Stroker in 2002 WJ...

[SilverXJ]

If you are going to use the Rugged Ridge header for your model year and the 0331 Alabama Cylinder head you will not need the O2 sims. As far as the Apexi or PSC1 you may be able to get away with out it. However the only real way to tell is to find out what the air to fuel ratio is.

[SilverXJ]

Not to hijack, but since we are on the topic of O2 sims.. I have two Casper's in mine. However, they no longer make them... anyone have a good source if one goes out?

[amcinstaller]

i think 505performance still has the turbo charger package. yea, here it is: http://shop.505performance.com/category.sc?categoryId=4
not sure how this would work with a stroker motor though.

[cmcb15]

Not to keep beating a dead horse but I want to get one final list together. My list is:

Stroker rotating assembly, "stock compression 8.8:1"
Alabama cylinder head complete assembly
24lb injectors (stock is 22.5lb)
Full gasket set

I know this list seems small but for someone that wants to keep things simple, stock looking, and make reliable power this should be it then?
I do have 4.10 gears and full exhaust so the extra CC's should do rather well. I am also hoping that this will help those who want to do a simple stroker in a newer Jeep with out a lot of cost and problems trying to get it running right. If anyone has any other input please chime in as I will be buying parts soon. I will definitely keep the site posted as to my results.

[Limeyjeeper]

On my 2000 it wasn't necessary to change the cover, just the cam sprocket, bolt, spring and pin.

Without the hardened pin in the timing case the camshaft will float more than spec as the retaining pin will not be under the correct tension and the retaining pin will burrow a hole in your timing cover -eventually.

The MAP adjuster (home made, Apexi, PSC1, etc) is what adjusts the open loop by adjusting the MAP sensor value the PCM sees. The PCM uses pre programmed maps, but it also adjusts them based on various sensors (throttle position and MAP mostly). In Closed Loop the engine can dial back the fuel using the O2 sensors mostly. For my application a simple home made map adjusted wouldn't work as it adjusts the MAP voltage over the whole RPM using one voltage. Mine was running rich at the top end and lean in the mid range. I used an Apexi to correct that as it has multiple RPM ranges to adjust. However, a PSC1 would work better.

I agree in closed loop that is correct. In open loop the problem is that the PCM does no fuel or timing trimming it simply selects a map based on initial sensor settings and off it goes. The MAP sensor might affect things, but as you said it is one size fits all. It is quite the problem. When I was dynoing my Stroker, which I did about 5 times, it was very apparent that the problem was open loop mapping, I used to throw rich mixture codes within about a minute of starting the engine. Smaller injectors stopped that problem, but I never totally solved the detonation on WOT problem. If the Apexi had been around when I did mine it probably would have helped me out a lot. The guys at Jeep told me that the mapping in the later OBD11 ECU was more sophisticated than the earlier ones, due to emissions issues. They were far more picky about keeping fuelling within spec, Hence the post 1999 - 2000 stroker concerns.
It is such a shame that the Jeep PCM is locked, it would be so cool to be able to reprogram the PCM like I can do with my Subaru.

[RAPTORFAN85]

Not to keep beating a dead horse but I want to get one final list together. My list is:

Stroker rotating assembly, "stock compression 8.8:1"
Alabama cylinder head complete assembly
24lb injectors (stock is 22.5lb)
Full gasket set

I know this list seems small but for someone that wants to keep things simple, stock looking, and make reliable power this should be it then?
I do have 4.10 gears and full exhaust so the extra CC's should do rather well. I am also hoping that this will help those who want to do a simple stroker in a newer Jeep with out a lot of cost and problems trying to get it running right. If anyone has any other input please chime in as I will be buying parts soon. I will definitely keep the site posted as to my results.

Thats a good place start
you may need a few other small things but you won't know until the time comes.

[SilverXJ]

Without the hardened pin in the timing case the camshaft will float more than spec as the retaining pin will not be under the correct tension and the retaining pin will burrow a hole in your timing cover -eventually.

