TRD Supercharger only making 1psi of boost?! Help needed!

Hello everyone,

I tired posting this in the TRD/ Magnuson 4.0 Supercharger Tips, Tricks, and Mods thread, but since I haven’t had an account for 60 days, I am not allowed.. Seems like a strange rule, but oh well…

2007 with a TRD Supercharger installed at the dealer when new. Currently has ~83k miles on engine/blower.


Everything was running fine until I recently switched some things up, and now I cannot produce more than 1psi of boost… Before going on vacation last week, I decided I wanted to install some mods that should in theory help my MPG on the highway:

• Installed a URD Y pipe (eliminating the rear two cats)
• Installed two brand new rear Denso o2 sensors.
• Cleaned the MAF (with the proper MAF cleaner)
• Cleaned the Throttle Body (it was dirty!)
• Disconnected the battery to “reset” the ECU

Now my brand new SpeedHut boost gauge initially spikes to ~2psi before immediately coming back down to 1psi and will not go higher, regardless of gear, RPM, or load...


I hooked my vacuum gauge up to the bypass valve and applied 15” of vacuum. The actuator rod moved freely and held the vacuum without leaking down… When releasing the vacuum I heard a slight “tink” sound, which sounds like it is adjusted properly as well?


Some things to note: When I installed the URD Y pipe, I installed new gaskets from RockAuto that were a little on the loose side, which has caused a slight exhaust leak, and is now throwing a pending code: p0420, p0430. I am going to order the proper URD gaskets for the Y pipe, hoping that will clean up my the high LTFT % I am now experiencing, but I don’t think that should cause my boost problems……?

Also, the belt is tight and relatively new, so I don’t think it is slipping..

I installed new plugs right when I got the truck and was boosting just fine after installing them.

Lastly, on my last trip, my hand calculated MPG was 20.5, this trip was 18.5.... That could be from the exhaust leak and high fuel trims though...


Any help would be appreciated!


Thanks,
Anthony

 

Wow what a bummer. Does it sound any different? Loss of power? Is it possible there is a boost leak somewhere? It doesn't sound like you did anything that would create a leak on the intake side.

Maybe that gauge is bad?

Maybe the ECU is cutting timing so badly from the exhaust leak that it can't build boost?

 

Clogged cat/exhaust is another possibility of no boost

 

See my responses to your questions in red above.

 

I removed the rear two cats, installed the URD Y pipe, and also installed a 3" Magnaflow muffler and resonator, replacing the 2.25" Gibson exhaust that was on the truck. I would think the exhaust is flowing better then it ever has. Unless my two primary cats all of a sudden clogged out of no where, its hard to believe this would be the cause.. I would think as the cats started to clog, it would slowly reduce the amount of boost, not just happen all at once.. I suppose anything is possible though..

 

Yeah you’re right and I’d think the same

 

Where are you located, @MadChicken ?

Do you have a laptop and HP Tuners dongle you can take some logs?

 

Do you have the old ones to put back in?

Where did you source these and are you sure you got the correct and real ones (not counterfeits that people have claimed exist on Amazon and other places)

EDIT: the rears…. Shouldn’t affect the fuel trims.

 

Is the gauge just not showing "boost" and the truck feels fine, or does the truck feel neutered? I ask because I wouldn't rule out a bad gauge.

 

Located in SoCal. Whittier, 90602 to be more exact.

No HP Tuner, YET. I was trying to get some more aftermarket parts installed first before getting her tuned..

O2 sensors came from RockAuto. Part #:

$49 DENSO 2344260 Denso 234-4260 Oxygen Sensor

DENSO 2344260

My thinking is that since I have a known exhaust leak right at the flange where the URD Y pipe connects to the headers, I am potentially introducing unmetered air right before the rear O2 sensor. Could that not throw off my fuel trims, if the ECU thinks I am running lean?

 

At idle I sit at about 20" of vacuum. Upon acceleration, I will hit ~2psi before it backs down to 1psi and then it will not go any higher. The truck definitely feels neutered compared to before I was experiencing these problems. I was also getting up to ~6ish PSI on my gauge...

 

Also worth noting: After using my handheld vacuum gauge to test the bypass valve, I also went ahead and did the "FPR mod" by connecting the hose to the back of the supercharger where my boost gauge is connected to.

I then went for a test drive with the hopes that maybe the bypass valve had somehow gotten stuck and things would be back to normal. As I approached 4500rpm, I noticed what seemed to sound like a few quick misfires/pops.. It didn't sound good, so I immediately let off the gas.. Does the Ultragauge have any way of logging? I would love to see what my timing is doing.

 

Ultra gauge as far as I know doesn’t have the bandwidth/polling interval to get you great data.

It also does not have logging.

 

Yeah, OP has this hidden in a quote inline response:
It definitely feels low on power.. Getting up to freeway speeds felt seriously labored and took way too long..

 

Check vacuum lines and post how they're routed

 

How dirty is your air intake filter. Had mine almost clogged from going to Moab and was only getting 1-2 psi. Once I cleaned it, got back to normal boost readings.

 

I bought a Gen 1 TRD intake off of a fellow board member that included a brand new URD dry filter. The filter has maybe 1000 miles on it now..

 

That got me thinking though.

Since I removed my throttle body to clean it, is it possible I somehow messed something up and now the throttle blade is only partially opening, acting like a massive restriction on the intake side?

 

Here is what I would check.

Take out the maf and verify everything is installed correctly and make sure o ring isn't damaged.
Take out the throttle body and verify the same thing with the o ring. Make sure it's seated in the groove and isn't causing a leak.
If you still have the old o2. Swap those back and see if anything changes.
If none of those work then swap back the old Y pipe to test.

If none of these resolve the issue then likely the maf or throttle body could be malfunctioning after the cleaning.

 

Got a pic of the vaccine routing for FPR and boost? Also if you did the FPR mod you need a time you should run that without it. @JustDSM would that alone cause this much? for now revert for and gauge and see.