# Regrounding the MAF



## 94SE-R_wi (Sep 14, 2004)

Is it true that if you reground the MAF you will get a few extra HP. i read in a mag. that the B13's had problems with the ground wire on the MAF's.
-ben


----------



## Twiz (Aug 24, 2004)

The MAF housing doesn't have anything to do with the sensor inside. Later models have a plastic MAF housing. The sensor is a resistor which changes its value according to its temp (amount of air needed to cool it down). That's why you risk to screw up the MAF if you disconnect the housing from the rest of the throttle body while engine is running. The resistor gets too hot... no air to cool it down...therefore it gets shot. It wasn't grounded when Nissan put it in there... I wouldn't ground it... you may get a short in between the sensor and housing... I'd say very rare but possible.


----------



## 94econobox (Dec 1, 2004)

Twiz is right, the housing has nothing to do with a hot-wire sensor, such as the MAF. Tricking the sensor into thinking more air does nothing to help you, it'll just screw up your air to fuel ratio and cause the ECU to work harder trying to figure why the MAF and O2 sensors don't agree on your mixture. I'd focus on getting more air into that senso instead.


----------



## lshadoff (Nov 26, 2002)

94SE-R_wi said:


> Is it true that if you reground the MAF you will get a few extra HP. i read in a mag. that the B13's had problems with the ground wire on the MAF's.
> -ben


With time, the electrical connections under the hood slowly degrade. Usually this is not a problem, but in the case of the MAF signal it can be a problem. The signal wires from the MAF are surrounded by a grounded shield to reduce noise in the signal. A marginal ground connection to the shield degrades the MAF signal sent to the ECU, and the engine runs poorly. Running a good ground to the MAF ground wire at the connector restores the MAF to its original operation, and the lost horsepower from the bad ground is regained.

Lew


----------



## Twiz (Aug 24, 2004)

Of course you can test the signal sent to ECU with and then without the ground and you'll notice no diff in voltage.


----------



## lshadoff (Nov 26, 2002)

Twiz said:


> Of course you can test the signal sent to ECU with and then without the ground and you'll notice no diff in voltage.


The problem is not that there is no ground to the shield. The problem is that a poor ground will put a slight varying voltage on the shield (noise), and affect the MAF signal. Did you measure the MAF signal with an oscilloscope to +/- 0.005v? That is the voltage change that the ECU can measure, and noise greater than that will affect the A/F ratio.

Lew


----------



## Twiz (Aug 24, 2004)

Okay I'll take your word for it ... I give up


----------



## 94econobox (Dec 1, 2004)

It would be very sloppy engineering on Nissan's part not to filter the incoming signal at all. That's really not something I'd expect given their engineering track record. Also, since this is a two-input control system, I doubt any noticeable performance increase due to an improved shield ground or reduced contact resistance for the element. All in all, this won't hurt anything, but don't expect this to be a serious upgrade.


----------



## lshadoff (Nov 26, 2002)

94econobox said:


> It would be very sloppy engineering on Nissan's part not to filter the incoming signal at all. That's really not something I'd expect given their engineering track record. Also, since this is a two-input control system, I doubt any noticeable performance increase due to an improved shield ground or reduced contact resistance for the element. All in all, this won't hurt anything, but don't expect this to be a serious upgrade.


There is no performance increase from grounding the MAF. It is not a mod. It is correcting a fault, so you get back the power lost by the MAF not adjusting the A/F correctly (which reduces the power and/or economy).

Lew


----------



## 94econobox (Dec 1, 2004)

Yeah, what he said.


----------



## 94SE-R_wi (Sep 14, 2004)

Thats really what i ment to say(get back the power loss). i was just wondering ifyou all have ever heard of it. So Thanks guys.
-ben


----------



## Twiz (Aug 24, 2004)

You could ground it and see if you feel any difference which I highly doubt then test drive it for a few days then you could remove the ground lead if it's useless.


----------



## NismoPC (Jul 28, 2002)

Twiz said:


> The MAF housing doesn't have anything to do with the sensor inside. Later models have a plastic MAF housing. The sensor is a resistor which changes its value according to its temp (amount of air needed to cool it down). That's why you risk to screw up the MAF if you disconnect the housing from the rest of the throttle body while engine is running. The resistor gets too hot... no air to cool it down...therefore it gets shot. It wasn't grounded when Nissan put it in there... I wouldn't ground it... you may get a short in between the sensor and housing... I'd say very rare but possible..





Twiz said:


> Of course you can test the signal sent to ECU with and then without the ground and you'll notice no diff in voltage.





Twiz said:


> Okay I'll take your word for it ... I give up





Twiz said:


> You could ground it and see if you feel any difference which I highly doubt then test drive it for a few days then you could remove the ground lead if it's useless.


Are you knowledgable on the SR20DE at all? If not, please don't comment.

Nissan addressed this issue several years ago in a publically posted TSB and even explains how to do it. It was a fault that needs fixed on several years of SR20's. This is a common problem amongst the Nissan community of SR20 owners. 

The earlier MAF ground is located on the intake manifold and corrodes over time within the insulator (ODB-I). The later years ground is connected directly to the ECU (OBD-II), but still run into the same issue. 

Basic fix: Leave current ground alone and connected. Add new ground wire to the MAF connector, then connect other end to centralized engine ground. This is located on the intake manifold.

Will take care of engine purging, loss of power, etc.

http://www.se-r-list.org/TSBs/NTB93-118-1.jpg
http://www.se-r-list.org/TSBs/NTB93-118-2.jpg


----------



## Exalta (Jan 21, 2003)

That would be a nice enhancement since the tropical weather here is eating up my engine wires fast.

Anyone got pics?


----------



## Jed118 (Nov 15, 2004)

My experience with nissan MAF's is that they are garbage. That's why my GA16DE has 3 spare MAFs stolen from junkyards... I always pull these when I can!

**edit

Shit maybe I should start taking the harnesses instead (or in addition to) MAFS. My car does "stumble" sometimes and hesitate... same as with the 91 maxima I had! Im going to do this TSB to my sentra as soon as it's closer to 0 deg outside... it's bloody cold out there now!!!


----------



## 94SE-R_wi (Sep 14, 2004)

NismoPC said:


> Are you knowledgable on the SR20DE at all? If not, please don't comment.
> 
> Nissan addressed this issue several years ago in a publically posted TSB and even explains how to do it. It was a fault that needs fixed on several years of SR20's. This is a common problem amongst the Nissan community of SR20 owners.
> 
> ...


This is what i was talking about....
Now would this "power loss ect. " happen all the time if the ground was corroded? I have been having some engine power loss..i just dont think its running up to par. Now you said to run another wire to a engine ground? So do i splice into the current ground? Or do i runa whole new ground and disconnect it from the other ground? Thanks
-ben


----------



## NismoPC (Jul 28, 2002)

94SE-R_wi said:


> This is what i was talking about....
> Now would this "power loss ect. " happen all the time if the ground was corroded? I have been having some engine power loss..i just dont think its running up to par. Now you said to run another wire to a engine ground? So do i splice into the current ground? Or do i runa whole new ground and disconnect it from the other ground? Thanks
> -ben


Leave the other ground alone. You need to splice into that ground right at the MAF connector pin. If at all possible, you should attempt to solder the new wire directly to the pin. Then put a round connector on the other end and connect that to the centralized ground location on your intake manifold. You should be able to see it. There will be a couple of ground wires going to this same bolt. Just loosen the bolt, put the new ground on with the others and your done.


----------

