Hi,
I am having very strange problems with my car ... and the problem is that the problem comes and goes.
The jist of it is that it sparatically goes into fail safe mode, then out ... then in ... at the worst possible times, it also use to stutter really bad under load. As the temperature increases, the stuttering problem seems to go away. So heres what i've done.
Changed the fuel filter. Put in new plugs, with gap of .31. Changed the MAFS. Checked MAFS connection wiring. Checked fuel pump wiring. Added grounds from - terminal to body, block to body.
After doing that, the car was running really great!, no more stuttering but it would still go into fail safe mode. So i did some more.
Changed the TPS, reset the new one for about .5v at idle. Checked the ECU harness plug where it goes into ECU ... there was some corrosion dust on the plug for the ambient temp sensor, i cleaned it off with some sandpaper. The ECU ground was weak, and broke while i was checking it out, so i resoldered. I found the MAFS signal wire, i checked the conductivity from the plug into ECU to where the white wire goes into the grey cover (with the ground around the outside) i also checked the ground around the white wire, and all the other MAFS wires, i could only get conductivity from the signal wire (which is what should happen). I also checked the wiring from the MAFS plug all the way to where it goes into the grey cover ... and then the signal is good going into the ECU. I also added an extra ground to the MAFS connection (at the actual MAFS) and grounded it to the body. I unplugged the battery for almost a day to let the ECU really reset.
So after all this ... well tonight, i drove the car around, the car did not go into fail safe mode (though this doesnt mean its fixed because it goes in and out of it), i drove for about 7 minutes. Heres what was strange though, the ECU light was on the entire time i was driving ... what does this mean?, i checked codes after i replugged in the battery after it has been unplugged for almost a day, i got the code for TPS and MAFS, shouldnt unplugging the battery for the day clear the codes? or is my ECU detecting a problem already ... Also, the car feels a little under powered after the initial acceleration so above 3500, and very occasionally hiccups under throttle, like the timing is off. ... i dont want to, re do timing, i know this is frowned upon, but can i just rotate the CAMS till it feels right again?
I know there is a lot in the post, but its been a few weeks of frustration all in one post.
Do you think i fixed the problem? my last resort is to just wire the MAFS signal wire straight to the ECU harness plug, and maybe the coolant temp wires too.
Thanks
´Nik
Please help with SR20 electrical problem
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Jesse SR20
- Posts: 280
- Joined: Fri Jun 25, 2004 8:37 pm
- Car: 1990 S13 fastback
- Location: Your mom's house.
Re: Please help with SR20 electrical problem (skyliner)
Have you tried using a different ecu ?
Just a thought.
Just a thought.
Re: Please help with SR20 electrical problem (Jesse SR20)
I have not, but i dont know anyone with an SR20 in my area ... damn canada.
What does it mean if the ECU light is on while you are driving?
If my car feels just alittle bit out of timing since i switched the TPS, can i just rotate the CAMS a little to fix it without redoing timing all around?
What causes a sparatic entering and exiting of safe mode?, could fixing the ECU ground, adding another ground to the MAFS, and cleaning up the ambient temp prong fix the problem?
... ****, someone wants to buy my car this weekend, and i don't want to sell a car that goes in and out of safe mode ... i can't do that, i need this fixed asap.
What does it mean if the ECU light is on while you are driving?
If my car feels just alittle bit out of timing since i switched the TPS, can i just rotate the CAMS a little to fix it without redoing timing all around?
What causes a sparatic entering and exiting of safe mode?, could fixing the ECU ground, adding another ground to the MAFS, and cleaning up the ambient temp prong fix the problem?
... ****, someone wants to buy my car this weekend, and i don't want to sell a car that goes in and out of safe mode ... i can't do that, i need this fixed asap.
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SpeedRacer1
- Posts: 3144
- Joined: Fri Jul 26, 2002 7:44 pm
- Car: 1990 240SX, G35
Trying to change the cam timing is a stupid idea.
What do you mean by safe mode, the ECU runs in different safe modes depending on the sensor thats malfunctioning. The ECU light should be on while the car is on. To reset codes all you have to do is fix the errors, rotate the screw back to the other position and start the car.
I would try messing with your TPS a little bit, even the slightest changes to the voltage can cause it to run differently.
What do you mean by safe mode, the ECU runs in different safe modes depending on the sensor thats malfunctioning. The ECU light should be on while the car is on. To reset codes all you have to do is fix the errors, rotate the screw back to the other position and start the car.
I would try messing with your TPS a little bit, even the slightest changes to the voltage can cause it to run differently.
