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Discussion Starter #1
Hello, ive got Johan tuning my jeep, and were having some issues with it. Some info on the jeep. Its a 426, 9.25:1 compression, ported heads, headers and connection pipes with cats, fuel system with -6 lines, ford 80lb injectors, kenne bell 2.8l supercharger with a 148mm oval throttle body fuel pressure at 50 psi. Tuning with diablosport.

Issues are, At stop lights sometimes it will stumble and rpm will drop as well as leaning out then catch its self, rev up a bit and then continue to idle fine. When i am cruising and let off the throttle, it feels like i dont pull my foot off the pedal at all and continues to cruise. Johan adjusted the throttle body flow and got it better, but it still doesnt go into full decel. The afrs also do not go full lean under decel, sometimes even go rich. He has played with the flow more, and got it to go into decel and shut off injectors most of the time but then the throttle was delayed and it just wasnt any good to drive. Played with it a little more and the tune in it now, it sat for 2 days and wouldnt start without me giving it some pedal, drove a bit and put it in park and it dies, and then hard started again. It also goes rich when i pull off the pedal, to about 12.3ish then goes to 16ish and then evens out around stoich. I have some logs with the stumble in it if anyone cares to look, as well as idle, cruise and pulls. Another issue, though minor is on cold start it will idle up and down for a little bit. I am unsure of the condition of the injectors fyi, the guy i bought the jeep from ran e85 sometimes. Ill be happy to provide anymore info that may help figure it out. Johan is saying he thinks maybe its some mechanical issue but im not convinced yet, seeing as how making changes to the throttle body table has made a difference. Curious what everyone thinks!
 

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Discussion Starter #3
I have thought about doing this but have only heard good things about johan.
 

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I have had great experience with him as well but if you think the tuning is in question you should get a second opinion.


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Discussion Starter #7 (Edited)
Ive emailed jerseyboy for a second opinion. Any other recommendations?
 

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Discussion Starter #8
Wow... These are issues people had back in 2008 with forced induction builds...

Why such a big TB????
I bought the jeep with this throttle body, kenne bell has proven them to make power. Do you have any insight BJB?
 

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I bet if you go smaller with the TB your issue goes away, or at least eliminates a possible factor!!
 

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Can you port a manifold that big to match? Is there enough material?? Either way, excessively big TB...

My vote is for TB as well.
 

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Gents that's the TB that comes on the KB blower. Wes had one on his. If Dave Katz got it to work it isn't the problem LOL


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Gents that's the TB that comes on the KB blower. Wes had one on his. If Dave Katz got it to work it isn't the problem LOL


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My question still stands. Can you port a manifold that large? If not, seems insanely stupid to market a TB that large...
 

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I'm dumb. KB. I knew that. Thanks for clearing up my oversight. No idea why I was thinking stock mani..........
 
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