Does the MAF and injectors need to be compatible as in EEC-VI?

[ranger7ltr]

I have a 99 Explorer Sport that has 13 lb/hr injectors... I have tried to replace them with 19 lb'hr spares that I had but the engine ran rich according to the check engine light and the code scanner I use...And finding 13 lb/hr injectors for this truck is impossible so far.. I keep ordering replacement injectors and getting 19's

If I change the MAF to one that has a sensor for 19 lb/hr injectors should I be able to run 19 lb/hr without running too rich or is the MAF calibration in the PCM and needing to be altered there?

 

[techieman33]

you should have 19lb injectors, as far as I know they all had them. You shouldn't need to adjust the pcm if you get a maf calibrated for 19's though.

 

[ranger7ltr]

Maybe different injectors for a Calif vehicle? This one started life there...

I really wish I had 19's in this truck but the original Bosch part numbers are 0 280 155 962 which are 13 lb/hr... Actually 12.7 lb/hr according to Bosch..

I have bought replacement injectors from Rockauto and Autozone and they are either red or orange and the bosch numbers were 0 280 155 700 and another number but both were 19's...

When I installed the new 19's I had the engine ran fine but it was definitely a bit rich... It showed on the plugs and the scanner was showing a steady high voltage reading on all o2 sensors... It was running rich...

 

[CDW6212R]

Something else is fishy there with that truck, all Explorers then had 19lbs. injectors. If you were in another country I could see a possibility that something is different, but in the USA they are all 19lbs. Assume that, and work on finding something else wrong, not the injectors.

Calibrated MAF's are old school technology, that's for tricking a stock PCM to function with different injectors then the PCM is designed for. The right way to change injector size is to retune the PCM, not to mess with the MAF curve. Regards,

 

[jah81592]

Some SOHC 4.0l's even had 24# injectors-j

 

[CDW6212R]

Thanks James, I do recall someone long before mentioning having 24's, but it wasn't clear if they were stock parts. The 19's are the size used on OEM since 1986 or so on all 302's. The 4.0 has bigger cylinder CI, so nothing smaller than a 19 would make any sense.

 

[ranger7ltr]

How do I change the PCM calibration for injectors? Any potential drawbacks?

Thanks James, I do recall someone long before mentioning having 24's, but it wasn't clear if they were stock parts. The 19's are the size used on OEM since 1986 or so on all 302's. The 4.0 has bigger cylinder CI, so nothing smaller than a 19 would make any sense.

After looking long and hard into this issue with this truck I have kinda an answer...

There are INDEED 2 different fuel injectors for the 4.0 liter V6 Ford Explorer... There is the FJ300 for the Federal engine...and there is the FJ304 for the California engine...

The Standard Motor Products FJ300 appears to be the orange 19 lb/hr injector that I tried using to replace the Standard Motor Products FJ 304 white 14 lb/hr injector that my truck actually has installed on it from the factory...

I have confirmed this through 4 different sources including my local Advance Auto parts, Rock Auto, BWD Automotive, and even the local Ford Motorsports Dealer.. Although the dealer was, by far, the most difficult source to get information from...

So I have determined that the injector size is programmed into the PCM and I can use any number of means to alter that...Xcal, Sniper, etc...Would I need to alter any other parameters to run the bigger injectors or would the PCM and sensors simply monitor the operating conditions and adapt to the new injector size?

Any info appreciated....

 

[CDW6212R]

Ah good, then the PCM is programmed to open those injectors longer. You would need a new program in the PCM to change injector size. The best way would be with a flasher like SCT's. It could be possible to change the program to another stock OEM for a non CA engine, but I wouldn't want that. Don't go after the stock programming, get the aftermarket tuner advantage.