My 1993 5.2 has been acting up lately like the plugs are fouled out or its loading up? I have trouble code "14 map sen. voltage low" and "21 o2 sensor".


What would cause "low voltage" on the MAP?


would the O2 kill my mileage?


I bought the truck in WA by my dad and he and I drove it back to Ohio best tank was 21 averaged 18 mpg. Around town it was ok 17 - 18 now its dropped off to 14 - 15.


Thanks
Lee

 

The O2 most assuredly will kill the gas mileage, since if it's bad, the ECU is supposed to enrich the mixture to keep from predetonation. I'd replace that soonest.

MAP Sensor Voltage Low may be caused by a failing MAP sensor, by a failing ECU, or by excessive oxidation on the contacts. Due to age, I'd seriously consider a new MAP sensor and then worry about the ECU and the rest. That also, BTW, will kill gas mileage if it fails.

RwP

 

Thanks, funny a week or two a go my voltage reg. went out and I bought a bypass regulator on it. So I wonder if the ECU is going bad? I was thinking about buying the mopar performance one?

 

It might be, but the voltage regulator is pretty much stand alone on the older Dakotas inside the ECU.

What you can try first is to disconnect the battery, then disconnect/reconnect the ECU's connector about five or six times, then reconnect the battery.

If there's oxidation on the pins, that'll polish it off and may fix the problem for now.

RwP

 

I found using dielectric spray cleaner and put some of that petroleum jelly made for electrical connections on the pins made my ECU work better. I've put it on all the elec connections for new parts I have installed. From a high of 21 I am getting 19mpg and I have an exhaust leak and need a new CAT. It was down to 9 at one point when I first bought it.