DWALKER

2.9L engine starts fine but runs very rich. Lots of black smoke.
Had EEC IV rebuilt but still does the same.
What all sensors should I look at and where might I find them? found the O2 sensor but don't know how to test it.

Any help would be greatly appreciated !

Bert

See if you get any codes using these instructions and post back. Ford Ranger/Bronco II EEC-IV Testing

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Bert

DWALKER

I tried to get the codes and the computer wouldn't talk to me so I sent it in for repair. Will try again as soon as I get it back.
I have a question however : When I first start the engine, it isn't in closed loop yet so is it really paying attention to the sensors at that point ?

Bert

It doesn't watch the O2 sensor until at operating temerature and engine run at 2000 rpm for 2 minutes. That's when doing the KOER test.

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Bert

DWALKER

I tried once again to get codes from the computer and it didn't respond at all so, once again I returned it to Auto and Truck Electronice in Rogersville Tn for repair. The tests I ran however were Key on, Engine Off, looking for a code 11.

jimbot58

Here is one possibility as it happened to my '86: there is a fuel pressure regulator that is vacuum powered on the left side (facing front) that reduces the pressure from the pump (around 90psi!). Mine had a bad diaphragm and two things were happening-the pressure overwhelmed the injectors forcing too much gas into the cyls, and the broken diaphragm allowed raw gas to be sucked into the crankcase through the vacuum line.

So check the pressure on the fuel rail-I think it should be less that 30 psi, but I don't remember for sure- I no longer have those shop manuals.

Also look (and smell) the oil! It may be contaminated with fuel, both from the vacuum line and the extra gas leaking past the piston rings into the crankcase. Be sure to change oil in either case once you have corrected the problem. Too rich running engines can have the oil contaminated no matter what the cause.