98-3.0 to 4.0 swap completed not running properly


Jakes98

10+ Year Member

Joined
May 24, 2013
Messages
7
Points
1,501
Vehicle Year
1998
Transmission
Manual
I have a 98 Ranger and I recently swapped out the 3.0 to the 4.0. It was a create motor from Detroit. I have one problem it keeps bringing up a code saying its to lean in bank 1 and 2. The motor came complete with wiring harness and sensors but I had to replace the harness as it was for a windstar, also I had to replace the fuel rail because it had a return line and my truck doesnt. Heres the problems im having with it, it doesnt start up right away it takes awhile, also the exhaust is very hot, and it lacks power. When its been running and hot the the air intake starts howling and it takes forever to start when hot. Anybody that can help would be greatly appreciated. Thanks
 
Hot exhaust manifold/header means lean condition, hot Cat converter(glows red) means rich condition.

Both O2 sensors are reporting lean so I would go with that,..... assumption.

Fuel rail change........yes the '98 would have a 60psi fuel rail with no return, older Ranger would have a 30psi fuel rail with regulator on rail and return line.
What injectors did you use?

Is/was the '98 a flex fuel vehicle?

If the 8th digit in the VIN# is a V that means the 3.0l was a Flex Fuel engine, this would mean the computer can adjust for different types of fuel, and in the swap there could have been missed connection that is telling the computer incorrect fuel information.

EDIT: oops, doesn't look like flex fuel was offered in '98 models
 
Last edited:
I didnt change the injectors they are the same ones that came with the motor.I did install new o2 sensors.Should I have changed the injectors when I changed out the fuel rail? Are there different types of injectors for the different fuel rails? Thanks
 
Last edited:
The pre-1997 injectors have a different part number than the 1998.

The 1998 4.0l shows part# FJ579

The 1993-96 4.0l shows part# FJ693

I would think this had to do with the change in fuel delivery system, 30psi pre-97 to 60psi post-97.

So yes I would try the '98 injectors, that is what your Computer is expecting to control.

The '98 computer is programed for the rail pressure and injector "nozzle size", so it knows how long each injector needs to be open to allow X amount of fuel into the intake.
If the nozzle size is changed then too much or too little fuel will be the result.


EDIT:
I forgot you don't have '98 4.0l injectors, just the '98 3.0l injectors
They have a different part# as well

So not sure where to go from here, the computer is set to run the 3.0l fuel levels, the 4.0l would require more fuel, so lean condition would be the result.
The 3.0l injectors might work, worth a try since its free, just your time.
New/used injectors are not cheap, hate spending money on something that may not be required.

I assume the computer is the '98 3.0l, you didn't change that?

Now interesting enough, the motorcraft CM-4890 fuel injector is listed as being used on the '98 3.0l AND the '99 4.0l, so swapping to the 3.0l injectors might work, but again this depends on the computers ability to adjust the fuel enough to compensate for the larger engine requirements.
 
Last edited:
More info would help a lot.
What engine harness are you using?
What ECU?
What injectors?
The 4.0, is it SOHC or OHV?
Right now you have your stock 3.0 fuel rail on the 4.0 engine?
 
Its a 4.0 ohv and I did change out the computer for a 98 4.0. The fuel rail is also off a 98 4.0,and the harness came off a 98 4.0 as well . I did find out that the motor was for a 97 Aerostar not a windstar. I checked with Autozone and the injectors have different part # for a 97 Aerostar and the 98 Ranger.
 
Remove air cleaner, with engine running put your hand over the intake plenum/MAF entrance, restricting air flow, engine should start stumbling, if it doesn't then you have a vacuum leak somewhere.

I would try the '98 60psi 3.0l injectors.

Not sure if the 30psi injectors will allow enough fuel to pass in the time allotted, I would assume they would pass more fuel, lol, but assume = ass U me

Fuel injectors on most engines don't fire individually, they fire in Banks, the 4.0l fires cylinders 1, 2, and 3 at the same time, then 4, 5, and 6 the next time.
This keeps the intake full of fuel vapor, if 1 injector is misfiring or sticky(slow) you usually don't notice much, a light misfire now and then, computer will open the other 2 injectors longer to compensate for leaner mix on that Bank.
If the 30psi injectors are all slow to open against the 60psi pressure then over all lean mix could be the result, the 3.0l injectors are setup for 60psi, and they are free to try :)
 
I am going to change out my injectors.That makes the most locical sense.I will inform with the progress. And thanks for all the help, I really appreciate it.If your ever in southern Cal send me a message because I want to buy you some beer!!
 
Jakes98 said:
I am going to change out my injectors.That makes the most locical sense.I will inform with the progress. And thanks for all the help, I really appreciate it.If your ever in southern Cal send me a message because I want to buy you some beer!!
Click to expand...

I was born in Whittier and grew up in Riverside, when it was mostly orange groves, lol :)
I met a Canadian girl, got married.........so live in Canada now, but I like it.
 
I live in Corona been here since it was orange groves. Oh how things have changed.
 
Update, Turns out I needed the fuel pressure damper.I was using the fuel pressure regulator on the fuelrail when I needed a fuel pressure damper.Since mine is a returnless fuel line the fuel pressure regulator is part of the fuel pump.
 
Thanks for the update :icon_thumby:
 
Turns out it was the fuel pump. Had a crack in the line that's goes between the pump and the pressure regulator. Turns out I had no fuel pressure because if that. Easy fix.
 
You must log in or register to reply here.

Sponsored Ad

TRS Events & Gatherings

Where We Were in 2025 – The Ranger Station

Latest posts

Featured Rangers

Want to see your truck here? Share your photos and details in the forum.

TRS Latest Video

Official TRS Merchandise

Follow TRS On Instagram

Latest Album Photos

IMG_4690.JPEG
IMG_4689.JPEG
IMG_4688.JPEG
IMG_4679.JPEG
IMG_4656.JPEG
IMG_4625.JPEG
IMG_4562.JPEG
IMG_4561.JPEG
IMG_4560.JPEG
IMG_4559.JPEG
IMG_4558.JPEG
IMG_4445.JPEG

Product Suggestions

Back
Top