Big change of plans...

[adsm08]

I would suspect an issue with the speed sensor or the calibration.

You don't happen to know the gearing and tire size of your donor do you?


Also, where in PA are you?

 

[85_Ranger4x4]

Sir, you just described how a carb'd car runs.

One that has been neglected for a long time...

I am not real up on Explorers but when you change the gearing in a later F-150 but don't reset it in the PCM it goofs the shift points up.

 

[adsm08]

I am not real up on Explorers but when you change the gearing in a later F-150 but don't reset it in the PCM it goofs the shift points up.

Ranger, F150, Explorer, Taurus, pretty much anything with a VSS and electronic speedo.

 

[RangerSVT]

Even though you don't have codes for O2, that's your problem for your lean issue. Install the cats and downstream O2's for both the lean condition and for inspection. The surging could be from vacuum leak and/or dirty Maf. Unless you install the rest of the donor's emissions, you will need to delete them through a tune prior to inspection...

SVT

 

[85_Ranger4x4]

Ranger, F150, Explorer, Taurus, pretty much anything with a VSS and electronic speedo.

97-98 F-150's have a gear in the t-case/trans you have to change.

 

[RangerSVT]

97-98 F-150's have a gear in the t-case/trans you have to change.

Anything after 96 can be changed by flashing the ECU...

SVT

 

[adsm08]

I don't think his exhaust setup is to blame here.

The downstream O2 sensors basically do nothing to determine air/fuel ratio. They are catalyst monitors, and the signal is compared to the upstream to see that it doesn't switch along with them. He may actually have found a rather ingeniously redneck way to avoid cat efficiency codes.


Seriously though, what part of the state are you in? I'd love to take a crack at these lean codes if you are close enough.

 

[RangerSVT]

I've experimented with the down stream O2's on several of my own vehicles, ranging from a 2.3 to the 4.0, all OBD2. Without cats I've had rich conditions with downstream sensors installed in factory locations. I've found that pulling the down stream sensor(s) out of direct flow of the exhaust mimics using cats, which tricks the ECU and throws no codes and corrects AF ratio, at least in my vehicle findings. I own the Rotunda scantool and used this in my experimenting, not just guessing results. About the lean concern, have you checked for vacuum leaks? Checked for dirty maf? Do you know if the donor had any issues you are experiencing?

SVT

 

[Range98]

That's what my thinking was by leaving the downstream sensors out of the exhaust flow. I used the explorer rims on my truck. But I'm in Pottstown, and I quickly checked for vacuum leaks but couldn't find an obvious one and I haven't checked the maf sensor yet. I just found it odd that it began running rough out of nowhere cause it ran like a clock for months but I've always had the lean code

 

[Range98]

And no I test drove and ran the donor cold and it ran without an issue

 

[RangerSVT]

How is your fuel pressure? Did you change the fuel filter when you did the swap?

SVT

 

[Range98]

I checked fuel pressure right after doing the swap and it was fine and I used the filter from the donor

 

[RangerSVT]

How many miles were on the donor? I'd check the fuel pressure again if you have a tester, and I'd change the fuel filter regardless, cheap insurance...


SVT

 

[shane96ranger]

What year was the donor Explorer?

Rick and Adsm.... could this be an issue with the no return fuel system?


Sent from a Commodore 64 using a 300 baud modem

 

[RangerSVT]

That could play an issue, but the ECU can be flashed to run either returnless or return. 96-98 is return, 99-01 is returnless, 98-01 has pats, 96-97 no pats.

Did you run or are using a return line for the fuel system? If not, it is an issue, but would cause a very rich condition.
Shane, the donor is a 97, stated earlier...

SVT