703 injectors for 92 4 liter?

[1989 comanche mj]

The neon 703s

 

I have been reading for hours on the internet about these, and they are either great or terrible.  Then I read they are ok for 96 and back, but no good for 97 and newer because of the higher pressure.

 

Are they a good upgrade, or just money that could be spent elsewhere?  My 92 has all new exhaust from the header back, no leaks all welded mandrel bent 2 1/4 with a new ntk?  factory o2 sensor.  I have read that increased exhaust flow can cause a lean condition.  Also all new cap rotor taylor wires and factory plugs.

 

I have also been reading about putting on a different regulator, pr211 to increase pressure a little.  Any sense in that?  It seems the 92 mj runs at 31 to 39psi WOT where my 97 4 liter tj runs at 49psi constant.  I am guessing there must be a reason the factory kept increasing pressure over the years.

 

My 89 mj 4 liter has an assortment of yelllow ford injectors in it, all with different part numbers.  They are 4 hole ones, I know because I cleaned them.  One was sealed with a big glob of silicone instead of an o ring.  On this I am putting in 90 stock injectors just to rule out other problems it may develop.

[Tex06]

I ran 703s from the junkyard in mine for a while. Stock '92 4.0L, had no issues. Only changed them out because I mistakenly thought I was having a fuel delivery issue.

 

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[johnj92131]

Your 92 is designed by the factory to run properly at 32-39 psi.

 

Your 97 is designed to run properly at 49 psi

 

Do not make the mistake of thinking more pressure is better.  Or the mistake of taking one part from column "A" and another from column "B" then expect it to work properly.

[HOrnbrod]

The 703's will run fine in a stock NA 92 4.0 engine using the stock FPR if that is your question. Do you have emissions testing in your location? If so, you should get it tested after you install these injectors. An A/F gauge is always nice to have so you can monitor the actual a/f ratio under varied conditions.

[ARareBreed]

I also did hours and hours of research on injectors before typing in my credit card number. I found the 703s are the best 4 hole upgrade you can do to a stock 4.0HO engine between 91-96. You'll be spending between $110-$130 on eBay. Don't go by what is typed into the listing, I don't trust them. Use the pictures, all 703s are black and have the P/N on the side of the injector.

[1989 comanche mj]

Fortunately I don't have emission testing here.

 

I ordered the 703s off ebay for $103. It takes 3 revolutions before it starts:  Turn the key to start and it goes wob wob wob then starts.  Has a new tank fuel pump and I cleaned the original injectors.  Pressure stays at the rail after shut off and has 31 39psi.

 

  I decided against them for my 97 TJ because it starts quick, and doesn't have a fuel filter.  I figure those 4 little holes would clog quick with just a sock in the tank and no real filter.  Terrible cheap skates not putting a fuel filter on an off road truck!

[SBpunk]

Fortunately I don't have emission testing here.

 

I ordered the 703s off ebay for $103. It takes 3 revolutions before it starts:  Turn the key to start and it goes wob wob wob then starts.  Has a new tank fuel pump and I cleaned the original injectors.  Pressure stays at the rail after shut off and has 31 39psi.

 

  I decided against them for my 97 TJ because it starts quick, and doesn't have a fuel filter.  I figure those 4 little holes would clog quick with just a sock in the tank and no real filter.  Terrible cheap skates not putting a fuel filter on an off road truck!

Sounds like your starter is going south on you. Battery is struggling to get it to do a good rotation so its cranking over multiple times. My 89 Wagoneer was doing it too. Ate through two batteries before I figured it out. Thought it was fuel/choke/carb issues for the longest time.