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Discussion Starter #1
After 3 years of ownership (purchased at 101k miles), I'm finally starting some upgrades. I initially set out to just BLACKOUT this beauty, but I've caught the performance bug.... This thread is to document the upgrades as they happen (a follow up to an initial thread I started, which was locked for some reason).

First upgrade from old eyesores (wheels):
IMG_5424.JPG
To...20 inch Black Rhino Mozambique rims with Nitto Terra Grappler G2s
IMG_5509.JPG

Also changed the antenna to... IMG_5414.JPG
 

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Discussion Starter #2 (Edited)
After my initial aesthetic improvement phase, decided to upgrade things that matter to performance... Starting with exhaust

Initial: Stock
https://youtu.be/RvLwltATxzw

Upgrade: Corsa Sport Cat-back Performance Exhaust
https://youtu.be/OXwBAOMPFEc

Very nice (thanks to my bro... Face full of smoke, lol)

Of NOTE, at the same time that the exhaust was installed, my manifold was milled/reinstalled (had quite the leak due to broken bolts and warping), as well as replacing the radiator/thermostat, and a coolant flush/fill
 

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Discussion Starter #3 (Edited)
UPDATE: New exhaust sounds fantastic, especially when creeping along through the city, with ever so slight acceleration... Not imposing, but a nice growl.

As an aside... After the New exhaust/manifold fix, I reset the MPG, and thus far running around 14.6 all around... Was at 12.9. I'd imagine it'll be a little lower after my normal driving patterns (mix of city and short distance country side driving, with one day of interstate use).

Also, I've been throwing a P0420 engine code for the past three years. I'd hoped the manifold fix would clear it up, although the code came up after leaving the mechanic. Not sure if these codes are automatically saved and just come on at specific intervals (was coming on about once a month for 3 days at a time and then would go away without manually clearing it), but I've cleared the code manually with my UScan unit, so we'll see if it comes back (I've had the Jeep assessed at a couple mechanics, but the root cause of the code was never truly found: one tried changing spark plugs/timing/etc, the other (current) felt that the manifold issue could be the cause, but couldn't guarantee it).

Next UPGRADE:
IMG_5555.JPG

Just waiting on a BT catch can to arrive, at which time I'll install the AIRRAID MIT/BT catch can, a well as clean the throttle body...any recommendations for cleaning the throttle body are welcome as I've never attempted it in the past... Watched videos, but have received varying messages with regards to cleaner use/etc. It looks like removing the throttle body is best (removing the negative lead before hand), with use of CRC throttle body cleaner and a tooth brush/denture brush. My impression from videos/write-ups was that you aren't supposed to move the butterfly once it is off the vehicle due to sensor memory, which can cause trouble codes once placed back on the vehicle. As I don't own a more advanced diagnostic unit that has a "throttle body re-learn" function, I want to be careful. My understanding is that the vehicle's computer will generally re-learn without issues, unless you have trouble codes.
 

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If you've been driving with exhaust leaks for 3+ years you possibly have toasted the catalyic converters.....hence the P0420. Was your leak(s) on the passenger side or the driver's side, or both? Exhaust leaks cause the PCM to create an artifical rich condition. Since fixing the leaks, things are now at least closer to normal, which is why your fuel economy has improved.

Anyway, you may want to have the cats. checked by a reputable mechanic.
 
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Discussion Starter #5
If you've been driving with exhaust leaks for 3+ years you possibly have toasted the catalyic converters.....hence the P0420. Was your leak(s) on the passenger side or the driver's side, or both? Exhaust leaks cause the PCM to create an artifical rich condition. Since fixing the leaks, things are now at least closer to normal, which is why your fuel economy has improved.


Leak was on the passenger side... Unfortunately I don't know the exact timeline for the leak, but I'd imagine it has been present for the entire time that the code has been present (I didn't actually appreciate the leak visually until this past Dec). My mechanic felt it was likely running rich as well... And truthfully it started to show issues with efficiency more prominently from Dec on, so the leak may have become more prominent around that time. Although I'm not sure of the integrity of the catalytic converters, my current mechanic is fairly thorough (should've been going to him from day one... Old mechanic kept guessing) and didn't seem to indicate any specific issues with them.
 

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Are you sure the driver's side exhaust manifold is not leaking too? The P0420 code is for the driver's side (Bank 1) cat. efficiency below threshold. P0430 would be for the passenger side (Bank 2) cat. In any case, your fuel economy is more "normal" now, so there may not be any huge leaks. I'd have your mechanic or local muffler shop check the cats. though to see what's going on. If you have the "smog nazi's) where you live, you'll for sure fail.

One other thing to consider is maybe changing the O2 Sensors (all 4), as with over 100K on it they're probably not in tip top shape and are probably for sure getting a little lazy. When they go bad (they mormally go slowly like spark plugs unless contaminated) they tend to go bias to the rich side, which could also cause the issue you're having.
 
