FCA mod done. Now I got a surge. Tho it woks well

J

JasonCzerak

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Aug 10, 2006
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So I took the instructions from http://www.relentlessdiesel.com/forum/viewtopic.php?t=19

I didn't "break" anything. So I did something right. Truck idles, and goes WOT and you can drive "normal" per say.

Smarty on 9, TST no timing on 2hp/0tq/2rail std program.

When on moderate throttle say, 1/2 peddle. Rail pressure around 17,5000 It get a bucking serge while under 60mph. no so bad over 60 cuz you need more peddle to really accelerate... I do need more then the 10 miles I went to get a complete description of all driver situations. However I'm sure someone has done this and didn't get it right like me?

I used the smallest dremel cut off wheel and cut near the top just like the pictures. tho I could of been more "Accurate". I for sure have the bottom half of the triangle there. I didn't make it more open to the top. As in making the triangle taller (better idea?). Just wider.

I did drill out the one hole on the pump cover. Left the other in place since it was in spec with the numbers on the site.

Maybe I just need to change my driving habits?


As for performance, Holly poop this truck gets up and goes. I know I got more HP!!!! :) I moved the TST up to 5 with the smarty on 9 (170hp + 100hp). above 2500rpm the Rail holds at 22.5 all the way up to 3500rpm. In 6th I got to 1800 degrees at 115mph... Officially too to much fuel for this stock turbo.

With the TST on 5 and lower then 2500rpm, I can still drain the rail and get some popping due to rail drainage.. I didn't do much with the tst on 2. but I did kick up to 5 while on the WOT highway run.. pulls strong, but fell down on it's face at 115. most likely due to temperature (1800 egt).
 
JasonCzerak said:
pulls strong, but fell down on it's face at 115. (1800 egt).
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you sure it wasnt your governor kicking in? or do you have a top speed eliminator?
 
redneckcummins said:
Take the FCA back apart and clean everything real well. do some more sanding and deburing.
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I plan on doing that after I eat here :) Just took the truck for a many mile run here and it's running good.. I can consistently keep the TST box on 4/0/2 and EGT stay in check with an additional 3 degrees of static timing as well. All this on top of the latest release of Smarty software on #9.
 
Took the FCA apart. few things.. one, I made sure the cap that the spring is held in by was all the way seated down. I couldn't find a drill bit exactly .130. But I have the hole cleaning drilled to .125. figured the next size up .140 would be a little to big.

I took the dremel polishing pieces to it and ran over the entire cylinder. I did go in easier the time, no binding, less force. maybe this will fix it?

After looking at my cuts, heh, really bad. I can do better then what I did. one is on a little angle and not straight. I bet that doesn't help much. So at the very least I'll re-do it with a new stock cummins part. later this week.

No test drive yet. but I'll find out on my way to work tomorrow.
 
Chris at Relentless tried this himself on my truck. It also surged the same way. He ended up trying 3 different modded FCA's each modded a little different and they did it too. He gave me a stock FCA back and said it was the first truck he had ever seen do that!

I later ran a DarkSide stage 3 cp3 with NO surging issues. go figure.
 
973604x4 said:
Chris at Relentless tried this himself on my truck. It also surged the same way. He ended up trying 3 different modded FCA's each modded a little different and they did it too. He gave me a stock FCA back and said it was the first truck he had ever seen do that!

I later ran a DarkSide stage 3 cp3 with NO surging issues. go figure.
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maybe the triangle has to just be bigger, and widened up more drastically half way up and not a drastic shape change? something difficult, if not impossible to do with hand tools.

Can anyone open up a working modded FCA and take some pics and some measurements?
 
What about any of the other SW's? mine stock pump did weird stuff like a surge/runaway with the smarty, mainly on 9
 
JasonCzerak said:
maybe the triangle has to just be bigger, and widened up more drastically half way up and not a drastic shape change? something difficult, if not impossible to do with hand tools.
Click to expand...

Chris tried 3 different cuts with no success on my truck. My truck just did not like this mod for some reason....maybe yours is the same way?
 
973604x4 said:
Chris tried 3 different cuts with no success on my truck. My truck just did not like this mod for some reason....maybe yours is the same way?
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Well, I can drive around the surge very easily. So I think I'll keep it.

feelmecummin,

SW9 works freaking awesome before I modded the cp3. I suppose I can kick it down to 7.
 
feelmecummin said:
is there any runaway? or just a surge? keep us posted
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Right now it's broke :) I pulled the FCA to polish is a little more and I missed some thing in the FCA and she surges when you idle it over 1800rpm. parked hte truck been tracking down a new FCA locally here. at 2pm I'm ordering something from cummins to get back up and running.. I'm going to get two to have a backup :)
 
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