KN SRI Random Boost Issue
 

Hi guys, checked the forums for my answer but didnt get the answer I was looking for.

Installed my KN SRI yesterday, car ran fine for a couple hours, then boom, no more boost. Got out of car, checked everything, crank case vent hose a bit loose, clicked it back, then car runs fine again.

Today I drive for about 20 minutes no issues. Then the problem appears again. It seems to only happen a couple minutes after heavy load or full WOT.

All connections are tight, no boost leaks, no codes. Turbo still spools, but at low psi.

Im guessing MAF sensor...inspected it, has tiny almost not noticeable little scratches (normal with use?). Wouldn't a faulty MAF throw a code?

Changed position of filter. The "N" of the KN faces 11 o'clock.

Or maybe I just need a retune. Car was previously tuned for airbox mod and drop in filter.

Help appreciated. Thanks in advance. Not a big issue, but the random no boost is getting on my nerves.

Could have been an over oiled filter getting residue on your maf. Try maf cleaner for starters.
My gut says your fuel trims are way off and putng you in limp mode.

What are your mods btw do you have something to check codes or monitor fuel trims?

I will try cleaning it with MAF cleaner. I did touch it with my greasy fingers during the install, and simply cleaned it with a rag, I guess those sensors really are sensible.

Thanks for the input!

My friend has a monitor, will check that too. Mods are in my signature, but problem appeared right after that component install so it must be Short Ram related

How did u check for boost leaks

It would be short ram related if it got oil from the filter on it as well as fuel trims being screwed.

The k&n usually doesn't skew trims too bad stock tune but being tuned for the modded airbox may have made it allot worse then stock for skewing trims.
Since you already know about turning the filter to help with trims I imagine it might be the tune.

It has to be filter related indeed. It cant be a boost leak since the problem appeared right after the mod. The filter elbow is properly sealed to the turbo as well

Ill try the maf cleaner!

New questions :

Would a broken maf throw a code?

Would a dirty maf throw a code?

Do the vaccum tank delete, problem solved.

Usually it would. It may go into limp mode without a cel but there could be a logged code.

Alright here is the update. At 12 and 11 oclock now the car never goes into limp mode but flashed a check engine at wot. 18 afr. Chokes. If I drive normally its all good. Maf is fucking up I guess. Only code I got was a pending P0302 cylinder 2 misfire.

Tuning time?

What are your fuel trims doing?

Likely bad plug or coil on cyl 2 if that is the only code. Switch coil 2 with coil 4 and see if the misfire changes cylinders. If still on 2 replace plugs your coils are fine. If still misfiring report back.

What term said ^^

But it only does it when the filter is aligned at a certain position. And its a pending code not a solid light. I hate random issues.

Will switch both coils and keep you updated.

Or clean the MAF since a defective one might can trigger that code as well

It should have other codes pending normally with a malfunctioning MAF. It's possible but unlikely.

Problem update

1) Changed all the plugs, same problem, misfires randomly in every cylinder. There was a burnt plug in cylinder 2. We changed all the plugs with gm stock gap...

2) Switched the MAF, same problem, LTFT still hovering around +17


SO im really wondering if the gap could cause all this lol

If it's adding fuel it's because it's seeing too much air. Its got to be the fact your tuned for a modified airbox IMO.

Makes sense as well. However I don't think it would cause the engine to choke at wot...or I might be wrong

Have you cleaned the maf yet?

Put your airbox on and see if it fixed the issue to eliminate variables.

Alright, updates, good news this time

I did switch all my plugs for new ones since one was burnt, but kept the stock gap of 0.35

Reduced the gap to 0.32, misfires almost gone, did a heavy 3rd gear pull with only slight hesitation

Should I keep reducing? 0.30?

Thanks all for your time

I think .30 is the gap im running if i remember correctly

Might as well squeeze them down to 0.030 so as they wear the gap will not be too wide.

Contacted my tuner, said to buy stocker NGK ILTR5D and put gap at 0.28.

I had NGK ILTR6IX before, one step colder, seems it didnt like the new sri setup.

Thanks all again for your help, much appreciated

What u had one step colder plugs? Should have said so from the beginning and pretty much everyone would have told u that's ur problem

And ngk is not stock plug, scrap ngk and go to stock acdelco. Bet u ur car will run fine then

Car ran great for a year with one step colder plugs, it was tuned for it ;) Its the engine bay cleaning that fucked everything up

Check it out : https://www.cobaltss.net/forums/prob...swered-223223/

KN SRI Random Boost Issue
 

trust us, the lnf likes the stock plugs much better. There are zfr cobalts running stock plugs, which have a much higher heat load than a ko4 can put on an engine. Until you see the actual issues that occur with running to hot of a plug you don't need to decrease, decreasing can actually make your car run worse.

Yeah I can't recall why I went one step colder. Must have been a mistake on my side. I heard the same and will keep running the stockers from now on :twothumbs

that's awesome that u posted a link for spark plugs for an lsj, unfortunately this is the lnf we are talking about, totally different engine.

or so u thought. mine ran good to, or so I though, then I listened closer and it sounded like it was gurgling, people asked what was wrong with it lol.

It covers both the LSJ and LNF man

doesn't matter anyway, that thread is old, all the lnf guys know better now. that's why we all say stick with stock