jeepsnhondas

ok my friend told me he grinded down somthing on the distributor he told me what is just that i forgot but he took off the distributor and grinded down something so he can adjust it like how u adjust the dizzy ona honda n stuff. can i do that to my 89 xj and will it work better???

my firend did his on his 93 xj.

jeepsnhondas

Can someone just let me know ryt now kuz i dont have a computer n i wanna knw before i have to leave thanks

EVcherokee

It willn't so a bit of good, the renix, I think the OBDII also, dizzy's don't have anything to do with timing, just spark distribution, cam postion sensing for the ECU and timing indexing

Stay with me..The ECU controls all the timing advancing and retarding and uses the CPS to reference this. The best description I heard on how it works is like a clock...the CPS is the second hand and the dizzy just tells the ECU weather its AM or PM. you can tweek the timing a little bit with a high altitude CPS(it has slotted holes), but anything to far(where all the power is) will be corrected by the ECU. I used to have a better understanding, because I looked into doing just this, the conclusion...basicly your stuck with the ECU settings.

There isn't even a way to effectively rich up the air charge either, you can mod the MAP sensor, but as soon as the motor get out of warm-up mode, it ignore the MAP sensor and relies on the O2 sensor, which we all know keeps the A/F mix at 14.1/1 most of the time. You can install an O2 simulator, but then you run into driveability issues.

The best solution for complete control over timing and A/F, is to go with a Mega squirt EFI, or a different aftermarket setup, a carb like a Motorcraft 2100 and a GM HEI or Duraspark Dizzy. I'm in the process of gathering parts to convert to a 2100 with Duraspark dizzy and ditching all the sensors and the ECU.

N20jeep

slotting the cap of the dizzy will alow you to adjust the timing.

simply turning the dizzy will not affect ignition timing.

alloutperform

^ kinda but in all reality if you turn the distributor it will affect spark timing the ecu only compensates for throttle input on detonation (pinging)...what he is grinding i do not know but you better know exactly what is being done before it is tried or atleast have a spare distributor...

Desert Rat

Nominated!

N20jeep

no, turning the dizzy on a 4.0 will NOT affect the ignition timing.



DO NOT grind the dizzy itself. if you slot the holes on the cps you can move it slightly.

alloutperform

it still distributes spark via cap and rotor turning the whole mess still changes when the rotor passes each plug lead thus affecting timing

N20jeep

you're not understanding.

the 4.0 dizzy is not like a traditional dizzy. by moving it you are not actually changing the position internally.

the 4.0 dizzy ONLY controlls fuel syncro.

N20jeep

thanks you for this completely useless post.

thanks for helping to clutter up the tech section with garbage

alloutperform

the shaft that connects the rotor to the drive gear is solid and floats in the body of the dizzy (as it is known across the pond) that is fixed to the cap if you turn the body it is doing the same thing

N20jeep

no reason for me to keep trying to explain to you how the 4.0 ignition system works. apparently my words arent clarifying it enough.

do some research on ignition timing control on the 4.0

you will find that the dizzy position does not affect ignition timing at all, only fuel synchro. timing is strictly controlled by the CPS


better yet, put a timing light on it and turn the distributer. see for yourself in the simplest way.

Desert Rat

Trust me, that post was not useless.

jeepsnhondas

ok thanks but how do i slot the cap?? just let me know what to do. thanks

N20jeep

you slot the mounting holes on the cps

now, why exactly do you want to change your timing?