Computer Calibration

[Sky1785]

My '91 Navajo was having a terrible time with gas mileage, below 10mpg. So i took it in and they replaced the thermostat the o2 sensor and the crankshaft position sensor and then reset my computer. Well the mileage was good for about 20 minutes then died again so i took it back, he scanned and was getting the same o2 code as before but when he did a diagnostic on the sensor it checked out fine and it was brand new. So he went through the menu on his computer checker thing and it said there was a calibration update for my 'puter and unless i could find a Ford/Mazda recall on it i would have to pay $60 for the calibration at the Ford dealer here in town, I didn't notice any other posts about this so i was wondering if anyone had had this problem and any advice yall had, thanks.

 

[MyExpWork]

Sounds kind of funny to me only because wasn't it getting normal gas mileage before this? Unless the sensors are new and the computer needs to be calibrated to them.

But, to calibrate to just calibrate it doesn't make sense to me because if nothing has changed, why would you need a recalibration?

Brian

 

[410Fortune]

The EEC-IV computer cant be "calibrated". The program or "profile" can be changed, but Ford would do this by installing a remanufactured EEC-IV brain box and charge you $600.

Now if it ran fine for years with the current computer, then the profile is fine and your problem lies elsewhere.

Now it is possible that your computer itself is bad, you can try swapping it out with another one form a junk yard (about $50) or with a freinds, just make sure they are the SAME!!!! All the computers have a calibration code on the stickerm they must match or the trucks must be the same, for example yours is a 91 so it has a single 02 sensor and a MAP sensor, so a 93 EEC probably wont work. (might but I havent tried)

Is the 02 code the only one the computer is giving?
02 code is emissions/fuel related. The other components in the fuel system are the MAS sensor (clean it) in your case the MAP sensor, coolant temp, intake temp, and the canister purge solenoid. a BAD EGR can also do this.

Now the 02 sensor code means one of two things, you are running lean or you are running rich. This can be caused by many things, everything from weak fuel pump, dirty fuel filter, to bad EEC or MAS sensor.

If you go to Autozone and have them scan your codes (CEL on) they will provide you with a full print out of how to step by step diagnose/eliminate the codes.

This is exactly the same proceedure that the Ford shop manuals would tell you to do , that the Ford service department would perform (At 70$ per hour!) so it can really save you some serious $$$$....

 

[Pendarus]

I have to differ with you about the rercalibration. Ford has for later model explorers changed the profiles a few times. The update is uploaded by a programmer at the dealer with the computer still in the truck. Just the same way newer trucks are reprogrammed by the performance programmer instead of installing a chip.


I hope that all made sense!

 

[Jason_25]

Originally posted by Pendarus
I have to differ with you about the rercalibration. Ford has for later model explorers changed the profiles a few times. The update is uploaded by a programmer at the dealer with the computer still in the truck. Just the same way newer trucks are reprogrammed by the performance programmer instead of installing a chip.


I hope that all made sense!

If you read the post he said EEC IV. 96 and later explorers use EEC V.