Idle......
01-27-10, 09:47 PM
#1
Idle......
Hey guys, I know there's about a thousand threads on idle but I kind of have a specific problem that I couldn't find an answer to.
I ajusted the TPS and at idle it will rev to 1600 rpm then drop to 1400 rpm over and over. Sometimes it will randomly idle good at 1500.(High I know). Always runs fine however when driving, just the idle thats bad.
So heres the deal, where the TPS is you can hit the throttle, if I turn it the opposite way it goes down to 800 and idles perfect, but as soon as i let go its back to surging around 1500. I set the TPS to stock and then turned it in from there and it doesn't really make a diffrence all the way to bottoming out.
Is it possible that something got turned or something so the screw isn't ajusting in the right range, like it should let me go lower but somethings messed up? I hope this makes sense.
By the way the throttle cable isn't tight or anything so I don't think thats it either. Thanks in advance for any help.
I ajusted the TPS and at idle it will rev to 1600 rpm then drop to 1400 rpm over and over. Sometimes it will randomly idle good at 1500.(High I know). Always runs fine however when driving, just the idle thats bad.
So heres the deal, where the TPS is you can hit the throttle, if I turn it the opposite way it goes down to 800 and idles perfect, but as soon as i let go its back to surging around 1500. I set the TPS to stock and then turned it in from there and it doesn't really make a diffrence all the way to bottoming out.
Is it possible that something got turned or something so the screw isn't ajusting in the right range, like it should let me go lower but somethings messed up? I hope this makes sense.
By the way the throttle cable isn't tight or anything so I don't think thats it either. Thanks in advance for any help.
01-28-10, 12:39 PM
#2
Jesus is the Messiah
That sounds like multiple problems working together to me. It would be hard to troubleshoot from here, but I'll take a crack at at.
You shouldn't have enough air to get to 1500 unless you have a vac leak or the throttle set wrong. Because the car is surging, that is a sign of running lean, a symptom of a vac leak.
I'm also going to assume when you set the TPS wrong in such a way that it idles at 800, you're actually DUMPING fuel in, way too much, so the engine is actually bogging down to 800, and that is why it is running so smooth (rotaries love idling smooth when they're insanely rich)
Based on the above assumptions, I'll suggest trying to find a vac leak, check your timing, set your idle, then worry about setting your TPS correctly.
Please let me know how it turns out, I'm interested to see if my guess is even remotely right
You shouldn't have enough air to get to 1500 unless you have a vac leak or the throttle set wrong. Because the car is surging, that is a sign of running lean, a symptom of a vac leak.
I'm also going to assume when you set the TPS wrong in such a way that it idles at 800, you're actually DUMPING fuel in, way too much, so the engine is actually bogging down to 800, and that is why it is running so smooth (rotaries love idling smooth when they're insanely rich)
Based on the above assumptions, I'll suggest trying to find a vac leak, check your timing, set your idle, then worry about setting your TPS correctly.
Please let me know how it turns out, I'm interested to see if my guess is even remotely right
01-28-10, 01:16 PM
#3
I have the TPS set to stock. I meant it idled right if I turn the throttle the opposite way. Hard to explain i guess.
I'll try to look for a vacume leak, I don't really know where to start, but I'll just browse through some threads I guess. Thanks for the help.
Oh and by the way if I turn the TPS up so it idles high, like 2400, it idles steady, but like I said I have it set to stock, where it is surging between 1400 and 1600.
I'll try to look for a vacume leak, I don't really know where to start, but I'll just browse through some threads I guess. Thanks for the help.
Oh and by the way if I turn the TPS up so it idles high, like 2400, it idles steady, but like I said I have it set to stock, where it is surging between 1400 and 1600.
01-30-10, 01:49 PM
#5
It's got to be the TPS screw. I hooked the multimeter up to the TPS and ajusted it with this screw so I dont see how it could be anything else.
I was looking at it today and the peice on the actual TPS that goes in and out when you push the throttle doesn't go all the way in when I'm not hitting the gas, but when I turn the throttle the opposite way so it idles good it pushes this peice in more. Could it be a bad TPS?
It also idles alot better when I unplug the TPS, still bounces a very little bit, but you can't hear it, you can just see the needle moving a very little bit on the tach.
Also, is spraying carb cleaner on the vacume lines the best way to look for leaks? Thats what I found when I searched. It said when you spray it on the leak your idle will rise, but mines already high. Thanks again for your help.
I was looking at it today and the peice on the actual TPS that goes in and out when you push the throttle doesn't go all the way in when I'm not hitting the gas, but when I turn the throttle the opposite way so it idles good it pushes this peice in more. Could it be a bad TPS?
It also idles alot better when I unplug the TPS, still bounces a very little bit, but you can't hear it, you can just see the needle moving a very little bit on the tach.
Also, is spraying carb cleaner on the vacume lines the best way to look for leaks? Thats what I found when I searched. It said when you spray it on the leak your idle will rise, but mines already high. Thanks again for your help.
02-19-10, 08:50 AM
#6
Rotary Spirit
i have similar problem, it is a 86 gxl stock s4 manual, the previous own had the air pump(motor)? not sure if thats how it called, it is near the header, the opening is blocked by a plate.
anyway, my idle plays rough around 1500 rpm after the engine warms up. i had read so many threads, still didn't help.
here is the list i had been done tryin to fix the problem.
1. took BAV out, clean internal with carb spay, check to make sure it work by jumping 12v directly from the battery, it "click", which means it works.
2. wipe of dust near the throttle body plates area, didnt take the whole throttle body out, maybe i will take the whole thing out and do a complete clean up later on.
3. used multimeter to check the tps resistant while the engine is cold, come out to be 1.197 kohm, which seems right(from other thread)
4. spay engine starter fluid to engine bay while idling rough, no sign of change, no vacuum leak i guess.
5. unplug tps while idling rough, rmp stays at 2k.
yea, my problem still didnt solve. hope u went thru my steps to find out wat the problem is.
anyway, my idle plays rough around 1500 rpm after the engine warms up. i had read so many threads, still didn't help.
here is the list i had been done tryin to fix the problem.
1. took BAV out, clean internal with carb spay, check to make sure it work by jumping 12v directly from the battery, it "click", which means it works.
2. wipe of dust near the throttle body plates area, didnt take the whole throttle body out, maybe i will take the whole thing out and do a complete clean up later on.
3. used multimeter to check the tps resistant while the engine is cold, come out to be 1.197 kohm, which seems right(from other thread)
4. spay engine starter fluid to engine bay while idling rough, no sign of change, no vacuum leak i guess.
5. unplug tps while idling rough, rmp stays at 2k.
yea, my problem still didnt solve. hope u went thru my steps to find out wat the problem is.
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