89 Bronco II new to me

[grumpy old man]

Got up this morning feeling better than I have in a long time. Decided to take the Bronco over to the test station and see if it would pass. Managed to get about 4 miles and the CEL came on. Made a u turn back to the house. While the resistor improved the driveability quite noticibly, it still has the code 41. But it has added 51, 61, and 63. I have given up for the day. I am rapidly remembering why I considered Ford to be a 4 letter word the last few years I actually wrenched professionally. I will get back to it eventually, probably a couple of days after I get over the intense desire to introduce it to 5 gallons of gas and a match.

 

[L\Bronco]

Got up this morning feeling better than I have in a long time. Decided to take the Bronco over to the test station and see if it would pass. Managed to get about 4 miles and the CEL came on. Made a u turn back to the house. While the resistor improved the driveability quite noticibly, it still has the code 41. But it has added 51, 61, and 63. I have given up for the day. I am rapidly remembering why I considered Ford to be a 4 letter word the last few years I actually wrenched professionally. I will get back to it eventually, probably a couple of days after I get over the intense desire to introduce it to 5 gallons of gas and a match.

Hey Grumpy, sorry for your luck.
41 is still HEGO signal always low, (below .1VDC)
51 is ECT voltage greater than threshold voltage. (more than 4.75VDC)
61 is ECT sensor below threshold voltage (less than .2VDC)
63 is TP sensor below threshold voltage. (less than .2VDC)
I would clear codes and check for 5V at The TP sensor on the Orange\white wire.
If its good, road test again and see what resets. (You may have set the new codes during your diagnostics\repairs )
If 1 resets clear codes again and re road test with the ground circuit shorted to ground using your switch. (Make sure the bypass ground is on the O2 sensor side of the harness.)
Good luck.
Cheers

 

[Tiha]

Did this resistor by chance affect the signal of the ECT and TP?

Or maybe those sensors were bad and not showing a code because of the bad resistor?

 

[L\Bronco]

Did this resistor by chance affect the signal of the ECT and TP?

Or maybe those sensors were bad and not showing a code because of the bad resistor?

I was thinking the same thing Tiha, the ground bypass should take it out of the equation.
Cheers

 

[grumpy old man]

Bronco, are you sure that the code 41 sets at below .1? The O2 voltage at the break out box stone cold in the morning starts at .096 and as you drive it steadily drops and settles down dancing around .054 to .058. It may have set because I was switching the bypass on and off looking for any change in the O2 voltage, none observed.

Could driving it with the break out box connected cause problems?

The ECT sensor was among the last sensors changed and I did connect it tio an ohmmeter wrapped my hands around it and blew hot air on it. Even warming it up that little bit made a noticible change in the ohmage across the sensor.

The emissions manual has test procedures for all the sensors involved. Will go through all those and fix anything I might find. I will do a road test with the bypass off and see what happens. No codes I will unplug the switch pllug in the permanent bypass and head for the test station. If get codes I will erase them and roadtest again with the bypass on.

I have the new ECM in and if both tests fail I will plug in the original ECM and try the same thing. I will remove the break out box to remove it from the equation.

Maybe tomorrow morning depending on my state of mind.

 

[L\Bronco]

ronco, are you sure that the code 41 sets at below .1? The O2 voltage at the break out box stone cold in the morning starts at .096 and as you drive it steadily drops and settles down dancing around .054 to .058. It may have set because I was switching the bypass on and off looking for any change in the O2 voltage, none observed

Hey grumpy, Im not 100% sure on the threshold voltage (it was a loooong time ago) more important is the time factor. The module counts the time since startup and if the voltage stays low for too long, the 41 sets
Not sure of the breakout boxes effect without seeing the tool in person. Theoretically, it should not, but you never know.
Good luck
Cheers

 

[grumpy old man]

Where I am right now is I went back to the original ECM. I was thinking that the 41 only appeared after the introduction of the reman. Put the original back in without the break out, BYPASSED the resistor, replaced the TPS cleared all the codes and took it out for about a 20 mile ride. Runs great no CEL. On my way to the test station in the AM. If it passes with no problems I will put it back together and call it a day. If my system is as rare as it seems to be I can't help bur wonder if the reman ECL is incompatible. What I do know is that if it passes smog with no CEL I am not touching anything, just putting it back together and done.

I do have another thought. Just for curiosity I was looking on insurance salvage for a totally wrecked 4.0 liter ranger and found 2. She has two more years in college so as long as it holds out no problem, but if something jumps up out of the woodwork I will do a 4.0 upgrade. Her drive to and from college takes her through several mountain ranges in California and Oregon. An additional 70 +_ cubes cant hurt and the 4.0 system probably does not have any weird surprises like the current 2.9. Just a thought.

Am starting to feel a little hopeful.

 

[L\Bronco]

Where I am right now is I went back to the original ECM. I was thinking that the 41 only appeared after the introduction of the reman. Put the original back in without the break out, BYPASSED the resistor, replaced the TPS cleared all the codes and took it out for about a 20 mile ride. Runs great no CEL. On my way to the test station in the AM. If it passes with no problems I will put it back together and call it a day. If my system is as rare as it seems to be I can't help bur wonder if the reman ECL is incompatible. What I do know is that if it passes smog with no CEL I am not touching anything, just putting it back together and done.

I do have another thought. Just for curiosity I was looking on insurance salvage for a totally wrecked 4.0 liter ranger and found 2. She has two more years in college so as long as it holds out no problem, but if something jumps up out of the woodwork I will do a 4.0 upgrade. Her drive to and from college takes her through several mountain ranges in California and Oregon. An additional 70 +_ cubes cant hurt and the 4.0 system probably does not have any weird surprises like the current 2.9. Just a thought.

Am starting to feel a little hopeful.

Fantastic!
Good luck tomorrow
Cheers

 

[grumpy old man]

OK the new computer sets the code 41almost instantly the old computer takes about 25 miles with the bypass on or off. The emissions manual has no flow chart for fixing the 41, the only reference is that it is lean and no switching detected on the O2 sensor. searching the internet apparently I am not the only one chasing a code 41 and it seems that no one has found any definitive answer for curing it.

Talk to me about the 4.0 swap, yes I am dead serious.

Dwight

 

[grumpy old man]

I have totally given up on this thing. It is throwing a code 41 lean and is still running pig fat. I know of nothing left to do so am looking for a donor truck. The engine only has 80 K on it and the trans is fresh so I should be able to find someone that would be interested at a reasonable price for the pair. I have until the end of summer to comlete the swap so we will see.