# revs



## Pondo (Feb 21, 2008)

i am having a prob with my tach my rev count not showing anymore how do u rectify this issue


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## rogoman (Dec 16, 2004)

The tach unit itself may be bad or the electrical connectors are not secure.

By the way, it would be nice if you could tell us what car and motor combo you have. We're here sitting in front of a computer monitor, not by your car.


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## Pondo (Feb 21, 2008)

oh my bad sorry abut that....

91 NX Coupe - 1.6L
GA16DE
N/A for now will do turbo soon
Bone Stock
SAFC II installed

am not even gettin a count on the SAFC am worrying if i have the wrong wire to the AFC...manual for AFC does hav diagram for ga16 searched n found that its a blue/orange wire. Tried a different ECU, tried a different tach( out of a car thats its workin) and same thing no rev count..

My engine just got rebuilt n now i dont have revs showin so i can tune proply..


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## rogoman (Dec 16, 2004)

Check all the ground connectors.


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## BeyondBiscuits2 (Jan 18, 2006)

What diagrams did you use to install your S-AFC 2? Depending on where you got the information, they could have told you the wrong wire combos. When we installed a knob-style S-AFC on my GA16DE, the wire listed for the MAF was wrong, we had to source the correct one. Did Apex'i provide you with all the information?


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## Pondo (Feb 21, 2008)

i got that info from a thread sumwhere on here...all other wires matched up correct, i had that no RPM read issue b4 rebuild of engine(ECU damaged also n got repaird)...problem still there after rebuild n everything is hooked back up proply...like a said tried a dif custer n dif ecu out of similar car to see if its just my repaired ecu n still no RPM read out...
I used a fsm on a b13 1993 sentra to try to locate that RPM wire (found a thread sayin RPM read outs can be found from wire from distributor or MAF) thought it would be sumwhere on transaxle..anyho - i notice that an orang/blu(93 FSM) wire can be found on the MAF,distributor and ECM relay all tied in together...I took a look at mine n saw 2 orange wires on MAF and Distributor n 1 on ecm relay..so i remove safc wire from blu/org n spliced it to ecm relay its tied in to the 1 from MAF and distributor accordin to FSM (playing smart).... Well it didnt work, so i went ahead and tried the other 2 orange wire on ECU but no luck...

dont know wat the heck else to do n fsm for 91 nx ga16de is so freaking hard to find...


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## BeyondBiscuits2 (Jan 18, 2006)

Well, I have the wiring diagram for the '91-'94 Sentra and NX1600 in front of me, and the orange/blue wire you speak of goes to the E.C.C.S. relay and from there to the CPS sensor. My best guess is to the try the blue/white wire from ECU position 3. It goes from the ECU to the ignition coil. The B13 GA16DE and B13 SR20DE ECUs are interchangeable, and on the SR20DE wiring diagram, position 3 simply says "tachometer". Try that wire and see what you get.

As for the throttle position sensor you messaged me about, on the ECU, positions 20 and 37 are wired to the TPS on the B13 GA16DE. Position 20 is a white wire (I assume signal), and position 37 is a red wire (I assume power). There is also a grey wire that comes off the TPS, which I am assuming is the ground. That wire also runs through the engine coolant temperature sensor and EGR temperature sensor before linking with the ECU at positions 21 and 29.

If you had a 2nd generation GA16DE (OBDII), tach signal is incredibly easy. You just simply look at the distributor (which has the coil built inside), and trace the two wires coming off of it (I believe blue and black). The blue wire, which hits the ECU at positions 22 and 30 (it branches itself for some reason) is your tach signal. At least, that is the wire you use to run an aftermarket tachometer off of. But, since the 1st generation GA16DE (OBDI) has a separate coil, you get into a whole different wiring situation.


