After months of no MAF on my LS3, the solution was... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

davepl · 12-21-2016, 10:04 PM

...to install a honeycomb in front of the MAF.

I'd been fighting what I thought was an air/vacuum leak. The MAF wasn't seeing all of the air, the car would go lean, both banks of O2 would throw codes for being lean, and eventually a low air mass code for the MAF.

I tried everything, different pipes, different filters, straight pipes with no bends, all to no avail. I was by this time very certain that it wasn't actually related to the MAF. Had tried a different MAF too.

As a last resort I bought a section of 4" pipe with a MAF mount and a honeycomb from eBay, and it works nicely. It's a straight 6" pipe that I can't put a filter on, so some kind of intake tube will need to be constructed, but at least it runs happily now!

**chev3600** · 12-22-2016, 08:32 AM

Amazing that something so simple can be the fix. Glad it's running well for you. Any chance you could run a 6" inlet filter or just not enough room? http://www.spectreperformance.com/mo...x?prod=HPR9605

davepl · 12-22-2016, 01:44 PM

Right now I have it sticking straight out from the throttle body pointing at the radiator, so I need to fabricate a new intake tube that incorporates the air straightener.

As it sits, it runs well, but no filter at all!

e015475 · 12-23-2016, 12:02 PM

How about a pic of your setup?

I've had problems with MAF errors before too - mostly shows up when the car went for a dyno tune.

Would be nice to see what setup worked for you.

Andy4639 · 12-25-2016, 12:20 PM

Just throwing it out there. This is my cold air setup. It's been in the truck over 3 years now with no problems. The tuner did some fine tuning to get it right but in the end it's never thrown a bad code.

davepl · 12-25-2016, 01:53 PM

Andy, I think you've got the old style hot wire MAF there that reads a long cross section of the pipe. The "problem", or challenge, with the new MAF is that it sniffs a tiny section of the center of the airstream and deduces the rest. If the air has raced around a corner and is along the outside wall, it doesn't get seen and is not read by the computer.

Here's my current setup, that works well but clearly is temporary. Tilt your head, forum software is broken when it comes to rotated photos...

Andy4639 · 12-25-2016, 10:10 PM

Quote:

Originally Posted by davepl

Andy, I think you've got the old style hot wire MAF there that reads a long cross section of the pipe. The "problem", or challenge, with the new MAF is that it sniffs a tiny section of the center of the airstream and deduces the rest. If the air has raced around a corner and is along the outside wall, it doesn't get seen and is not read by the computer.

Here's my current setup, that works well but clearly is temporary. Tilt your head, forum software is broken when it comes to rotated photos...

That's messed up right there. You mean to tell me a new car want read right if the ninty is put on the throttle body! Dang.

davepl · 12-26-2016, 02:48 PM

I think I'm OK with a 90 (which I will definitely need) but it will need to be downstream of the MAF, so that there's nothing in front of the MAF except straight pipe, a honeycomb mesh, and a filter. After that it can bend.

I actually talked a guy up there in the crate engine dep't at GM and he led me to believe the instructions are insufficient - they say all is well as long as you've got 6" on either side of the MAF, but given the way air is sampled by this type of MAF, doesn't work so well in real life.

Dave

Custom 68 · 12-27-2016, 10:14 AM

I think that is the case on all the MAF even the older ones. They work better and are more predictable with the straight pipe. Some will work with the bends but it changes the air velocity as it "bends".
It does sound like the older ones are a little more forgiving than the new styles.
I am glad it worked out.

davepl · 12-27-2016, 03:00 PM

Indeed.... the old style measure -across- the entire width of the tube pretty much, whereas the new ones sample just from the very middle. Of course even with the older one you could have it turned 90 degrees from where the air was "building up" and still miss it.

Ran pretty well with the MAF though. I did notice it sometimes way rich or lean (under 10.0 or over 17) but the car itself doesn't have a wide band so it doesn't know HOW far it's off, even though I do with my gauge. But it'd usually come back to center right away.

