idle problem
06-05-02, 12:36 AM
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idle problem
i have a 86 na rx-7 and it will idle over 1000rpm when it is warm and when you are driving and come to a stop sometimes it will die or if it goes under 600-700 rpm it will die sometimes too it runs fine but it just has idle problems
06-05-02, 01:44 AM
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Hey, I got something like that: the 3K startup is normal, as is the 1200-1500 for a couple of minutes until the car is warmed up. Then the idle is supposed to drop to 750-800rpm, and stay there rock solid.
Well mine is a bit rocky (+-100rpm) when the car is pretty hot, and when coming to a stop, the rpms will drop to about 600 and then come back up.
Now that I read all this that I wrote, I know its either the TPS (which is electronic, so if it buys the farm, I have to buy a new one...
and 
), or a vacuum leak, which I really need to fix.
Anyone else have any ideas about this ?
Well mine is a bit rocky (+-100rpm) when the car is pretty hot, and when coming to a stop, the rpms will drop to about 600 and then come back up.
Now that I read all this that I wrote, I know its either the TPS (which is electronic, so if it buys the farm, I have to buy a new one...
and ), or a vacuum leak, which I really need to fix.Anyone else have any ideas about this ?
06-05-02, 09:48 AM
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if mine goes down to 600 it will die sometimes but that is only when i start driving it if i let it warm it up for 15min it will idle over 1000 rpm and the rpm goes up in down sometimes and about +-50-60rpm
06-05-02, 03:43 PM
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Does it die when you apply the brakes, or turn on the ventilation, or turn on the headlights ?
If it does not die, do the rpms drop significantly (almost stalls) and then go back up to where they should be (with some bouncing) ?
If yes, you're not alone. I have same problem.
Check your TPS adjustment and the BAC valve (there is a bit of controversy about whether or not the BAC valve is involved on the S4, but it is worth checking).
I know that adjusting the TPS has helped a fellow forum member, it has not helped me though.
I also can tell you it's not coming from the alternator.
If your TPS and BAC are ok,
then really dunno.
hugues -
If it does not die, do the rpms drop significantly (almost stalls) and then go back up to where they should be (with some bouncing) ?
If yes, you're not alone. I have same problem.
Check your TPS adjustment and the BAC valve (there is a bit of controversy about whether or not the BAC valve is involved on the S4, but it is worth checking).
I know that adjusting the TPS has helped a fellow forum member, it has not helped me though.
I also can tell you it's not coming from the alternator.
If your TPS and BAC are ok,
then really dunno.
hugues -
06-05-02, 04:18 PM
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I am having the an idle prob. too. What mine does is goes to 3k when cold and in about 2 min goes to 2k then when the temp gauge hits C it starts doing the idle hunt 1500-2000 then one warmed up it runs at around 750 but keeps acting like it wants to stall hasn't yet. I have adjusted the TPS untill my face was blue I did it with the lights from Mazdatrix and going off of my S-afc sensor voltage. It runs almost like a piston car with a big cam in it. I have a 91' TII and was wondering do you need that stupid BAC is there a way to bypass it? My air pump is no longer operational everthing has been blocked off. Could that be making it do this? I know on my 90' GXL if I would disconnect it it would idle all kinds of funny.
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06-06-02, 11:59 AM
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Hey the Ace:
Does your car's rpm drop down (a lot) only when you apply brakes (just a tap just to turn on the stop lights on) ?
Does is also do it when you turn on the ventilation (heater) or turn on the headlights ?
Hugues -
Does your car's rpm drop down (a lot) only when you apply brakes (just a tap just to turn on the stop lights on) ?
Does is also do it when you turn on the ventilation (heater) or turn on the headlights ?
Hugues -
06-09-02, 09:32 PM
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I almost have the same problem. Atleast your cars actually jump to 3000RPM when started; mine has never done that since I've owned it. It would start and go to about 1500RPM stay there for a bit then maybe 15mins later down to 700-800RPM and steady as a rock. But just recently it won't hold an idle at all. It starts and almost immediatly stalls. Actually it'll put up a good fight then stall.
(read post:https://www.rx7club.com/forum/showth...threadid=86588 ) I've tested and re-checked my BAC and I still don't know, but I'll figure it out soon!
(read post:https://www.rx7club.com/forum/showth...threadid=86588 ) I've tested and re-checked my BAC and I still don't know, but I'll figure it out soon!