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## Pondo (Feb 21, 2008)

first off if i dont have a diagram showin positions i cant say i know the positions ur talking about lol....so ill do this blind

ok ...i came home today located my throttle sensor n took note of the wire...them very same colors were there so i decided to take a look at that ecu again...my harness hav 2reds on one side n so does diagram 4a so i jus counted off to throttle n found the same white wire thqt had knock sensor soliced on (there is a thread here that have it this way trust me)..hok uo throtle turn on afc n bam damn thing showin when am depressin n unlike b4 stock @ 100%(SmILE ON FACE YESSSS FINALLY)

so now where does the wire for knock sensor go..counted off from throttle end up on a white red wire (is this correct)..

looked at MAF plug up n saw green yellow, white, 2 oranges no orange/blu...count off again n found same grn/yellow so i go ahead n cut that...my thrt position is set 30lo 80hi when ignition is on, AFL goes to jus about 35.6 (is this what suppose to happen) goes back to 0 on turn offf..

my distributor has blak,orng,blu,yel no orng/blu or blu/orng what ever and 
coil have grn/yel and blk/red so nope no blu/white...
conden/resis got grn/yel, blk/blu,blk,red,blu
....... why they aint jus make one damn standrd thing jeesh is same car... so here again stuk with no RPM...and remember no rpm is on my cluster wish i could put my cluster in ur car to see if its my cluster the prob...used another ecu n still got no rpm read out on cluster... if it says tachometer it might be the one leading to clustor..right?

now tuning...cant i have a good fuel save set up for everyday drive on 1 saved data n a rich burn setup for racing on the other since theres 2, even tho am N/A...need help setting up ma high - low also if you dont mind...


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## BeyondBiscuits2 (Jan 18, 2006)

I will have to send you a copy of my wiring diagram, I'll have to scan it as soon as I get home.


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## Pondo (Feb 21, 2008)

much appreciated


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## Pondo (Feb 21, 2008)

u hav forgotten me friend...still waiting on that diagram!


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## BeyondBiscuits2 (Jan 18, 2006)

Sorry, I have been having trouble with it. I have Windows Vista on my laptop, and our scanner is apparently not compatible with it (its a few years old). So, I am hoping to be able to stop over at my friend's house and use his, but he hasn't answered my phone calls and I had to work all weekend. I'll get them to you as soon as I can, I promise!


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## BeyondBiscuits2 (Jan 18, 2006)

Here you go... found this on Autozone's website. Looked all over the internet for this stupid thing, and while looking for a part this afternoon, found it for you. Hope it helps.










Here are also the chassis wiring diagrams for the B13 Sentra and N14 Pulsar.


















P.S., do you know what number the GA16DE MAF is? The S-AFC 2 manual says the S14 is 5 in 5 out, and the Z32 is 2 in 2 out, but I could find nothing for the GA16DE. I have a Maxima MAF we will eventually use, and my friend knows it is coded number 3, but still nothing for the GA16DE.


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## Pondo (Feb 21, 2008)

i found online one guy sayin 02 14 for z32 maf and 14 14 for b14's i bin using that since...

i see it hav MAF sensor is it this wire am suppose to cut to use for AFL on AFC .....or is the grn/ylw from the MAF meter

these are so different from what i have cuz for example in the distributor i have no org/blu in it just a plain orange..in MAf its 2 oranges no org/blu i guess my harness is stil way different from the b13 sentra's or the N1 pulsar...

do u use the knock signal... i dont know which tihs is eether..diagram doesnt have it


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## BeyondBiscuits2 (Jan 18, 2006)

Pondo said:


> i found online one guy sayin 02 14 for z32 maf and 14 14 for b14's i bin using that since...
> 
> i see it hav MAF sensor is it this wire am suppose to cut to use for AFL on AFC .....or is the grn/ylw from the MAF meter
> 
> ...


First of all, thanks for the info on the S-AFC 2, I'll try the 14 14 setting and see what I get (since I technically have a B14 MAF).

Now for your question; the air flow wires on the S-AFC are designed to intercept the signal from the meter to the ECU. That is how it adjusts the voltage and such to affect airflow. You want to connect the white wire to the side of the airflow wire facing away from your ECU itself. You then connect the yellow wire to the side of the airflow wire facing in the ECU.