**First c10** · 12-28-2016, 12:02 AM

Davepl, I had the same problem with my sons truck. Even with a spectra truck intake for a 2011 which is what the motor came in. It was always lean. I ended up tuning out the MAF.
Did you have to calibrate the MAF after adding the eBay part?

davepl · 12-28-2016, 03:19 PM

No, it's 100% stock tune (except for the reluctor speedo VSS count for my Tremec). I can see it doing some block learns at the edges of the envelope but it seems to be pretty much spot on. The MAF screen should not interfere with or change the MAF calibration at all, I don't think... it just straightens the air, doesn't restrict it any real amount.

There are a lot of other things that will cause these symptoms, like an exhaust leak, vacuum leak, mis-routed PVC that ingests unmetered air, bad grounds, and so on...

**First c10** · 12-28-2016, 06:19 PM

Cool. Do you have a link to what you bought?

davepl · 12-31-2016, 05:19 PM

Yes, this was it here. It has the GM MAF mount. You can also just buy the honeycomb insert, apparently.

http://www.ebay.com/itm/252080319202...%3AMEBIDX%3AIT

12-21-2016, 10:04 PM	#1
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	After months of no MAF on my LS3, the solution was... ...to install a honeycomb in front of the MAF. I'd been fighting what I thought was an air/vacuum leak. The MAF wasn't seeing all of the air, the car would go lean, both banks of O2 would throw codes for being lean, and eventually a low air mass code for the MAF. I tried everything, different pipes, different filters, straight pipes with no bends, all to no avail. I was by this time very certain that it wasn't actually related to the MAF. Had tried a different MAF too. As a last resort I bought a section of 4" pipe with a MAF mount and a honeycomb from eBay, and it works nicely. It's a straight 6" pipe that I can't put a filter on, so some kind of intake tube will need to be constructed, but at least it runs happily now! __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible

12-22-2016, 08:32 AM	#2
chev3600 Senior Member Join Date: Jan 2009 Location: Raleigh, NC Posts: 444	Re: After months of no MAF on my LS3, the solution was... Amazing that something so simple can be the fix. Glad it's running well for you. Any chance you could run a 6" inlet filter or just not enough room? http://www.spectreperformance.com/mo...x?prod=HPR9605 __________________ 1949/1954 with LS swap-yeah! http://s260.photobucket.com/albums/i...0/AD%20trucks/jumbled mess of unorganized photos

12-22-2016, 01:44 PM	#3
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	Re: After months of no MAF on my LS3, the solution was... Right now I have it sticking straight out from the throttle body pointing at the radiator, so I need to fabricate a new intake tube that incorporates the air straightener. As it sits, it runs well, but no filter at all! __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible

12-23-2016, 12:02 PM	#4
e015475 Registered User Join Date: Nov 2013 Location: Show Low, Arizona Posts: 778	Re: After months of no MAF on my LS3, the solution was... How about a pic of your setup? I've had problems with MAF errors before too - mostly shows up when the car went for a dyno tune. Would be nice to see what setup worked for you.

12-25-2016, 12:20 PM	#5
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: After months of no MAF on my LS3, the solution was... Just throwing it out there. This is my cold air setup. It's been in the truck over 3 years now with no problems. The tuner did some fine tuning to get it right but in the end it's never thrown a bad code. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

12-25-2016, 01:53 PM	#6
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	Re: After months of no MAF on my LS3, the solution was... Andy, I think you've got the old style hot wire MAF there that reads a long cross section of the pipe. The "problem", or challenge, with the new MAF is that it sniffs a tiny section of the center of the airstream and deduces the rest. If the air has raced around a corner and is along the outside wall, it doesn't get seen and is not read by the computer. Here's my current setup, that works well but clearly is temporary. Tilt your head, forum software is broken when it comes to rotated photos... Attached Images __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible

12-26-2016, 02:48 PM	#8
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	Re: After months of no MAF on my LS3, the solution was... I think I'm OK with a 90 (which I will definitely need) but it will need to be downstream of the MAF, so that there's nothing in front of the MAF except straight pipe, a honeycomb mesh, and a filter. After that it can bend. I actually talked a guy up there in the crate engine dep't at GM and he led me to believe the instructions are insufficient - they say all is well as long as you've got 6" on either side of the MAF, but given the way air is sampled by this type of MAF, doesn't work so well in real life. Dave __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible

