Having issues with my 2.9

[dasroach]

I have an 86 ranger with the dinky little 2.9. Problem is after the truck warms up it will cut out and run rich. ive replace fuel filter, plugs, wires, cap and rotor. I even reset the timing and it still wont run right......What next?

 

[Tedybear]

Sounds like it's hitting a major problem when the computer goes into 'closed loop' operation.

If memory serves, there was a spot for a check engine light--but it wasn't used? (memory is kinda off lately) However the first step would be to pull the codes from the onboard computer and see if anything triggered the fault. I'm guessing it'll be a yes, as what you've described points directly to a sensor fault.

fault detected in closed loop===LIMP MODE!

Limp Mode is just as the name says. It's using a preset amount of values that'll make the truck run, but like crap..it's built into the system in order to allow you to drive to shop and have it checked into.

Peek around the tech lib. and look at the information regarding the EEC-4 system and it's method of pulling codes. Don't bother wasting mega bucks on a super scanner--at most a cheap multimeter (analog works best) and a paperclip or jumper is all you'll need. (the multimeter will be used if the onboard check engine light is not there...or blown)

S-

(and welcome to the site)

 

[dasroach]

Thanks for the adv. this will sound stupid but the check engine light has never come on since I've owned the truck. I know it has a replacement engine with only 35000 miles i have all the paperwork.... Also on the driver side fenderwell there are two 3-pronged connectors, one male, one female and i have no clue where they go but they are different sizes?

 

[IMenriched]

Thanks for the adv. this will sound stupid but the check engine light has never come on since I've owned the truck. I know it has a replacement engine with only 35000 miles i have all the paperwork.... Also on the driver side fenderwell there are two 3-pronged connectors, one male, one female and i have no clue where they go but they are different sizes?

The check engine light might never come ...but you'll still have codes

the one connector that looks abit like a house ...I'm thinking is the dianostic one. & you'll use both.

In the Tech Library here on TRS show you haw to get codes from your unit.
http://www.therangerstation.com/tech_library/OBD_I.html

have pulled the little vacuum line off the FPR (fuel pressure regulator)....if you get a dribble of gas coming from it, (It should be dry) then your FPR is done.

 

[dasroach]

Well found out why my check engine light never came on.......Never was one to begin with the back was never even drilled out. I really appreciate the advice thx

 

[dasroach]

Alright well it looks like i got work to do. Flashed codes 21, 31, 54, 63 and 66...where do i start?

 

[The Fox]

http://www.therangerstation.com/tech_library/2digitcodes.html

Looks like the coolant temp sensor is going out, and the TPS is also not working right.
Nick

 

[dasroach]

anyone know what a good tps should read with an ohm meter?

 

[Tedybear]

If memory serves? Pin 1&3 should have 5k (give or take 5-10%). Multimeter on pin 1 or 3, and the other lead on pin 2. Slowlyyyyyyyyyyyyy rotate the throttle up and down. On the ohm scale you should have a very gradual increase/decrease depending on direction of the rotation. You can also set the meter to DC volts, ground the black lead, red to the center pin (I've normally just pushed 'em into the rear end of the plug) At closed throttle you should have about .80vdc-.95 vdc. (normal specs are listed in the tech section, should be about .92ish or so...I'm lazy and don't wanna look it up) This of course is with the ignition 'on' engine OFF!! (don't want to suck a meter into the fan LOL) You can run the throttle full open/closed as well, and the voltage reading should increase/decrease gradually. You're looking for dead spots or jumpy voltage readings.

The sensor itself isn't that expense to replace, but CHECK IT when you get a replacement. I've gone through 2 from advance that both where DOA. One was a used one that some putz cleaned up and returned claiming he/she didn't need it. The other one? Internal spring was not installed correctly. There's a return spring that keeps the part that rotates in the switch against the mini steel actuator. (otherwise it would work just once--and not return to the 'home position')

S-