Hi guys new here. I have a 87 f150 300 6 4.9l. It has some trouble idling and staying running. First thing I did was attempt to read engine codes but the light just stays lit up it will not blink. I used the jumper from the single pin connector to the ground on the bigger one and also tried going from small pin to battery ground but still will not blink. I jumped the small pin to the battery ground while it was running and the idle lowered and smoothed out for a few seconds. Is this a bad Computer? Any help would be appreciated.

 

It is hard to win a staring contest with a check engine light. You always blink first...

Get yourself a code reader from e-bay. They are relatively inexpensive, and save time, as all the connections are internal- just plug & play.

Scott

 

Given your symptoms and troubleshooting steps I would say you have a bad computer. One more last ditch effort is to clean the pins on the data ports with contact cleaner and/or small finger nail file. If the computer will still not initiate the KOEO tests, it's probably bad. Pull it out and open it up for inspection.It comes out from inside the cab on your truck.

 

Your 1987 does not have a CEL for reading codes.
You will have to do it manually or buy a reader.

http://www.troublecodes.net/ford/eectest/

 

When was your last complete tune up ?

 

Why would you state that? Based on the OP's problem statement the CEL turns on and stays on.

 

I don't have my 1987 EVTM with me for I am on the road.
Seems to me the 1987 has the emissions lights but not a CEL tied to the ECA.
I have not asked yet, but he has not indicated whether or not his light is lighted all the time the key is on or when the engine is running.
I belive this is the page out of the 1987 EVTM;

 

I believe also if the oil pressure is low, that light will come on as well.

As I am thinking, there are 2 lights, one for the Emissions, and one for low oil pressure.

The warning indicator page of the EVTM will be the page to review.

 

Yes there is a red Engine lamp in the dash on these older trucks, not the same as the yellow Check Engine Light.

For reference:

 

I think the yellow CEL started in 1988.
The OP should be able to Identify what lights he has.

OP, do you have a Tachometer in your dash?

 

1987.....

Diagram for reference:


Location A/B 20 is the red Engine lamp. Location B/C 20 is the yellow Check Engine lamp.

 

 

What color is your light ?

Does this light ever turn off ?

 

Alright I ordered the diagnostic tool should be here in a few days. I cleaned connectors and attempted a retest with same results no blinking light. I do not know when the last time up was. I just bought it for $200 drove it home with the knowledge that it had some issues. I checked plugs (they are motorcraft) they look fine. Wanted to try and narrow down the problem before I start throwing parts. The light I am seeing is the "engine" as seen in the picture above. It stays on all the time. Yes I have a tach. After looking at the dash picture I think I have mistaken the "engine" light for the "check engine" light. (Sorry for my ignorance this truck is older than me lol.)

 

Based on your response Vinny was correct, you are seeing the Engine light (red), not the yellow Check Engine light (yellow). Does the yellow CEL light up when you cycle the key from Off to Run? If not, it may be missing or burned out.