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Discussion Starter #7
Ha, "smog Nazis", like it. Luckily I'm in Indiana, so I can pretty much do any thing I want with my vehicle and be ok. I recall getting a P0430 code once in the 3 year period, but no other times... The P0420 code consistently would flip every month or two. I haven't changed the O2 sensors, but that was something I was considering as well. I'd prefer not to change the cats, as they are fairly pricy, but if they had an issue I would. I guess what it comes down to is whether it's 100% necessary (If the cats are the issue), as I'm in a less regulated state. Thanks for the input, much appreciated.
 

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You're right, the cats. should be the last resort, as they are very spendy...for the factory setup anyway. If your mechanic has a real good quality computerized scanner, he should be able to monitor, in real time, the O2 Sensors and give you a pretty good idea on whether they're working properly. You may want to have a look at the thread I did a few years back. It may give you a little more insight on the O2's:

http://jeepgarage.org/f183/oxygen-sensors-and-their-role-in-engine-management-a-primer-20300.html

Hope this helps.
 
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Discussion Starter #10
You're right, the cats. should be the last resort, as they are very spendy...for the factory setup anyway. If your mechanic has a real good quality computerized scanner, he should be able to monitor, in real time, the O2 Sensors and give you a pretty good idea on whether they're working properly. You may want to have a look at the thread I did a few years back. It may give you a little more insight on the O2's:

http://jeepgarage.org/f183/oxygen-sensors-and-their-role-in-engine-management-a-primer-20300.html

Hope this helps.


Thanks for the help, I'll take a look.
 

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Discussion Starter #11 (Edited)
You're right, the cats. should be the last resort, as they are very spendy...for the factory setup anyway. If your mechanic has a real good quality computerized scanner, he should be able to monitor, in real time, the O2 Sensors and give you a pretty good idea on whether they're working properly. You may want to have a look at the thread I did a few years back. It may give you a little more insight on the O2's:

http://jeepgarage.org/f183/oxygen-sensors-and-their-role-in-engine-management-a-primer-20300.html

Hope this helps.


So, after reading through your thread and then going back through some old live data I ran in Oct of last year with my UScan unit (when the code was on: P0420), it appears that banks 1/1 and 2/1 fluctuated between about 0.02-0.8 and banks 1/2 and 2/2 fluctuated less so, mostly staying around 0.7-8 (but still some fluctuation lower in the range of 0.2-0.5 from time to time)..... So, now after the manifold fix/new exhaust (no current trouble code showing/erased), I ran live data again (just now) and the biggest difference I saw was that banks 1/2 and 2/2 stay much more consistent around 0.7-0.75 with very little fluctuation, with banks 1/1 and 2/1 fluctuating between 0.02-0.8 like before. Based on the readings, it appears that the cats are at least running as one would expect (if my understanding of your thread is correct).

And.. The cats were at about 950F.
 

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All those numbers are within the acceptable ranges for both up and downstream sensors. The downstream sensors will sometimes drop below (sometimes well below) .450mV, but should only do so at low or idle RPM. At ~950*F, you must have been at or near idle. Usually at cruise, on the highway, you'll be getting well in excess of 1000*F....usually ~1300-1500*F or more, depending on engine load. If all is well, both banks' readings will be very close to each other in temperatures. The only other thing your scanner may not be able to read is whether or not the crooscounts are rapid enough to maintain a more exact fuel mixture. I don't know if there is a certain number crosscounts or + or - width (how high above and below the mid-point of .450mV) is acceptable. If your code does not return and fuel economy stays within the "normal" range, you may want to just drive it until things deteriorate. Good luck and keep us posted.
 
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All those numbers are within the acceptable ranges for both up and downstream sensors. The downstream sensors will sometimes drop below (sometimes well below) .450mV, but should only do so at low or idle RPM. At ~950*F, you must have been at or near idle. Usually at cruise, on the highway, you'll be getting well in excess of 1000*F....usually ~1300-1500*F or more, depending on engine load. If all is well, both banks' readings will be very close to each other in temperatures. The only other thing your scanner may not be able to read is whether or not the crooscounts are rapid enough to maintain a more exact fuel mixture. I don't know if there is a certain number crosscounts or + or - width (how high above and below the mid-point of .450mV) is acceptable. If your code does not return and fuel economy stays within the "normal" range, you may want to just drive it until things deteriorate. Good luck and keep us posted.


Yeah, these readings were from driving for about ten minutes across town from the gym to the store at 30-45mph. Thanks for the help, hopefully the code won't come back, but we'll see. Thanks.
 

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Throttle body cleaning; do not use throttle body cleaner ! Disconnect battery neg, remove air intake, remove the TB, just 4 bolts and one electrical connector. Use rubbing alcohol, and soft cloth and a lot of elbow grease. It will take a good deal of time, but you only have to do this once, after putting on a catch can it stays clean for good. To get at the crevices use q tips soaked in alcohol. You can move the butterfly open, not an issue and make sure to clean every little bit of gunk until it looks like brand new. I also put a new OEM O ring on the TB, just a couple bucks.
Don't waste money on aftermarket intakes. Those and catbacks only make more noise, not any noticable power, plus low end torque and tip in throttle response is lost, making it less fun to drive than with stock components. A taper ported TB and CMR tune will yield far better power results, for less money.
 
