jeepin89701

Can 0.3lbshr at 43.5 psi cause a running rich/lean condition in a 4.6 jeep Stroker engine?

dave1123

Whatever the flow rate of the injectors, the PCM cycles them to maintain the proper mixture. In other words, if you have injectors that have a humongous hole for a nozzle, the PCM will cycle them at a faster rate to maintain a mixture that's within normal parameters. There IS a limit to what the PCM can do, however!

jeepin89701

I guess that a .3lbshr should be controllable by the PCM, I'm just attempting to get ahead of an issue before it holds me up. If I was recommended to run 24lbshr and have injectors that have been tested at 24.3lbshr I shouldn't have an issues. just the normal 40 miles or so for the PCM to adjust. THANKS Dave INFO in anyway helps

dave1123

The trick with an injector is it's atomization of the fuel. 3-hole injectors have smaller holes and the spray pattern is more diverse. When I changed the head on my 4.0, I noticed a teardrop shaped clean spot on the side of the intake passages where the injectors had washed them clean. This, to me, shows the stock injectors don't really atomize the fuel very well. In jet turbine engines, the injectors are "patterned" during a service inspection to make sure the spray is a true teardrop shape or the power output will not be up to par or result in a burner can failure.

In my opinion, automobiles need as fine a spray as possible to insure a better burn.

jeepin89701

So this is an engine with about 35 miles on it, during the build I picked up some injectors that where advertised at 24lbshr, It sounded like it was lean at idle and idle dropped to a stall when stopping. I checked for PSI at the rail and it was a little low, I got a new adjustable fuel regulator and at the rail it's 44PSI is perfect for my needs. So I pulled the injectors and took them to my local trust worthy jeep shop and he tested them at 44psi and got 22.9lbshr(not enough). I have started looking for Other injectors that will get me the 24lbshr I need (Denso 24.3lbshr at 44psi/Holley 24lbshr at 44psi both are 4 hole). Being a new motor, I don't have any build up in my intake and the plugs look new still. I will try the tear drop inspection the next time I get it apart that far. Going to get the new injectors and get them in my jeep See where I go from there...

dave1123

Somewhere in my musings, I remember reading that the OEM injectors are known to leak or fail entirely. This article stated the manufacturer, but I don't recall. It also stated the injectors from a 94-95 Dodge Neon were better.