Larger MAF housing problems

[kindred4x]

Hey guys im having a problem. I went to the local junk yard and found a larger MAF housing from a 4.6. So I installed the larger housing on my truck and it ran like total crap. So im guessing it didn't work because the MAF sensor is calibrated to my stock size housing? Which makes sense to me but confuses me also. I heard that first gens housing can be swapped with a second gens housing which is larger and will run fine. Did i hear right? If i did then how come the second gen sensor can't be swapped to a larger housing and run fine? For example the C&L MAF housing is a larger housing but uses stock ford MAF sensor, shouldn't the truck run bad without a tune? The only people that come to mind that have the C&L also have been tuned to that size housing, but i thought stock users can also use the larger housing? Is there anything i missed to mess up my install of the larger housing?

 

[cybergasm]

Wel i just did this conversion you mentioned but i used a 5.0 MAF housing not the 4.6 housing and had no problems at all with the install just swapped the MAF sensors and after the computer relearn the MAF sensor everything was fine.

I think u may need to find a different housing to make it work on yours

 

[kindred4x]

Thats strange because i thought the 4.6 and 5.0 housings are the same size? Well im going to try it again today. lets see what happens

 

[gmanpaint]

Anybody know if either the 4.6 or 5.0 MAF housing (plastic tube) will be a direct bolt on to a stock 4.0 OHV conical tube style filter housing? I need a different mount to fit a 80mm 4.6 MAF into my stock set up. Here is my stock ring mount (55mm maf), the mounting is wrong for the larger MAF base. It would be great to just be able to swap this part to make it fit, but I have no idea if this is possible or not.

 

[2000StreetRod]

MAF sensor change

The cross sectional area of a 80mm MAF sensor is 2.16 times the cross sectional area of a 55mm MAF sensor. That means for any given engine speed the air flow measured by the 80mm MAF sensor will be less than half what is was for the stock MAF sensor. The PCM utilizes the O2 sensor outputs in closed loop to establish the air/fuel ratio and may be able to compensate for the incorrect MAF sensor measurement but will probably set an engine lean diagnostic trouble code. The PCM utilizes the MAF sensor output to determine engine load and then uses the load as an index to look up ignition advance and other parameters in stored tables. In open loop (moderate to wide open throttle) the PCM uses stored tables to establish A/F ratio and ignition timing. The tables are not changed thru any "learning". The engine will be running dangerously lean at WOT and your OHV V6 has no knock sensor to prevent detonation. The only way your engine's performance will increase and run reliably with the 80mm MAF sensor is with a custom tune. I have gone thru the entire process and speak from experience. Ignore those who say otherwise as they do not fully understand how the fuel injection system works.

 

[gmanpaint]

Dale,
Thank you so very much for your time and well thought out post.

Does this all pertain to a OBD1 as well? This is for the ******* 95 OHV.

I am kind of under the assumption that the two systems will work in a different manner when increasing the MAF size, but I could be wrong and over my head here. This Granatelli MAF is configured for 19# injectors and uses the 4 pin (abcd) connector.

 

[gmanpaint]

Went shopping in the rain at a local JY. Found some parts off a couple Fords to try this. I measured my stock air filter housing, & MAF housing, and went searching.

I found a Maf/air filter housing with a mount ring that fits perfect for the 80mm MAF off an E-150 conversion van. The complete housing is exactly the same size in length as the EX. It is about 1.5" larger in diameter. It will need a bigger air filter. The inlet on the filter side is the same size, and will fit in the fender opening. The outlet side on the MAF side is larger. It will need an adapter to fit on the stock tube.

Going to try to make an adapter out of 2 clamps and a rubber boot. This is the only thing that will be a challenge to make the air flow smoothly. If this wont work with my OHV, I can switch back to my stock set up easily.

On a side note...I found that the larger V-8 engines had twin 55mm MAF's. Pretty neat to see that set up.

 

[gmanpaint]

Okay, after spending some time on this housing thing, I give up trying to make the larger housing work

Just way too much messing around with this & that. While it looked like it would fit right in, it didn't. So.... I opted to break out the Dremel tool and reshape the bigger mount to fit into my stock housing. Way easier, and do not have to change anything but the filter size. That is next on the agenda. If I cant find a filter for this to fit both the larger intake to the MAF, & the filter housing, I am going to scratch all this and break down and get an open air filter set up with a MAF plate....

I tried at least...LOL!