Headgasket job underway

[madman1234509]

Well got the truck back tonight. Put about 50 easy miles on it without going over 30 pounds of boost. Waste gate is shut, havent bothered dialing it in yet. Truck runs awesome for the most part. Didnt notice a big difference in sound at idle. When the torque converter isnt locked and I get over 2k rpm, I dont even have to get on it that hard, it sounds like a completely different truck, and even when I roll off the throttle too. I dont know if I should contribute that to the cam and valve springs or the down pipe.

**After some driving I decided to roll onto the throttle while the torque converter was locked, running the spartan 310. I rolled into it keeping the converter locked. Once spooled the truck does this kind of pulsating/surging thing. Its so strange. The only thing that fluctuates on the dash daq that I notice is the fuel rail pressure, keep in mind I installed ported fuel rails, but dont have any other fuel mods. The rail pressure only gets up anywhere from 21k-23k. Would this cause a surging/pulsating? The truck still pulls while its surging. Im not sure.... Its dark out with kind of crappy roads tonight with some light snow, so maybe in the morning ill load up the 275 tune and see if itll hold rail pressure and how it acts. My buddy just put ported rails on his with all stock fuel and has no problems but his lift pump is also brand new, mine has 97,xxx miles on it.

I also need to post pics tomorrow of the modded CAC pipe. Its the stock pipe but has now been moddified and made larger, looks pretty sweet in person. Ill have to get it coated one day when I have more custom plumbing under the hood

 

[UpstateDieselGuy]

Glad to hear that you got out on the road.

 

[madman1234509]

I'll have to stop up soon. Going to try to get it figured out today

 

[dstryr]

I had the surging issue with a stock truck on just a tune. Traction bars get rid of the issue. Just put my OUO bars on this weekend and no more surging.

 

[madman1234509]

I dont think this has anything to do with needing traction bars. You car hear the surging in the motor/turbos/exhaust. My fuel rail pressure would drop to 21k

 

[Breaking Habits]

Hey man,

I had issues with this "surging feeling" but it was because of serious axle wrap, like dennis was saying. The wrapping up caused my foot to slightly bounce on the pedal and that was it. surrrrrge. New traction bars helped substantially. The cam will change the sound on your truck, as we discussed over the phone, mine came alive like a monster!

Jared

 

[madman1234509]

Thanks for the input. I really don't think my foot is bouncing though, ill try to be more conscious of it. Getting ready to go out again to mess with it. I logged itast night at WOT and the only thing that fluctuated was fuel rail pressure. I'll turn it down to 275 to see if it does anything different

 

[UpstateDieselGuy]

Good Luck!

 

[Breaking Habits]

Keep us posted Wayne, I wanna hear that thing thing rips like none other!

 

[MINK]

Mine was doing the same thing no matter the tune after ported rails. Turned out to be an ebp sensor issue, once that was fixed it has gone away exept for on my race tune you can feal it at times - guess ill try some traction bars next.

 

[Dzchey21]

Not.sure if its the rails or what but I.have had issues with it off and on for awhile depending on.tune ect. Xrace used to do it like crazy... now not at all but its something to.do.with.the valves in the injection pump. Tuning plays a big roll in it for sure

 

[madman1234509]

Just been driving around all afternoon. Honestly it does pull very hard. It doesn't pulsate with the torque converter unlocked, sounds sick, and flat out pulls. When I took upstatedieselguy for a ride he told me to log vgt duty cycle. Sure enough its all over the place and the graph looks like saw teeth. It does it 1/2 to 3/4 throttle. Once you get to wot it clears up and is smooth. Doesn't seem to be a loss of power when doing it. Boost and bp are consistent and don't fluctuate. Rail pressure seems to be ok now, maybe even a little higher

 

[UpstateDieselGuy]

The truck definitely pulls hard. The data log of the VGT Duty Cycle is very smooth with quick changes matching the demand on the VGT, except as he described, when the converter is locked and you roll into the throttle. It begins to lug a slight bit before the fuel starts to hit and begins to cut in and out via exhaust tone. It acts as though an exhaust brake is cycling while accelerating. While this is going on the Data Log is very jagged and it matches the cycling of the VGT perfectly. The sound is very similar to when I would kick in the Tow/Haul with Eric's Towing Tune with aggressive braking in my 6.0L, except that it is cycling.

 

[MINK]

keep me updated on what you find out.

 

[madman1234509]

I'll post some videos later... Is there a sensor that if it goes bad itd make the vgt cycle when it shouldn't?

 

[MINK]

I'll post some videos later... Is there a sensor that if it goes bad itd make the vgt cycle when it shouldn't?

mines having the same issue - my ebp sensor fixed the majority of my issues though...Are you reading ebp okay?

 

[BFT]

One way you can see if your EBP sensor is bad is if it reads negative or 0 at idle, and you will see negative readings when getting on the throttle. It'll feel like major turbo lag.
If it is bad it will throw a code

 

[madman1234509]

Ebp reading is 14.1 with key on and engine not running. I don't know whats going on... Maybe too much fuel at part throttle? Vgt acting up? Messed around with the gate a tad. The regulator I have on it now is pretty touchy so a little at a time. No matter where I set it it still does it.

 

[BFT]

I meant your boost, sorry

 

[madman1234509]

No negative boost readings. No codes. No lag. Drives awesome otherwise.