Anyone know what the normal PCM parameters are for 2004 Wrangler 4.0 42RLE?

Geeknahalf

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Hi All,

In my previous post I mentioned using an older style exhaust, for the 4.6 stroker I built. However, I used the banks torque tubes designed for my year and the factory exhaust so I could retain the factory locations for the O2 sensors. Unfortunately, I'm having all kinds of issues with it running right.

It starts right up, vibrates like crazy, eventually smooths out a bit, and runs enough I can drive it to work and back. (I go super easy on it.)
I don't hear any pinging or knocking, there's no CEL, it idles fine for the most part, and during acceleration it vibrates like its stumbling on itself.

I have checked and double checked the base timing and the installment of the cam sync, both are set properly. The PCM is original. I've replaced the coil pack, cam/crank sensors. Gave the wiring harness a serious manhandling listening for any signs of changes, and no difference.

I have a very basic scanner that lets me see some live stream data and I've been watching it as I drive. At idle, timing adv. ranges between 7.5 - 14 degrees, most of the time, and goes to around 34 or higher when i give it small amounts of gas. A couple of times it remained at 27 while at idle. Other times it will hit 0 when i let off the gas. The bank 1 stft (short term fuel trim), O2 numbers, are relatively numerically close to their bank 2 counterparts; I don't see any drastic differences, and the numbers are pretty low both in both pos and neg ranges. That said, I have never looked at the live data before so I have no idea what's normal and what's not.

I'm looking for someone who knows what the numbers should be, and would be willing/ able to help determine/diagnose the issue(s). I cant find anyone where I live who can do this. I am more than willing to pay for the services.

Much appreciate any help/advice.

R
 
Last edited:
Hi All,

In my previous post I mentioned using an older style exhaust, for the 4.6 stroker I built. However, I used the banks torque tubes designed for my year and the factory exhaust so I could retain the factory locations for the O2 sensors. Unfortunately, I'm having all kinds of issues with it running right.

It starts right up, vibrates like crazy, eventually smooths out a bit, and runs enough I can drive it to work and back. (I go super easy on it.)
I don't hear any pinging or knocking, there's no CEL, it idles fine for the most part, and during acceleration it vibrates like its stumbling on itself.

I have checked and double checked the base timing and the installment of the cam sync, both are set properly. The PCM is original. I've replaced the coil pack, cam/crank sensors. Gave the wiring harness a serious manhandling listening for any signs of changes, and no difference.

I have a very basic scanner that lets me see some live stream data and I've been watching it as I drive. At idle, timing adv. ranges between 7.5 - 14 degrees, most of the time, and goes to around 34 or higher when i give it small amounts of gas. A couple of times it remained at 27 while at idle. Other times it will hit 0 when i let off the gas. The bank 1 stft (short term fuel trim), O2 numbers, are relatively numerically close to their bank 2 counterparts; I don't see any drastic differences, and the numbers are pretty low both in both pos and neg ranges. That said, I have never looked at the live data before so I have no idea what's normal and what's not.

I'm looking for someone who knows what the numbers should be, and would be willing/ able to help determine/diagnose the issue(s). I cant find anyone where I live who can do this. I am more than willing to pay for the services.

Much appreciate any help/advice.

R

Contact FRP (@Flyin' Ryan Performance) about getting a custom tune for your Jeep.
 
I’m in the process of it, thanks.
Any info on the parameters anyone?

As Chris said Wranglerfix might be able to help. It's interesting that you're having driveability issues as others here have stroker and no issues. But they have older rigs.
@Woodrow
@Rickyd
Can you guys offer any help since you have strokers?
 
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As Chris said Wranglerfix might be able to help. It's interesting that you're having driveability issues as others here have stroker and no issues. But they have older rigs.
@Woodrow
@Rickyd
Can you guys offer any help since you have strokers?

It’s definitely odd thats for sure. The research I did indicated that many are running strokers with no issues. The only “wild” component that I can think of is the Edelbrock head, but even that isn’t really all that much.. maybe the cam? It’s a comp cam SKU 163-301-5, designed to be run with the eddy head, think that might be it?
 
It’s definitely odd thats for sure. The research I did indicated that many are running strokers with no issues. The only “wild” component that I can think of is the Edelbrock head, but even that isn’t really all that much.. maybe the cam? It’s a comp cam SKU 163-301-5, designed to be run with the eddy head, think that might be it?

Do you know if the cam is PCM compatible? I have a Dodge magnum V-8 in my TJ and Comp cam makes 3 cams that are supposedly PCM compatible and don't require any tuning.
I'm wondering if the older PCM is more forgivable than the newer ones?
 
Do you know if the cam is PCM compatible? I have a Dodge magnum V-8 in my TJ and Comp cam makes 3 cams that are supposedly PCM compatible and don't require any tuning.
I'm wondering if the older PCM is more forgivable than the newer ones?

That cam is supposed to be for the 4.0l with an edelbrock head specifically. I'd be interested in a nitrided version!
 
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That cam is supposed to be for the 4.0l with an edelbrock head specifically. I'd be interested in a nitrided version!

It'll be interesting to see what turns out to be the issue.

The cam I have is definitely not stock tune friendly.
 
How did you set cam sync?

Was the cam degreed on assembly?

@Jezza what do you think?

I didn't know until recently that you even could set the cam sync on the 4.0. Was discussing it with my son and he was talking about how to do it on his XJ after he'd seen my video of me setting it on my engine. I'd given him a SnapOn MT2500 so he can set his.
 
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I didn't degree the cam, however, I did line the dots on the timing gears with #1 piston on TDC and install the sync using the cap that came with it
 
Do you know if the cam is PCM compatible? I have a Dodge magnum V-8 in my TJ and Comp cam makes 3 cams that are supposedly PCM compatible and don't require any tuning.
I'm wondering if the older PCM is more forgivable than the newer ones?

have no idea if the PCM is compatible, assuming it is...
 
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cant beat the I6 reliability, 250K miles on it and only a burnt valve. Like to see an LS do that.. :)

Don't get him started,,,,

have no idea if the PCM is compatible, assuming it is...

I'd guess it would be but you could contact Comp just to verify.

I'll ask all the obvious. Are all your O2 sensors good? IAC & TPS & CPS? Did you hook back up all your grounds? Made sure you had tightened down all the nuts and bolts to each ground? These are the things that caused others issues after doing an engine swap.

Have you checked for vacuum leaks? Intake manifold leaks?
 
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It sounds like a fuel problem to me. Did you install different injectors or are they stock? Monitor your long and short term fuel trims when it is running rough. I don't like to see any of the fuel trims more than 10% positive or negative. Ignition timing at idle is going to jump all over the place as it helps to control the idle speed. When you are accelerating lightly it should smooth out and be 20s to 30s depending on load and a bunch of other things. Most of the other parameters are common sense. Temps and pressures should be reasonable values. Map sensor should be close to 95kpa koeo, and go down when at idle. Usually below 40kpa or so, but that depends on vacuum. Tps should read sub 20% or so closed and go up to 75-100% at WOT.

I'm pretty sure that's the same cam I have, and it's not that aggressive. I also have the Edelbrock head and the torque tube header. It ran fine with no stumble.