Ok, I looked at the TPS stopper and the top few threads were dirty, like they had been exposed to the elements longer. So I moved it down to there and tried it out. The roughness seems to be gone now. It runs a bit rough, but I still need to calibrate the TPS like you said above. Not really sure how or why that would cause a momentary roughness, but whatever.
This stuff is what I tried the other day before learning the stopper should not be toyed with.
-I tried turning down the idle with the adjustment screw. It doesn't seem to do anything.
-Also, I remembered you shouldn't be able to start the motor on full throttle. Well, I can. AAC gummed up? The connection is still good. That might give reason for it running good still but just running way too high. Might need to take off the idle control stuff and clean it all up.
'91 240sx -Starts but won't run...
also, you said you have an AFC? check the splices to the efi harness. especially if you didnt solder the wires, you may have a bad splice. if you crimped the connections, or used vampire clips, you probably want to use a heavier connector or remove the connections and solder them.
if you can, get to the ecu, and check the voltages from the maf and tps at the back of the ecu harness.
if you can, the best way to do it is to check the voltage drop from the output of the sensor to the input of the ecu. you need long meter leads for that.
if you can, get to the ecu, and check the voltages from the maf and tps at the back of the ecu harness.
if you can, the best way to do it is to check the voltage drop from the output of the sensor to the input of the ecu. you need long meter leads for that.
just had to fix too many "installations" that involved twisting wires and black tape.
once you cut up the efi harness, and dont solder, the corrosion that builds up over time in the connection makes the resistance go up and causes wacky ecu responses. its just another culprit you have to rule out.
thats why i hate the splicers and vampire clips the companys throw in the boxes to ease installation. causes hard to find problems after time.
and if you are gonna use that crap, use some dielectric grease so the conection doesnt oxidize.
once you cut up the efi harness, and dont solder, the corrosion that builds up over time in the connection makes the resistance go up and causes wacky ecu responses. its just another culprit you have to rule out.
thats why i hate the splicers and vampire clips the companys throw in the boxes to ease installation. causes hard to find problems after time.
and if you are gonna use that crap, use some dielectric grease so the conection doesnt oxidize.
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PMan_S13
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- Car: Building car -> breaking car -> fixing car -> start over
any response about the air regulator? That technically would be an air leak, it is jsut inside the system.
I can look over the whole system again, but I've already searched for loose hose clamps and chewed up vacuum lines twice and found nothing.
I have checked the TPS for smooth voltage while applying throttle. It is travels without any dead spots.
I'll look at the ecu again. But the way I installed all the connections would make it difficult to corrode. I stripped a lot of the wire so I could double it over, then covered it with dilectric grease and put clear aquarium line over top of it before hooking the two ends together. So it's basically sealed together with grease. But I might as well take a look, just to put it out of mind.
As far as the full-throttle-start goes. Does the TPS have to read a certain voltage to send a "do not start" message to the ecu? That would at least be helpful in trying to sort out some of this mess.
I'm going to go put the air regulator and aac back on, check around for anything loose again, and get the TPS back on track and report back if anything good happens.
I can look over the whole system again, but I've already searched for loose hose clamps and chewed up vacuum lines twice and found nothing.
I have checked the TPS for smooth voltage while applying throttle. It is travels without any dead spots.
I'll look at the ecu again. But the way I installed all the connections would make it difficult to corrode. I stripped a lot of the wire so I could double it over, then covered it with dilectric grease and put clear aquarium line over top of it before hooking the two ends together. So it's basically sealed together with grease. But I might as well take a look, just to put it out of mind.
As far as the full-throttle-start goes. Does the TPS have to read a certain voltage to send a "do not start" message to the ecu? That would at least be helpful in trying to sort out some of this mess.
I'm going to go put the air regulator and aac back on, check around for anything loose again, and get the TPS back on track and report back if anything good happens.
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PMan_S13
- Posts: 575
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- Car: Building car -> breaking car -> fixing car -> start over
I'm thinking the problem is somewhere "inside" the system. Where ever the extra air is coming from, it must be getting registered. Otherwise I don't think it would run so well with such a huge intake leak.