(air flow wire)---^(white wire) (yellow wire)^---(ECU)

Depending on where you are and where your car was manufactured, the actual colour of the wires might be different. Basically, it may be trial and error before you find exactly what wire you are supposed to use. As to whether to use the MAF sensor or MAF meter, I figure you'd want to use the sensor? After all, the sensor is the thing itself that actually measures the airflow ratio. Try that green wire first, and if it is a no go, go for the MAF meter.

As for the knock sensor, I know most people do not actually use it. I think it is probably important, since you don't want to be getting detonation and not detect it through your S-AFC 2. I also have checked the diagram, and cannot find the knock sensor wire on the ECU. Your best bet in this case is to simply crawl under your car, cut the signal wire from the knock sensor itself, and splice the purple S-AFC 2 wire in at that location and then run it through the firewall. It might save you a good deal of time trying to find the position on the ECU.


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## Pondo (Feb 21, 2008)

BeyondBiscuits2 said:


> First of all, thanks for the info on the S-AFC 2, I'll try the 14 14 setting and see what I get (since I technically have a B14 MAF).
> 
> Now for your question; the air flow wires on the S-AFC are designed to intercept the signal from the meter to the ECU. That is how it adjusts the voltage and such to affect airflow. You want to connect the white wire to the side of the airflow wire facing away from your ECU itself. You then connect the yellow wire to the side of the airflow wire facing in the ECU.
> 
> ...


Man i wish i could shake u hands ur bin the most help and only person giving help in plenty details

ok i really think ill stay with MAF meter cuz diagram has red and green from ECU an there is no such on mine LOL no solid greens but it has me wondering now about the 2 red wires on the ECU i thought these were hot wire but they not, they dont power the AFC so i used an alternate source could one of em be the sensor wire...... man my harness gettin a lotta surgury done on it...

Results - 
green/yel wire on ecu that i also see on maf harness...i had my thrt positon set 30 80 and everytime i turn into ignition it the reading hits 27-30 it doesntt move much really even at full thrtle turn on car just about the same...Now i tried the white it goes straight to 100% (thickest one that i see in MAF) its the only other thick 1..the other is ther thrtl position sensor which is workin fine... Now i move it to 10 -50 and the reading is below 10 when i turn into ignition does basically the same thing again....

Could it be because i havnt set my Hi Lo's as yet it affects the reading showin me that it using this amount of airflow since no air correction is set (still at 0).....

ON to knock signal i hav it wired to a whit/red wire same postion i got from manual since i dont see any on any diagram here...now once my car on n i do sensor chek i get a voltage... if i do knock setting i get a reading if i go to monitor a reading is there but goes to 0 on open throttle..so this only works on idle right? u say go under my car no wireing under there....in my engine i only have crank angle sensor,ignition coil,resistor condensor, power transistor, aflow meter,fusablbe plugs,altnator.ac,radiator, throotle sensor, power steerin pressure switch, oil pressure switch,FICD solenoid valvle and thermostat..thse are the only plug ups i have in the engine area so my conclusion is the just ignore it cuz ma car dont support knock sensor, what do u thnk? throtle sensor n RPM is coming strait off harness...


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## BeyondBiscuits2 (Jan 18, 2006)

Pondo said:


> Man i wish i could shake u hands ur bin the most help and only person giving help in plenty details
> 
> ok i really think ill stay with MAF meter cuz diagram has red and green from ECU an there is no such on mine LOL no solid greens but it has me wondering now about the 2 red wires on the ECU i thought these were hot wire but they not, they dont power the AFC so i used an alternate source could one of em be the sensor wire...... man my harness gettin a lotta surgury done on it...
> 
> ...


Sounds like having a B13 Sentra is terrible in terms of S-AFC 2 installations. I wish I could help you more, but I have a B14 GA16DE wiring harness and ECU and they are not the slightest bit compatible .

