Hey everybody, new here but i'm a long time ford truck owner. I'm working on a friends truck and it has me pulling my hair out, was wondering if you guys could help. Its a 92, F-150 w/ a 4.9l . Basically, it runs like crap and sometimes won't run at all, I scanned the codes and got the dreaded "running in failure mode" code and basically most of the engine sensors are throwing a "low voltage code". I can't find a pin-out for this particular model on the internet but I did go ahead and check to make sure I was getting power at the computer harness, and it is, in several locations. Basically, can someone point me in the right direction for a pinout for this truck and how I should test each pin once I get it?? I'm just trying to determine if it needs a new computer, I don't want to buy parts that it doesn't need!! I really appreciate any help as this truck has me at my wits end!!!

 

Bill posted a pinout for a 4.9L truck with OBD-II a few months ago. Take a look here: https://www.ford-trucks.com/forums/9...n-diagram.html

 

Thank you for the reply....I printed that one off yesterday and it doesn't match the pin locations on this computer?? I'm not sure what is causing the difference, maybe because it falls on the year where everyone was switching over to OBDII.

 

I just realized that this is a 92, not a 96

So I need the eec iv pinout.

 

Ok, I got the eec IV pinout and did some probing and it appears that the computer is getting good voltage and the grounds have continuity. I am now leaning to a spark or fuel supply issue.... the pressure is reading about 50 psi when I turn the key on. I am getting good strong spark at the coil. I'm gonna do some testin a the TFI using some info that I got here. Any help or suggestions is appreciated.

 

What are the exact codes you are getting? Fuel pressure looks good. You need to verify the injectors are getting the signal to pulse on/off. Use a noid light on them to see if the pulse is getting to them.

Strong spark at the coil....what about at the plugs?