straight pipe added and a code

[RdyPlr1]

So I removed the mufflers and had a shop fab up some straight pipes. I installed some dei heat tape. Drove around for about two days and got a cel.. checked code:

P006800 manifold pressure/throttle position correlation.

I was driving and punched the gas and car went into limp mode ... CEl, traction light and another light came one. Is it possible I didn't tighten the pipes from manifold to the first cat? Any thoughts?

Edit: Adding the straight pipe was NOT the cause of the cel.

[01sapphirebob]

Do you have the ARROW controller for your car? If not, thats probably why.

[RdyPlr1]

Why would I need a tune for a muffler change?

[texasram]

You need a tune for almost anything on the gen v

[ViperGeorge]

Do you have headers? What did you do with the down stream O2 sensor? Is it possible you melted the O2 wire? This will cause limp mode and other assorted problems. Check your ASD fuses.

[RdyPlr1]

I removed the entire exhaust so the shop could measure up the pipes.. no headers.. the o2's went right back in their place when I put the exhaust back in. Nothing got moded but The pipes. What is the asd fuse? Obviously located on the fuse box, is it numbered ?

[nx91notch]

The sensor that measures that isn't remotely close to the exhaust. It's on the passenger side of the intake manifold. As to why this code showed up now I don't have an answer.

*edit: I just looked at the diag flow chart for this code and one of the possible causes is restriction in the exhaust. One of the steps was to check for exhaust leaks and/or a restriction. Obviously with the mufflers gone I doubt there is restriction. Check for leaks and go from there.

[RdyPlr1]

The sensor that measures that isn't remotely close to the exhaust. It's on the passenger side of the intake manifold. As to why this code showed up now I don't have an answer.

*edit: I just looked at the diag flow chart for this code and one of the possible causes is restriction in the exhaust. One of the steps was to check for exhaust leaks and/or a restriction. Obviously with the mufflers gone I doubt there is restriction. Check for leaks and go from there.

Thanks for checking... Yea, can't imagine there's restriction, but maybe I didn't tighten down the one or both of the clamps enough. Maybe why the code is "manifold pressure" , it's leaking out.

Here's some pics of what I did:

[SRT BILL]

I'm no engineer but that straight pipe looks small in diameter. Any cat back would have some type of chamber for the exhaust to fill before exiting out the end. Your restriction could be the straight pipe. Just say in.

[nx91notch]

I'm no engineer but that straight pipe looks small in diameter. Any cat back would have some type of chamber for the exhaust to fill before exiting out the end. Your restriction could be the straight pipe. Just say in.

After seeing his pics I think I agree with this.

[Dave1968]

I was thinking the same thing. What about using 3" or so, would that mimic the expansion of the muffler enough? Is all this going to help much - I thought the mufflers were just straight through, they can't be very restrictive - is there a big weight savings getting rid of them?

[RdyPlr1]

Ugh... iT sounded nice too. There goes four hours of wastes time. I'm may step up and buy a system.. I'm not going back into those sills to return to stock.

[RdyPlr1]

I was thinking the same thing. What about using 3" or so, would that mimic the expansion of the muffler enough? Is all this going to help much - I thought the mufflers were just straight through, they can't be very restrictive - is there a big weight savings getting rid of them?

The stock muffler are straight through yes, however they have holes inside the piping and I think that's what Bill is referring to when he said "the exhaust to fill". The weight savings is small, certainly not worth the time to remove sills... Which I have to do again apparently :stickmen_burningsti

[Sub Driver]

You need a tune for almost anything on the gen v

Incorrect. Not needed for a simple catback change.

[sadil]

I still think you might have a leak, over the code setting for a lack of restriction on the pipe. What kind of gaskets did you use between tbe cars and headers?

[CHAP]

Ugh... iT sounded nice too. There goes four hours of wastes time. I'm may step up and buy a system.. I'm not going back into those sills to return to stock.


Do you have cabine drone with the straight pipe ?

[ViperGeorge]

I removed the entire exhaust so the shop could measure up the pipes.. no headers.. the o2's went right back in their place when I put the exhaust back in. Nothing got moded but The pipes. What is the asd fuse? Obviously located on the fuse box, is it numbered ?

