Couple of mods.....now no power

[MudnRox]

I have a 2013 Tahoe with the 5.3L. Installed an Airaid Jr(using factory filter)and a Magnaflow cat-back. No other changes. Vehicle now feels like it just doesn't want to move. Its like it can't get out of it's own way. I have to mash the gas pedal to about 3/4 throttle to get the vehicle moving when leaving a stop light or sign. Problem started a few weeks after exhaust was installed. City mpg is down but hwy has remained close to stock mpg.

Dealer told me to remove cat back and re-install factory exhaust. They claim the drop in back pressure is the problem. Dealer could find no other issues with vehicle. No codes were present at time of dealer visit. No check engine light either.

Is this a tuning issue or should I look at something else??? I dont mind spending the money for a tune but I just want to make sure that it will solve the problem.

 

[NathanJax]

you need a tune. You're getting more air in and more air out, but the fuel isn't keeping up because of the stock tune...

 

[MudnRox]

Thanks. That's what I was thinking. Just needed a second opinion before I pulled the trigger

 

[Zed 71]

What is the size of the new exhaust piping?
What is the configuration - dual, single, x-pipe, etc.
Which Magnaflow muffler?

 

[OHSIXX]

Hit up Blackbear-they will set ya straight...you need a tune to adjust for the CAI and exhaust.

 

[MudnRox]

What is the size of the new exhaust piping?
What is the configuration - dual, single, x-pipe, etc.
Which Magnaflow muffler?

I just entered year, make, model, and engine on Magnaflow's website and got part #16564. That's the kit I got.

Here's the specs on the kit as listed on Magnaflow's website:

5 x 11 x 22in. Muffler; 3.0in. Tubing; 3.5in. x 5.5in. Oval Polished Stainless Tip; SINGLE PASSENGER SIDE REAR EXIT


As for the Airaid Jr. I'm using the Airaid tube with the stock AC Delco filter.

It sounds really nice, which I like. But right now the drive-ability is non-exisistant. Not sure why but it will go into 5th or even 6th gear at 30 to 35mph. This in turn cause the engine to "lug down" unless I shift manually. Currently using 1-4 in town driving and 5th on hwy. 6th gear gets me nothing as far as power or any kind of acceleration.


I was thinking about going back to stock exhaust since the problems started after the Magnaflow was installed. It ran just fine with the Airaid tube and factory filter. I'd love to have a tune but not sure about kissing the warranty goodbye.

My first Tahoe was an 05 5.3L with a CAI and Magnaflow. I had no issues with it at all. Traded it for an 09 5.3. It also had a CAI and Magnaflow exhaust, and ran fine without problems. So I pretty much expected the same from the 13. I guess two out of three ain't bad. LOL

 

[sumo]

I just entered year, make, model, and engine on Magnaflow's website and got part #16564. That's the kit I got.

Here's the specs on the kit as listed on Magnaflow's website:

5 x 11 x 22in. Muffler; 3.0in. Tubing; 3.5in. x 5.5in. Oval Polished Stainless Tip; SINGLE PASSENGER SIDE REAR EXIT


As for the Airaid Jr. I'm using the Airaid tube with the stock AC Delco filter.

It sounds really nice, which I like. But right now the drive-ability is non-exisistant. Not sure why but it will go into 5th or even 6th gear at 30 to 35mph. This in turn cause the engine to "lug down" unless I shift manually. Currently using 1-4 in town driving and 5th on hwy. 6th gear gets me nothing as far as power or any kind of acceleration.


I was thinking about going back to stock exhaust since the problems started after the Magnaflow was installed. It ran just fine with the Airaid tube and factory filter. I'd love to have a tune but not sure about kissing the warranty goodbye.

