MAF problem

[e_classic]

Problem: ONLY when on throttle between 1 ½ to 3000 rpm range engine breaks up (like its stumbling)

History:

Just bought a 95 240sx with about 116 thousand miles. Car was totally stock and had been sitting for about 1 ½ years.

I immediately did a minor tune up; changed oil, oil filter, air filter, and spark plugs.

Jocked it stock for about 1 ½ months until, I got a great deal on a S-AFC used from a friend. Car ran great, my only change to the stock settings was starting @ 3 thousand RPMs and higher I gradually leaned the engine out to 10% more air.

Problem started about one week after putting in the apexi controller.

Check engine light pops up.

Checked code on ECU. Reads CODE 12

I read a post on here somewhere to check the MAF wires at the intake. It reads 1.38 volts steady on my output wire @ idle and raises with my throttle. Is that my problem right there??? The post that I read said the output should read 0.5 volts @ idle. Positive and negative are straight (12volts steady).

Any help with this is greatly appreciated.

PS

All variables have been eliminated…such as

All connections to the ECU from the S-AFC I have check and double checked.

S-AFC was working great in my friends car….it went straight from his car to mine in under an hour.

Just to be sure a have disconnected the S-AFC and rerouted the MAF wire (if you’ve installed this controller you know what I am talking about.)

Still have same problem without S-AFC plugged in.

Thanks E

[NISTECH]

no on the .5 volts at idle. the idle voltage looks good. .5 volts is with the car off key on. do a good check on your air flows ground. it should be the wire that registers 0 volts. if it is more then .02 volts you need to run an alternate ground but keep the original in place or you'll still trigger the cel. splice into the original and run it to your intake manifold. see if this helps and post back

[e_classic]

Checked ground wire, it was reading .02 so i spliced in and grounded it to the intake manifold anyway. While i was doing that i disconnected the negative off my battery and let it sit. Once i was done with my wiring, i reconnected the battery and turned over the car and let idle for about 10min without any revs, letting the engine do its thing.

Unfortunately i didn't get far down my street before the same problems reoccured at the same rpm range.

As a side note, the problem is not constant. It occurs in spurts that last about 30-60secs with small delays in between that vary.I have noticed that the longer my drive the more often the problem occurs. It does not matter what gear i'm in or what speed. It will happen as i go through all the gears and while i'm crusin in 5th at what ever speed.

Thank you for your time- E

[NISTECH]

Can you get ahold of another known good air flow meter? if so try it out and see if it works.