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.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.
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.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.
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).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.
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
Are you knowledgable on the SR20DE at all? If not, please don't comment.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.
This is what i was talking about....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.
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.
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.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