My first Tahoe was an 05 5.3L with a CAI and Magnaflow. I had no issues with it at all. Traded it for an 09 5.3. It also had a CAI and Magnaflow exhaust, and ran fine without problems. So I pretty much expected the same from the 13. I guess two out of three ain't bad. LOL

That tubing is way to large for the 5.3 Stock is 2 7/8in. No more than 3 inches for 5.3
I believe 3.5 is sutiable for the 6.2 motors
you need Kit #16672
V8 5.3L; Excl. Hybrid
5 x 11 x 22in. Muffler; 3.0in. Tubing; 5.5in. Oval Polished Stainless Tip; SINGLE PASSENGER SIDE REAR EXIT

 

[MudnRox]

That tubing is way to large for the 5.3 Stock is 2 7/8in. No more than 3 inches for 5.3
I believe 3.5 is suitable for the 6.2 motors
you need Kit #16672
V8 5.3L; Excl. Hybrid
5 x 11 x 22in. Muffler; 3.0in. Tubing; 5.5in. Oval Polished Stainless Tip; SINGLE PASSENGER SIDE REAR EXIT

16564 Specs:

Exhaust Type: Single
Type: Cat-Back
Diameter (IN): 3 Inch
Exit Position: Rear Passenger Side Exit
Includes Muffler: Yes
Material: Stainless Steel
Outlet Type: Single
Exhaust Tip Type: Oval
Includes Exhaust Tip: Yes
Exhaust Tip Size (IN): 3-1/2 Inch X 5-1/2 Inch
Exhaust Tip Material: Stainless Steel
Muffler Quantity: 1
Muffler Configuration: Single Inlet/ Single Outlet
Sound Level: Smooth Deep Tone

16672 Specs:

Exhaust Type: Single
Type: Cat-Back
Diameter (IN): 3 Inch
Exit Position: Rear Passenger Side Exit
Includes Muffler: Yes
Material: Stainless Steel
Outlet Type: Single
Exhaust Tip Type: Oval
Includes Exhaust Tip: Yes
Exhaust Tip Size (IN): 5-1/2 Inch
Exhaust Tip Material: Stainless Steel
Muffler Quantity: 1
Muffler Configuration: Single Inlet/ Single Outlet
Sound Level: Smooth Deep Tone

 

[Regency]

Yeah I wouldn't be surprised if you're losing back pressure due to the exhaust size. Dealer is probably right. Nothing a tune can do to help with back pressure.

 

[TheFuzz]

Even 3" tubing isn't needed until you get into the realm of forced induction and are making a lot of power. The stock exhaust flows more than adequately for these motors. I'd take the exhaust system off, sell it, get a tune for your intake, and add a magnaflow 12589 muffler if you want to retain the louder exhaust note.

 

[73shark]

The stock exhaust is 2 7/8". Not sure another 1/8" would make the vehicle not move w/o 3/4 throttle.

Too little back pressure can affect the torque curve but still it sounds like there's more happening here than that.

I had the factory catback on my 2007 and even tho it had a straight thru muffler, there was no change in low speed throttle response.

 

[Zed 71]

IMO 3-inch diameter piping is too large for the 5.3L. Yes it does not sound like much of any increase, but the frictional losses are exponential regarding changes in diameter. The flow is now turbulent (versus laminar) and now the exhaust velocity decreases which reduces exhaust scavenging. A tune would definitely help to reduce this and address the annoying 6-speed.

In my opinion better to stick with stock piping diameter and just change the muffler then tune. Hopefully one of the tuners will chime in. If you get the EFI tuner you can change back to stock when you visit the dealer.

 

[MudnRox]

IMO 3-inch diameter piping is too large for the 5.3L. Yes it does not sound like much of any increase, but the frictional losses are exponential regarding changes in diameter. The flow is now turbulent (versus laminar) and now the exhaust velocity decreases which reduces exhaust scavenging. A tune would definitely help to reduce this and address the annoying 6-speed.

In my opinion better to stick with stock piping diameter and just change the muffler then tune. Hopefully one of the tuners will chime in. If you get the EFI tuner you can change back to stock when you visit the dealer.

Ok just a question here as I'm trying to learn. If the tube diameter is too large for the engine, then why would Magnaflow make and market the product?? As I stated before I had the same kit, as well as a CAI, on a 2009 Tahoe 5.3L and had no problems.

