• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

mpgs and power back! (throttlebody cleaning)

SC06GT

SC06GT

New member
This has been a long time coming. For the past 2 years I've been trying to figure out the loss of MPGs and random hard starting (thought it was my fuel pump going slowly). After watching a video on youtube I suspected my throttlebody. Apparently carbon build up in normal on these 3.8L throttlebodies (I know quite a bit about these things but didn't know that!) Anyway, holy hell was mine bad!!!

I removed it and cleaned it up really well. Took before pics of both sides (note how black the inner side was!!) Anyway, on my drive to work today, back to 30-31mpg on the highway. Throttle response is WAY better, and the hard starting is gone.

I'm sure there's a thread on this but wanted to share my experience.

I also removed my 2004 silverado's throttle body and cleaned that (wasn't nearly as bad carbon wise). I will be checking my wife's 06 base grand prix tonight.

Last pic is of the supercharger body. I just bought new fluid to once again swap for the super charger... only way to clean this passage is to remove the upper supercharger I'm assuming? If I'm going that far and have to already remove the fuel rails, I might as well remove the upper intake, thermostat, heater helper hoses and replace them (with the aluminum ones), replace the belt and coolant hoses. And do a coolant swap.
 


360c5f829a6725418f037b9d6a18ff04.jpg
30ca8dae0340c1d9cc0419672abf8f3e.jpg
8b44dabcab8c65607bc38d851c1d4c61.jpg



Sent from my iPhone using Tapatalk
 
You don't have to clean the supercharger mouth, there would be no difference in how it performs even if it was clean. Ideally you want to remove the rotor pack, seal off the neddle bearings and go to town with some oven cleaner or really good brake cleaner and a soft brush to get all of it off. The EGR pipe in the opening there is what causes the soot to stick to the throttle body.

The reason your silverado doesn't get that problem is because there is no EGR valve on those engines, 2000/2001 was the last year. They just get a little oil/grime build up from the factory PCV system.
 
Thanks for the response DIRKA DIRKA (your avatar is killing me ahahah!)

So I could technically block off the far end, and the EGR passage and clean it out, heck I could use my shopvac to ensure i suck stuff out while I clean it...

We'll see, that worries me a bit, I don't want that crap getting sucked into the motor.
 
SC06GT said:
Thanks for the response DIRKA DIRKA (your avatar is killing me ahahah!)

So I could technically block off the far end, and the EGR passage and clean it out, heck I could use my shopvac to ensure i suck stuff out while I clean it...

We'll see, that worries me a bit, I don't want that crap getting sucked into the motor.
Click to expand...

Just take the blower off and clean it.

It's easy to do. You could in theory smooth out the inlet to make it easier on yourself instead of scrubbing everything out, too.
 


Looks like removing the blower requires removing the fuel rail, correct? Along with some vaccum lines, the rear plug wires ect... I need to change the supercharger oil, assuming that would be best done after this, lol.
 
would be it worth anything to clean the EGR valve? Those damn things are troublesome on aging cars.
 
SC06GT said:
Looks like removing the blower requires removing the fuel rail, correct? Along with some vaccum lines, the rear plug wires ect... I need to change the supercharger oil, assuming that would be best done after this, lol.
Click to expand...

Removing the blower is a few steps...yeah. Fuel rail is four, 10mm nuts. That just pops right out and you can slide it aside to the right hand side of the engine bay after you've un-plugged the sensors around it on the harness and the injector clips. You'll need a 15mm wrench to push the tensioner down to remove the belt. Take apart whatever intake system you've got, unplug the throttle body...then on the back side of the blower you've got a couple worthless brackets with the main o2 plug and the MAP sensor. After all that business is out of the way, you'll need to unbolt the blower itself...be sure to unplug the BBV and any other misc. brackets like the EGR and such so you don't bend/damage stretch anything. It actually is very straight forward and simple. I even think the '04+ blower gasket is metal and re-usable. If not; they're like $10 at the blower parts store listed under the Intake Plenum Gasket. It'll come with the O-Rings and everything you'll need to stab it back on, too.

SC06GT said:
would be it worth anything to clean the EGR valve? Those damn things are troublesome on aging cars.
Click to expand...

I deleted the EGR on every 3800 I've ever owned. No more carbon build-up, no issues if the valve fails, no chances of hunting a super hard to find vacuum leak via the gold accordion tubing, not to mention it really cleans up the engine bay. Nothing but positives. Some people say you lose gas mileage but I never noticed anything.
 
blueguy91 said:
I deleted the EGR on every 3800 I've ever owned. No more carbon build-up, no issues if the valve fails, no chances of hunting a super hard to find vacuum leak via the gold accordion tubing, not to mention it really cleans up the engine bay. Nothing but positives. Some people say you lose gas mileage but I never noticed anything.
Click to expand...

dumb question. how do you delete it? block off plates? does this make the car not pass smog? I'm in CA (FML)....
 
Remove it, block the 2 ports and tune out the codes.

It would still pass an emission test as the EGR is only active once the vehicle is running and certain speed/rpm/load are met. Basically it's only going to turn on at freeway speeds in 4th gear. If the vehicle is subject to a visual inspection and they know exactly what the vehicle should and shouldn't have, it would likely fail.

You could still block off the ports and leave the EGR in place to pass visual and disable the codes in the computer.
 


Simple enough; I had a penny RTV'd in each bracket.

Worked like a charm.

I think ZZPerformance still sells the nice looking aluminum pieces to block it off for like 10 bucks.
 
Read post #9 again, that will answer your one question, there really isn't much more to it. It stops carbon build up and the smaller chance of the part failing someday or being an issue.

Yes the CEL/SES will be on if you don't tune the code out.
 
SC06GT said:
So If I block the EGR valve off and remove it.... I'll have a CEL/Check engine light though, correct? What are the benefits of removing that unit? I mean you stated a few things.... I could at the very least try it.

Would I need both the exhaust and intake blocks?

https://zzperformance.com/3800/exhaust/egr-blockoff-plate.html

I don't have my car infront of me so I can't just look lol.
Click to expand...

Yes; you need both plates to block off both parts of the EGR.

As Cam said as well; I explained that all in post #9. You will need a tune to get rid of the CEL.
 


You must log in or register to reply here.
Back
Top