Surging

madman1234509 · Feb 6, 2012

Ok so as many of you know Ive had some issues with my truck since getting it back from having a bunch of things done to it over the last few weeks, I wanted to start this thread to get out of the thread about my hg job. So here is the story

My truck went in for a head gasket job, heads were cracked, have brand new heads, new ford gaskets, arp studs. Made a custom downpipe, custom egr delete with a 50mm jgs waste gate and a regulator. Custom CAC pipe and intake elbow. RCD cam, valve springs and ported rails. And a crank case vent mod

Problem. The main problem im having is when the torque converter is locked, on every tune, I mainly just run the 310. Roll into the throttle, the truck does this surging, you can hear it in the exhaust note, and sitting in the truck. It doesnt loose a ton of power or anything but its very noticeable. It ONLY does this with the torque converter locked, when I get on it without it locked it runs awesome. The two main things Ive notive is exhaust back pressure spikes all over the place when this happens, but it relatively low. And VGT duty cycle is all over the place during this. The truck also shudders a tad bit only around 55mph barely on the gas just cruising but thats not my main concern right now.

I have take the waste gate off since then, pressure tested all ports, does leak, pressure tested the regulator, doesnt leak... pressure tested the entire intake system on the truck with no leaks. The waste gate is currently closed completely with the regulator until this problem is resolved. I unhooked the VGT and drove it, didnt surge anymore, but obviously you cant just drive around with the vgt unhooked all the time. The highest boost I can see with the tq converter locked is like 38 pounds. No codes read with the DD. Otherwise the truck runs awesome. I drove it over 700 miles this weeeknd with no issues. Here are some vids, and a graph pic. I can get pictures or info of whatever you need. EP reads 14.1 with key on. Boost gauge doesnt read negative or any crazy numbers. Throttle position sensor doesnt fluctuate or do anything crazy.

All videos are 1/2-3/4 throttle with the torque converter locked
Here you can kind of hear the surging
http://youtu.be/LJ9fANpBZPU

Gauges on DD
http://youtu.be/MUlXOZcQ__Q

VGT duty cycle all over the place
http://youtu.be/14otGAZEHvs

Spatel23 · Feb 6, 2012

which trans and tc are you running?

madman1234509 · Feb 6, 2012

Completely stock. I've never seen more than 5 rpm of tc slip at any time

Also the last 3/4 of the graph I posted is where I rolled onto the throttle with the tc locked. You can see how exhaust pressure, vgt duty cycle and boost all spike up and down. I never can get over 38 psi and exhaust pressure is relatively low. Running Spartan 310, regulator/waste gate closed off still.

dstryr · Feb 7, 2012

Traction bars solved it for me.

Powerstroked162 · Feb 7, 2012

Wonder if its gate flutter.....

Are you sure you have the gate hooked up properly? It can be very easily done backwards sometimes and cause issues. Also, what spring pressure are you running in the gate? 50mm seems big to me. Doesn't the Elite kit use a 45? I know its a 40something

madman1234509 · Feb 7, 2012

Thats what Ive wondered... But we pressure tested all ports on the gate with no leaks, and the valve itself by taking the gate off the truck, with pipe that goes from the up pipe to the gate still attached, clamped a plate to the end of it and pressurized it, the springs alone held a little over 20psi. The top port of the gate is referenced to exhaust pressure, the bottom port is referenced to boost pressure (with the regulator inline) So I would imagine the 20 pound springs plus the exhaust pressure is keeping the gate shut pretty hard. We also pressure tested the regulator with no leaks. I have the regulator cranked all the way so no boost is getting through and theoretically the gate would stay shut. Ive tripple checked the plumbing. My buddy with a tuner,exhaust,intake, full delete with custom elbow and ported rails has the same exact gate setup with the same size gate with no issues and full boost.

Hopefully sometime this week I am going to take the gate completely off again and block off the hole on the downpipe and up pipe and drive it. That will ultimately show if its the gate doing this or something else... I was thinking its one thing or the other causing the surging by the looks of the graph. Either the gate is opening dropping boost and exhaust pressure, the computer is seeing this and causing the vgt to fluctuate.... Or for some other reason the vgt is fluctuating at this point in time causing the exhaust pressure to fluctuate.

idkillinit · Feb 7, 2012

With the exhaust note change and back pressure Going crazy I'd keep checking the gate plumbing, make sure its functioning properly. Maybe change the spring. Try another gate. I know its a pita but def seems like a gate problem. You also said you did ported rails right. Have you monitored rail pressure. Ling shot but just a thought

madman1234509 · Feb 7, 2012

Lol rail pressure actually spikes higher now with the ported rails then it used to. It maintains pressure though. I have a spare gate that I can throw on, but im going to try and drive it without the gate first just to rule it out. Hopefully this week if I get a chance.

Has anyone ever had problems with the VGT fluctuating? Is there a position sensor or anything in the VGT actuator or turbo that could go bad?

idkillinit · Feb 7, 2012

When your saying regulator is shut does that mean your screwjng it all the way down. Clockwise. On my regulator down or clockwise makes less boost and up or counter clock is higher boost. I'm sire yoi know just trying to help

idkillinit · Feb 7, 2012

I'm pretty sure the vgt is completely off on my id tunes because i never hear it cycle. I imagine that could effect bp but you wouldn't hear a note change in the cab under load I woildnt think and it should still boost up.

madman1234509 · Feb 7, 2012

Regulator is all the way counter clockwise until it became really loose then I popped it back down to lock it.

I unhooked the vgt and took it out quick just to see when we were testing things and it didnt sure anymore, but it drove like crap, wasnt responsive and smoked bad. Made very little power, once the torque converter locked it had such little power I couldnt get it to kick out of it.

idkillinit · Feb 7, 2012

Well too far counter clockwise could cause it to flutter and spike. Does your regulator have a standard setting that is recommended to start at mine was all the way down and like 8 or so clicks back for base line

greasltn · Feb 7, 2012

I've always used boost to run the gate, not exhaust. You might want to try plumbing the gate differently and see if that helps. If the gate is fluttering that will cause surging and VGT duty to fluctuate.

WoodBoy · Feb 7, 2012

Shouldnt boost be referenced to the top port?

Dzchey21 · Feb 7, 2012

I think the spring in the gate is too light

Dzchey21 · Feb 7, 2012

I also think you need full boost to the side and regulated to the top. And use boost for all of it not exhaust

jdgleason · Feb 7, 2012

Powerstroked162 said:
Wonder if its gate flutter.....

Are you sure you have the gate hooked up properly? It can be very easily done backwards sometimes and cause issues. Also, what spring pressure are you running in the gate? 50mm seems big to me. Doesn't the Elite kit use a 45? I know its a 40something

:whs: ours is a 46mm.

madman1234509 · Feb 7, 2012

Dzchey21 said:
I also think you need full boost to the side and regulated to the top. And use boost for all of it not exhaust

I do get what you mean. But my buddy is plumbed the same way with no issues at all and his gate works perfect. I'm going to take the gate right off to start. After that if i need to replumb it i will. But right now I have 20lbs of spring pressure and at times say 55lbs of exhaust pressure pushing down on the piston. Then I have no boost and 55 lbs of exhaust pressure pushing up... You'd think it would just stay closed with the regulator closed off