Too much total timing

[MoparNJeep]

I've got a 1999 Jeep Cherokee 4.5L stroker with AW4 trans. My stroker has had everything replaced in on and around it. It's got almost 7,000 miles on it. Runs great and strong. But it had developed the FLEXPLATE knock.

I pulled the trans, tcase, and put in a brand new flexplate to get it fixed up. FLEXPLATE was compared to the one I pulled out and was exact match.

I fired it up ran great but seemed to have what i thought was a slight miss down low. I replaced my entire ignition system.. plugs, wires, cap, rotor, coil, cam position sensor, and even the distributor. I replaced these one by one with known good parts off my other jeep.

Well the miss is still there. I finally get a error code for intermittent loss of (cps or cks). I checked my wires and couldn't see any exposed or broken wires.

I hook up my Bluetooth obd2 reader to the Torque app. I'm looking at my total ignition timing. It's showing around 16-18° at idle. I check this to my other jeep and it's timing at idle is 8-10°.

Now the other problem is above 3000rpm the jeeps timing would jump to 42-44° total timing and ignition would start to break up. Strangly the tachometer would jump from 3000rpm to 4000rpm.

My other jeep a (2000sport) wouldn't hit more than 36° of timing.

The only things left I have to try is a new crank position sensor. which I've never heard of causing get this.
And changing the ECU.

I know this all developed when I changed the FLEXPLATE but I referenced it to the original and it was exactly the same. You can only put FLEXPLATE on one way.


So I'm baffled and could use some more ideas

[MoparNJeep]

I've got a 1999 Jeep Cherokee 4.5L stroker with AW4 trans. My stroker has had everything replaced in on and around it. It's got almost 7,000 miles on it. Runs great and strong. But it had developed the FLEXPLATE knock.

I pulled the trans, tcase, and put in a brand new flexplate to get it fixed up. FLEXPLATE was compared to the one I pulled out and was exact match.

I fired it up ran great but seemed to have what i thought was a slight miss down low. I replaced my entire ignition system.. plugs, wires, cap, rotor, coil, cam position sensor, and even the distributor. I replaced these one by one with known good parts off my other jeep.

Well the miss is still there. I finally get a error code for intermittent loss of (cps or cks). I checked my wires and couldn't see any exposed or broken wires.

I hook up my Bluetooth obd2 reader to the Torque app. I'm looking at my total ignition timing. It's showing around 16-18° at idle. I check this to my other jeep and it's timing at idle is 8-10°.

Now the other problem is above 3000rpm the jeeps timing would jump to 44-47° total timing and ignition would start to break up. Strangly the tachometer would jump from 3000rpm to 4000rpm.

My other jeep a (2000sport) wouldn't hit more than 36° of timing.

The only things left I have to try is a new crank position sensor. which I've never heard of causing get this.(changed crank position sensor and timing only goes to 40-41° now and 3000rpm and higher revs smooth.
Need to drive it and see how it does with a load to it now)
And changing the ECU.

I know this all developed when I changed the FLEXPLATE but I referenced it to the original and it was exactly the same. You can only put FLEXPLATE on one way.


So I'm baffled and could use some more ideas

[Trevordavis0521]

do you have a wideband? could be a fuel issue. or not enough octane. most likely its the computer from what it sounds like.

[Trevordavis0521]

my stock 4.2 has way too much timing 3000 and up and i get spark knock even though i have tuned it down to 6 degrees idle, its still too much in the midrange to high end even with 93 octane its still too much. Dont get the summit hei distributer haha.

[Russ Pottenger]

16-18° initial and 44-47 total is way too much.