Too much knock with this predator

[kennyob46]

I have tried various gas stations(BP,sunoco,shell)at different tunes(91cai and 93 cai).I have even used 93 octane gas on 91cai tunes.The problem is I get KNK LT retard and KNK st retard on all of them.If i go to stock i get 1.5-2.0 knk st retard(might be at the shift,it shows up about 1 second before it shifts.My car is the 5.7 charger.I dont get it.I dont see anybody else having knk lt retard issues like me.Any ideas?

[concoursd]

do you have a catch can installed ? Have you cleaned out the puddle of oil in your intake manifold recently? If your vehicle has more than 3,000 miles on it, and you didnt have a catch can installed since new, then you need to clean out the puddle of oil in your intake manifold and install a catch can.

[Mike_Levy]

You also need to tune it. These are not plug and play. All cars react differently. Its your responsibility to make it work for yours.

[kennyob46]

When you say tune it-you are referring to adding fuel at the different rpm ranges,correct?I was a little afraid to mess with it cause i hear you need a $400 O2 wideband sensor to do it correctly.As far as that puddle of oil goes,where exactly would i look on the intake manifold for it?I am a little wary about throwing down $100 on a catch can that i am not sure will fix the problem.But if i could clean the oil out like you said,and noticed a difference i would get one.Thanx for the response

[Mike_Levy]

Yes, adding fuel or removing spark. It can be done without a wideband, you just gotta monitor the KR.

The oil will be very obvious. Remove the throttle body and look in the intake manifold. Generally theres a puddle sitting in the bottom.

[kennyob46]

Yes, adding fuel or removing spark. It can be done without a wideband, you just gotta monitor the KR.

The oil will be very obvious. Remove the throttle body and look in the intake manifold. Generally theres a puddle sitting in the bottom.

thanx for the info,mike-i'll give this a shot tommorow

[Raven3416]

I have tried various gas stations(BP,sunoco,shell)at different tunes(91cai and 93 cai).I have even used 93 octane gas on 91cai tunes.The problem is I get KNK LT retard and KNK st retard on all of them.If i go to stock i get 1.5-2.0 knk st retard(might be at the shift,it shows up about 1 second before it shifts.My car is the 5.7 charger.I dont get it.I dont see anybody else having knk lt retard issues like me.Any ideas?

kennyob46 I had all kind of issues with my Challenger when I first started playing with it. The catch can is a must, and the 180* stat helped as well. Long story short, I couldn't get the knock out of my car with the 93 tune, so I ended up using the 91 CAI tune with 93 oct gas and 16% fuel across the Board. I stepped it up by 2% until I got to 16. That took all the LT knock out and I only have a little ST knock at shift which is normal from what I hear. You just have to play with it until the fear of destroying your engine goes away.

[kennyob46]

Thanx for the feedback raven-I took a look at the inside of intake manifold this morning.Very hard to see-I thought i seen what looked like oil pooled in the back,but when i pushed rag all the way back and tried to push down on it to get oil on rag none was on it.I am wondering if it was just the metal gleaming or something.There is definitely a large buildup of gunk on the throttlebody though.I think i will order the catch can tommorow just to be on safe side.Just hate spending money unnecessarily

[fireman2118]

Catch can is worth it. Once you see how much oil actually comes out of there, you'll be glad you got it. I drain mine at every oil change.

[kennyob49]

you fellas were right.I ran a can of Seafoam thru my intake and all lt knk is gone.Ordered my catch can yesterday.Thanx!

[brandy16]

you fellas were right.I ran a can of Seafoam thru my intake and all lt knk is gone.Ordered my catch can yesterday.Thanx!

I have never heard of seafom.What is it and how do you use it

[kennyob49]

you fellas were right.I ran a can of Seafoam thru my intake and all lt knk is gone.Ordered my catch can yesterday.Thanx!

I have never heard of seafom.What is it and how do you use it

It comes in a can from any parts store for about $10.You can also buy mopar combustion chamber cleaner from the dealer instead.You let your intake suck up a 3rd of the can and then let it sit for 5-10 minutes.You then start it up and a large amount of white smoke comes out of the exhaust.It cleans out all the build-up of carbon in the intake.

[concoursd]

Long Term Knock is primarily caused by the oil ingestion through the PCV on these hemi engines. Some users play with the tuning by adjusting the spark and fuel settings but this is really a bandaid and should only be done after the intake is cleaned and the catch can is installed. Then datalogging should be done to verify and adjust the tunes accordingly.

[2001z06]

I have tried various gas stations(BP,sunoco,shell)at different tunes(91cai and 93 cai).I have even used 93 octane gas on 91cai tunes.The problem is I get KNK LT retard and KNK st retard on all of them.If i go to stock i get 1.5-2.0 knk st retard(might be at the shift,it shows up about 1 second before it shifts.My car is the 5.7 charger.I dont get it.I dont see anybody else having knk lt retard issues like me.Any ideas?

kennyob46 I had all kind of issues with my Challenger when I first started playing with it. The catch can is a must, and the 180* stat helped as well. Long story short, I couldn't get the knock out of my car with the 93 tune, so I ended up using the 91 CAI tune with 93 oct gas and 16% fuel across the Board. I stepped it up by 2% until I got to 16. That took all the LT knock out and I only have a little ST knock at shift which is normal from what I hear. You just have to play with it until the fear of destroying your engine goes away.

Raven3416,

aren't you a bit concern that you had to add that much fuel? I would assume that DS with 91cai tune already had pretty close to ideal A/F ratio for pwr.

16% increase seems high BUT I can be wrong.

[concoursd]

I agree with 2001z06. I would check the A/F with a wideband o2 sensor before adjusting the fuel settings that much.