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Discussion Starter #1
Hey guys been a while since I have been up here i got a 17 JKU. For the first time today I was pulling into the gas station and my brake pedal got hard like abs kicked in and my brake light lit up on the dash. Ever since then it’s been Intermittent and when my pedal gets hard you can feel abs trying to over ride the pedal, then the light comes back on for a few min. Have y’all seen this it’s pissing me off. I have heard things about the battery with these. It’s also stuttering almost like a dead battery but cranks perfectly fine. 🤦‍♂️🤦‍♂️🤷‍♂️ Any help would be appreciated.
 

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Ah this started to make sense when I read it again cuz I think the part about your jk “stuttering” is the clue. Does it stutter or stall the most when you push in the brakes? Sounds like you have a leak causing the system to not be vacuum tight, you have a hose running from the throttle body to the brake booster and tee’d off that line is another hose going to the vacuum pump (located behind your front bumper). I would check those hose connections especially if you’ve done a vacuum pump relocation say for a new front bumper.
 

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Discussion Starter #3
Yea sorry I’m horrible at making stuff make sense lol. The stuttering isn’t really worrying me the rig has a ripp supercharger. I need to dig into that and, find my vacuum/boost leak. What is bugging me is when I hit the break on dry pavement my pedal gets hard and I can feel abs kicking in. Almost like I’m sliding but I’m not. A leak in the system wouldn’t cause the issue with the abs would it? When this happens my brake light comes on like the e brake is pulled and the hard the I press the pedal the harder abs tries to counteract it.


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Hmm I don’t know if the ABS system is monitoring vacuum level, wheel sensors for sure...but it wouldn’t be the craziest thing for a low vacuum to trip the ABS along with the Brake light. Had to remove the intake manifold as part of the supercharger install right? So that would be another place for a possible leak.
 

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Discussion Starter #5
The supercharger has been up there for a while now. I took the intake off last night just to double check all the seals and I spect the plugs to make sure they were no fowled out. The plenum gaskets looked to be in good shape and plugs looked excellent. Funny part is last night I had no brake issues, they started for the first time this morning.


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I guess all I can really say is sure seems like low vacuum caused by a leak or even a bad brake booster can cause both the hard brake pedal (no vacuum assist) and engine stuttering (improper fuel/air mixture).
 

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Discussion Starter #7
Ok well I will definitely look into it again I very well could have missed something. Thank you for your suggestions. I will post what I find tomorrow night.


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Ok well I will definitely look into it again I very well could have missed something. Thank you for your suggestions. I will post what I find tomorrow night.


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They may be bad suggestions lol the supercharger is adding an element I’m not familiar with, and not knowing where or how your vacuum hose would be setup to negate the boost supplied by the supercharger to still let a vacuum device like the brake assist work...
 

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Ok so did a little search and found the RIPP install manual for a 2012-2014 JK (didn’t see one on newer models so don’t know how much changed); shows a PCV or basically a check valve installed on the vacuum line, that makes sense. So that would be another component to check but if at low rpm like when you’re saying the issue is occurring there shouldn’t be much boost...geez now I’m kinda circling back to a leaking intake manifold or hose but at least I learned a little more on superchargers haha
 

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Discussion Starter #10
Lol that’s what I what I was looking for as well. So me going back to my old carb days I took parts cleaner and sprayed it around all the connections. I sprayed the intake and all the boots and nothing. No change in idle if I had a leak it should have changed it would have sucked that in and, affected combustion. I’m starting to draw a blank lol.


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Discussion Starter #11
So after messing with it this morning before work I feel like a complete dumba**. The booster line was barely connected when I touched it this morning it fell off.


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Still a good find! So brake issue is resolved, how about the stuttering?

Also since you got your safety issue fixed I feel like I can derail a tiny bit:
How long/many miles have you had the RIPP SC on? I’m interested in one myself depending on how my engine checks out when I’m ready to address power for bigger tires. Overall have you been pleased with the performance? It was positive to hear when you took the intake manifold off that everything looked good, any negatives arise from running the SC?
 

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Discussion Starter #13
The stuttering is still there a little bit but I’m going to call Ripp and get some more info.

The Jeep currently has 35k on it, the power band is awesome in it. I purchased the Jeep with the charger on it. When I pulled the plugs and looked through everything else it relatively clean except for blow by which some of it is from crappy oil the supercharger will cause som blow by. Other than that man it moves my JKUR on 35s with no problem.


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