4.0L OHV Injector specifications

[mrsolo2000]

I am in the middle of swapping a 4.0L OHV into my 1990 B2. The donor vehicle was a 1996 Explorer. However, I recently pulled an ECU, the ECU harness, EDIS6 module and upper and lower intakes along with the oil pump drive from a 1991 Explorer. I have the Ford electrical and vacuum troubleshooting manuals for my 1990 B2 (which covers a 1990 Ranger too) and I have the 1991 Explorer manual. I did a pin by pin comparison and it seems to me that the 1991 ECU and harness will integrate seamlessly into the B2. In fact, there's a cutout in the 1990 B2's front core support where the EDIS6 module attaches, same as the 1991 Explorer. Now that I got that out of the way.....the injectors in the lower intake from the 1991 Explorer look pretty ratty and rusted. The injectors from the 1996 lower intake are in good shape. I did a little digging on Rock Auto and the part numbers for the 1991 Explorer and 1996 Explorer are different (which was no surprise). I went to standard motor parts and went through their parts catalog, hoping to try and find out what the differences are between the two sets of injectors. Standard doesn't seem to publish their specifications. Anyone know what the differences are in fuel injectors between the 1991 and 1996 model year engines? I suspect the fuel delivery rate is going to be different.

 

[SenorNoob]

They are a different design. The newer ones were meant to work with sequential injection. (Faster reaction time, better atomization, ETC.)

That said I ran 94 injectors with a 92 ECU and 91 harness for 10 years with minimal problems. In fact I suspect the problems I did have were unrelated. (Stalling at the second stop sign when below freezing.)

While they are a different flow rate the later injectors are internally/electrically different.

The "late" injectors are not "spindle" injectors but "Disc Pintle" injectors so they can open and close faster

You'll notice on examination that they don't generate a "hollow cone" spray pattern
like the earlier injectors, the late injectors use a four cone spray pattern...

For the lurkers, bigger is not necissarily better.

There is only ONE correct ammount of fuel.

AD

 

[mrsolo2000]

Thanks for the reply. In the manufacturer's catalog, both injectors (for the 1991 Explorer and 1996 Explorer) are listed as MFI. Is it even worth trying to run injectors from a 1996 with a 1991 ECU? Were your 94 injectors for a SFI application?

 

[SenorNoob]

The 94 injectors were for SFI. I removed a SFI harness from the engine and used the 91 batch fire harness. MFI stands for Multi-point Fuel Injection. It can mean anything that isn't Throttle Body Injection (TBI) or carbureted.

Edit: It look like the same injectors I had were used through 96. 97 is the first year with a different part number. Unless I just happened to get lucky somehow, I'd say you'll be fine.

 

[mrsolo2000]

I am going to give it a go, thanks! By the way, is there a list of injectors for these engines and their associated flow rate?

 

[SenorNoob]

Not just Ford, and it's likely out of date, but this is the best I've found.

Stan Weiss' - Electronic Fuel Injector (EFI) Flow Data Table

 

[mrsolo2000]

Did some digging on the site you provided and other sites. It seems the only difference between the injectors (besides the color of the jackets) is that the injectors for the 1996 4.0l OHV have four holes on the nozzle versus a single hole/pintle on the nozzle of the 1991 4.0l OHV injectors. Flow rates are the same. I am assuming I am good to go using the 1996 injectors with the 1991 ECU.