Hi i have problem with my ford f-150 1989 302 efi 4x4 aut. it runs poorly at idle and almost dies when I turn on the lights. sometimes when I brake it dies but sometimes it runs good.
Does anyone know what it could be.

 

Ford Fuel Injection » How To Run a Self-Test

Go to that page and follow the instructions to pull diagnostic codes. If you're having difficulty, you can buy a code reader cheap @ just about any parts stores. I have the Equus Innova reader- purchased for $30 @ O'reilly.

Do you know when the last time it had a tune up was? Preferably the number of miles put on it since the tune up.

Anyway, poor idling is typically the result of a bad IAC valve or vacuum leak. There's several other things that can cause it, though. Here's links to info on the IAC and vacuum leaks.

Ford Fuel Injection » Vacuum Leaks
Ford Fuel Injection » Idle Air Bypass (IAB)

If it's almost dying/dying with basic electrical loads, there's a few things that can cause that.

1) Terrible wiring conditions [i.e. bad ground, wires rubbed through/broken, etc.]
2) Alternator is going bad [remove and take to auto store for testing]
3) Could be related to the poor running condition of the engine [i.e. the alternator has to work harder to provide power for those circuits, which in turn pulls more power from the engine.]

What's the condition of the serpentine belt? It's not likely the main problem but a stretched belt can cause power issues by slipping on the pulleys.

And welcome to FTE. Keep us updated on the situation and provide us with as much information as you can- the more you can tell us, the better we can help you.

 

thanks for the help I'll take a closer look tomorrow

 

I got the codes Hard fault present. and MAP / BP sensor out of self test range. and ECT out of self test range 0.3 to 3.7 volt.
what might be wrong but my little truck?

 

Take a look at the output values of the MAP sensor and the Engine Coolant Temperature sensors. I suspect the hard code is most likely from the MAP. The code for the ECT can be self induced if you did not warm up the engine before running the tests.

For reference:

Ford Fuel Injection » Manifold Absolute Pressure Sensor (MAP)
Ford Fuel Injection » Engine Coolant Temperature Sensor (ECT)

 

I have had the same problem before but when it died, I waited a few minutes then started it with no problems and ran without problems

 

what is the difference between 86 and 89 years eec
and Can it Cause problems if you use an older eec computer?

 

There are many factors that can make a PCM compatible or not. It really depends if the EEC you are using came from the same family (F-series/Bronco/van, etc.) engine and transmission type as well as California or Federal emissions.

If you do not choose wisely, yes there can be issues caused by an incompatible computer.

 

even if it has gone well for a long time?