As for the MAF, the green/yellow wire denotes around 27-30% in terms of air flow, and the white denotes 100%? Hmm, I don't know what to tell you. I haven't installed mine yet, so I don't know what is normal for the airflow rating with everything zero'd out on the S-AFC 2. Perhaps you should call Apex'i and ask them? They weren't any help to me, but maybe they can better answer your question than I can.

As for the knock sensor, maybe the B13 Sentra simply did not have one? It should be a little device bolted onto the block that detects an engine knock and shuts down the engine accordingly. I am not sure when Nissan made this a mandatory feature on their vehicles. If you can't find it, don't worry about it, that's my advice.


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## Pondo (Feb 21, 2008)

BeyondBiscuits2 said:


> Sounds like having a B13 Sentra is terrible in terms of S-AFC 2 installations. I wish I could help you more, but I have a B14 GA16DE wiring harness and ECU and they are not the slightest bit compatible .
> 
> As for the MAF, the green/yellow wire denotes around 27-30% in terms of air flow, and the white denotes 100%? Hmm, I don't know what to tell you. I haven't installed mine yet, so I don't know what is normal for the airflow rating with everything zero'd out on the S-AFC 2. Perhaps you should call Apex'i and ask them? They weren't any help to me, but maybe they can better answer your question than I can.
> 
> As for the knock sensor, maybe the B13 Sentra simply did not have one? It should be a little device bolted onto the block that detects an engine knock and shuts down the engine accordingly. I am not sure when Nissan made this a mandatory feature on their vehicles. If you can't find it, don't worry about it, that's my advice.


friend you been a great help.... am thinking of saving up to get a sr swap cuz it seems like they aint got nuttin for GA16 guys that wanna use em as projects... if too much is done to em am sure itll blow...


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## BeyondBiscuits2 (Jan 18, 2006)

I don't know, I think the GA16DE is a great powerplant. It is underrated, and can pull some real power, but you do have to spend some money. Wes has some good horsepower numbers on his GA16DE(T), and several other members here have similar results on stock internals. If you upgrade to the GA16i rods, I am sure you can pull at least 300hp using a turbo kit. After all, who all has gone as big as a T3/T4 or Holset HY35 turbo on their GA16DE? I don't know of any, but I am sure the engine could take it.


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## BeyondBiscuits2 (Jan 18, 2006)

Found out something new that might help you out, Pondo. The '95-'98 MAF setting for the GA16DE is 01 01. That might help you out since you said you were running 14 14. I tried that setting on my GA16DE, and it bogged down and ran rich. The 01 01 is running perfect. Also, my friend said not to worry about running the knock sensor, A'pexi doesn't have good software to detect it very well. You're better off not running it and let the engine's ECU detect knock on its own.


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## Pondo (Feb 21, 2008)

BeyondBiscuits2 said:


> Found out something new that might help you out, Pondo. The '95-'98 MAF setting for the GA16DE is 01 01. That might help you out since you said you were running 14 14. I tried that setting on my GA16DE, and it bogged down and ran rich. The 01 01 is running perfect. Also, my friend said not to worry about running the knock sensor, A'pexi doesn't have good software to detect it very well. You're better off not running it and let the engine's ECU detect knock on its own.


no wonder my car running so flippin slow n sounds like if its gettin too much gas...02 14 which i using right now is giving same results ill try in those TOday....am stil trying to figure out wha the heck is wrong why i cant get my tach in cluster to work....all fuses lookin good, wiring is good....


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## BeyondBiscuits2 (Jan 18, 2006)

Might just be the tach is faulty. It happens sometimes. The S-AFC 2 has a setting on the display where you can view RPMs, just set it on that and forget about the tach, I'd say.


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## Pondo (Feb 21, 2008)

tired a another workin ECU didnt even help
tried a working Tach on my ECU didnt help eetha

Ill try a analog tach see if it works....if not ill try a working ecu with working tach....workin killin me out so i cant get to do these run arounds


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