Any caveats before I pull the heads... | Page 2 | Ford Explorer Forums - Serious Explorations

  • Register Today It's free!

Any caveats before I pull the heads...

You would be better off getting a code reader and checking whats causing the light to go off... but first try unplugging your battery for awhile, then try again and see if the light persists. The dealer usually charges an arm and a leg just to talk to you. :)

Nick
 



Join the Elite Explorers for $20 each year.
Elite Explorer members see no advertisements, no banner ads, no double underlined links,.
Add an avatar, upload photo attachments, and more!
.





code reading

Well, I had the battery cable off for the rebuild process, and it didn't make any diffence. The Check Engine light was only intermittent at first - usually coming on when I was coasting downhill, or cruising on flat highway, and going off when the engine was under load (uphill, etc.). Then it started coming on more frequently; cyclically, like it was related to the opening/closing of the t'stat, or perhaps due to heating/cooling cycles of the O2 sensors. Now it comes on after the engine has been running for a few minutes (warms up good), and never goes off.

I'm assuming it's the O2 sensors, given the mileage and recent abuse they've taken (high heat, with periodic bath in antifreeze). I bought two new ones last night, but the truck was too hot to work on, so I blew it off until tonight.

I just found the instructions in the Haynes manual last night for using a voltmeter to read the codes, but it looks like that's a awful kludgy way to read 'em. Do you have a code reader of some kind that's a little easier to use, and if so, where'd you get it and what did it cost?
 






You don't need anything but a paper clip to read the codes on a 94.

It will display them on the Check Engine Light by flashing it for each code. See http://dalidesign.com/hbook/eectest.html on how to read/interpet the codes.
 






Antifreeze can kill O2 sensors.
 






NOW it's all done...

I replaced both O2 sensors last night (what a bee-eye-tea-sea-H!). This has fixed the Check Engine light problem.

Replacing the sensors would be a piece of cake if they didn't have to be plugged into the wiring harness on the back side of the block. What WERE they thinking? There was no obvious sign of damage or contamination to them, but they (or at leaste one of them) were apparently bad.

FWIW, those of you who may be doing a valve job/head swap/etc. ought to consider the possibility of replacing the O2 sensors while you're there. You've got to disconnect them to remove the lower intake manifold and heads anyway, so it's an ideal time to do the job. Wish I'd done it that way. I had to take the upper manifold off (again) to do the job - there's another half-hour I'd rather have spent inside instead of out in the garage - and wrestle with those %*&^@!$ connectors again. Took me 2 1/2 hours start to finish: 25 minutes to tear the top off; 15 minutes to remove and replace the sensors; 1hr 15 min to disconnect and re-connect the cables; 30 minutes to button it all back up. What a pain. I'll be glad when I'm rich enough to pay the dealer to do this crappy work. Sheeesh.

One last bit of good news. I found the vacuum cable assembly that goes to the EGR/EVR valves. They were on the passenger side of the engine, wedged down beside the air filter box, under the heater hoses. Don't ask me how they got there, but they're now in their rightful place.

Thanks again for your collective help.

Keep the wheels side down....

Michael
 






Hey! Thanks for the info! Im replacing my 02s (or was going to...) today but Im also doing a head swap in about a week! So I guess ill wait on the 02s then. Just saved me a ton of time! :)

Nick
 






Back
Top