Codes 21 and 24. Code 22 is your key error. Code 22 indicates the MAP sensor output is out of range, it's not temperature sensitive. Code 41 is a Stored or KOER code. No way you could have gotten that during the KOEO tests.




Originally Posted by 1988f150dude View Post
Does this mean I am not supplying the truck with proper battery voltage? Is the computer not supplying the sensor with enough voltage? I am to the point of asking for help.......

Given the codes above it could indicate the VREF signal output from the computer is out of range. It should be ~ +5VDC. If you did warm up the engine before running the KOEO tests then definitely verify VREF. If you did not, then warm up the truck and run the KOEO tests and Stored Code display again.Pay attention to when the codes were displayed and re-list them, by number, and during which portion of the KOEO tests and Stored Code display procedure.

Do not replace anything until you validate your test results are good.
 
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Old 01-15-2019, 10:46 AM
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Originally Posted by 1988f150dude View Post
I pulled the KOEO codes and received 21, 24, 22, 41, 11,11 . .
Engines are easier to diagnose over the internet when all the codes are listed, and in order of test.
KOEO - (O) Self-Test Codes =
KOEO - (C)(CM) Continuous Memory Codes =

KOER - (R) Self-Test Codes =

Make sure your A/C, Heat, Radio, etc. are turned off when testing.
 
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Old 01-18-2019, 07:19 AM
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Hello and good morning
The tests were performed by using a jumper wire and counting the numerous flashes of the check engine light. I will rerun the test because the engine was not warm. This is somewhat difficult to achieve because it won’t run more than a few seconds now and has hard starting. But the time consuming task is better than buying unneeded parts. I do however feel the map sensor can be replaced because it seems to show up on a regular basis during troubleshooting for these trucks. I plan to work on the truck today and will post progress thank you
 
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Old 01-19-2019, 08:57 AM
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The truck is up and running! Though we still have minor issues to address due to sitting in a coma for so many yrs . The truck has started and is operating. Replacing the MAP sensor showed immediate improvement but was not the complete resolve. Fuel pressure was tested and holding fine when we began this project. Through my tinkering and adding of fluids the in tank fuel pumps began deteriorating and I found trash in the filter that was not there at first. The tanks were dropped this resulted in damaged oem old fuel lines. Both tanks , both pumps, and all fuel lines replaced with stainless steel lines , new filter and the truck is running well. Once the tanks were opened up I realized how much damage old gas can do . It was amazing the components even worked the little bit that they did. Thanks for all the help.
 
 


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