How to test MAF to see if it's working?

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pumpiniron
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Re: (pumpiniron)

Postby pumpiniron » Mon May 07, 2007 5:12 pm

Ok so I put my ECU in diagnostic mode with the key in the ignition position and the light stays on the whole time but it doesn't flash or anything. Any idea what that might be?


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S13FASTBACKSR
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Re: (pumpiniron)

Postby S13FASTBACKSR » Tue May 08, 2007 2:59 am

If the ecu is good then it will throw a code 55....5 quick and 5 long flashes..if it doesnt flash at all your ecu is probably bad

pumpiniron
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Re: (S13FASTBACKSR)

Postby pumpiniron » Tue May 08, 2007 7:22 am

Oh dear... Bad ECU's, bad TPS, what next.

I'm going to get a TPS, find someone local with a ECU and test it out on my car first so that I know for sure if it's bad before I get a new one!

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S13FASTBACKSR
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Re: (pumpiniron)

Postby S13FASTBACKSR » Tue May 08, 2007 6:20 pm

i dont understand this..my ecu's l.e.d. does the diagnostic mode when the engine is running...??? lol wtf so wierd why is it different..this whole time ive been telling people to do it my way ive never heard of it opposite

pumpiniron
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Re: (S13FASTBACKSR)

Postby pumpiniron » Tue May 08, 2007 7:50 pm

How do you tell if an ECU is "bad"? I mean it seems to me if an ECU was bad it wouldn't even run or start up...

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S13FASTBACKSR
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Re: (pumpiniron)

Postby S13FASTBACKSR » Wed May 09, 2007 3:15 am

when you have a bad ecu it could do a number of things..only certain parts of it could go bad..Think of it like a brain..it has different parts of it that control different things of the body..the ecu has different parts of it that control different parts of the engine so therefore it could start up and run but run really bad..most of the time with a bad ecu the engine will start up..I just went back and read your problem again and it really sounds like the TPS especially since its sticking at 5v constantly..and when a tps would do that you would have the exact problems your having..I put my money on it that its def. the tps but hopefully not an ecu too..also to tell if an ecu is bad is to check the l.e.d. ....like i said i thought it stayed on when the engine is running but speed racer says if it doesnt blink when in diagnostic mode which is when the engine is off then its bad

pumpiniron
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Re: (S13FASTBACKSR)

Postby pumpiniron » Wed May 09, 2007 9:02 am

Well could the fact that the ECU is not blinking have anything to do with the fact that the TPS is unplugged during all of this?

Also it does blink I just noticed but only once...

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SpeedRacer1
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Postby SpeedRacer1 » Wed May 09, 2007 2:07 pm

The light is not the be all end all of how the ECU is working, its merely a tool. And like all things it doesnt always work good, or the same as every other ECU LED.

I doubt your ECU is bad, I am sure there is a reasonable explanation somewhere in your system. But without being there, diagnosing is hard to do.

pumpiniron
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Re: (SpeedRacer1)

Postby pumpiniron » Wed May 09, 2007 2:24 pm

My new TPS sensor gets here tomorrow, ordered a brand new one from a Sentra SE-R. So tomorrow we will know for sure if it really is just the TPS sensor or even worse!

pumpiniron
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Re: (pumpiniron)

Postby pumpiniron » Thu May 10, 2007 11:45 am

Installed the new TPS from the Sentra SE-R. Perfect fit so I can confirm it's a direct match! The car starts up and it doesn't seem to be running rich anymore at all HOWEVER it still runs like crap, has little to no throttle response, and misses at higher RPM's. I'm going to guess now that it's a bad ECU like suggested. I'm going to see if I can find someone local to let me borrow their ECU to test out!

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SpeedRacer1
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Postby SpeedRacer1 » Thu May 10, 2007 11:50 am

The TPS needs to be set perfectly. If its off by more than a mm or two in the wrong direction the car will still have drivability issues.

pumpiniron
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Re: (SpeedRacer1)

Postby pumpiniron » Thu May 10, 2007 11:59 am

Really? And how do I set it "perfectly"? Just keep messing around with it until the car sounds like it's running good?

Still it bothers me that my ECU light while in diagnostic mode just sits there with a solid LCD, doesn't blink or anything...

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SpeedRacer1
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Postby SpeedRacer1 » Thu May 10, 2007 1:04 pm

Closed voltage should be 0.15-0.85v.Full throttle voltage should be 3.5-4.7v.

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S13FASTBACKSR
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Re: (SpeedRacer1)

Postby S13FASTBACKSR » Thu May 10, 2007 2:18 pm

I always make sure my tps is as .45volts to .55volts at idle and 4.5volts at w.o.t. if you have these numbers and the same problem i think you also have a bad ecu on your hands

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Re: How to test MAF to see if it's working? (pumpiniron)

Postby SR20S13 » Thu Mar 20, 2008 11:26 am

yeah my car is having the same problem...

i checked my TPS and it was showing 11.8 ohms all the way closed when it shouldve be .7 ohms...and when i tried to adjust it it was always at like 11 or 12 ohms closed...

does this mean i have a bad tps?? which could be sendin my ecu into limp mode or what?!?!?

thanks for the help and goodluck with urs also...

AND I JUST SAW HOW OLD THIS THREAD IS...SORRY!

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sickzofive
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Postby sickzofive » Sun Mar 30, 2008 6:14 pm

my car completely shuts off when i plug my maf in and with it plugged in it wont even start... i just smell fuel from the inside... i take the maf harness off and voila she starts up ... i feel you , its frustrating..i have my own thread bout my issue.. i got a enthalpy tune and im having this problem. and my safc isnt even installed anymore.. GL on your prob.. if i come across anything ill let you kno

surfer240
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Re: How to test MAF to see if it's working?

Postby surfer240 » Thu Apr 15, 2010 5:11 pm

are u turning the screw on the ecu to get it to diagnostic mode? if the ecu led is on after the car is running for a few seconds ecu is bad i have delt with the same problem

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zachattack_5491
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Re: How to test MAF to see if it's working?

Postby zachattack_5491 » Sat Apr 17, 2010 3:38 am

This post has been brought back from the dead, but can anyone confirm how to tell if the ecu is bad? Ive spent a ton of money on buying parts and ive still got this same problem. Before I drop my entire budget for an ecu I'd really like to have a little verification that it's bad.

I've replaced the maf, o2, knock sensor, set tps and timing and I'm still blowing unburnt fuel from the exhaust.

Nismoowner66
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Re: How to test MAF to see if it's working?

Postby Nismoowner66 » Fri Jun 16, 2017 8:33 pm



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