Need some advice here, 87 BII. I've been trouble with my engine missing from time to time. I can turn my ingition off and back on quickly going down the road and it will stop for a bit, then does it again. My codes are as follows.

KOEO 34
Memory code 33
KOER 41
33
13
25

In that order, should i go buy an Oxygen sensor, i've checked the wires.
And should i clean or replace the EGR valve.
What would you guys recommend?

 

I would focus on the EGR first....clean, and or replace it.....see how it runs after that before spending good money on an 02 sensor that you might not need...
If the O2 sensor is bad with a low voltage output, you may be running rich....(at least that's what happenned on my Jeep...sensor said 0V...telling the ECU to add fuel to compensate for sensing a lean condition)....this fouled plugs a little and the sensor was all sooty when I inspected it....so if you can smell the fuel richness, you might want to inspect/replace sensor first...
other thoughts are...When was your last tune up? Have you cleaned the Throttle body lately with some Seafoam or combustion chamber cleaner? ...that might help...while your in there clean up your IAC if you have one....

good luck with it...

 

Thanks for the help, the Throttle Body and the IAC was cleaned about two years ago, i put new plugs in it two weeks ago and it cured the problem for about two days. I'm sure its running rich when it does it, black smoke and uses alot of gas.

I have a fairly new EGR I'll put on it and see what that does.
Will let you know, Thanks again.

 

SOP when dealing with EEC-IV is to resolve KOEO codes first, so, as McQue suggested, focus on the EGR system, specifically the KOEO 34.

Because KOEO codes are set with the engine off, they are almost always electrical in nature. I doubt that replacing the EGR valve is going to have an effect on a KOEO 34. KOEO 34 refers to a fault in the PFE sensor circuit, which is used by the PCM to control when and how far to open the EGR valve. My first step in this would be to focus on the PFE sensor.

A couple of other notes:

KOER 41: O2 sensors only operate from 600 F up. The KOER test isn't long enough to heat the O2 sensor that hot, so it is easy to get a false KOER 41 (especially where you don't have a CM 41) if you try to perform the test without preheating the sensor before performing the test. Did you run the engine up to temperature immediately before the KOER test? If not, then I would repeat the KOER test before I worried at all about this KOER 41.

KOER 25: the only times I've seen this was when I gave the engine a weak "goose" for the goose test. Make sure that when you goose it, that you give a good 3/4 to full throttle.

 

Visit this document for info on PFE sensors...

http://www.tomco-inc.com/Catalog/pfe%20sensors.pdf

McQue

 

Thanks, i found my vacume hose rotten on that yesterday, replaced it and was given the same codes. I have a bunch of parts from my 86 BII, except my o2 sensor all ready used it, i'll start swaping parts tomarrow.
I have a question, useing my reader to check codes, would these four KOER codes be considered inactive codes and show up eveytime i check them? I unhooked my reader as it was giveing me the KOEO codes and it erased my "memory codes" as its called. Would that have erased all inactive codes, including the KOER codes. Is it possible that i have fixed my problem with the EGR valve and i'm reading inactive codes? The truck does'nt run any better,
Oh, one more thing. I run the truck 30 miles into work this morning and then check my codes.

 

I use an Innova Equus code reader model 3145...
I allways remove the batteries from my code reader to make sure it does not hold any codes in the code reader memory...I also use the reader to clear any codes stored in the vehicles computer memory...If I am not sure that I have cleared vehicle codes, I disconnect the vehicle battery...and ground out the positive cable to drain any residual voltage stored.... next time I run my vehicle through the various checks with the reader, I am pretty sure I am getting good data....

McQue

 

Ok, i swapped the EGR and the PFE sensor out with used ones i had on my other truck, the EGR was couple years old and alot cleaner. Still haveing the same problem, takes spells of running rich. I run it about 10 miles and checked the codes again. I got code 11 on the KOEO test, so thats good. And on the KOER test i got 41,33,13,and 25. Any more ideas? Would a faulty O2 sensor create those other codes?

 

I am not convinced your EGR system is functioning 100% based on the code 33, but with the rich running condition and the code 41 (o2 lean) I would pull the 02 sensor...Here is a cut and paste article from the web about testing 02 sensors.

Testing O2 sensors on the workbench.
Use a high impedence DC voltmeter as above. Clamp the sensor in a vice, or use a plier or vice-grip to hold it. Clamp your negative voltmeter lead to the case, and the positive to the output wire. Use a propane torch set to high and the inner blue flame tip to heat the fluted or perforated area of the sensor. You should see a DC voltage of at least 0.6 within 20 seconds. If not, most likely cause is open circuit internally or lead fouling. If OK so far, remove from flame. You should see a drop to under 0.1 volt within 4 seconds. If not likely silicone fouled. If still OK, heat for two full minutes and watch for drops in voltage. Sometimes, the internal connections will open up under heat. This is the same a loose wire and is a failure. If the sensor is OK at this point, and will switch from high to low quickly as you move the flame, the sensor is good. Bear in mind that good or bad is relative, with port fuel injection needing faster information than carbureted systems. ANY O2 sensor that will generate 0.9 volts or more when heated, show 0.1 volts or less within one second of flame removal, AND pass the two minute heat test is good regardless of age. When replacing a sensor, don't miss the opportunity to use the test above on the replacement. This will calibrate your evaluation skills and save you money in the future. There is almost always *no* benefit in replacing an oxygen sensor that will pass the test in the first line of this paragraph.

McQue

 

Thanks, it may take a few days, but i'll let you know how that turns out.

 

Ok, i got to looking and found my vacuum hoses were cut off my DPFE switch. Its been this way all year and has been running great, so i would assume its not my EGR causeing my problem. I went ahead and got a new O2 sensor and will put it in today,

 

Its fixed, it was the O2 sensor. Thanks for all your help!

 

Good to hear it...have a great holiday season...enjoy your Bronco!