Installing a JEC MAF in place of the Aluminium MAF - results

douglas vincent · Post by **douglas vincent** » Tue Dec 13, 2005 2:47 am

Positive results.

I would max out the aluminium MAF at 5500 rpm or so, pegging 5.1 often.

Installed the JEC. 4.6 at 6500.

You do run rich though, so you need something to pull fuel with. I did some "live" tuning sitting in my driveway with the Perfect Power. I already had a -8 for idle and so the car started right up. I put in 0 and it started to bog and cough. I stuck in a 3 and it killed. So I am running a -8, -7, -6, -5, -4 ,-3, -2, -1 up the 0% deflection.

I will need to do some more dyno pulls to watch the wideband O2 to see if everything is close, but I suspect I am pretty happy now.

skid542 · Post by **skid542** » Tue Dec 13, 2005 2:53 am

That's awesome.

dzx · Post by **dzx** » Tue Dec 13, 2005 4:45 am

So it was running rich enough to kill your car? Are you still maxing out the maf? I was thinking of doing this since there are quite a few jec's sensors at the junkyard here. I thought you had a n/a maf to begin with?

Post by **Legacy777** » Tue Dec 13, 2005 4:49 am

dzx wrote:So it was running rich enough to kill your car? Are you still maxing out the maf? I was thinking of doing this since there are quite a few jec's sensors at the junkyard here. I thought you had a n/a maf to begin with?

The 90-91 MT n/a's came with the Hitachi ECU's & aluminum MAF's.

douglas vincent · Post by **douglas vincent** » Tue Dec 13, 2005 4:53 am

Rich enough to be boggy.

I am unable to test the maf to maf as a complete stock set up currently, guess why.....

But, when I had swapped the MAFs awhile ago on a different vehicle, the vehicle wouldnt run.

vrg3 · Post by **vrg3** » Tue Dec 13, 2005 5:04 am

The ECU's throwing a code 49 now, right? That might be causing some of the richness. The JECS sensor would actually show a lower voltage at a given airflow than the Hitachi one, so you'd actually expect it to lean things out some.

If you're feeling daring you could try grounding the blue wire at the MAF sensor's connector to trick the ECU into thinking it's still the correct sensor, eliminating the code 49 and any associated failsafe behavior.

douglas vincent · Post by **douglas vincent** » Tue Dec 13, 2005 5:29 am

You know, I just always made the assumption that it didnt run because it was too rich.

But....At -8 fuel while at idle, it idles just fine. At 0, it bogs and chokes at idle. at +3 at idle, it kills. So it does appear to be running rich.....Just no Wideband prooof. Anyone want to buy me a wideband?

azn2nr · Post by **azn2nr** » Tue Dec 13, 2005 6:25 am

rich will kill the car. in the snow if i load the motor up and let off so the bov goes off. it has enough richness along with the wheels comming to a halt that it up and dies.

dzx · Post by **dzx** » Tue Dec 13, 2005 11:04 pm

I wonder how the turbo ecu would respond to the plastic jecs maf

sammydafish · Post by **sammydafish** » Wed Dec 14, 2005 5:51 am

which Jecs MAF did you use? Is this one from a Nissan? I remembe some talk about trying one from a Z32

douglas vincent · Post by **douglas vincent** » Wed Dec 14, 2005 7:24 am

The NA 91-94 version

douglas vincent · Post by **douglas vincent** » Wed Dec 14, 2005 8:20 am

If you have the Perfect Power program installed, you can load this 2nd, 3rd and 4rth gear pull and see that I max out at 4.59

http://www.vincentfurniture.com/photos/ ... MT6030.raw

sammydafish · Post by **sammydafish** » Wed Dec 14, 2005 6:50 pm

what did you do about the wrong AFM code? did you get it and did you do what VRG said?

douglas vincent · Post by **douglas vincent** » Sun Jan 22, 2006 5:50 am

Nothing yet. I did cut the wire but it didnt do anything. I just left the CEL on. It comes on all the time anyway due to misc stuff.

vrg3 · Post by **vrg3** » Sun Jan 22, 2006 7:27 am

Ground the wire.

Project_Legacy · Post by **Project_Legacy** » Sun Jan 22, 2006 6:44 pm

so, basically wat you are trying to get at is that the legacy N/A MAF from 91-94 would be better for... boosted N/A's? uhh what else would this help with? SS's and TW's with upgraded turbos? i cant quite figure it out...

douglas vincent · Post by **douglas vincent** » Sun Jan 22, 2006 6:59 pm

ANY boosted legacy.

The aluminium MAF which came on early NAs and all Turbos max out the voltage versus airflow at a lower airflow compared to the plastic JECs MAF.

douglas vincent · Post by **douglas vincent** » Sun Jan 22, 2006 10:05 pm

Hey, grounding the blue wire worked!

I missed the "blue" word and had done the white wire, which doesnt have a tab on the aluminium maf, instead.

Started the wagon, NO CEL!

Post by **Legacy777** » Sun Jan 22, 2006 11:03 pm

douglas vincent wrote:Hey, grounding the blue wire worked!

I missed the "blue" word and had done the white wire, which doesnt have a tab on the aluminium maf, instead.

Started the wagon, NO CEL!

Do you notice any difference in how the car runs now?

douglas vincent · Post by **douglas vincent** » Mon Jan 23, 2006 7:08 am

Not sure yet. While I did drive 250 miles today since I did the blue wire ground, it was almost all 3rd, 4th and 5th gear miles on freeways and highways. The hesitation was "maybe"(?) less, but I did get awesome (comparatively) milage. The milage went up to over 20 from an average of 14.

dzx · Post by **dzx** » Mon Jun 02, 2008 2:24 am

when you cut the blue wire, did you ground the side coming from the ecu?

douglas vincent · Post by **douglas vincent** » Mon Jun 02, 2008 3:40 am

You T- the wire, not cut, and ground.

Arctic Assassian · Post by **Arctic Assassian** » Mon Jun 02, 2008 4:54 am

I need to get me one of these.

dzx · Post by **dzx** » Mon Jun 02, 2008 7:06 am

Thanks Doug, that would have driven me mad for a while.

Boostedballs · Post by **Boostedballs** » Tue Jun 10, 2008 2:02 am

Ok, so I will see a performance increase by switching my aluminum MAF for the plastic one from a N/A car?

What's the deal with the Nissan MAF?

I'm still having issues with surging under boost and the MAF and MAP are my next shotgun parts.

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Installing a JEC MAF in place of the Aluminium MAF - results

Installing a JEC MAF in place of the Aluminium MAF - results