12-27-2016, 10:14 AM	#9
Custom 68 Registered User Join Date: Nov 2001 Location: Springfield, MO Posts: 2,939	Re: After months of no MAF on my LS3, the solution was... I think that is the case on all the MAF even the older ones. They work better and are more predictable with the straight pipe. Some will work with the bends but it changes the air velocity as it "bends". It does sound like the older ones are a little more forgiving than the new styles. I am glad it worked out. __________________ Dave 1968 Custom Chevy with turbo charged 5.3 gen III 4l80e swap 1967-71 GMC 3/4 ton long step 4x4 (not sure what year exactly?) "A good friend will bail you out of jail...but a true friend will be sitting next to you saying "that was frekin awesome". "If it doesn't fit force it...If it breaks then it needed to be replaced anyway!"

12-27-2016, 03:00 PM	#10
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	Re: After months of no MAF on my LS3, the solution was... Indeed.... the old style measure -across- the entire width of the tube pretty much, whereas the new ones sample just from the very middle. Of course even with the older one you could have it turned 90 degrees from where the air was "building up" and still miss it. Ran pretty well with the MAF though. I did notice it sometimes way rich or lean (under 10.0 or over 17) but the car itself doesn't have a wide band so it doesn't know HOW far it's off, even though I do with my gauge. But it'd usually come back to center right away. __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible

12-28-2016, 12:02 AM	#11
First c10 Registered User Join Date: Dec 2012 Location: Los Banos CA Posts: 2,705	Re: After months of no MAF on my LS3, the solution was... Davepl, I had the same problem with my sons truck. Even with a spectra truck intake for a 2011 which is what the motor came in. It was always lean. I ended up tuning out the MAF. Did you have to calibrate the MAF after adding the eBay part? __________________ 1956 Chevy Bel Air 2 door 1956 Chevy 210 4 Door 1970 K20 LWB project the Hulk build w/Supercharged 4.8L-ly2/4L60E HULK BUILD 1970 C10 Yellow/White Deluxe LWB w/ 5.3L-LC9/6L80E 1968 K10 LWB Dark green my son calls it "THE HULK Jr"HULK JR SOLD GO GO!!!

12-28-2016, 03:19 PM	#12
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	Re: After months of no MAF on my LS3, the solution was... No, it's 100% stock tune (except for the reluctor speedo VSS count for my Tremec). I can see it doing some block learns at the edges of the envelope but it seems to be pretty much spot on. The MAF screen should not interfere with or change the MAF calibration at all, I don't think... it just straightens the air, doesn't restrict it any real amount. There are a lot of other things that will cause these symptoms, like an exhaust leak, vacuum leak, mis-routed PVC that ingests unmetered air, bad grounds, and so on... __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible

12-28-2016, 06:19 PM	#13
First c10 Registered User Join Date: Dec 2012 Location: Los Banos CA Posts: 2,705	Re: After months of no MAF on my LS3, the solution was... Cool. Do you have a link to what you bought? __________________ 1956 Chevy Bel Air 2 door 1956 Chevy 210 4 Door 1970 K20 LWB project the Hulk build w/Supercharged 4.8L-ly2/4L60E HULK BUILD 1970 C10 Yellow/White Deluxe LWB w/ 5.3L-LC9/6L80E 1968 K10 LWB Dark green my son calls it "THE HULK Jr"HULK JR SOLD GO GO!!!

12-31-2016, 05:19 PM	#14
davepl Registered User Join Date: Aug 2006 Location: Redmond, WA Posts: 6,332	Re: After months of no MAF on my LS3, the solution was... Yes, this was it here. It has the GM MAF mount. You can also just buy the honeycomb insert, apparently. http://www.ebay.com/itm/252080319202...%3AMEBIDX%3AIT __________________ 1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.