I don't remember the fuse numbers but they are located in the Power Distribution Center in the engine compartment. There are two. The O2 wires, if they touch or are too near the exhaust pipe, can melt. When this happens it is common for the ASD fuse or fuses to blow. If they blow the car will barely run and will have no power. You will also get various warning lights and a CEL. One to many codes will show up as well.

However, after looking at the pictures you posted I would agree with the others, the pipes look awfully small in diameter. What size pipe did you use? Even so, do be careful about how the O2 wires are run to minimize their exposure to exhaust heat.

[Steve M]

As long as that pipe is 2.5" in diameter, it isn't a restriction.

There are a few sanity checks performed by the PCM on the intake side of things. Airflow is measured by the MAF sensors (one in each intake tube), and there's also a MAP sensor in the manifold. It looks at the MAF readings, compares that to the reported throttle blade angles, and looks at the air pressure reported by the MAP sensor...I'm not sure what the threshold is, but if the airflow before the throttle bodies doesn't jive with the pressure being reported in the intake manifold, it'll set this code and throw the car into limp mode.

My advice is to go over everything on the intake side of things...make sure there are no loose connections (MAF sensors, throttle bodies, or MAP sensor), and make sure there are no vacuum leak sources (loose clamps, loose MAP sensor, loose throttle bodies, or loose vacuum lines from the PCV or brake booster). If the problem persists, then try swapping back to the stock exhaust (or something like it)...I don't think that'd be the problem here, but these PCMs are borderline retarded when it comes to not liking mods.

[RdyPlr1]

I still think you might have a leak, over the code setting for a lack of restriction on the pipe. What kind of gaskets did you use between tbe cars and headers?
No gaskets used.




Do you have cabine drone with the straight pipe ?
Yes, a bit more then stock.

[RdyPlr1]

I don't remember the fuse numbers but they are located in the Power Distribution Center in the engine compartment. There are two. The O2 wires, if they touch or are too near the exhaust pipe, can melt. When this happens it is common for the ASD fuse or fuses to blow. If they blow the car will barely run and will have no power. You will also get various warning lights and a CEL. One to many codes will show up as well.

However, after looking at the pictures you posted I would agree with the others, the pipes look awfully small in diameter. What size pipe did you use? Even so, do be careful about how the O2 wires are run to minimize their exposure to exhaust heat.

After the car went into limp mode, I turned it off. When I started back up all the lights turned off but the CEL. So if it were a fuse I think the car would have stayed in limp mode. I'll check them to be sure though.. You're the 4th person that said the pipes are too small. I'm in denial only because I've got hours into the installation, we'll see in a few days. I will move to a 3'' diameter pipe before i drop $2100 on a system.

[AZTVR]

As long as that pipe is 2.5" in diameter, it isn't a restriction.





However, after looking at the pictures you posted I would agree with the others, the pipes look awfully small in diameter. What size pipe did you use?
You're the 4th person that said the pipes are too small. I'm in denial only because I've got hours into the installation, we'll see in a few days. I will move to a 3'' diameter pipe before i drop $2100 on a system.

The way that I read the above posts, people were looking at your photos and saying that the photos made the pipe appear small. They didn't say that it actually was too small.

Like Steve M. said, if you used the same size pipe as the muffler input/output had, I don't see the pipe as causing more restriction than the muffler did. However, I am no automotive or mechanical engineer.

[ViperGeorge]

The way that I read the above posts, people were looking at your photos and saying that the photos made the pipe appear small. They didn't say that it actually was too small.

Like Steve M. said, if you used the same size pipe as the muffler input/output had, I don't see the pipe as causing more restriction than the muffler did. However, I am no automotive or mechanical engineer.

Agree with this. The pictures make the pipes look small, but are they? What size did you use? If you used at least 2 1/2 inch I don't see the pipes causing the problem. Also if on a restart the car was not in limp mode but you still had a code it would not be a fuse.

[RdyPlr1]

Right, it's not a fuse. The pipes are 2 1/2 inch

[ViperGeorge]

Right, it's not a fuse. The pipes are 2 1/2 inch

In that case it would not seem that the pipes would be the culprit. Maybe just a coincidence. Check for loose connections are anything that you may have disturbed when you removed the sills and installed the pipes.

