Installed intake, now stalling: wtf

[Melbowski]

Long story short, I put on a new intake and now the car stalls between shifts. Also when I push the clutch the rpm drops like a brick, I have to speed-shift into every gear before it stalls. WTF is going on here?

BOV is recirculated, did a boost leak test a few weeks ago and all was good and tight. Emmisions are deleted and capped, maf is plugged fully in, valve cover vent is hooked up. None of this ads up, my car ran great for months, even ran great that day, then I switch the intake and it stalls thereafter, no other changes at all.

This is not an uncommon mod, and it doesn't appear that this is a common problem. Searching yielded mostly 1gs with bad caps, and 2gs that never posted a solution, so I'm pretty lost on it.

Also it only happens when it's warmed up fully, idle is normal beyond stalling/recovering. Fuel ratios have not changed on my wideband so it doesn't appear to be leaking. I'm really at a loss. I'm open to any ideas, thanks in advance.

 

[smorton]

Could be crankwalk Pushing the clutch in places pressure on the thrust bearings; its what happened to my friends eclipse. BEFORE I get flamed for this post, there are other options besides cw; explore those first.

 

[laser5spdturbo]

What kind of vacuum does the car pull at idle ? Sounds like a vacuum leak . Or a bad MAF sensor

 

[97gst_spyder]

There's a leak somewhere... One of the 4 total vacuum ports are leaking or not hooked up or something like that.

 

[Melbowski]

Fully rebuilt 6-bolt rules crankwalk unlikely, especially with less than 20k on it. Thanks for the input though.

Other than valve cover vent everything else is deleted. All ports on intake are capped and sealed.

Vacuum at idle when warm is 18"-20" iirc, I'll double check it shortly though. Thanks for the ideas so far. MAF crossed my mind, but seems odd it'd just up and die with the swap. I'll swap the MAF from my 3000GT into it and see if that changes anything. If I can't figure it out I'll probably try swapping the stock intake back in. Gotta have it running well to get to work. Keep the ideas coming guys, I appreciate it.

 

[Angmah]

I second the MAFS or a leak being the cause of the havoc you're going through. Not sure which has a specific coding that might cause some compatability issues for you. Can't seem to recall if it was the MAF or MAP sensor. I believe it is the MAP, and you should be in the clear. Just in case though, a heads up for you.

 

[Groundation]

Did you do a boost leak test after installing the intake?

It sounds like it could be a boost leak, especially if the problem started after your intake install. I would remove the intake and then install it again being careful and checking around the intake area for possible leaking hoses etc.

 

[Matrout218]

Did you resirculate the blow off valve?

 

[Matrout218]

Nevermind sorry rest of post wasent showing on my phone

 

[TurboATM]

ah, i had this same issue on my old 2g i had...i tried everything, checked everything...i ended up selling the intake to someone and it worked perfectly for them.

Im really interested in what happen!

 

[GSXUAL]

Do you mean a intake MANIFOLD? if so, did you leak test it after the install? It's very likely the gasket may be broken. Did you change the gasket with it? And did you clean both matting surfaces before re-installing?

 

[LiquidX]

You fully attached the couplers onto the turbo so there is no leak? You fully attached the MAS onto the intake so there are no leaks? The MAF is plugged in and emissions blocked off.

If that's the only thing you took off then you have a leak some where, simple as that. Try re attaching the MAS being sure it's inserted far enough onto the pipe and the same with the other end onto the turbo.

 

[g4ebguy90]

if he had a boost leak, i mean seriously it would be a problem all the time, not just between shifts, Yes shifts could be from the bypass valve the crank hitting the crank sensor... so yeh... explore those and stat with the easiest, i mean u just installed the intake and it started doing this right, therefore it probaly is intake related

 

[tonyseagle]

Have you tried putting your old one back on to see if that fixed it? This would rule out the new intake.

 

[Melbowski]

Alright, I poked around a bit today to see what I could find. First and foremost it is not an intake manifold, just a shiny ebay intake. Double-checked vacuum at idle, it's 20-22". The BOV is recirculated. I pulled the intake back out, no holes, no leaking caps (two ports are capped), nothing wrong with it. Swapped my MAF (have a spare I'm "borrowing" from my 3000GT) and reinstalled making sure not to miss any vacuum lines (there's only 1 with emissions deleted). Tightened it down good on the turbo with a brand new 2 1/4" coupler, everything seemed leak-free. Take it for a spin and it does the exact same thing...

So I swapped everything back over to the stock air-box and reinstalled that. Now she runs absolutely perfect once again. I'm really stumped on this! The MAF is ruled out, a major boost-leak (post-turbo) would have maintained the same problem so that's ruled out, and I can't imagine I had a similar leak on two separate installs. I really don't know what the deal is with it, so for now I'm leaving it stock. Once I find my flash/logging cable (how the hell do I misplace a $200 openport cable!?) I'll have to do a log with the stock box, and a log with the intake; that'll at least give me some insight as to what the computer sees and maybe why it seems to be rejecting the intake.

Thanks for the help guys; wish I had come up with an answer though. In any case at what point does the stock air-box really pose a major restriction? Its got a K&N filter in it, and pulls cold air from the fender so it doesn't seem that bad off. I plan to run 18psi with the my 14b (walbro 255; 750cc injectors) as I hear that's about the end of its efficiency range, will the stock air-box pose a hindrance with that much boost? Thanks again for all the advice, if I figure out what the deal is with my intake I'll be sure to post it up.