I'm also wondering if it is even truely idling at all. I set the throttle body low enough so I can blow into the intake pipe and it will hold pressure. But it still is running really high. I can even unplug the harnass for the aac/air regulator and it keeps running, not as good, but it doesn't die and doesn't drop down below 1700. Since that stuff is supposed to control the idle, shouldn't it die if disconnected?
I'm also wondering if it is even truely idling at all. I set the throttle body low enough so I can blow into the intake pipe and it will hold pressure. But it still is running really high. I can even unplug the harnass for the aac/air regulator and it keeps running, not as good, but it doesn't die and doesn't drop down below 1700. Since that stuff is supposed to control the idle, shouldn't it die if disconnected?
Do a leak down check on your fuel system see if you have an injector leak.You'll need a fuel gauge for this test.
The car wont always die when the aac valve is unplugged. the 1 inch hose going under your intake from the air ducting pinch it off with a pair of pinch off pliers. The car should die if its fully warmed up. If it does then you know your problem is with the idle control valve. that hose is the feed for that valve and at idle that is the only way your intake gets air. If it dosent die and the rpm only drops you are getting air from somewhere else.
The car wont always die when the aac valve is unplugged. the 1 inch hose going under your intake from the air ducting pinch it off with a pair of pinch off pliers. The car should die if its fully warmed up. If it does then you know your problem is with the idle control valve. that hose is the feed for that valve and at idle that is the only way your intake gets air. If it dosent die and the rpm only drops you are getting air from somewhere else.
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PMan_S13
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- Car: Building car -> breaking car -> fixing car -> start over
Man, this is getting aggrivating. I had the TPS off so I could see if the contacts were corroded or something, but I put it back on when I realized that I couldn't take the cover off without breaking it. Anyway, after I put that on I realized that even if you pushed the accelerator to the floor it would not open the TB enough to touch the upper stopper. So I adjusted the cable and then reset the TPS to ~4.0v at full throttle. Now at fully closed it is at 0.415v so I set it back up to 0.5v.
Well anyway, after doing all this, I wanted to start it to see that it is at least back to square one. Well it won't start unless I give it gas and it won't idle at all and it runs pretty bad. It just revs down to nothing. So confusing, now I'm having very different symptoms. That TPS is driving me crazy...
Well anyway, after doing all this, I wanted to start it to see that it is at least back to square one. Well it won't start unless I give it gas and it won't idle at all and it runs pretty bad. It just revs down to nothing. So confusing, now I'm having very different symptoms. That TPS is driving me crazy...
nistech, since he moved the throttle stopper screw and lost the factory calibration, is there a procedure to recover the proper setting?
this is really getting wierd. i would say to double check the plugs, wires and distrib. them make sure the ignition is timed right.
check the injectors by unplugging and reconnecting them one at a time. if the idle stabilizes, you have something else to look at.
if you have an air compressor and hard intake piping, you can check for intake leaks with some home depot equipment.
get a black rubber cap for pcv pipe that corresponds to your intake diameter. drill a hole in the center of the cap, and use some brass fitings to connect a pressure gauge inline with a shraeder valve [tire valve stem type valve]. use silicone to make it airtight. [if you have a boost gauge, all you need is a tire valve stem. you can use your boost gauge to watch the pressure. just drill a hole in the rubber end cap, and silicone the valve stem into the cap. go from the inside out. the flare of the valve stem's base should seal against the inside of the rubber cap with a little silicone to make it airtight.] use a big hose clamp, and your good to go.
what you want to do is connect the cap to the intake pipe and pressurize the intake to 15 psi. before you do this, use a screwdriver to hold the throttle plate open. once the intake is pressurized, watch the gauge to see how fast the intake tract looses pressure.
also, listen for escaping air to pinpoint the leak.
im pretty sure you said that this is a kadet project.
this is really getting wierd. i would say to double check the plugs, wires and distrib. them make sure the ignition is timed right.
check the injectors by unplugging and reconnecting them one at a time. if the idle stabilizes, you have something else to look at.
