I recently discovered the ability to run the koeo/koer tests using a jumper wire and was excited to give it a try. I sat in my truck with a pen and paper ready to record any codes that were given. When I turned the key to the ON position nothing happened. I only got the usual check engine light flash that flashes every single time you turn the key to the ON position whether or not you have a jumper in place. I only heard one click under the hood and then nothing.....and still nothing. I then attempted to try the other methods using a voltmeter and also running the STI to the negative battery terminal. All methods were unsuccessful. I did accidentally disconnect the jumper wire while the key was still in the ON position when I was upset that nothing was working, and I heard a click. I have briefly looked over the wiring and I cannot see anything that seems to be an issue...yet. Does anyone have any advice on where I should start to resolve this issue? Do I have to hold the clutch down to initiate the test? I don't remember holding down the clutch for some reason I know my truck starts whether or not I am holding it down. My check engine light is currently OFF. I recently installed a 3g alternator is there anything that I could have possibly done during this procedure possibly grounding something that shouldn't be? Could my ECC be shot? My truck starts every time and runs fine except for a rough idle when cold. I am new to all of this but excited to learn about my truck. It is a 1986 f-150 5.0 2wd manual transmission.

 

You can try some of this stuff. Just make sure your self-test plug is not all corroded up.

Fuel Injection Technical Library » No Codes?

 

A 1986 doesn't have a Check Engine light, first year for that (connected to a computer) was 1988. For yours, I would imagine the EMISSIONS light would be used but I really don't know.

In any event, you should be able to pull codes with a voltmeter or test light, so follow the instructions posted above.

 

Interesting. Ya I just assumed it was a check engine light its so faded you can't read what the light says. I guess I will just have to troubleshoot it using the list from oldfuelinjection. I guess I was just looking for some common areas where anyone with experience has found issues in multiple vehicles or multiple occurrences. Like for instance a plug that is prone to corrosion. Anyways thanks for the help. I'm just glad the truck starts every day without fail! I guess it could be worse.

 

I'm assuming a electrical tester with very long leads would help? Unless anyone knows of an easier way.

 

We use to pull codes with an analog test meter . So long I can't remember exactly how . Count the pulses of the needle I think . Gm was easier , paper clip , count flashes of light , Dodge , cycle key 3 times , flash codes through light .

 

Fuel Injection Technical Library » How To Run a Self-Test