Intake ISSUEs. Turbo spitting/knocking
 

:helpme: Morning fellow evo owners!
I come to you for some assistance on some issues I've come upon. I did search along the threads to find some MAF and intake issues but none had the same problem as I am currently having however, I apologize if this might have been discussed before but I'm in need of some immediate assistance. I figured to ask you guys ( and possibly solve the issue myself) before I call AMS or get my car checked out.


I have an AMS intake tuned and I have had it tuned this way for a year now with no major issues. About 1 month ago the Crank case bung fell off (not into the turbo) so I was forced to run the vacuum hose freely for a while with no issues. I recently got my replacement bungs from AMS, took the intake out and placed the bungs back into their appropriate places.
I also bought a different vacuum hose that is LONGER but skinnier to run from the crank case to the bung (the reason I did this is because the stock vacuum hose although wider it was barely making it to the bung outlet and was pulling on the bung which eventually caused it to fall). I don't quite see if this hose is the issue but it might be too narrow and too long which might be causing the crank cases air to NOT make it into the intake MAYBE but I'm not convinced.


Anyway, I took her out for a drive and anytime I was going to build some boost the turbo would choke up and spit causing the car to hesitate and knock back plus lose all acceleration. This was a problem similar to the one I had when I had the wrong tune on an old intake... but again the tune has been fine all this time, also I uninstalled the tune from my Cobb AP and in the stock tune it still did the same issue, so the Tune is NOT the problem. I checked the vacuum hoses they are all fine, the MAF sensor is plugged in the hoses are in their place I don't understand why the turbo is choking up. The only thing I changed was the vacuum hose of the crank case... My next step is to take the intake all apart again and re-install it but again, everything is plugged in and seems good to go. My AP also doesn't show any engine malfunctions.


Finally sorry for the long read, I greatly appreciate any help you guys can provide.




UPDATE: Finally resolved the issue! Thanks for all the suggestions and help guys, seems like the Fuel Pump malfunctioned and Evo is getting fixed up and should be ready to go this coming week!

From your description it sounds like the new hose has thinner sidewalls. Is it possible the hose is collapsing and causing issues?

It is possible, thank you for the assistance. Do you think the vacuum hose can cause this reaction like that? I'm interested in learning why and how a thinner vacuum hose can cause this malfunction (maybe the air traveling from the crank case is having trouble escaping and making its way back to the engine???) but that's just me guessing I don't know. I sure hope its the vacuum hose because I will just either 1 Run it to the ground/air or 2 just get another thicker hose or try to make my stock one work.


I will put the old hose in it again and see how she reacts. If that doesn't work, I will take the intake apart and re install it.

To be honest it's only a guess given that is the only delta, that I recall, from where you started.

Running the same intake... Anyway. So the bung fell off the intake because the line was to short? Did you lose the whole line? Or did you find it hanging off the crankcase? Are you sure the turbo didn't suck it up? That actually happened to a member here and ruined the turbo. Highly doubt it's the new line, but that's my opinion.

Hey guys just an update. The vacuum line was not the issue.
The turbo did not suck it in, the line was hanging off the crank case with the bung on it but the rubber was cracked. Plus I was driving the car with that hanging that was for a few days while my replacements got here.
So my turbo was fine all along until I took that intake out, disconnected the whole thing and put it back together. The vacuum line was not the issue so now I'm really confused as to what is going on there. I will take the intake out and re install it and try to see if that works... If not I'm out of luck man, I have no freaking clue what the hell went wrong all of a sudden

Nkryptd read my mind. There are some cheap hoses out there that r flimsy and may suck close with enough pressure. Y not just go find a longer section of the original hose. Do that before u report back. If it still is happening then u may wanna have a boost leak test done or inspect your intake for other damage. And r u sure u didn't move around any other vacuum lines?

Since you said it was driving fine with the line just hanging there... Sounds like something went wrong when you removed/installed the intake again after receiving the replacement part. Any check engine light or codes?

Since none of us can actually see whats going on..

It's not the tune. So either you installed the intake incorrectly, damaged something like the MAF taking it out, or it is a vacuum problem.

Re-install the intake like you said, and make sure that all the couplers are installed correctly. That's probably where your problem lies. But I would also buy a new vacuum hose than use one that is different anyway. It's not expensive..


Also check the BOV and make sure all that's ok too..

Like I said do a boost leak test....

Thanks for all the help guys. I have no codes on my dash or AP so that's not it. I replaced it to the stock vacuum line and it still was having issues.
At this point I think something is not tight enough and might be popping off or leaking air. My next step today will be to uninstall the whole intake and reinstall it to see if that will do the trick. If not I will take it in to see if there is a leak anywhere. I'll update the page later today and see if it was maybe just my fault.
Thanks again guys I appreciate it

Bad news fellas. I took the intake out and put it all back together, no luck. I'll have to take it in to get it checked out for a boost leak. Looks like something else went wrong that I'm not aware of that has nothing to do with the intake.
The car has been sitting in my garage for a week without me using it during the time the Bung came off of the intake. The garage has been getting extremely hot so idk if that could've loosened some things or caused a leak. I'll get it checked out and update you guys.
Thanks again for all of you who helped me try to figure this out

Well, something is not right. I seriously think its something that you accidentally unplugged or pulled off during uninstalling/installing the intake.

If you take it somewhere, don't go in to boost. You don't want to damage the turbo..

Is the small hose on the nipple on the BOV connected both on the BOV side and the wastegate side? Did you possibly unplug one of the lines on the boost solenoid? You didn't install the BOV backwords or something did you??

is your BPV leaking? the hoses around it rotted or or corroded. did the return hose slip off of the Ic? i had a problem once where a coupler was lose and it was still tight, but not cranked all the way and i couldn't boost. mad scientist is in FL. take it there