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Discussion Starter · #1 ·
I signed up to this site today because I have gone to it many times in the past for information and I've always found a lot of great stuff here.

I know that this question may be in the wrong forum, but I thought I'd start here because working on my exhaust is how my problem started.

Today I installed a MBRP cat back exhaust on my 2014 Silverado with a 6.2. The installation was pretty painless, I started the truck up after the installation and the idle seemed abnormally high for about 30 seconds and then the idle returned to what seemed like a normal idle speed. I let it idle for 3 or 4 minutes while checking for leaks, and then backed out of the garage. While parking the truck it died and it will not start. It cranks over fine but does not fire.

I guess the one good thing is that the kids are home from college and they were able to get my truck pushed back in the garage.

I called MBRP thinking that maybe there is a step I wasn't aware of that was preventing my truck from running properly, or at all. They have not had anyone call with this problem before. They suggest I put the stock exhaust back on and give it a try... I'm not going to do that.

Has anyone heard of anything like this before or do you have any suqqestions?
 

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What would be the though that an exhaust system behind the cats would prevent the engine from running? Would seem none of the engine control systems would have been effected. Is there any possibility that there is a blockage in the new system? Is it possible the cat got damaged and is now blocked to the point the engine will not run? Were there any CELs when the engine first ran?
 

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Did you have to disconnect any oxygen sensors during installation? Perhaps one came off during startup? Another thing would be to check and see if there is any blockage in the exhaust. Disconnect the intermediate pipe and try starting.
 

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Well that's strange. Disconnect it from your third cat and let it hang and then start your truck and see if it runs normal. It would have to be a pretty big blockage to cause a running issue

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Discussion Starter · #5 ·
Thank you for the suggestions I appreciate it.

No I have never had a service engine light and I didn't notice one when I first started the truck. The truck only has 25,000 miles.

So I unhooked the intermediate pipe and the truck will not start. It still cranks over fine but doesn't fire.

I did not unhook any sensors and they are no where close to where the work was performed when the exhaust was installed.

Maybe it's all a coincidence and my truck has developed a new issue, but I find that hard to believe.

When I talked to the service rep at MBRP he told me that the new free flowing exhaust probably unmasked another problem I had. I don't believe that either.

I'm not sure where to go from here, maybe I need to buy a code reader to see if there is a code or else begin the process to see what is missing such as fuel or spark???? I've checked fuses along with looked at all connections and anything I could have interfered with but I haven't noticed a thing.
 

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Discussion Starter · #9 ·
Well I disconnected the battery for half an hour and it still turns over but won't start.

If I hold the pedal to the floor it sometimes acts like it is on the verge of starting but it doesn't.

I'm probably going to need a new starter when this is all over.... :(
 

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you say it died while running and it was starting to idle okay at that time. try something stupid like removing the gas cap.
Do you get any codes ? Can you here the fuel pump running when you turn on the key ?

Check fuses to fuel pump, when you floor it and it sounds like it's trying to start it almost would have to be fuel related and not ignition wouldn't it. Check your wiring at the pump and anywhere that you were working under the truck, maybe a connector got pulled loose.
I don't know how to do this but I think you can check for fuel at the fuel rail through some sort of valve. Someone else will have to chime in.
 

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The next step I would think is to ignore the exhaust system as the culprit, and start back at square one with an engine that turns over but doesn't catch. Check the fuel system, maybe test for spark, and keep an open mind that something else is the cause like a pinched line, loose connection, something bumped, knocked or affected even unintentionally during your project.
 

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Discussion Starter · #14 ·
It was a bolt on. Zero welding.

I've looked everything over and can't find any problems. I'm not saying that there isn't any because obviously there is a problem somewhere, I just haven't found it yet.

The installation was very straightforward and I'm extremely surprised to be having a problem.

Because of the high idle when I first started the truck after the installation leads me to believe there is some sort of an ECM problem. Although if it was an emissions thing shouldn't it just have gone into some sort of a limp mode?

I've checked and I do have spark at least on #1. My fuel pump definitely turns on when I turn the key on.

My wife is very impressed....
 

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Fuel pressure test is probably next in line. You can get a fuel pressure test kit at most of your local auto parts stores. I know Auto Zone has them on the loaner tool list where you can pay for them and get a full refund when returned. I am pretty sure Advanced Auto and Nappa will also have them on a similar system. Definitely sounds like a fuel issue. It's funny how sometimes these coincidences happen. Not funny to you right now though I am sure.
 

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Being that's it's a 2014 and still under warranty I would contact your dealer before you start pulling things apart. It almost sounds like the immobilized.

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The odd part to me is that it was running and died. The high idle was probably expected to happen until it learned the exhaust. The dying while running is confusing.
 

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You weren't by chance running it with the intake tube off ? or the air filter box disconnected ? something get sucked into the throttle body ?
 

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I would go with the recommendation as suggested to take it back to the dealer by this point. An exhaust system change should not affect warranty since exhausts are a replaceable part at least once in a vehicles life depending on quality.
 
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