Hi Guys,

I have been getting a CEL being caused by the dreaded P1416 error code. I have ordered new check valves and will eventually be changing both. I realize that I will have to remove the whole intake to get to the damned valve on the passenger side.

However, I keep reading that there are people who successfully changed the valve without removing the intake. I would love to hear from them. How did you do it? If there is an easier way, please post it.

I know that some have simply relocated the passenger side check valve. I would prefer to keep it stock.

I wonder if anyone has used the same method as the OPS replacement by cutting an access hole in the area below the wipers? Can this method also allow access to the check valve.

 

Why are you afraid to pull the intake-it pretty simple. Just make sure you have an INCH-POUND torque wrench since the torques are very small for the intake.

 

Yah, I guess I will go that route. It's just that I was reading that some GM technicians can do it without pulling the intake. I was just curious as to how they do it.

PS: I'm a little worried with disonnecting the fuel line. I see that I have to find some special tool. Can it be done without?

Thanks for your help............

 

The little tool for the fuel line costs about $5 at any good auto parts place.
Make sure you get one for a 3/8" line.
Takes but a few seconds to remove.

Ron

 

Even if you were able to access it's location without removing the intake, unscrewing the check valve from the AIR tube piping would still be a challenge.

I had to exert a fair amount of torque on a pair of large open end wrenches to break it loose. In my case, this would not have been possible without removing the intake.

 

Before tackling all that work, have you tried disconnecting the air feed hose, just under the alternator, and blowing a load of throttle body cleaner up the hose, toward the check valve?

 

I tried that first. I actually did it twice. I sprayed large amounts of carb cleaner through the pipe along with air at 40 - 50 psi. It did absolutely no good. Actually, I couldn't even get the air to pass through the check valve. It appears to be almost completely stuck in the closed position. No problem with the driver side valve.

I just don't understand how it could get so bad after 35k miles. Oh well, I'm picking up my new check valves today. I'm just happy that this problem does not affect performance.

 

For moral support - "You can do it!"

You will be more happy that you removed the manifold and give yourself more room to operate - Just mentally go over it and take your time and don't rush! Walk away when you need to.

Take pictures if necessary to help you remember how things go! (that always helps me)!

Enjoy it because you will know more about your Vette this way too!

Keep us posted on your results!

Thanks,Matt

 

Cleaning attempts will only provide a short term fix for the real problem.

Once the rubber diaphragm in the check valve becomes hard and brittle, nothing will restore it for the long term.

 

Pull the manifold. It's so easy a cave man can do it.

 

OK thanks guys! I have just picked up two new check valves and will be pulling the intake in a week or two. I just need to pick up a 3/8 fuel line disconnect tool at my local autoparts store. I should be set after that.

This forum is the best! It's good to know that there are like minded members who are ready to offer a hand if I run into any problems.

 

Here's a good thread to read if you haven't done so already:
http://forums.corvetteforum.com/c5-t...eck-valve.html

I'm always happy to answer any questions that you might have about it.

Good luck, you can do it.

 

I did this repair and found the most difficult part was getting the bolt loose to remove the valve. BTW you don't have to take the bolt out. I also had to saw the old valve off the threads.Also I broke the plastic piece that thread through the back of the engine above the valves so be careful there. As for removing the intake: get new gaskets for the intake. They come in a box of eight. Do you have an inch pound torque wrench? It is not hard but it is intense if it is your first time to take off the intake. Search that out and also add some additional plastic pipe to the back of the intake. That will save you from haveing a vacuum problem later.

 

Just to keep everyone updated, I have removed the intake and have just replaced the passenger side air check valve. Here is what I learnt in the process. Hopefully it will help others faced with the same task.

1) Disconnecting the fuel line was easy using the 3/8" disconnect tool. There was very little to almost no pressure in the line. I did press the schraeder valve using a screw driver and a rag. I guess the fact that the car had been sitting for three days may have helped. Just make sure to remove the fuel filler cap.
2) You do not need to drain your coolant. There was very little coolant that came out of the small coolant lines connected to the throttle body. Just have a rag handy.
3) Be very careful when lifting out the intake manifold. There will be a lot of dirt and sand accumulated around the mating surfaces. I used a shopvac to clean the area before I lifted it off.
4) Removing the air check valve without removing the whole air pipe from the engine is NOT an option in my opinion. It took me several hours of cursing to get to the rear bolt that holds the pipe in place. Then it took me another hour or so to unscrew the old check valve from the pipe. It was completely rusted into place. I really thought that it was going to break off at one point. I don't know how some people were able to unscrew the damned thing without removing the air pipe from the engine.
5) I really thought I wouldn't need new intake manifold gaskets because of my low mileage (35K) but I was surprised at how flattened the originals looked. I had a pretty hard time finding aftermarket replacements. Most places (NAPA, Canadian Tire) told me it would take over a week to get them. I broke down and went to the GM dealer. Well, for all you Canadians out there, they cost me $166.00 + tax. Outrageous! But, I had no choice at this point since the dealer could have them for me the next day. Talk about being reamed! So be forewarned, OEM gasket set will put you back quite a bit.

I will be re-installing everything tonight. Hopefully, there won't be any surprises.

 

Maybe, maybe not.... I cleaned cleaned mine with the throttle body cleaner last year, and I'm still OK.

 

Well, when I finally got my air check valve out and took a look I understood that no cleaning in the world would've fixe it. It was blocked solid. No air whatsoever was getting through. The rubber diaphragm was completely hardened.
I guess it is different with everyone. The cleaning may work for some people but I suspect that it is only a temporary fix, at best.

I get the feeling that the air check valve problems are more prevalent with cars that are not driven regularly, such as mine.

 

Now that you have boasted about it, you will start getting those annoying
P1416 codes again today!

Just kidding of course; I hope the cleaning attempt will work for awhile.

 

No, you're probably right!!

 

I just put everything back together and no more P1416 code. I just have a few more thoughts on my intake removal experience.
The GM manual says to first torque the intake bolts at 44 in/lbs. Then go over it a second time with a torque of 89 in/lbs. Well, this was almost impossible to do. I had a hard enough time torquing to 44 in/lbs. The new gaskets are just too soft. I was completely bottomed out. It felt like the intake assembly was going to crack if I torqued any further. I stopped at 44 in/lbs. I'm pretty sure that it will be ok. I did use thread locker.

Well, that's it. Job done. Thank you all for your help.

Ps: before anyone asks, yes I was using an Inch/Lbs torque wrench and not Foot/Lbs.

 

I tried, but after an hour of getting no where it was obvious that it's basically impossible. I've heard of guys removing it but then relocating the check valve to another location. I guess when you need to just remove something it can be done by yanking and tearing stuff up ... but trying to install a new check valve in the same location is basically impossible IMO.

I took advantage of having my intake manifold off. I relocated the oil pressure sensor and sealed up the knock sensor covers and also did a TB by-pass mod.