2 x cps = +6* timing

[Talyn]

This is just a cheap and easy way to add 6* to the base timing. I had a spare know good CPS and a bad CPS. On the good CPS I redrilled the locating hole on the passenger side mount ~.5" in and then cut off the excess. I then cut off one side of the mount of the bad CPS. That was drilled and tapped for the bolts. The driver's side mount of the good CPS was marked and drilled. The cut off part was mounted to the good CPS using screws which go into the new threaded holes on the mount as well as nuts to lock them in. I used a washer to take up the space between the transmission and the offset mount.

This moved the CPS about 1/2" and added about 6* of base timing. I used a dial back style timing light and checked the timing before and after the modification. Its a bit ulgy and I could probably finished it a bit better but it works. I placed the CPS as far as it would go toward the passenger side without having to modify the bell housing.

It seems to have a bit more pickup at mid range and I haven't noticed any pinging yet. If it does I can dial it back through the AEM FIC.

Back side:

Front side:

Installed:

 

[Boostwerks.com]

Awesome! I've thought about doing the same thing on our rig. It'd be nice to use the 91 octane more effectively when out of boost.

 

[eflores]

They actually made one from the factory for use on renix models...I run them on all mine

 

[Talyn]

I know, but mine isn't a renix.

 

[eflores]

Well I figured that much just throwing the info out there

 

[userbmx1315]

my 4.6 can only run 91, would 6* of timing help it lower the octain needed?

 

[Talyn]

Well I figured that much just throwing the info out there

Going off the pictures on Rockauto I don't think it advances it that much.

my 4.6 can only run 91, would 6* of timing help it lower the octain needed?

No, it would make your engine ping more. You might be able to go the other way with it though, towards the driver's side to decrease timing. However, since you currently need 91 octane, you may be able to advance it w/o ping.

 

[Super mud]

I've done this on my Renix though I actually just put the CPS in the vice loosley and tapped with a hammer end to slide the magnet along the mount though placed a bolt in the end I was hitting to prevent smashing the bolt hole. I've seen it other places on the forum too.

Though I'm wondering if I got too much timing cause every once in a while I get a backfire (through the intake) with sudden throttle input and I've heard timing can cause backfire or afterfire (out exaust) depending on which way it's gone. Then I wonder if I run 91 with the advance if it will improve and smooth things out.

 

[Talyn]

put the CPS in the vice loosley and tapped with a hammer end to slide the magnet along the mount

I tried that on the faulty sensor first. That didn't work out so well.

Though I'm wondering if I got too much timing cause every once in a while I get a backfire (through the intake) with sudden throttle input and I've heard timing can cause backfire or afterfire (out exaust) depending on which way it's gone. Then I wonder if I run 91 with the advance if it will improve and smooth things out.

Adjusting the timing that little wouldn't cause that issue. I think you have something else going on.

 

[cruiser54]

I've done this on my Renix though I actually just put the CPS in the vice loosley and tapped with a hammer end to slide the magnet along the mount though placed a bolt in the end I was hitting to prevent smashing the bolt hole. I've seen it other places on the forum too.

Though I'm wondering if I got too much timing cause every once in a while I get a backfire (through the intake) with sudden throttle input and I've heard timing can cause backfire or afterfire (out exaust) depending on which way it's gone. Then I wonder if I run 91 with the advance if it will improve and smooth things out.

I've done that at least 10 times with excellent results. But, my friend tried it on his and the molded plastic came all apart.

 

[Shorty]

This is just a cheap and easy way to add 6* to the base timing.

have you noticed any slower cranking or harder/easier starts? I've always felt like mine is more retarded than it needs to be, but I've been hesitant to futz with it as of now.

 

[cruiser54]

No difference in cranking at all. Just futz with it.

Shorty, what year is your Jeep?

 

[Talyn]

No difference in cranking at all. Just futz with it.

x2 Cranking is unchanged. I was cautioned that when messing with timing it could possibly making cranking harder and if you go to far it would bust the nose on the starter. I don't think 6* is enough to do that.

I definitely feel a nice mid range increase since driving it after the mod.

 

[cruiser54]

Everything to gain, nothing to lose.

 

[Shorty]

No difference in cranking at all. Just futz with it.

Shorty, what year is your Jeep?

an '88 and a '94. The '88 is the one I've been wanting to futz with for the most part.

 

[cruiser54]

Then do this, too, before proceeding. Unplug your CPS. Probe both wires in the connector of the CPS. Set your meter to AC volts. Crank the engine over and read the meter. You want .5 AC volts.

What I'm getting at is if you're gonna remove the CPS to modify it for the advance, be aware of what the existing output voltage is because you can increase that if needed by drilling out the mounting holes with the first bit that doesn't fit.
Then upon installation hold the CPS down closer to the flywheel as you tighten the bolts.

 

[MoFo]

Does anyone know how much the RENIX High Altitude CPS increases the advance?

 

[Talyn]

Judging from the pictures I have seen of them it looks like 2-3*.

 

[cruiser54]

Judging from the pictures I have seen of them it looks like 2-3*.

Probably pretty close. I'd say 5* max if I were to guess.

 

[fzsk4p]

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