4.7L stroker questions

[962dr4x4]

ok i am new at this i need help i just dropped a prebuilt 4.7 stoker in my 96 xj and i am having issues, i am getting a false CPS/miss fire reading after it gets warm and then it starts sputtering and cuts off it will start right back up and drive but the further i go the worse it gets and it also idles rough when it warms up also, the only thing i changed was the injectors when i installed it (24lb)

 

[Dr. Dyno]

You may need to index the distributor.

 

[cruiser54]

You may need to index the distributor.

Good thought. Some guy did a nice write-up on that. Here's a link LOL.


http://www.angelfire.com/my/fan/dist_index.html

 

[markaboo929]

I have an 03 4.0-soon to be replaced 4.6 stroker-running on the renix set up.What I did was use the returnless 03 fuel line by using the single line from the tank to the rail..plugged the stock return hose BUT what I did was install an 03 grand cherokee fuel filter/regulator which is regulated to 49 psi.I do not like warm/hot fuel returning to the tank--ONE of the reasons for a return less type fuel system.Waht I did for a air/fual ratio monitoring was installed a Pro-Sport A/F ratio gauge hooked up to the factory 02 sensor---yes it is a titania sensor that goes from 0-5 volts insted of norm .0-1.0 volts.Ther pro sport unit is ment to work with the wide band set up which is 0-5 volts and also with the .0-1.0 volts zirconia style--most common has a swith on the back.Cheap gauge too!!!! plus it lets me know when the Renix is in closed loop.By the way does happen at a low temp--I have a snap on 2500 scan tool it really does go closed loop in about 40-60 seconds after a cold start up....myth has been busted about the whole t-stat closed loop thing...
http://prosportgauges.com/digital-air-fuel-ratio-and-volt-gauge.aspx
It shows as a digital number as well as the led sweep...

 

[962dr4x4]

great thank you! Ill give it a shot

 

[markaboo929]

Waht I do like is the fuel pressure is very consistent not relying on engine vac to regulate it.Start ups are quick compaired do when it was I was using the renix rail and return.

 

[gradon]

True about it going from cold-start OL to CL in less than a minute, but if you disco the cts located at the t-stat, you can force it into open loop(and keep the aux fan on constantly, and give yourself a CEL). Playing around with different resistor values inline with the CTS can maybe turn the fan and cel off(I have a manual switch to turn them on) and still keep it in OL. This might be helpful to strokers and boosters who don't want to be forced to 14.7:1 most of the time.

 

[markaboo929]

It is the RENIX system...no check engine light...if you disconnect the CTS or IAT sensors they default to a hot value of 240 degrees...keeping it in closed loop.Renix goes open loop to closed loop depending on the 02 sensor...thats why when they stop working it goes rich...open loop.The air fuel ratio gauge I have reads the stock renix sensor...I know when it works or not right away looking at my gauge.Which is a lambda sensor I have not ran any e85 fuel in it to see if it is a true lambda sensor like a wide band type.THAT would be sweet it it actually can make the stock fuel mapping tune/run on e85.