GM Maf screen MIA!

bmxrider154 · 03-24-2007, 08:53 AM

I was swapping MAF's trying to diagnose a tuning issue and noticed that the screen that was there before, is gone! I found this pretty odd considering it had to go through the motor. I haven't heard of this happening to anyone else and thought I would post this to let people know. And before you ask, it was there before.

I had a valvetrain issue last spring where a chunk of one of my exhaust valves was taken out and my spark plug in the cylinder was destroyed. I'm wondering if the screen caused that whole disaster. When it happened, the car was running fine and all of a sudden saw 42counts of knock. Car was towed home

How much pressure can these screens really withstand? I'm debating on whether or not to take the screen out on my current maf.

RipperXX · 03-24-2007, 11:37 AM

Wow, thats got me scared

. Will removeing the screen cause any negative effects on a blow though setup?

bmxrider154 · 03-24-2007, 11:53 AM

I would like some more input on the effects of removing the screen as well. I know it's there to direct the air but I highly doubt it will have any effect at WOT or even at idle. I'm not exactly sure how long it had been missing but I had zero ill effects up until yesterday when I pulled it off. I couldn't tell a difference after I installed the replacement that had a screen. Most say it will/could only have an effect at idle when the airflow isn't as high.

My problem happened to be another ruined Bosch WB sensor.

TURFNNSURF · 03-24-2007, 06:03 PM

I have had a stock 3" GM mas in a blow-through setup, and ran 22psi Daily and have seen 26psi spikes at the track without having the screen get loose. I currently run a ported 3" GM mas without the screen at 27psi daily and 30psi at the track. I can tell you from logs on dsmlink that the screen DOES effect the fuel trims at idle and cruise NOT so much at WOT though.. I had to make airflow adjustments to my lower airflow sliders to keep my fuel trims stable when I put the screen back in to my ported GM mas.

Bottom line is that it's perfectly fine to run the car with the screen removed, you can tune for it with the translator or with an SAFC if you don't have link..

bmxrider154 · 03-24-2007, 07:57 PM

I'm not too sure what caused mine to detach, and like I said not sure when either. At the end of last year I was running 30lbs on my race gas tune, probably happened around there. I didn't think it would effect anything at WOT and not surprised it effected the idle and mid fuel trims. Dialing the trims in is no big deal, I either make the adjustments with the translator or burn a new chip. I'm probably going to take the screen out just to be safe, definitely don't want to take any risks at this point. I know the can fail, so don't want to chance it.

RipperXX · 03-25-2007, 09:42 PM

What hold it on? Reasion I ask is if it's some type of adhesive maybe it got to hot?

bmxrider154 · 03-25-2007, 09:46 PM

I'm not totally sure what holds the screen in place. I know there is a little groove that it sits in and I think there are a few very tiny tack welds that hold it in place.

I guess i'm the only one this has happened to?

TURFNNSURF · 03-26-2007, 05:14 AM

That little groove is supposed to have a metal retaining ring or snap ring type retainer fit into it to hold the screen in place. If that is missing, then that could be the very reason your screen got sucked into the intake track. It is possible that the screen is still in the intake manifold pinned in one of the intake runners by the intake valve stem. If you are really concerned about the situation I would suggest you pull the intake main off and check the inlets to the head..

gdmbat85 · 03-29-2007, 09:19 AM

Wait, what? correct me if im wrong, but the air is suposed to flow through the screen first, then through the sensors of the MAF. If it came loose and got sucked into the intake, wouldn't it have got stuck against the sensors or atleast damaged them, if not taking them out completely?

danyz250f · 03-29-2007, 10:40 AM

The screen is not in mine, I have not noticed any ill effects.

PRESSURIZED · 03-29-2007, 12:43 PM

I have heard of these screens falling out before. Best thing is (like the balance shafts) is to eliminate it.

If you remove the screen you may have to do a couple adjustments to get it perfect but honestly you probably wont even notice the difference.

eclipse_turbo97 · 04-26-2007, 07:19 PM

My brother has an LS1 Z28, he says its very hit or miss with removing the screen on the MAF. He said personally he wouldnt remove it, hes never heard of any of them actually "falling out". Not saying its never happened he just hasnt heard of it. And depending on what year MAF you have more problems can occur than others. You want to stay away from the earlier model MAfs 98-99 preferably.

turborebel · 04-28-2007, 08:27 PM

Has anayone tried the after market sensors like the Granatelli, or Summit mass airflow sensors? My screen is still in place, but if it had come off I would take the intake manifold off to see if anything was still in the head.