if you have an air compressor and hard intake piping, you can check for intake leaks with some home depot equipment.
get a black rubber cap for pcv pipe that corresponds to your intake diameter. drill a hole in the center of the cap, and use some brass fitings to connect a pressure gauge inline with a shraeder valve [tire valve stem type valve]. use silicone to make it airtight. [if you have a boost gauge, all you need is a tire valve stem. you can use your boost gauge to watch the pressure. just drill a hole in the rubber end cap, and silicone the valve stem into the cap. go from the inside out. the flare of the valve stem's base should seal against the inside of the rubber cap with a little silicone to make it airtight.] use a big hose clamp, and your good to go.
what you want to do is connect the cap to the intake pipe and pressurize the intake to 15 psi. before you do this, use a screwdriver to hold the throttle plate open. once the intake is pressurized, watch the gauge to see how fast the intake tract looses pressure.
also, listen for escaping air to pinpoint the leak.
im pretty sure you said that this is a kadet project.
not to my knowledge and being this isnt even a USDM car I cant even see if its somewhere in the service manual. I have never had to reset one so I am not familer with the adjustment procedure. Even if it were out of calibration it wont keep the car from running. It woul only cause a high idle.
Disconnect the tps and start the car see what it does, That is a fail safe it should run and idle speed if everything else on the car is ok.
Disconnect the tps and start the car see what it does, That is a fail safe it should run and idle speed if everything else on the car is ok.
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PMan_S13
- Posts: 575
- Joined: Thu Dec 19, 2002 6:48 am
- Car: Building car -> breaking car -> fixing car -> start over
Ok, got the car running halfway decently.
Well, I am happy to say that the airflow meter I just got is not from an s13. At least not from a DOHC s13, because at 1000rpms it reads in at 2.2-2.3volts. Either that or the thing is busted.
Borrowed one from a friend that is in town, and plugged it in. Runs much better; smoother, non-rich, more stable. Still not 100%, but easily drivable. I am going to talk him into selling it to me.
I had to pull all the spark plugs and clean them off. Running for a combined 15 to 20 minutes with lots of richness fouls plugs pretty bad. Ran much better with clean plugs. Only little issue is I can't get #1's plug wire to attach fully. So it misses every few times it fires (and makes a popping sound from too much unburnt fuel in the exhaust). I proved this fact by unplugging #1 injector and the popping noise from muffler stopped and then returned when replugged. Stupid badly designed plug wires.
With those issues out of the way I still have the TPS to finish off. I toyed with the stopper screw until I got it to about the 1000 rpm range, but here is the issue. I find it difficult to tell if the car is idling (as in the idle control valves are keeping the car running) or "on throttle" (as in the throttle body is letting air in and this is what keeps the engine running). If there is even a transition it is near impossible to tell.
Well, I am happy to say that the airflow meter I just got is not from an s13. At least not from a DOHC s13, because at 1000rpms it reads in at 2.2-2.3volts. Either that or the thing is busted.
Borrowed one from a friend that is in town, and plugged it in. Runs much better; smoother, non-rich, more stable. Still not 100%, but easily drivable. I am going to talk him into selling it to me.
I had to pull all the spark plugs and clean them off. Running for a combined 15 to 20 minutes with lots of richness fouls plugs pretty bad. Ran much better with clean plugs. Only little issue is I can't get #1's plug wire to attach fully. So it misses every few times it fires (and makes a popping sound from too much unburnt fuel in the exhaust). I proved this fact by unplugging #1 injector and the popping noise from muffler stopped and then returned when replugged. Stupid badly designed plug wires.
With those issues out of the way I still have the TPS to finish off. I toyed with the stopper screw until I got it to about the 1000 rpm range, but here is the issue. I find it difficult to tell if the car is idling (as in the idle control valves are keeping the car running) or "on throttle" (as in the throttle body is letting air in and this is what keeps the engine running). If there is even a transition it is near impossible to tell.
