3.0 rough at higher rpm

[broussard91]

I have a 99 ranger that had the 2.5 in it i swapped it for a 99 b3000 3.0 the motor ran fine in the other truck when i swapped it i had to change ecm to a late 97 (98 on title) pcm the motor runs like a top til it gets warmed up then it misses and black smokes when given throttle any advice what to check are change both motors had return fuel lines and idk if the 97ecm motor had return wasent gettin struck by lightning in junk yard to find out only wires that have ben cuf is the oxygen sensor after cat and spliced back hopefully correct there where 2 white wires and 2 other collors and rodded out the cat

 

[RonD]

When cold the ECM(computer) runs the engine in Choke mode, rich fuel mix with high idle.

The ECM reads the coolant temp with a TWO WIRE sensor called the ECT(engine coolant temp) sensor.
This sensor is only used by the ECM.

The dash board temp gauge uses a ONE WIRE sender that looks similar and they are usually located near each other.

Make sure the two wire ECT sensor is hooked up or ECM will run engine in Choke Mode all the time.

Yes, improperly installed or wired O2 sensors can cause the rich mix you describe when engine is warmed up.
A cold engine needs the rich mix so you wouldn't notice the issue until engine warmed up.
You will need to find the correct wiring diagrams for the model years of all the components.

The downstream(after cat) O2 sensor is not used for engine air/fuel mix, it is there to check if Cat is working, only the 2 upstream O2 sensors are used for rich/lean engine mix.

 

[broussard91]

The engine constantly reads cool even when its ben runnin 30+ minutes also if i get on it hard and let off it high revs for a few seconds then goes back to regular idal also the wire i cut is one after cat not sure but think its only one on my exhaust i think ima just get a new 02 senser im not to good with light collors they all look the same

 

[broussard91]

Also i have no codes my check engine light aint even on

 

[broussard91]

Still runnin cool but seems to be better at runnin after i decided to check my vaccume lines from the old manifold i got from the junk yard and found that there was a dirt dobbler nest in brake master cylinder vaccume line still smokes but not as bad the line from valve cover to intake i havent checked yet but would it cause the smoking if its plugged?

 

[RonD]

What is the outside temp where you live?

Dash board temp gauge should be above 1/4 after 5 minutes, almost to 1/2 when fully warmed up(8 minutes), going up a long grade it might reach 1/2.
Running cool long term means engine damage from dirty oil, and wasting gas because fuel mix is based on engine temp, warm engine needs less fuel.

So either you have no thermostat, or the wrong thermostat.
190 or 192degF is stock t-stat.

 

[broussard91]

I have the 190 thermastat but took out the switch that goes to the heater core and just direct lined it

 

[RonD]

That's the by-pass valve and shouldn't effect the engine temp because it is on the engine side of the t-stat.
The point of the t-stat is to maintain MINIMUM engine coolant temperature, so when all the coolant in the engine(and by-pass) reaches 190degF average the t-stat will open a bit and allow circulation of EXTRA heat into the radiator.
On some engines in cold weather the t-stat never opens because there is no EXTRA heat, i.e. 4cyl LIMA engines.

To test if t-stat is working, start cold engine and feel upper rad hose, it will be cold.
Let engine idle for 2 or 3 minutes then feel upper rad hose again, should still be cold, if it is warming up with the engine then t-stat is stuck open, replace it.

Engine should take about 5 to 8 minutes to warm up to 190degF, depends on outside air temp, and that's when upper rad hose would start to warm up

I think the center line on Ford Temp gauge is about 210degF, 1/4 would be about 140degF

 

[broussard91]

I just looped the heater core hoses together with our heater core now runs normal temp but now after it warms up anything above idel it starts cuttin out

 

[RonD]

I just looped the heater core hoses together with our heater core now runs normal temp but now after it warms up anything above idel it starts cuttin out

Computer runs in Open Loop when engine is cold, that means a rich air/fuel mix, higher idle and advanced spark timing, the data is uses is in a table it's memory, it only uses the MAF sensor(air flow) and Throttle sensor(foot on the gas pedal) at this time.

O2 sensors can't work until they get above 600degF, computer monitors O2 sensor data and after about a 5 minute warm up the O2 sensors get up to operating temp.
At this time the computer switches to Closed Loop, or Feedback operation.
It bases the air/fuel mix only on what the O2 sensors are telling it, if O2 reports lean then computer adds more fuel, if O2 reports rich computer adds less fuel.

From your description the problem happens when switching to Closed Loop.
This could be from a worn out O2 sensor or a vacuum leak, in Open Loop computer is adding extra fuel so small vacuum leak is not as likely to effect performance.

 

[broussard91]

I can hear a slight whistle i disconnected and removed plug in from sensor right after cat still was runnin rough once i put the 99 gauge cluster in it seems to be runnin alot smoother and not missin amd poppin also im havin cluth problems my last trans did exact same thing cluth pedal hard to press and once its pressed its a waiting game for it to come back changed slave in other trans and helped but still had problems shifting its a perty recoginazable clunk when it returns

 

[broussard91]

I also just put 5 gallons of 93 octane with octane boost injector cleaner water remover and seafoam kill are cure it seem to smoke less also