Last edited by Scracho; 06-09-02 at 09:40 PM.
06-10-02, 03:12 AM
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Originally posted by hugues
Hey the Ace:
Does your car's rpm drop down (a lot) only when you apply brakes (just a tap just to turn on the stop lights on) ?
Does is also do it when you turn on the ventilation (heater) or turn on the headlights ?
Hugues -
Hey the Ace:
Does your car's rpm drop down (a lot) only when you apply brakes (just a tap just to turn on the stop lights on) ?
Does is also do it when you turn on the ventilation (heater) or turn on the headlights ?
Hugues -
Biggest effect in the idle rpms is the power steering. If I contiually turn wheel right and left, the rpms will drop to 600 and stay there.
Heater does not affect rpms at all. I can tun it on/off all I want, rpms stay rock solid.
And the A/C affects the rpms, but in a "proper" way. The rpms will climb to about 1K with the A/C on, and stay there. Actually the idle is much steadier with the A/C on (higher, but steadier)....
06-13-02, 07:53 AM
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Your idle is a bit high. Should be 750 rpm. I have the feeling it was raised to avoid stalling at stop lights or under some types of elec loads.
You may want to make sure your TPS is properly adjusted (at least at idle), since it may not have been adjusted when the idle speed was changed. This will make sure the ecu knows what the idle speed is supposed to be in case the ecu compensates for loads in 1) and 2)
1) What happens when you're at idle and u turn on the headlights ?
the rpm should drop slightly (maybe 50-100 rpms) and go back to regular idle speed.
2) What happens when you're at idle and just tap on the brakes (just enough to activate the stop lights) ? Do you get same behavior as with the headlight test ?
If you're ok on 1 and 2, but you get the big drop when you push hard on the brakes, then it is probably a vaccum leak at the brake booster, and that should be easy fix.
If in both cases,
you get huge drops in rpm, then
I would check first the charging system (battery+alt+wiring) since it is easy to check. Go to autozone, and have them check it on the car. If you're mechanically and electrically enclined, you can do a more thorough check using the troubleshooting procedure of FSM88 (www.fc3s.org) section: engine elec.
If ok, I would check the engine compression. Maybe it cannot handle the added load.
Hugues -
You may want to make sure your TPS is properly adjusted (at least at idle), since it may not have been adjusted when the idle speed was changed. This will make sure the ecu knows what the idle speed is supposed to be in case the ecu compensates for loads in 1) and 2)
1) What happens when you're at idle and u turn on the headlights ?
the rpm should drop slightly (maybe 50-100 rpms) and go back to regular idle speed.
2) What happens when you're at idle and just tap on the brakes (just enough to activate the stop lights) ? Do you get same behavior as with the headlight test ?
If you're ok on 1 and 2, but you get the big drop when you push hard on the brakes, then it is probably a vaccum leak at the brake booster, and that should be easy fix.
If in both cases,
you get huge drops in rpm, then
I would check first the charging system (battery+alt+wiring) since it is easy to check. Go to autozone, and have them check it on the car. If you're mechanically and electrically enclined, you can do a more thorough check using the troubleshooting procedure of FSM88 (www.fc3s.org) section: engine elec.
If ok, I would check the engine compression. Maybe it cannot handle the added load.
Hugues -
06-13-02, 11:25 AM
#17
One thing hardly ever mentioned is that you must ground the check connector at the driver's side, front of the car when making idle and TPS adjustments. Otherwise you are fighting the ECU.
ON the S5, ground it to the neg. terminal of the battery if you want. On the S4, it has 2 terminals instead of the single one on the S5. Ground those to each other, a loop, if you will. All this per the FSM for those who find this hard to believe.
Also, I use two voltmeters instead of those damn lamps, even though the FSM suggests lamps.
Ralf
ON the S5, ground it to the neg. terminal of the battery if you want. On the S4, it has 2 terminals instead of the single one on the S5. Ground those to each other, a loop, if you will. All this per the FSM for those who find this hard to believe.
Also, I use two voltmeters instead of those damn lamps, even though the FSM suggests lamps.
Ralf
06-15-02, 11:14 PM
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it goes down more when you turn the lights on than the brakes and i don't get a big drop when i push on the brakes hard and i get a bigger drop when you turn the lights on