EVcherokee

I'd like to do a couple things here:

1. Have control over my timing: in my experiences OEM recommended timing is generally a little on the retarded side(no pun intended). I only use recommended timing settings as a starting point and advance from there to find that "sweet spot" to get the best power and fuel economy.

2. Ignition upgrade: The GM HEI puts out more bang right? When I was younger a GM HEI shorted through a friend of mine and put him on the ground!

3. More parts commonly available: The GM HEI setup is everywhere, the renix system was used for only, what, two years?

4. Reliability: The more sensors I can remove but retain EFI the better, might be switching to a motorcraft 2150, but for now, I'm keeping the EFI. Gotta get ready for the zombie apocalypse on 12-21-2012..

I've thought about and heard of guys grinding the ears off and manually cranking the dizzy to advance it, but from what I understand, the renix system would just compensate for this and retard it to where the system thinks its best.

I know the Renix system reads the cam postion sensor, but is it just for engine timing or does it determine other things from this? Would doing this also make the CPS sensor unnecessary? That would be sweet!

My hope is that I can just cut wires coming from the ECU and rewire in an HEI dizzy, but not make the ECU have a seizure. Any experiences, or input from Renix elders is appreciated. TIA

mud-dog27

Hmm interesting thought unfortunately i have nothing to add but would be interested as being able to manually adjust timing would be nice, i googled it but there dont seem to be much mention of this other then this one thread from pirate http://www.pirate4x4.com/forum/showthread.php?t=571974

could message the guy and hope hes still active and has some input

EVcherokee

Yeah I searched all over and found a lot of info on putting GM HEIs on earlier 258's, but not the Renix 4.0 EFI. I also found some info about using Fords duraspark setup with a TFI coil and it being more reliable, because it isn't as sensitive to water. So thats where I'm leaning now. Apparently both the GM HEI and the Duraspark dizzy fit Jeep 258s and 242s(4.0l), just gotta swap drive gears.

I've never used a TFI coil, but I've used the duraspark dizzy and ICM with a MSD coil on a couple trucks and my old Thunderbird and I loved it. With that setup I also used the "big cap" to avoid crossfires from running 60-70K volts.

I did some digging on what sensor does what, and the ECU uses the cam position sensor and the CPS to determine when to open the injectors..crap.., but if the pulse coming from the GM HEI/ Duraspark dizzy works with the ECU, I'm golden.

I wanna ditch the EFI, but I don't like flooding out when I'm off angle.

notop46

You could megasquirt the EFI and ditch the factory ECU (if you solve the ignition). This allows you to hook up a laptop,see what the sensors are doing and tune the engine the way you want. I put a TPI and MS on my 72 SBC Chevelle and I love it. Starts quickly, no throttle bog or black cloud on accel, and great driveablity.

EVcherokee

Thanks for the Megasquirt idea, I've never even heard of them, but since I searched around I'm realizing a lot of guys are running them.

Nobody's running a different dizzy other than a stock one on a Renix...c'mon guys!

retreaded jeeper

the HEI setup on old I6's was the way to go and simple. now days it's mute alot has advanced

EVcherokee

Thats what I'm going for. simple.

I also don't like the idea of a preset, out dated computer determining my timing and spark control, when I know most OEM specs hold back a lot of power and fuel economy. I'm pretty darn sure the GM HEI and the duraspark dizzy with a big coil puts out a lot more spark than the Renix or the OBD successor too. There is a reason why most hot rodders are still running late 70's HEI and duraspark setups...

EVcherokee

Ok found out the cam position Sensor(sync sensor) has nothing to do with timing at all, just indexing the timing sequence. All the Ignition timing and fuel injector pulse timing is determined by the CPS and the ECU figures out how to use it. It was described like a clock: the CPS tells the time, but the sync sensor tells whether its am or pm. Rotating the renix dizzy, willn't affect timing at all..

So apparently a Renix motor will run without receiving a signal from the dizzy, but will run rich and have a rough idle. As we all know, a renix willn't run without the CPS.

SOOO...a normal kick*** dizzy willn't work in a Renix motor. The Renix dizzy is one of a kind, more reason to get rid of it.....crap......this is why I HATE this system, everthings linked...its like a ***** house....One A-hole comes through with crabs and now the whole towns itchin..maybe I just need to megasquirt or carb it and be done..