[RdyPlr1]

Will do ^ , I'll update when I find the fix.

[Batmobile]

So I removed the mufflers and had a shop fab up some straight pipes. I installed some dei heat tape. Drove around for about two days and got a cel.. checked code:

P006800 manifold pressure/throttle position correlation.

I was driving and punched the gas and car went into limp mode ... CEl, traction light and another light came one. Is it possible I didn't tighten the pipes from manifold to the first cat? Any thoughts?

Did you hit the rev limiter my 2016 would do this all the time till I installed the arrow pcm and my exhaust same code

[RdyPlr1]

Definitely not. Was going about 40 Mph and hit it.. didn't even get to 3500

[Corjet]

that exact thing happened to me a week ago but in my case its an aftermarket air box.Took it to the dealer and they did the relearn and it was gone ! + they blamed the air box

[The_Ruski_Driver]

Interested in hearing the cause. I was considering straight pipes as well due to cost.

[RdyPlr1]

Problem solved... So I didn't think of adding this to the post, but after reading Steve M's post # 18 and Viper George post #24, I now have to add (it's embarrassing) that the day before when I washed my car.. I put a large Uhaul blanket in the engine bay to cover up the intake and vents so water doesn't get into the compartment... YOu know the story from there.. I forgot about it and drove away for two miles :eek:. So adding the pipes wasn't the reason for the cel. We cleared the code and now its good to go. I will get my go pro out tomorrow and add a video of how the straight pipes sound at idle and at wot if anyone cares.

[sadil]

Looking forward to str8 pipe videos!

[texasram]

Problem solved... So I didn't think of adding this to the post, but after reading Steve M's post # 18 and Viper George post #24, I now have to add (it's embarrassing) that the day before when I washed my car.. I put a large Uhaul blanket in the engine bay to cover up the intake and vents so water doesn't get into the compartment... YOu know the story from there.. I forgot about it and drove away for two miles :eek:. So adding the pipes wasn't the reason for the cel. We cleared the code and now its good to go. I will get my go pro out tomorrow and add a video of how the straight pipes sound at idle and at wot if anyone cares.
Are you married? if so dont tell her, or be prepared for the utmost mockery, in what world did you think you needed to do that though, you can drive through torrential downpour and it not affect anything

[RdyPlr1]

I like keeping the engine bay looking clean, it has nothing to do with me thinking it would affect anything.

[texasram]

I like keeping the engine bay looking clean, it has nothing to do with me thinking it would affect anything.

Simple wipe down > M.I.L's everywhere

[RdyPlr1]

Milfs I like, Mils I can't live with, I'll try that next wash.

[The_Ruski_Driver]

Problem solved... So I didn't think of adding this to the post, but after reading Steve M's post # 18 and Viper George post #24, I now have to add (it's embarrassing) that the day before when I washed my car.. I put a large Uhaul blanket in the engine bay to cover up the intake and vents so water doesn't get into the compartment... YOu know the story from there.. I forgot about it and drove away for two miles :eek:. So adding the pipes wasn't the reason for the cel. We cleared the code and now its good to go. I will get my go pro out tomorrow and add a video of how the straight pipes sound at idle and at wot if anyone cares.

Easiest fix ever 2016!!! LOL

Also- interested in the videos - more importantly - if you can quantify on a scale of 1/10 for the following criteria:
Stock vs Straight Pipe
Interior drone windows up
Interior drone windows down
Interior "loudness"
Exterior "loudness"

Much appreciated!

[BJG32]

Easiest fix ever 2016!!! LOL

Also- interested in the videos - more importantly - if you can quantify on a scale of 1/10 for the following criteria:
Stock vs Straight Pipe
Interior drone windows up
Interior drone windows down
Interior "loudness"
Exterior "loudness"

Much appreciated!

me three!