Re: (SpeedRacer1)
Hi Speedracer, ... actually i've searched on these forums quite a bit, and was hoping you'd respond.
I wont touch my timing then, ill play with the TPS to get my power back.
When i say fail safe mode, i mean limp home mode, as in i can't rev past 2400rpm, and the problem comes and goes, sometimes it hits it, and i can keep the revs constant and it jumps back up and revs higher, then hits it and waits till i let off the trottle and then the fuel cut goes away. Other times its really pronounced. I was reading the FSM, and it said that the ECU only goes into this mode when there is a problem with the MAFS, on a random website, they say the coolant temp sensor can do this too, im doubting that though.
I've tried to fix these problems (ECU reading TPS and MAFS), i've replaced my TPS, and it made a huge difference in throttle response, so i doubt that it is the problem, plus i've heard ... well from you, that you can run without the TPS. I've changed the MAFS, i've checked the wiring from the MAFS to where it goes into the protective grey wire (with the insulating ground), and i've checked conductivity from that point to the ECU, it was good, i also checked the insulating ground to the MAFS signal wire on the ECU, there was NO conductivity, so im assuming that its not shorted from that point to the ECU ... I also added an extra ground from the connector to the MAFS, to the body.
I'm glad that the ECU light being on while im driving isnt a bad sign, but it never used to be on while i drive (this was before i started code checking though).
I'm running out of time and wits with this car. My next step is to by pass the main harness with the MAFS signal wire, ie, solder a new wire to the MAFS signal wire, then run that beside the main harness and then solder it where it reaches the ECU. If there is a short somewhere, this should stop it from effecting the MAFS ... keeping me out of fail safe mode.
If this doesnt get rid of the code , well im out of ideas, maybe the ECU is garbage.
I wont touch my timing then, ill play with the TPS to get my power back.
When i say fail safe mode, i mean limp home mode, as in i can't rev past 2400rpm, and the problem comes and goes, sometimes it hits it, and i can keep the revs constant and it jumps back up and revs higher, then hits it and waits till i let off the trottle and then the fuel cut goes away. Other times its really pronounced. I was reading the FSM, and it said that the ECU only goes into this mode when there is a problem with the MAFS, on a random website, they say the coolant temp sensor can do this too, im doubting that though.
I've tried to fix these problems (ECU reading TPS and MAFS), i've replaced my TPS, and it made a huge difference in throttle response, so i doubt that it is the problem, plus i've heard ... well from you, that you can run without the TPS. I've changed the MAFS, i've checked the wiring from the MAFS to where it goes into the protective grey wire (with the insulating ground), and i've checked conductivity from that point to the ECU, it was good, i also checked the insulating ground to the MAFS signal wire on the ECU, there was NO conductivity, so im assuming that its not shorted from that point to the ECU ... I also added an extra ground from the connector to the MAFS, to the body.
I'm glad that the ECU light being on while im driving isnt a bad sign, but it never used to be on while i drive (this was before i started code checking though).
I'm running out of time and wits with this car. My next step is to by pass the main harness with the MAFS signal wire, ie, solder a new wire to the MAFS signal wire, then run that beside the main harness and then solder it where it reaches the ECU. If there is a short somewhere, this should stop it from effecting the MAFS ... keeping me out of fail safe mode.
If this doesnt get rid of the code , well im out of ideas, maybe the ECU is garbage.
Re: (skyliner)
Update,
I went out and adjusted TPS, got some more power back, but still feels slower than usual.
I tested my MAFS at two different spots. 1 right at the MAFS, and the other at the ECU. Both where giving the proper numbers.
0.8v on1.7v~1.8v idleapprox 2.1 at 2500vI even grabbed the harness at spots and was shaking it, to see if it would effect the signal, and it didnt.
Checked codes and was getting, TPS, MAFS, and A/T controller (my car is 5sp, but ecu is a 63)
So i took her out for a long drive 30min, highway and street. She was running so smooth, it was great, but it felt like when i pressed the throttle down and held it at a certain spot, the car would do really quick stuttering, and either a) stop stuttering and keep accelerating, or b) the stuttering would get really fast and close together, and then i would get a fuel cut, that would go away really quickly, or until i let off the throttle some. Then i could just keep driving like nothing ever happened. The stuttering happened maybe 4 - 5 times the entire trip, and the fuel cut happened twice.
Anyone know what could be causing this, or any ideas that i could try. Frankly im out of ideas, im begining to think that the ECU is going. I desperatley need this fixed by saturday.