I have talked with Magnaflow about the problem. They have never had any complaints about this kind of situations with this vehicle. I even asked if there was a kit more suited for the engine and vehicle. They assured me I had the right kit for the application. But they were very helpful in trying to determine the problem. Of coarse they say its not related to exhaust. I also double checked to make sure their muffler was non-directional(thinking maybe it was installed backwards).

I have a dyno-tune scheduled for next Tuesday at a very reputable local shop. I stopped by there today and talked with him for quite a while. He's certain he can resolve the issue. The vehicle will be checked bumper to bumper and by diagnostic computers before any tuning is started. I will keep you all posted.

Thanks for the advise, opinions and help as I'm trying to sort thru this mess. I learn something new every time I get on the site.

 

[TheFuzz]

Good luck man. I'm interested to see if this really is just a tuning issue or if there is something more going on. Every vehicle is different. Some are built on the looser end of tolerance, some tighter. Maybe your motor is too close to either end of the spectrum and tolerance stacking between the motor and the exhaust is causing some kind of issue. Who knows.

 

[JennaBear]

Have you checked your intake tube? Maybe it is loose, common issue. Doesn't sound like something a tune will fix.

Sent from a jelly bean.

 

[MudnRox]

Have you checked your intake tube? Maybe it is loose, common issue. Doesn't sound like something a tune will fix.

Sent from a jelly bean.

Yes I have checked it.

 

[cjweb11]

I'm no expert, but is it really possible for a properly installed intake tube and 3" catback to have this effect?
I ask bc I have the Airaid Jr tube/dry filter and a 3" catback without any tuning (yet) and i feel response is slightly better if anything, while mpg has dropped just a little.
If Jenna has her doubts about a tune being the answer then I certainly have my doubts too

 

[doubletapdrew]

Breather hose still attached to valve cover and Airaid Jr?

 

[tights24]

Yeah, I agree with a lot of the other comments. I don't see exhaust and CAI causing a problem like you're describing. These are very common items that millions of folks have installed on their vehicles with no serious adverse side affects. Of course this is just my opinion once again, but I think minimal changes like what you have done do not need a tune to make right. Especially as drastic as you mention.

I'm not up on the exhaust system on these trucks but is it an easy bolt on system from the cats back? If so, it may be worth putting your old exhaust back on to see if it makes a difference. Same with the CAI. See if you can narrow it down.

Some questions I have:

1. Is your MAF clean and/or did you bump it by chance or leave it unplugged?
2. Did you check the inside of the catback tubing AND muffler for packing material? on a previous vehicle Magnaflow saw fit to have the muffler stuffed with packing material........
Good luck.

 

[MudnRox]

Breather hose still attached to valve cover and Airaid Jr?

Yes it is.

---------- Post added at 07:02 PM ---------- Previous post was at 06:48 PM ----------

Yeah, I agree with a lot of the other comments. I don't see exhaust and CAI causing a problem like you're describing. These are very common items that millions of folks have installed on their vehicles with no serious adverse side affects. Of course this is just my opinion once again, but I think minimal changes like what you have done do not need a tune to make right. Especially as drastic as you mention.

I'm not up on the exhaust system on these trucks but is it an easy bolt on system from the cats back? If so, it may be worth putting your old exhaust back on to see if it makes a difference. Same with the CAI. See if you can narrow it down.

Some questions I have:

1. Is your MAF clean and/or did you bump it by chance or leave it unplugged?
2. Did you check the inside of the catback tubing AND muffler for packing material? on a previous vehicle Magnaflow saw fit to have the muffler stuffed with packing material........
Good luck.

1) I'm guessing the MAF is clean, but I did not clean it as the vehicle had about 4K on it when it was installed. I got the Airaid JR with the dry filter, but I'm still running the factory filter. And yes the MAF is plugged in. Not sure if it was bumped at any time but it sure wasn't knocked around.

2) I personally did not install the exhaust. It was done at a buddys shop in exchange for some adult beverages. I would like to think that he checked it. But I will double check myself first chance I get. That is honestly something I had not thought about. Thanks for bringing that up. I did consider the possibility of the muffler being directional and I did check for that.