6.7 fueling problem after twins install??!!

O

oldsmokey97

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Aug 5, 2006
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A buddy of mine has an 08 6.7 CR. He has a black max prgrammer from H&S.
About a month ago, he put a S475 under his stock turbo. It has pretty good power for still having stock cp3 and stock injectors. It ran very good with no problems.
Then, about a week ago, he bought a 64/71 and bought my 80mm from me and built twins out of those and scraped the stock/S400 setup.
NOW.... when he lays it to the floor... it runs REALLy good BUT, at about 3000 rpm, the truck starts to cutout. It feels like he is peddling it real fast. The whole truck will surge.
Anything below around 3000, it runs perfect. But above that, it surges real bad.
Last night.. put on a Airdog II which is the "165gph" with the ex. regulator. Did not seem to help.

Rail pressure on WOT run sees around 22k when the truck surges, it drops to about 17k. I think thats what is says, because when it does surge, it happens soo fast. Power will cut out, come back, cut out, come back about 3-4 times in about 2 sec.

Could the rail be running dry?? IF so, why. Stock inj. are still in it. Only fuel mods are the H&S black max and airdog.

If it is fuel... why did it not do it with the smaller twins.

Any ideas?

Lance
 
Lance did he try a boost fooler yet? He needs to look at the quadzilla lik I told him..
 
aer212 said:
You need a boost fooler with h&s programmers.
Click to expand...

I dont know much about all the computer stuff but.. would not running a boost fooler cut back on fuel that bad and then get right back on it.

Like i said its weird. The truck seems like the throttle is on an on/off toggle switch and someone is sitting there flipping it on and off real fast. It will pull hard and suck you back in the seat and then at around 2800-3000 it will shut down and you will almost hit the dash. Then as soon as you almost hit the dash.. it is full fuel again. It will keep doing this untill you let off and give it some space.

Lance
 
wpeschel said:
Lance did he try a boost fooler yet? He needs to look at the quadzilla lik I told him..
Click to expand...



No. They just put the Airdog on it last night. Just trying to get it half ass figured out for this weekend. It still runs damn good untill about 3k. So should still make decent pull on the rollers.

Lance
 
Someone else posted about it on cf, let me find the link.
 
posted about this truck???? huh.... may have been. The guy that owns this truck dont get on the forums much (if any)

Lance
 
Here is a quote from someone else," Some guys may think otherwise but i have seen first hand that it is needed.Unless something has been done with the programing on the smarty and xrt you will get to about 40psi with the xrt and then hang on.(Bucking bull)With the smarty it just leveled out at 42ish and thats it. Add a boost fooler and then it will allow you to get the rest". Another quote," Mine only fools up to 40psi,If i want more than 40psi i have to run my quad fooler are it will just stop at 40psi.With the fooler i can hit 70psi.Not sure if this changes from version to version but this is what it does on both the 14 and 14tnt. The xrt does the same thing except when you hit 40psi with it you better hang on are it will buck you out of the seat.The smarty just stops pulling at 40". Another one," Fuel rail might be an issue over time but i do know for a fact that in the 40psi range the xrt will not boost fool.It will buck,pop,jump ect ect.You will need a boost fooler to give you the rest of your boost". Finally here is one straight from Casey@h&s," RJP is correct, you need a boost fooler past about 38-40 psi. What you are most likely experiencing is de-fuel based on boost. Try a boost fooler and you should be good to go.
 
If he decides to buy one to see if it fixes the problem, will you post the results back in this thread? I havn't used any H&S products so I'm curious myself.
 
yes i will post results.
The truck put down 478 on the rollers yesterday. Started bucking again.
The truck has MUCH more potential. Just need to try the boost fooler and see what it does then.

Lance
 
boost fooler fixed the problem.
No more bucking....

he is feedin it more fuel in the near future

Lance
 
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