code 41 1990 f-250
Hotshot
Joined: Jun 2015
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I don’t know when it changed to Bosch but the ‘87 & ‘89 had NTK oxygen sensors with Ford engineering numbers on them.
Hotshot
Joined: Jul 2020
Posts: 10,359
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From: Near Salt Lake City
You may know how hairy the H manual diagnosis gets for that code 41 and doing pinpoint tests
The PCED in section H is the fuel control
You need to see if the O2 sensor is slammed rich or not and if it is switching or not (back probe the sensor or use the breakout box)
It could be an intake air leak or need an O2 sensor. processor, wiring etc.
Check for an unmetered air leak
Feed it some propane and watch the O2 numbers
The PCED in section H is the fuel control
You need to see if the O2 sensor is slammed rich or not and if it is switching or not (back probe the sensor or use the breakout box)
It could be an intake air leak or need an O2 sensor. processor, wiring etc.
Check for an unmetered air leak
Feed it some propane and watch the O2 numbers
Tuned
Joined: Aug 2010
Posts: 275
Likes: 23
You may know how hairy the H manual diagnosis gets for that code 41 and doing pinpoint tests
The PCED in section H is the fuel control
You need to see if the O2 sensor is slammed rich or not and if it is switching or not (back probe the sensor or use the breakout box)
It could be an intake air leak or need an O2 sensor. processor, wiring etc.
Check for an unmetered air leak
Feed it some propane and watch the O2 numbers
The PCED in section H is the fuel control
You need to see if the O2 sensor is slammed rich or not and if it is switching or not (back probe the sensor or use the breakout box)
It could be an intake air leak or need an O2 sensor. processor, wiring etc.
Check for an unmetered air leak
Feed it some propane and watch the O2 numbers
In my '88, I show this diagram:
Ford diagram from H manual for 1988 7.5L
My question is in regard to the piece you replace on the exhaust system, it looks similar, but without the baffles and other crap inside. Do you put just one O2 sensor in it? I need to pass smog once, then I can do what I want to it. Do you recommend converting over from EFI to carb? The EFI stuff seems like a huge problem for most everything.
Hotshot
Joined: Jul 2020
Posts: 10,359
Likes: 2,594
From: Near Salt Lake City
I would not switch it to a carb
Code 41 and the converter have little to do with one another
The "piece you replace on the exhaust system" means what?
The converter you pictured?
Pass I/M once? Where? Most I/M counties, if not all, will not allow a carb swap and pass
EFI is a problem only when it's broke
Your 88 is harder to diagnose
You need to monitor the O2 sensor voltage (not disconnect it)
You need to see if the truck is slammed lean or if the O2 is switching like it should be
If you have a couple of dead injectors the sensor will be slammed lean
Grab a 1988 PCED, look over the pinpoint tests for code 41
Code 41 and the converter have little to do with one another
The "piece you replace on the exhaust system" means what?
The converter you pictured?
Pass I/M once? Where? Most I/M counties, if not all, will not allow a carb swap and pass
EFI is a problem only when it's broke
Your 88 is harder to diagnose
You need to monitor the O2 sensor voltage (not disconnect it)
You need to see if the truck is slammed lean or if the O2 is switching like it should be
If you have a couple of dead injectors the sensor will be slammed lean
Grab a 1988 PCED, look over the pinpoint tests for code 41
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