[RdyPlr1]

So Here is what I came from: c6Z cam, head work, HF cats Headers , intake , BB mufflers.. https://youtu.be/MAW-trL_494

1= almost nothing 10= nasty drone, sell the car

Corvette:
Stock vs Straight Pipe
Interior drone windows up 2.5
Interior drone windows down 3
Interior "loudness" 9
Exterior "loudness" 11

Viper https://youtu.be/g9OQGLT5eZc

Stock 4 vs Straight Pipe 5.8
Interior drone windows up 5.8
Interior drone windows down 5.4
Interior "loudness" 6
Exterior "loudness" 6.5

Hybrid Fusion J/K

at some point my cats are coming off for some High flows and I will update with HF cats, Straight pipe and then HF with stock muffler. I think when the cats come off, it'll really sound like it should.

[sadil]

What kinda revs were you hitting? I can upload a video of a stock exhaust until 4k RPM, similar angle, and it definitely seems like your setup has unlocked a little bit of race car rasp!

[The_Ruski_Driver]

So Here is what I came from: c6Z cam, head work, HF cats Headers , intake , BB mufflers.. https://youtu.be/MAW-trL_494

1= almost nothing 10= nasty drone, sell the car

Corvette:
Stock vs Straight Pipe
Interior drone windows up 2.5
Interior drone windows down 3
Interior "loudness" 9
Exterior "loudness" 11

Viper https://youtu.be/g9OQGLT5eZc

Stock 4 vs Straight Pipe 5.8
Interior drone windows up 5.8
Interior drone windows down 5.4
Interior "loudness" 6
Exterior "loudness" 6.5

Hybrid Fusion J/K

at some point my cats are coming off for some High flows and I will update with HF cats, Straight pipe and then HF with stock muffler. I think when the cats come off, it'll really sound like it should.

I had almost the same exact setup on my previous car- funny- I came from a Heads/Cam Z06 as well, sounded just like that and I had the same Katech spoiler too!

Thanks for the notes, it appears to me that the straight pipe barely does anything for loudness. My Z was def a 9 on the loudness and I loved it, seems like you need to do headers on these to wake them up and piss away your warranty, which I'm not financially able to do. Oh well, staying stock!

[BJG32]

I had almost the same exact setup on my previous car- funny- I came from a Heads/Cam Z06 as well, sounded just like that and I had the same Katech spoiler too!

Thanks for the notes, it appears to me that the straight pipe barely does anything for loudness. My Z was def a 9 on the loudness and I loved it, seems like you need to do headers on these to wake them up and piss away your warranty, which I'm not financially able to do. Oh well, staying stock!

Highflows definitely help, but you will get a CEL .

[Camfab]

After listening to your C6 Z and then listening to an essentially stock Viper is painful. Glad your issue was something simple.

[RdyPlr1]

What kinda revs were you hitting? I can upload a video of a stock exhaust until 4k RPM, similar angle, and it definitely seems like your setup has unlocked a little bit of race car rasp!

About 4500.. I took video with my $350 black edition gopro and it sounded worse then my 4 year old Android phone.


I had almost the same exact setup on my previous car- funny- I came from a Heads/Cam Z06 as well, sounded just like that and I had the same Katech spoiler too!

Thanks for the notes, it appears to me that the straight pipe barely does anything for loudness. My Z was def a 9 on the loudness and I loved it, seems like you need to do headers on these to wake them up and piss away your warranty, which I'm not financially able to do. Oh well, staying stock!

I'm convinced that there is nothing better sounding then a v8 427 cam/heads/exhaust . To be honest, the video really doesn't sound as good as listening to it live. The straight pipe does sound better. But nothing like our vetts




After listening to your C6 Z and then listening to an essentially stock Viper is painful. Glad your issue was something simple.

Completely Agreed. That's why my cats will be coming off at some point. I'll add the o2 90 degree spacers and when the light comes on, I'll clear it as needed.

[BJG32]

FYI...I deleted my mufflers this weekend. I have Hiflows with Arrow PCM. Due to weather I only took it around the neighborhood, but it sounded fantastic.

Simple DIY....no muffler shop needed. Cost less than $50 total, it's lighter and sounds better than the pricey muffler systems. I'll drive it more and get sound clips soon.

[RdyPlr1]

^ Nice man.. I just bought some HF cats (no arrow) .. I'm contemplating if I should keep the straight pipes on or go to the stock muffler. Can you get some sound clips?