87 ranger 2.9 running like crap...need help.

warno · Sep 27, 2012

my 87 ranger is running like crap. when i first start it up it will die unless i hold the throttle for alittle while. it has misfires pretty regularly, especialy when it's damp outside.

things i know are wrong.

the o2 sensor is not plugged in. due to the fact there is no wire running down to it.
does anybody know where i could get a wiring schematic to figure out where i need run the wire from the o2 sensor too?

the air box is all beat to hell and doesn't completely seal shut.
would this matter at all?

can anybody give me any other ideas i should check out. i would really like to get this thing running better before winter time.

Flash Gordan · Sep 27, 2012

What about the other "usual" stuff? Cap, rotor, plugs, wires, ignition coil, distributor module?

warno · Sep 27, 2012

i do need to check that stuff too. i just want to get a list of stuff to run through.

i guess i should have added that the exhaust smells really bad of gas. it's almost as if there is just way too much fuel. what all controls the computer to run the injectors on this engine, so i can check all that too?

a31ford · Sep 28, 2012

The Fuel Regulator (little can DR side of the plenum, near the rear of the engine with a vacuum line running up to the side of the plenum), generally when the diaphragm ruptures, it will suck excess gas into the engine, and the exhaust will smell raw.

It will also get horrible gas mileage....

85RangerST · Sep 28, 2012

First scan the trouble codes…don’t have a scanner no problem then use test light method. See tech lib here on TRS: http://www.therangerstation.com/tech_library/OBD_I.html

You may have a faulty EGR. Try unhooking the vacuum line running to it.

The air box shouldn’t be an issue…the vacuum box under it though is part of the EGR system and would cause problems after the engine reached operating temp. Same goes for the O2 sensor.

jhammel85 · Sep 28, 2012

Start with that O2 Sensor and the usuals that Flash mentioned. The 02 can control how much gas goes in as well.

I'd start with a haynes / chilton manual for the o2 sensor wiring.

warno · Sep 28, 2012

i suppose i should have also said that the check engine light is not on. i will try to get that stuff you guys mentioned checked out.

azhrei · Sep 29, 2012

no o2

don't bother with the o2 I haven't had one in years on my 87, I went to replace my y pipe with headers and found the wire broke... I didn't bother putting it back in... so I doubt that is your problem since it sounds like it was running ok without it.

armadillon · Sep 29, 2012

^I would DEFINITELY ignore this. Like JHammel85 said, the O2 can help with any fuel issues. Considering it's detecting how much o2 is in the exhaust and helps adjust the mixture accordingly... Yes, you can run without them, but it runs like poo poo and could definitely be contributing to your problem. From personal experience, adding O2s to my 89 Mustang 5.0 did beautiful wonderful unicorn things to it. Do things right, not half-assed because it's an inconvenience.

warno · May 4, 2014

ok digging this thread back up here.

I recently found time to finally work on the O2 sensor issue. I found the wires that were supposed to go down to the sensor. the weather pack plug apparently found it's way on to the header when the previous owner had the truck and it melted all to crap. and the wires burned off. so I soldered on some new wires and got a new O2 sensor put in the exhaust.

I took the truck out for about a 10 minute test drive (some highway and in town driving) and it ran worse with the new sensor in then it did without it. it would idle ok, but as soon I would go to take off it would start sputtering and acting sluggish. had very little to no power along with a miss fire almost constantly. it seemed like it was loading up with fuel, because the exhaust smelled like fuel worse then before.

it ran so bad the whole time I was driving it, that I cut the wires that I just ran down to the new sensor. it instantly ran better. all the power it had lost came right back and the miss fire went away.

so my new question is, why would it run like absolute crap with a new O2 sensor in the system and then run better without it?

SenorNoob · May 4, 2014

Are you sure you have the polarity of the O2 sensor wiring correct? It'll run either way but will immediately go super-rich if it's backwards.

Don't ask how I know. ;brownbag;

a31ford · May 4, 2014

Something to note:

The computer MUST be "reset" BOTH the battery cable off, AND, with the battery re-connected, the code reset sequences (both) doing a computer read through the diagnostic connector under the hood (engine lamp reading) KOER and KOES The reason for this is that the computer HAS EEPROM (Electrically Erasable Programmable Read Only Memory).

Simply removing the battery cable only does 1/2 of the stored codes and NOT the EEPROM codes.

As well, the wire orientation DOES matter in the HEGO sensor, as there IS a common ground for the heater and the 3rd leg of the O2 sensor portion of the HEGO.

You will have to verify that the correct wires are in the right positions on the sensor connector, and THEN do the reset(s) of the computer.

This way the computer has a "clean slate" to work from, to re-learn the HEGO.

Greg

freedom5 · May 6, 2014

It takes sometimes up to 100 miles for the computer to adjust to a change/or new sensors. A 10 minute test drive isn't quite enough. Also you need to disconnect the battery for up to 30 minutes for the computer to reset.

warno · May 7, 2014

ok i'll try to trace the wires back to make sure I hooked up the 02 senor right. and i'll do the erase sequences for codes.

liamkeough88 · Jun 10, 2014

Updates?

87 ranger 2.9 running like crap...need help.

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