Intake installed, Spitting and sputtering now...

[summerisway2hot]

So, before I start, my stock BOV is recirculated, and will be replaced by a 1g soon. nearly everything is stock, except what I am about to discuss.

I bought an Injen style intake off ebay (college student, tight on money but wanted something simple to start with, hopefully ill be able to start building it this summer), installed with little to no problem (aside from the fking bolts), and the intake seemed to work perfect. I reset the ECU, ran the car for about half of the ride back to where i was going (went about 12 or so miles) then began to run it harder. Since installing it, when boosting hard, and then going into neutral (e.g. coming onto a road, giving her the juice, then going into a driveway) and it should idle, it does not. Sometimes, it will stall, but oftentimes, the car will sit and sputter for a while until it figures out that 100 rpm is not good for it and it should run at 800 or so. This only happens directly after the car has been under heavy boost and is then coasting. If it is not under boost, and then coasts, it is fine. After looking at the intake pipe, it looks like it does not have the part in the hard snorkel that the soft snorkel had going from the BOV recirc line to nearly the end of the snorkel. Given, I have little experience in turbocharged cars (into turbo diesels... large turbo diesels, worked with 4 8500 hp diesels for most of the summer) and I am not particularly familar with the inner workings of the recirculation of the BOV. My best guess is that the sudden discharge of pressure into the intake pipe does not all go through the compressor anymore, it blows out through the mass air flow sensor, which just senses the mass of air passing it, and thus thinks that the car is getting more air, giving less fuel, and then, bang my problem happens. Can anyone tell me if my idea is right, and if so, any way to solve it? My best idea so far has been to weld a directional part directly where the BOV recirc. line comes off to direct it toward the compressor instead of directly into the pipe. Any other ideas, possibilities of problems, etc?

 

[Gstclipse69]

As long as the bov is recirculated back into the intake after the mass then it is fine. There is no need for any directional flow. Are you sure the mas is plugged back in? Can you post a pic?

 

[summerisway2hot]

Pictures included, and the MAS is plugged in, the car wouldnt boost up as it normally does without it would it? The problem only occurs when trying to idle after a lot of boost.

 

[Gstclipse69]

I assume it did not do this before? If you cut the ac on at idle does the rpms drop any? It looks like everything is hooked up properly. I am thinking now more along the lines of the isc possibly being faulty.

 

[summerisway2hot]

Since the car has been sitting so long, the AC doesnt blow cold, but the compressor does engage, and, from the last time i turned it on, the RPMs bumped up about 50 or so. Just to be clear- ISC=Idle speed control?

What I was wondering was more along the lines of how does the MAF actually work, does it just record air going past it, in either direction, or does it only work in one direction, or does it take the direction into account? Just looking at it, id have to guess it can only work and say "this is how much air is going past me" regardless of direction, which I think would create my problem. Also keep in mind it only does this directly after being under boost, when the BOV releases the pressure.

 

[jjrock5]

Im assuming by "resetting" the ECU, you unplugged the battery?? Well you're never supposed to unplug it, now you need to do a 6 bolt swap!!

No but seriously, when you unplug the battery and start your car back up, all your sensors also have to 'reset' themselves and the car feels horrible for the first ~50-75 miles (in my situations). Symptoms are: the car idles like at 200 RPM and wants to die, on take off the car sputters, loss of power, when you go from gear (while driving) and put it in neutral, the car's RPM blast downwards in the 200-300 RPM range and feels like its gonna die just from that, and once in a while the car will actually die on you. This lasts for a while and is flippin annoying but it goes away. Make sure all you connections are tight and that you hooked up the vaccum lines along the side of the new intake. Good luck.

Oh and clean that damn engine bay!!

 

[summerisway2hot]

Thanks, the car sat for 7 years, I got it running and the next day drove it to college... so not too much time has been allowed for cleaning of the engine bay. When I actually get some time it will definately get done. I hope this resolves itself like you said, its been about 150-200 miles but we'll see.

 

[Cmele89]

the way i see it is u might have left a vaccuum line unpluged chekc around that injen intake im pretty sure theres some vac lines make sure they are plugged if your not using it. And to answer your question yes the MAF sensor works by measuring the amount of air going past it your recirculate tube is behind it so its not measuring what comes out of there. so yeaa your pretty right thereeother than that the setup looks good and just for Sh*ts and giggles you should spray carb cleaner through your throttle body while it runs a couple times to clean it out then use some seafoam and cleann that bad boy out.. just a thought

 

[blade970]

Do you still have all the stock intake stuff. If you do, just hook all of that back up. If the problem goes away this will help pinpoint what is happening. If the problem didn't go away then It's probably caused by something you did when installing the intake.

 

[summerisway2hot]

Alright, so here goes.
I checked both ends of all lines going to the intake. all secure. I put the stock one back in, reset ECU, no problems. Put the injen one in. same problem. I think that because the pressure is so high coming out of the intercooler piping and that it isnt redirected as in the factory snorkel, it could be backing out through the MAF. It is making me very angry. I want it to be fixed, but im out of ideas.

 

[#40Fan]

Pull the new one again and put it next to the old one and compare the flanges that bolt to the head. Post some pictures of them too.

 

[GSXSixteenG]

Pull the new one again and put it next to the old one and compare the flanges that bolt to the head. Post some pictures of them too.

Lol, he's talking about his intake pipe, not to be confused with the intake manifold.

I would say try and hook up your original and see if it goes away. How many vacumn lines do you have hooked into the Injen style pipe? I'm pretty sure mine has 3 for a reference.

 

[#40Fan]

Oopsy. Was reading too fast and missed it.

 

[summerisway2hot]

The new one has the same number of holes as the old one, the differences lie in the materials (rubber vs. metal), one male fitting on the injen is female threaded with a nipple on the tube (not a big deal, remove the tube from the nipple instead of the intake) and the only other difference is that the blow off valve does not have a tube to direct it toward the compressor wheel.

Now, maybe its sounded like ive been saying something else, but my engineering background tells me that if you shoot 14psi into a pipe that is just a bit below atmospheric pressure, that sudden surge could cause some of the air to go out through the MAS, espeically since that sudden surge is no longer pointed at the compressor, it is instead pointed at the opposite wall. Could air being blown off into the intake create a higher pressure than outside, which would thus cause the MAS to read air moving past it, not knowing that the air is in fact going the wrong direction? That would explain why it only does it at idle after boosting, due to the fact that it takes less air to run at idle than after shifting. I am at a loss. I am thinking about possibly putting in something to direct the air toward the compressor wheel, as opposed to just shooting the other side of the wall.... I still cant believe no one else has had this problem, with a properly installed intake (which I believe I did)...... ahhhhhhhhhh