Hardened pin on the time cover? In any 4.0L I have taken apart I have only seen a dimple protruding from the cover. As that what you are referring to? If so, my 2000 has it.. don't know about later years. If not would you happen to have a pic of what you speak of?

In open loop the problem is that the PCM does no fuel or timing trimming it simply selects a map based on initial sensor settings and off it goes. The MAP sensor might affect things, but as you said it is one size fits all. It is quite the problem. When I was dynoing my Stroker, which I did about 5 times, it was very apparent that the problem was open loop mapping, I used to throw rich mixture codes within about a minute of starting the engine. Smaller injectors stopped that problem, but I never totally solved the detonation on WOT problem. If the Apexi had been around when I did mine it probably would have helped me out a lot. The guys at Jeep told me that the mapping in the later OBD11 ECU was more sophisticated than the earlier ones, due to emissions issues. They were far more picky about keeping fuelling within spec, Hence the post 1999 - 2000 stroker concerns.
It is such a shame that the Jeep PCM is locked, it would be so cool to be able to reprogram the PCM like I can do with my Subaru.

The PCM does do trimming based on MAP sensor. That is the whole basis for any adjustable map device. What it doesn't do is monitor the O2 sensor and trim based on that. It would indeed be awesome to have a PCM that we can reprogram. Nick Ianuzzi ([email protected]) is suppose to have some form of programing, but i haven't spoken to him about it.

-Chris

[bratcop]

CMCB, have you gotten any further with your build?

I am looking to do the same with my 2001 that I bought with a cracked piston. I am only concerned at this point with the MAP Sensor/ECU issue at this point. I am building to about 9.2 to 1 and need it to be reliable for her, yet fun for me. I have the skillz to build the adjustable map sensor, however, it sounds as though it is a rather simplistic/one-size-fits-all approach. What have you learned/decided etc? For what it is worth, I think I will stay with the stock injectors...

Joel

[SilverXJ]

I think you would need something with more points than just the one on the home made map sensor. Apexi, FTC1, PSC1, or Omnichip will all fit the bill. Also, I would recommend a wide band O2 sensor with data logging so you can tune the devices (Omnichip you can't do yourself though).

[bratcop]

so if I went with the PSC1-003, would I need a wideband o2 sensor to check the air/fuel ratio? I was hoping the software with the psc1 would display that information....maybe?

[SilverXJ]

You will still need the wideband O2. The PSC does not have that option built in.

[bratcop]

Isn't the stock o2 sensors already getting that information? A wideband o2 is costly as a diagnostic/limited use tool...just trying to find another way to get the information without buying it....

[gradon]

You can use an obd-2 scanner to help zero the fuel trims(raise or lower the values @ diff rpms and loads on the piggyback ecu/calibrator), but you'll never know the afrs in open loop unless you have a wideband o2. You could be too lean or too rich at WOT, and not getting as much power as you could or else using excess gas w/o any power increase. Tuning is an important part of the engine building process.

[bratcop]

I understand the tuning part of the equation...however, I am used to simply use a screw driver to turn fuel mixture screws until it sounded right....last two builds were carbed '79 302 and 67 CJ5 Dauntless V6 (Buick 225 c.i.). Do parts houses or rental places usually rent these types of tools? With a wideband, must I but a new bung in my exhaust, or can I simply remove one of my o2 sensors and thread the diagnostic one in there for tuning, then revert back?

Joel

BTW, thanks for all the assitance, I truly appreciate it.

[gradon]

The lc-1, lm-1, and lm-2 wideband o2 packages can simulate narrow band sensors and have outputs if you want to replace a stock narrow band--probably more accurate than it anyhow. I have a 2-bung cat so I left the other two alone. I do like the idea of using mine in place of the upstream sensor. It seems like there would be less of an error and the chain would be simpler and possibly faster. Edit: you do have to still wire them to the pcm via tapping the wires in the sensor harness--your pcm will throw codes if you simply unplug them; however, I have read of people using just the signal wires and keeping the stock sensor connected to the heater wires while temporarily zipped out of the way to avoid throwing codes.