Mechanics

FORD RANGER ENGINE PROBLEM

1994 Ford Ranger • 142,000 miles

I have a 94 ranger 4.0 5 speed. The engine good until it reaches operating temp, then, it feels like there is a breakdown in the ignition, then, it will clear up & run fine, but, a few seconds later it will do the same. I ran diagnostic test with codes 41, 21, 15, 38 KOER. KOEO codes 538,411,412,121. Also, the first code to show up KOER is cylinder identification: cylinder 6. I have replaced coil, TPS, plugs& wires.
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Karnack93
February 24, 2013.



Fuel pump pressure is within factory spec when key on and with engine running and when shut down

Tiny
Karnack93
Feb 24, 2013.
Ok, when was the last time you had the injectors cleaned? Not an additive, they never work, but done professionally? Makes a huge difference.

Roy

ASEMaster6371
Feb 24, 2013.
I haven't. Another thing is when the engine begins to load up at idle there is smoke coming from tailpipe, but, when the engine clears up the smoke disappears

My question at the time: I have a 94 ranger 4.0 5 speed trans. I'm having with the engine's performance. When I am driving and there is no load on engine it acts as if there is a breakdown in the ignition, but when it is at full throttle it runs great. I hooked up my scanner and ran KOEO and got codes 538,411,412,121. KOER codes: cylinder 6, 21, 15, 38, 25, 14, 41. The expert suggested I have the fuel injectors cleaned. Hell, what about the other problems.

Tiny
Karnack93
Feb 24, 2013.
Greetings

Those codes are almost always a result of operator error during the KOER test. You likely missed pushing the brake pedal after engine id was output and missed the dynamic response test (aka goose test) just before the codes are output. Try testing again and let me know what you get.
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Bluelightnin6
Feb 27, 2013.
As far as the other codes, I suggested the injector cleaning as a start. One problem can cause many others to come up.

I would use this as a starting point before moving forward. You said you did not have it done. I would get it done, have the regulator checked and then we move forward eliminating this as a possible failure.

Roy

ASEMaster6371
Feb 27, 2013.

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