6speedsd said:
In the past mth I've swapped in a 06 turbo...my original has a good bit of shaft play. Started off with with VGT solenoid that came with it...boost surged 3-5 psi with any load on it. Swapped my original solenoid back on, and the surging was gone. But a day later, I'm back to all the lag. Like it'll shift to 2nd before I ever get to 5psi...that's how laggy it is. Normal average acceleration from a stop it won't build over 10-12psi. If you go on and mash on it, she'll build up to around 25psi. All this lag has thrown all my shifts off (timing and harshness). Part of me thinks my original solenoid is just acting stupid, but before I buy another one, I want to rule out everything else. I've monitored MAP, BARO, and EBP KOEO, and they are correct. MAP was like 14.6psi, with the other two within .5psi of it. I've cleaned the EBP and tube (neither were really that dirty). This new turbo I cleaned before I installed it, so it's not sticking. Can't find a boost/exhaust leak anywhere. Checked the MAP hose and fitting in the intake...neither were clogged. No codes at all.
What would happen if I unplugged my EBP sensor? Would the truck still run/drive/boost as normal? I read somewhere if you unplug it, it'll revert back to other inputs, and thought maybe I could either confirm or rule out an EBP problem that way. I haven't watched MAP/BARO/EBP while driving. If it is actually a bad solenoid that's fine, but I don't just start throwing parts at stuff. Is there a way to test the solenoid?
If it matters, truck is an 05, no cat, IDP tunes. And it's not tune related. Does this with Erics tunes and I have one from Matt that it does it with as well. Have any opinions or suggestions?
First thing I would do is to monitor what the VGT duty cycle is doing. I have had weird issues on trucks before that even with a new solenoid, wiring, etc... that the vgt duty cycle was not cycling. Your vgt duty cycle should cycle between .15 and .85. It should change as you drive and if you mash the peddle, etc... if it is just stuck on one number then you have narrowed it down. If it is cycling then you know that the solenoid is functioning (just not sure if it is functioning correctly).
I know the rule of thumb is that you only need to do a vgt relearn on early models... but I have had issues with later models that were fixed by doing a vgt relearn. I don't think it is because it needed a "relearn" but that maybe another sensor was out of whack and caused the vgt to "learn" wrong and got confused... this is not your "acutally" vgt relearn but it is what I always do.
turn head lights on
unplug both batteries
touch battery cables together (negative to positive)
let sit for 10 minutes
hook up batteries again
turn off headlights
start truck and let idle for 10 minutes
shut off
start truck and let idle for a few minutes again
test drive nice and easy to make sure everything is working
gradually increase your driving style up to WOT
There are so many things that can cause the issue that you describe. It could be because the vanes are stuck, solenoid is not working right because it is bad, or another sensor is reading incorrectly and causing the vanes to get out of whack.
These are a few of the more common problems. I can tell you that TONS of guys are running around with these issues right now and don't even know it. Go through them all and check them out.
Exhaust leaks are a big problem. Bigger turbos will usually make leaks worse. Check the ypipe bellows and the ypipe to turbo connection. Those are very common. An easy way to check it would be to have someone stick the truck in drive, hold the brake, and give it some gas. Push the pedal as hard as you can without causing the truck to move. Look for any smoke coming out from behind the turbo. If you see any smoke then you need to find and fix the leak.
Boost leaks are also a big problem. The most common areas are the boots on the charge pipe, plastic ends on the intercooler, and the plastic hot side charge pipe on the drivers side. If you have a plastic charge pipe on your drivers side then replace it ASAP. They will not hold up under high boost. You can check for boost leaks in the same way as an exhaust leak. MAKE SURE THE TRUCK IS COLD. Have someone stick the truck in drive, hold the brake, and give it some gas. Push the pedal as hard as you can without causing the truck to move. Use your hand to follow the lines from the turbo to the intercooler and then from the intercooler to the intake manifold. Feel for any leaks. Some people use soapy water too.
Pull and check all of the following sensors. Use your programmer to make sure they are reading right.
MAP sensor located on passenger side by the air box. Make sure the tube going from the sensor to the motor is not cracked. Make sure the tube and sensor are clean and not plugged.
MAF sensor is located between the air filter and turbo. make sure it is clean and plugged in.
EBP sensor is located off the exhaust manifold on the drivers side. There is a tube going from the exhaust manifold to the sensor. It is very common to clog and have issues. Clean out the tube and make sure the sensor is not clogged.
IAT sensor is connected to the top of the intake manifold near the fuel bowl/oil filter area. Pull it out and make sure it is clean. It is very common to get covered in crap. Clean it and make sure it is connected right.
Baro sensor is located under the dashboard. Make sure it is plugged in and reading right.
VGT solenoid. The vgt wire/pigtail are very common to have cracks, slices, and breaks in it, especially right where it plugs into the solenoid. Double check everything to make sure it is working right. An easy way to check and see if it is working right is while the truck is running. plug and unplug the sensor. You should be able to hear the exhaust sound changing when you do that.
Unison ring - if the slot in the unison ring is wallowed out then it can cause weird uses with the vgt vanes
Worn out unison ring actuator arm - after the unison ring wears out, the actuator arm that goes inside the unison ring can also wear out an become worn. This can mess with the vane position.
Internal turbo issues - I have seen where something was inside the that got caught in the gears, or vgt cavity and cause things to stick
Hope that helps a little. I know it was a lot of info but it should help to find the problem
