Lean codes and little to no power

[stanleyb308]

This truck is a 98 Ranger with a 3.0L gas only. I bout it cheap not running. The previous owner had replaced the engine but could not get it to run right. Turned out the engine that was swapped had one cracked head along with the IAC valve being stuck closed. After I got everything replaced and back together the truck ran ok but very rich. Come to find out the engine was out of a newer flex fuel model truck and had flex fuel injectors. I picked up a set of remanufactured OEM gas injectors but now it runs lean and has even less power. I know my fuel pressure is good is 60psi KOEO and 65psi running. It maintains 65psi when I rev the engine also. I've tried twice to find a vacuum leak with with brake cleaner with no luck. The truck seeems to run better when it is completely warmed up. When its cold it has hardly any acceleration and after a minute or so wide open throttle trying to get up to speed it just falls on its face. Feels like you turned the igintion off. One other thing I find strange is the engine will immediately die if I unplug the MAF.
I'm starting to wonder if the PCM wasn't swapped from the the truck the engine came from. Ford was no help on figuring out if I have the correct one or not. Any Help would be greatly appreciated!
The codes:
P0171 Lean bank 1
P0174 Lean bank 2
P1151 Lack of HO2S1 switches?
P1131 Lack of HO2S11 switches?

 

[franklin2]

Here is a list of 3.0 engine computers in 1998. Do you reckon "low emissions" is the flex fuel computer?


Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x2, AT, Federal emissions, ID F87F-ABA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x2, AT, Federal emissions, ID F87F-ABB
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x2, AT, Federal emissions, ID F87F-BNA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x2, AT, Federal emissions, ID F8PF-EKA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x2, AT, low emissions, ID F87F-AFA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x2, AT, low emissions, ID F87F-AFB
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x2, AT, low emissions, ID F87F-BSA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x2, AT, low emissions, ID F8PF-ENA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x2, MT, Federal emissions, ID F87F-XA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x2, MT, Federal emissions, ID F87F-XB
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x2, MT, Federal emissions, ID F8PF-EPA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x2, MT, low emissions, ID F87F-AAA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x2, MT, low emissions, ID F87F-AAB
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x2, MT, low emissions, ID F8PF-ETA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x4, AT, Federal emissions, ID F87F-ACA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x4, AT, Federal emissions, ID F87F-ACB
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x4, AT, Federal emissions, ID F87F-BPA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x4, AT, Federal emissions, ID F8PF-ELA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x4, AT, low emissions, ID F87F-ADA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x4, AT, low emissions, ID F87F-ADB
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x4, AT, low emissions, ID F87F-BRA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x4, AT, low emissions, ID F8PF-EMA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x4, MT, ID F87F-YA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x4, MT, ID F87F-YB
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x4, MT, ID F87F-ZA
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x4, MT, ID F87F-ZB
Electronic Control Module, (RH rear engine, thru firewall), 6-183 (3.0L), 4x4, MT, ID F8PF-ERA

 

[RonD]

No, Low emissions is Calif, or New York in some years, Federal is other 48 states

Look at 8th digit of VIN
U = gas only
V = Flex Fuel

O2 sensors last 12 years or 100k miles, ONLY sensors that wears out
If you don't know how old they are change them, or you are basing diagnostics on false codes

O2s are "the word of God" to computer, it has no other sensors to test O2 feedback with
O2s are not used when engine is cold and warming up, they need to be heated above 650degF before they work, even new ones, lol

 

[franklin2]

Maybe they didn't have flex fuel in 1998? And the engine he has is from a later model that did?

 

[stanleyb308]

Maybe they didn't have flex fuel in 1998? And the engine he has is from a later model that did?

I know when ordering parts it doesn't give an option for flex fuel or gas. The 8th digit is U. I'm thinking they swapped a complete engine. I'm pretty confident the O2 sensors are working. With the FF injectors it was obviously getting to much fuel and throwing rich codes for both banks. I guess I could throw new ones in at this point just to see. Almost at the end of my rope with this thing.

 

[RonD]

3.0l gas only ran 14lb/hr injectors thru 2000
3.0l Flex fuel used 24lb/hr injectors thru 2000

In 2001 Ford change computer software and dropped the Fuel Sensor on flex fuel models
So both gas only and flex fuel could then use the same 19lb/hr injectors, or 21lb/hr

Its the computer software that is setup for injector size
Lean and Rich codes are about OPEN TIME for each injector

Computer does on the fly open time calculations based on RPM and load, then checks feedback from O2 sensor
Say it calculated 100ms(millisecond) open time for each injector, this is 0 fuel trim
If O2 showed high oxygen(lean) then computer changes to 102ms, +2% fuel trim
If O2 show low oxygen(rich) then computer changes to 98ms, -2% fuel trim

If fuel trim gets close to 20% either way for any length of time computer will set lean or rich code
2001 and up 3.0l computers had more leeway so E85 could be used without a fuel type sensor

So injector size and fuel pressure play a role, as does O2 sensor feedback
MAF sensor and air temp sensor also play a role, they are used to calculate the WEIGHT of the incoming air
Gasoline's air/fuel mix of 14.7/1 is a weight ratio
14.7 pounds of air to 1 pound of gasoline
Which is why injectors are rated in pound per hour(lb/hr)

How long did this vehicle run rich?
That could have compromised the O2s, carbon coating

 

[stanleyb308]

I drove it for about two weeks before installing the correct injectors. Is it possible to clean the O2 sensors or they must be replaced?