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PMan_S13
- Posts: 575
- Joined: Thu Dec 19, 2002 6:48 am
- Car: Building car -> breaking car -> fixing car -> start over
Well the motor seems to be fixed.
I have it idling at 900rpms (that's right were I want it before someone starts flaming and it runs steadily. The plug wires were a bit of a pain. If ever removed again they will most likely need replaced. Any recommendations for quality plug wires? I've tried bosch, autolite, oem, and some other off brand. All were pretty horrible, but autolite survived the longest and are what I use now. The things just are incredibly difficult to snap completely onto the freakin sparkplug.
Anyway, I drove it up and down my road. I was kind of scared of it... just waiting for something to go wrong. But it didn't.
My only other things to ask are these. Besides the motor running pretty well, how do I know I've got the TPS and that stopper set right? Or to get to the point faster. If anything, what does the TPS do besides tell the ECU when to start idling functions?
Because if it only is in place to control idle on/off, then I can take a deep breath and relax. But if it actually has a hand in A/F adjustment, ignition timing, or something like I'm going to pull out my hair.
I have it idling at 900rpms (that's right were I want it before someone starts flaming and it runs steadily. The plug wires were a bit of a pain. If ever removed again they will most likely need replaced. Any recommendations for quality plug wires? I've tried bosch, autolite, oem, and some other off brand. All were pretty horrible, but autolite survived the longest and are what I use now. The things just are incredibly difficult to snap completely onto the freakin sparkplug.
Anyway, I drove it up and down my road. I was kind of scared of it... just waiting for something to go wrong. But it didn't.
My only other things to ask are these. Besides the motor running pretty well, how do I know I've got the TPS and that stopper set right? Or to get to the point faster. If anything, what does the TPS do besides tell the ECU when to start idling functions?
Because if it only is in place to control idle on/off, then I can take a deep breath and relax. But if it actually has a hand in A/F adjustment, ignition timing, or something like I'm going to pull out my hair.
Your ok if your a manual trans it has very little effect on your engine. It does have an effect on timing only when The throttle switch goes from on to off that signifies your stepping on the gas to accel so that starts the advance process but again it is a minor effect. you will know when its wrong when the idle jumps up and doesnt settle down to a normal idle. if you have an automatic then it is used to control shift points by amount of opening its at.
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PMan_S13
- Posts: 575
- Joined: Thu Dec 19, 2002 6:48 am
- Car: Building car -> breaking car -> fixing car -> start over
Yep, she runs great now. I think it actually idles better than it ever has.. it used to stall maybe 1% of every time I stopped at a stop light. But she's solid at 900 now.
Now I just got to finish breaking her in before I can get some boost and tuning through her.
Only thing that bothers me a bit is engine noise is a tad louder when cold... but I think it's just the combination of new internals, bearings, and all that jazz needing to seat itself properly.
But otherwise I got it licked. I knew I wasn't that bad of a mechanic =Plol
Now I just got to finish breaking her in before I can get some boost and tuning through her.
Only thing that bothers me a bit is engine noise is a tad louder when cold... but I think it's just the combination of new internals, bearings, and all that jazz needing to seat itself properly.
But otherwise I got it licked. I knew I wasn't that bad of a mechanic =Plol
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Magnes
- Posts: 101
- Joined: Thu Jan 30, 2003 6:58 pm
- Car: '89 240SX, done up with a chrome-plated ground wire to the engine.
I made the same mistake a while back, and I found that if the set screw is too far out (unscrewed) the throttle plate will 'stick' overnight. It sticks because it is in a position that it never was in before and the shaft or plate are not 'worn in' there.PMan_S13 wrote:Ouch, that sucks. This is a stupid question since you said you are never supposed to move it, but is there a way for me to line it back up? I suppose I just move it back to .465
Anyway, the TPS didn't change anything with me messing with it. It reads from .5v up to 4.06v, I don't think it was an issue.
If you try to get the screw as close as possible to it's original place, screw it out a bit further then in the morning check if the throttle sticks a bit (do this by hand at the throttle body). If it sticks screw it in a bit and try again in a few hours.
Hope that helps.