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Even though O2 sensors read OK, it is worth it changing all 4 out. I had no issues or codes and replaced all 4, and big improvement in throttle response and city mpg is up by 3. It is a huige PITA on the 5.7 to do all 4, just like about everything else on these vehicles.
 
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Discussion Starter #16
Throttle body cleaning; do not use throttle body cleaner ! Disconnect battery neg, remove air intake, remove the TB, just 4 bolts and one electrical connector. Use rubbing alcohol, and soft cloth and a lot of elbow grease. It will take a good deal of time, but you only have to do this once, after putting on a catch can it stays clean for good. To get at the crevices use q tips soaked in alcohol. You can move the butterfly open, not an issue and make sure to clean every little bit of gunk until it looks like brand new. I also put a new OEM O ring on the TB, just a couple bucks.
Don't waste money on aftermarket intakes. Those and catbacks only make more noise, not any noticable power, plus low end torque and tip in throttle response is lost, making it less fun to drive than with stock components. A taper ported TB and CMR tune will yield far better power results, for less money.


Good info, thanks. Was curious about changing out the throttle body/whether it would be worth it. Any recommendations on vendors for an aftermarket throttle body/what size would be recommended in a fairly stock Jeep? Was curious if an aftermarket throttle body would require a custom tune to be effective as well? Was looking at some of the tuners from Diablosport which seemed promising and could allow one to self-select specific changes that have been made to the vehicle; although my knowledge on tuners/custom tunes is limited, so I would defer to someone who knows/had experience, such as yourself (my last experience with Diablosport was on a 1995 Mustang GT, which made a world of difference/improvement on a minimally modified car). And, I should probably know this, but what is CMR?. Thanks.
 

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Discussion Starter #17
UPDATE: So, did a little investigation (forum search) and ended up looking into a Sprint Booster for improved throttle response.... Which I ended up purchasing through aFe (pockets were burning, lol). I figured that the overwhelming amount of positive responses/reviews on this forum was a good sign. Also, if I do a custom tune, this will only continue to add benefit I'd imagine.
 

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Discussion Starter #18
So... More forum searching and came across a couple threads on throttle bodies... The one that seemed promising was Fastman throttle bodies... Site seems legit... Any experience from anyone with his throttle bodies?
 

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I got a Modern Muscle TB, they are bigtime Mopar experts, build custom Hellcat engines, etc.. and use CNC machining to taper port a new OEM TB, so low end torque is great with their design. A straight through ported TB will suffer low end loss. I don't know if fastman hand ports, but if so it cannot possibly equal CNC performance, and that is all he doesm, not an engine builder or tuner. A tune is a great upgrade with the TB, and CMR is a custom tune for your vehicle, logging parameters and emailing them in. I use Hemifever with a Diablo Intune, and have CMR tunes for 93, 89 and even 87 octane which I run all winter. There is notable difference in giddyup on 93, and it get's best mpg, but cost of premium fuel is not worth running it in cold weather. The CMR 87 tune on mine still totally blows away any stock 5.7 running 89 fuel, and also tunes the trans which really makes a difference in shifting.
 
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I got a Modern Muscle TB, they are bigtime Mopar experts, build custom Hellcat engines, etc.. and use CNC machining to taper port a new OEM TB, so low end torque is great with their design. A straight through ported TB will suffer low end loss. I don't know if fastman hand ports, but if so it cannot possibly equal CNC performance, and that is all he doesm, not an engine builder or tuner. A tune is a great upgrade with the TB, and CMR is a custom tune for your vehicle, logging parameters and emailing them in. I use Hemifever with a Diablo Intune, and have CMR tunes for 93, 89 and even 87 octane which I run all winter. There is notable difference in giddyup on 93, and it get's best mpg, but cost of premium fuel is not worth running it in cold weather. The CMR 87 tune on mine still totally blows away any stock 5.7 running 89 fuel, and also tunes the trans which really makes a difference in shifting.


Great info, just looked up the Modern Muscle Extreme site. Appears to be good prices. I noticed that you have an 85mm TB, and was wondering what would be the reason for 85mm vs 87mm. Again, my knowledge of the physics of airflow, etc are minimal, but trying to learn. For my purposes, with minimal actual modifications: stock air box with drop in K&N filter, AirRaid MIT (waiting to install), Corsa CatBack exhaust (installed), aFe Sprint Booster (waiting to install), BT catch can (waiting to install).... What size would you recommend? Thanks in advance, as I know these are likely simplistic questions, but much appreciated.

Also looked at Hemifevertuning.com...I think I'll strongly consider this after the Aforementioned has been sorted out.
 
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