Possible tuning options for new stroker

[Jacoby88]

Recently installed a 4.6 stroker in my 95 zj. I can tell there is an considerable amount of power gain so far even with me babying it, however I feel like theres still some fine tuning needed

Some minor issues im having is a low idle that almost turns into a stall when letting off the gas and allowing it to idle by itself. like when shifting gears, coming to a stop, or simply just idling. when the idle drops it gets so low you can see the voltage drop and its well below the first hash mark on the tach. i also noticed that the temp likes to climb a bit at idle until I give it a little bit of gas to move fresh coolant in the engine (I have converted to a 16 inch electric fan so that issue isnt the fan clutch)

Some of the parts I have
- 62mm throttle body
- 24 pound injectors
- electric fan swap
- ax-15 swapped with tcu removed
- roughly a 9.5:1 compression ratio with .041 quench height
- accell ignition coil and wires
- comp cam 68-301-5 cam with edelbrock aluminum head

I cleaned the Idle Air control valve during the rebuild and every other sensor but the CPS is the same as when I had the 4.0 in it.

Ive heard of using adjustable voltage regulators for the map sensor, but from my understanding thats only good for tuning the af ratio, which Im interested in however I dont think will fix my low idle issue unless im wrong.

Im tempted to try adjusting the idle screw for the throttle body but on the fence because I dont want to start messing with something that otherwise seems to work fine.

any advice for the adjustable map sensor or other tuning options and the low idle are welcome thanks.

[Cheromaniac]

A MAP sensor voltage adjuster won't help since it'll only make a difference during open loop operation.
Unfortunately your tuning options are limited since your ECU is OBD 1. Therefore adjusting the idling screw would be your best solution for the time being until you find a more permanent tuning option e.g. Megasquirt.

[mpgMike]

An inexpensive stand-alone is the rusEFI (.com) UAEFI. It handles 6 cylinders for injectors and individual coils. It has several assignable I/Os for electric fan and such. It has a dedicated input for a knock sensor (which I added on mine) and the driver circuitry to run a Bosch 4.9 LSU Wide Band O2 sensor (which works). If you want to run the distributor, you'll have to desolder a 0 ohm resistor (just a jumper) and solder in a MOSFET. It costs around $240 US (about what an OLD MegaSquirt did), uses Tuner Studio (like MegaSquirt), and there are support groups online. Take a look.

Here is my build thread: https://www.jeepforum.com/threads/time- ... 4/#replies . The rusEFI stuff starts on page 7.

rusEFI1.png

[Jacoby88]

Thanks for yalls responses.
I adjusted the idle screw on the TB and it solved the one issue with when I rev in neutral it doesnt get close to stalling anymore, more of a smooth drop to idle which was how it was before the swap. Gave it about 8 different drive cycles to let the pcm "learn", but im still having the issue when it randomly will drop in rpm at idle and run kinda crappy. Almost like theres some extra load causing the rpms to drop. I know its not the ac compressor because the issue persists with the ac turned off or on full blast with no short cycling.

When I got it to operating temp I unplugged the throttle position sensor and that caused an instant check engine light and after one rev it stalled out so I assume thats not the issue.

When I unplugged the idle air control valve while it was at rough/low idle, it did not have an initial change in the idle until about 20 seconds when it jumped up in rmp slightly and smoothed out. however, after about a minute the issue seemed to return (this behavior was similar to what i was experiencing before). I drove it for about 3 miles and I couldnt really tell any major difference between when it was plugged in or not.

is there any way I can test the idle air control valve with a multimeter or some other test? I have a factory spare but its off a 96 and uses a different connector and I have the pigtail. I have access to alldata and ill see if theres any difference in pin layout but I dont know if theres anything different between the 95-96 sensor other than the connector. Either way there seems to be an issue with the idle

In regard to the rusefi I read up on the thread and will diffidently need to do some more research on that, never really delt too much with something like that, but I would like to get the idle situation figured out before tackling something like that unless that could potentially help with that issue.