3.0l gas only ran 14lb/hr injectors thru 2000
3.0l Flex fuel used 24lb/hr injectors thru 2000

In 2001 Ford change computer software and dropped the Fuel Sensor on flex fuel models
So both gas only and flex fuel could then use the same 19lb/hr injectors, or 21lb/hr

Its the computer software that is setup for injector size
Lean and Rich codes are about OPEN TIME for each injector

Computer does on the fly open time calculations based on RPM and load, then checks feedback from O2 sensor
Say it calculated 100ms(millisecond) open time for each injector, this is 0 fuel trim
If O2 showed high oxygen(lean) then computer changes to 102ms, +2% fuel trim
If O2 show low oxygen(rich) then computer changes to 98ms, -2% fuel trim

If fuel trim gets close to 20% either way for any length of time computer will set lean or rich code
2001 and up 3.0l computers had more leeway so E85 could be used without a fuel type sensor

So injector size and fuel pressure play a role, as does O2 sensor feedback
MAF sensor and air temp sensor also play a role, they are used to calculate the WEIGHT of the incoming air
Gasoline's air/fuel mix of 14.7/1 is a weight ratio
14.7 pounds of air to 1 pound of gasoline
Which is why injectors are rated in pound per hour(lb/hr)

How long did this vehicle run rich?
That could have compromised the O2s, carbon coating

I drove it about two weeks before installing the correct injectors. Is it possible to clean O2 sensors or they must be replaced?

 

[stanleyb308]

No, Low emissions is Calif, or New York in some years, Federal is other 48 states

Look at 8th digit of VIN
U = gas only
V = Flex Fuel

O2 sensors last 12 years or 100k miles, ONLY sensors that wears out
If you don't know how old they are change them, or you are basing diagnostics on false codes

O2s are "the word of God" to computer, it has no other sensors to test O2 feedback with
O2s are not used when engine is cold and warming up, they need to be heated above 650degF before they work, even new ones, lol

Just out of curiousity, if the O2s have to be hot to work would this mean the truck would be likely to run better before the O2s were warm? In my case it seems to run better after the truck reaches operating temp.

 

[RonD]

Computer uses pre-programmed air/fuel mix tables before the engine/O2s are warmed up
But these tables are changed by Long Term Fuel Trims(LTFT)
LTFT is used so computer doesn't have to "relearn" engine's changes over the years, i.e. small air leaks, lower fuel pressure, dirty air filter, lower compression, ect................small changes that happen to all engines over the years

If your cold start doesn't run as well as warmed up it could be the LTFT has not gone back to "normal" since changing the injectors and O2s, could take a week or two
Or could be ECT sensor is showing colder or warmer coolant temp that actual, until it warms up, so wrong Choke

 

[stanleyb308]

Computer uses pre-programmed air/fuel mix tables before the engine/O2s are warmed up
But these tables are changed by Long Term Fuel Trims(LTFT)
LTFT is used so computer doesn't have to "relearn" engine's changes over the years, i.e. small air leaks, lower fuel pressure, dirty air filter, lower compression, ect................small changes that happen to all engines over the years

If your cold start doesn't run as well as warmed up it could be the LTFT has not gone back to "normal" since changing the injectors and O2s, could take a week or two
Or could be ECT sensor is showing colder or warmer coolant temp that actual, until it warms up, so wrong Choke

Ok. I'll pick up the O2 sensors today and give it a try. I'm going to throw a fuel filter in it too for good measure. Is it possible to be starved for fuel but not see a drop in pressure? I feel like its unlikely but I have no idea how many miles are on the filter anyways. The coolant temp sensor seems to read correctly according to my scan tool. It was right at ambient air temp on a cold start and gradually rose to operating temp.

 

[RonD]

You can put on a fuel pressure gauge and then hold engine at around 2,500rpm while you watch the gauge, if its slowly dropping then there is a flow issue

Hard to test fuel pressure without engine load, steady higher RPM is best you can do with a static test

 

[stanleyb308]

You can put on a fuel pressure gauge and then hold engine at around 2,500rpm while you watch the gauge, if its slowly dropping then there is a flow issue

Hard to test fuel pressure without engine load, steady higher RPM is best you can do with a static test

Well I replaced the O2s with no change. I disconnected the battery while I changed them. I didnt have time to replace the fuel filter tonight. It’s definitely not the original but who knows how old. It cut the power off on me completely again on the test drive. I’ve never had anything like that happen to me. It’s like some kind of temporary limp mode. It’s strange.