1993 Explorer

I just changed engine in a 93 Explorer 4.0l, a/t.

The new engine runs great when cold. Once thermostat opens it runs great ONLY when check engine light is ON. Once light goes out, then it runs and idles rough - like it is just dumping fuel. The exhaust is black.

Have only drove about 30 miles max.

Please provide suggestions.

The new engine was also from a 93 Explorer.

Please advise.

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Reply to
partsmore
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Just to let you know you are not being ignored.

Did you scan for engine codes? It sounds like maybe it's burning a lot of oil and maybe some coolant along with it.

Did you do a compression check? Fuel pressure check?

Did you clean the intake sensors, air cleaner, throttle body, etc?

I think we not a lot more information.

How did you decide upon this particular engine? Did you run the engine before removing it from the other Explorer?

What made you decide to change the engine in the first place?

Reply to
Ulysses

Thank you. The valves (2) are out of the original engine. Yes, the other engine ran fine - 160 compression on all cylinder, 60 psi oil pressure - ran great.

HAVE not scanned (too old for my scanner).

Cleaned intake.

Treated with Seafoam (fuel)

Will take fuel pressure test today, and clean air cleaner and TPS.

It runs gret cold, and when check engine light is ON. After 15 miles or less, then light went off, and runs terrible - overfueling!

Thank you for your help!

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Reply to
partsmore

Well, I don't think I've been much help. I'm pretty sure you can read the code on a '93 with a voltmeter by reading the "sweeps." If you don't have a repair manual maybe you can find the instructions online somewhere. Basically it does some kind of indication that it's reading, then you count how many times the meter moves--three times would equal 3, then there is a pause (if I remember correctly), then it moves again a number of times. On some later Explorers (not sure if '93 is "later" )you can install a jumper on the Diagnostic Test terminal (behind the fuse box in the engine compartment) and read flashes of the CEL. The jumper wire (according to Hayne's) goes from the "test terminal" to pin number 2 of the Diagnostic Test terminal. The volmeter goes from the positive battery terminal to pin

4 (STO). This is for the KOEO test. When it's done it will display 111. Then is says to remove the jumper and start over with the engine running (KOER normal temp). The first code will be 1/2 of the number of cylinders (3). It gets complicated after that involving turning the steering wheel, stepping on the brakes etc so I suggest getting the full instructions.

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Reply to
Ulysses

Sounds like it's running fine when in "open loop" mode, then when it warms up and goes to closed loop mode the problems start. In open loop it isn't relying on the sensors much, if any, to determine how much fuel to send to the cylinders, but in closed loop it does rely on the sensors. So my guess is you forgot to hook up one of the sensors, or it got damaged, or ???. Check to make sure all the sensors are connected, ... O2 sensors, MAF, Baro, Throttle position, and anything else that should have wires coming out of it.

Reply to
Ashton Crusher

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