EEC-IV Code "33".....EGR or PFE?

[Robb]

Got a '94 work Ex idling like garbage. KOEO test shows only "33." Reseting the codes, and running it right now.

33 is EGR not opening or something.

Time is precious, and I gotta shotgun this thing pretty quick. Should I start with a PFE? Or EGR?

Thanks

 

[griggs]

If I remember correctly these older EGR valves have a position sensor mounted on the valve itself. If so, before you spend $, pull off the EGR Valve and clean everything and verify free operation. A stuck open valve would cause poor idle for sure. Have had same problem on other older EEC IV systems.
Jerry

 

[MrShorty]

Are you sure that wasn't a 111 pass code or a 33x? A '94 Explorer should be outputting three digit codes. KOEO test only shows 33, did it show 33 for both the KOEO codes (before separator pulse) and for the continuous memory (CM) codes (after separator pulse)? EGR codes on these, especially KOEO EGR codes, often point to a bad PFE/DPFE sensor. SOP on these is to start by resolving KOEO codes (because they are almost always electrical).

 

[Robb]

You're right MrShorty, I was being dumb. Forgot how to read these things, and forgot that you get the 1-1-1 if it is okay for both groups. I was thinking it only did that for the first group. So, KOEO is clear, but I definately have the CEL on most of the time. Time to run the KOER test.........................man I hate this EEV-IV junk.

 

[Robb]

I lied again. I thought I had everything cleared out............but a couple of times, I did get a 157 (MAS volt low), and now it is staying constant. I can't run the KOER.

I cleaned the MAS elements earlier (the first time I saw the code), is there anything else I can to to a MAS to check it? Or probably better off going and grabbing one?

 

[Robb]

nvm......................slapped a new MAS in there, and she runs 90% better!