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2002 3.0 ranger timing issue i think?


roadkill25

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So recently my 3.0 has been doing something weird that I believe has something to do with the timing. She's been running alright when cold but once it warms up and you start driving it she loses power and fuel makes it way into the exhuast. I've gone through pretty much everything at this point so I thought I'd consult ye old forums (which I haven't been on very much the past couple years and I'm trying to do better about being on here). I've checked the spark plugs, wires, coil pack, fuel pump, filter, compression, I replaced the maf and cam and crank sensors too. I don't think it's a valve problem because it runs fine about 40% of the time and the sparkplugs arent fouled. I don't think it's sparking at the right time and it's sending that fuel into the exhaust. I'm starting to think my computers going to hell because I'm running out of things that could be wrong. I figure if it hopped timing it should be running like shit all the time, not sporadically. Any and all input would be much appreciated been at this trying to diagnose and solve the problem a few weeks now.
 


Uncle Gump

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Have you out a scan tool on it?

What about the ECT?
 

RonD

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You are correct, not crank/cam timing, compression would also be very low

Cold engine starts and runs on pre-programmed air/fuel mix, choke mode, also called Open Loop

Once the engine, and O2 sensors, are warmed up the computer switches to Closed Loop and calculates air/fuel mix on the fly
The air/fuel mix is SOLELY based on O2 sensor feedback, there are no "backup" sensors for the O2s

And O2 sensors wear out, 12 years or 100k miles and they need to be changed

O2 sensors use a chemical reaction to detect Oxygen in the exhaust
The reaction can't occur under 600degF which is why O2s are "heated"
And don't work until exhaust/engine is warmed up
O2s generate their own voltage
0.1volt is high oxygen, lean
0.9v is low oxygen, rich
As the they get older, the voltage goes down, so a FALSE LEAN, and computer HAS TO run the engine Richer based on O2 sensor voltage, it has no choice, once computer goes into Closed Loop the O2s are "the word of God" to computer's calculations

Old O2 sensors will eventually set a code, "no switching" usually, but until then you are just wasting fuel
12 years or 100k miles, just change them

In 2002 spark timing is based on Crank Sensor and Cam sensor, these timing signals are compared in the computer, so if one is off computer will set a code, so not that

Best tool to have for a 1996 and up vehicle is a $10-$15 Bluetooth OBD2 reader, like an ELM327 and a $5 Torque Pro APP
Works with any vehicle sold in the US/Canada from 1996 and up, required by Law, still works in 2024 vehicles
With one of these you can see what ALL the sensors are sending to the computer in real time
So you can see what the computer sees and can look up what each sensor should be sending, so no wasted money replacing working sensors
 

bills4065

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First thing I would do, as Uncle Gump said check for codes.
You did not say anything about check engine light, I assume it was never on.
Your description sounds like an upstream O2 sensor stuck lean, the computer would be commanding more fuel for that bank , but that should trigger check engine light.
Another check: Do a wide open throttle check. At wide open throttle, no one cares about emissions. If truck runs fine at wide open throttle, your problem lies in closed loop operation.
 
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roadkill25

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All is noted, I'll start messing around with what ya'll said, thank you very much
 

roadkill25

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Have you out a scan tool on it?

What about the ECT?
If you mean scan as in obd my port is currently got no power to it so I've got to remedy that before I scan it. One of those problems I've been slacking on
 

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