does anyone have an answer to this problem? In the 94 f-150 my computer read an o2 sensor problem and i have replaced it with a brand new one. Also, i disconnected the battery to clear the codes. however, after the engine warms up for about 2 mins., the check engine light comes on again, and the computer still stores code as bad sensor. I have check sensor output reading and it reads ok. Also, checked computer side of harness plug and it is fine. have found no air leaks and compression test shows all 6 cyls within limits that are exceptible and fuel injectors are all clicking normally. the thing is burning alot of gas and i can really smell it at idle. could use a little help. So, if anyone might have some advice, " I NEED HELP ON THIS !!!!! " Thanks

 

If it were mine i would check and see if the fuel pressure was too high as a starting point.

 

thanks acogoff. will do that. just nticed egr valve not working but don't know if that might be a factor in o2 code readout.

 

How do you know your EGR isn't working ??

 

valve not moving when suction aplied

 

If the sensor is out of range (too rich or lean) it will set a code. Check fuel system pressures and the ignition system.
regards
rikard

 

seliniod has vac to it, but none through it, when revved up. i think it is bad.

 

timing is set properly will have to check fuel pressure to morrow. thanks 4 advice. "FORD TRUCK PEOPLE R #1"

 

If an EGR is stuck closed or not opening, you will not suffer any performance problems from it.

It's only purpose is to allow a small amount of exaust gases back into the input manifold during the light to medium power taxing loads on your engine to help cut down on the NOx (Oxides of Nitrogen) causes by high combustion temperatures.

It also won't cause an O2 sensor code, it has a code of it's own.

 

no vac from egr seliniod to egr while revving engine {6cyl inline 300}

 

Well, since someone switched my legs on this topic, I'll chime in here. The vehicle has to be moving or the EGR will not open. I don't know what the minimum speed is, but the expert that corrected me on this should know. This doesn't contradict what I've read about the Ford ECM's, but no mention was made of vehicle motion being involved in the documentation I read.

At idle, EGR closed. At WOT, again, EGR closed. Anytime an enriched mixture is needed (heavy engine load) the EGR will close. Buzzing around in city traffic, the EGR is closed more than it's open. On the highway, though, that's a whole different ball game. The EGR will open to reduce emissions and displace some of the fuel-air mix, which has the added side effect of helping the engine run cooler at higher RPM's with light throttle.