I went out and adjusted TPS, got some more power back, but still feels slower than usual.
I tested my MAFS at two different spots. 1 right at the MAFS, and the other at the ECU. Both where giving the proper numbers.
0.8v on1.7v~1.8v idleapprox 2.1 at 2500vI even grabbed the harness at spots and was shaking it, to see if it would effect the signal, and it didnt.
Checked codes and was getting, TPS, MAFS, and A/T controller (my car is 5sp, but ecu is a 63)
So i took her out for a long drive 30min, highway and street. She was running so smooth, it was great, but it felt like when i pressed the throttle down and held it at a certain spot, the car would do really quick stuttering, and either a) stop stuttering and keep accelerating, or b) the stuttering would get really fast and close together, and then i would get a fuel cut, that would go away really quickly, or until i let off the throttle some. Then i could just keep driving like nothing ever happened. The stuttering happened maybe 4 - 5 times the entire trip, and the fuel cut happened twice.
Anyone know what could be causing this, or any ideas that i could try. Frankly im out of ideas, im begining to think that the ECU is going. I desperatley need this fixed by saturday.
Re: (NateDogg)
I did check the plugs, changed them. It made the car run better, but didnt fix the problem. I also checked the resistance of the coilpacks, they were all ohkay.
The FSM said that the car will only go into the limp home fail safe mode if there is a problem with the MAFS. So im going to try to change that again, and then re adjust my TPS somemore. I changed the MAFS way back at the begining, perhapse it was also fuct. It was a junkyard MAFS.
Thanks for the ideas though.
The FSM said that the car will only go into the limp home fail safe mode if there is a problem with the MAFS. So im going to try to change that again, and then re adjust my TPS somemore. I changed the MAFS way back at the begining, perhapse it was also fuct. It was a junkyard MAFS.
Thanks for the ideas though.
Re: Please help with SR20 electrical problem (skyliner)
have you check for a hole in your innercooler or if all the inercooler hose are connected? check o2 volt during normal driving
Re: Please help with SR20 electrical problem (xero1)
I did check my IC piping, i actually havent checked the intercooler itself, ... i think i will tomorrow, though im pretty sure its awesome :P
I havent checked the o2 sensor either, this is because i drove without an o2 sensor for over a year before i replaced it, with no problem other than running rich.
I'm thinking, im going to check the wiring around the battery (the plugs you have to rewire for the SR swap). Thats the only wiring that ive done and havent re-checked.
... heres a question to whoever is reading this. Oil blowby, what kind of problems can this cause? because im getting some in the intake, could this be messing up my MAFS, hence the problem?
I havent checked the o2 sensor either, this is because i drove without an o2 sensor for over a year before i replaced it, with no problem other than running rich.
I'm thinking, im going to check the wiring around the battery (the plugs you have to rewire for the SR swap). Thats the only wiring that ive done and havent re-checked.
... heres a question to whoever is reading this. Oil blowby, what kind of problems can this cause? because im getting some in the intake, could this be messing up my MAFS, hence the problem?
Re: Please help with SR20 electrical problem (skyliner)
So today i rewired the plugs by the battery, 1 had some corrosion dust on it, i dont know if it was enough to hurt anything.
Adjusted the TPS to exactly 0.450V at idle. Couldnt find the idle switch though.
Took off my intake and cleaned all the oil out of everything, all the way into the turbo, then i plugged the hole that delievers the oil, and let the T in the valve cover vent to atmosphere for now, until i get a breather filter.
So when i drove her, she still felt slowish, and i would get popping out the back at certain spots, but it would go away if i pressed the throttle down more. The cars timing is definately off, lol i sound like a rally car with ALS a bit, i rev up and it pops all the way down again, sounds sexy, and i get unbelieveable pull when i floor it. Which would be the timing.
so thats tomorrows project, changing the timing by removing valve cover.
Adjusted the TPS to exactly 0.450V at idle. Couldnt find the idle switch though.
Took off my intake and cleaned all the oil out of everything, all the way into the turbo, then i plugged the hole that delievers the oil, and let the T in the valve cover vent to atmosphere for now, until i get a breather filter.
So when i drove her, she still felt slowish, and i would get popping out the back at certain spots, but it would go away if i pressed the throttle down more. The cars timing is definately off, lol i sound like a rally car with ALS a bit, i rev up and it pops all the way down again, sounds sexy, and i get unbelieveable pull when i floor it. Which would be the timing.
so thats tomorrows project, changing the timing by removing valve cover.