Reving up & down on its own on idle??
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Joined: Mar 2005
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From: York, UK
Reving up & down on its own on idle??
Any ideas whats causing the engine to rev up and down on idle? just as though somones sat in the car bliping the throttle from 1000 to 2000rpm
I did ask a FD specialist and they said its normal for a FD fitted with a Power FC?? cant see that without a reason?
another answer was somthing to do with the temp sensor? maybe correct as i have just fitted a alloy ast and rad hoses?
Any ideas?
I did ask a FD specialist and they said its normal for a FD fitted with a Power FC?? cant see that without a reason?
another answer was somthing to do with the temp sensor? maybe correct as i have just fitted a alloy ast and rad hoses?
Any ideas?
set up the idle in the TB, the screw one, the ait on bottom and the rev, also put a jumper wire on tne test plug between ten and ground, set up the idle to about 900, take the jumper out and the rev should be at 1000, easy
My 7 did the same thing when I had a vaccuum leak by my primary injectors. It would idle up and down like it was a big cam V8. Spray Carb Cleaner down by your rats nest. If it makes your engine rev up temporarily, then it is definiately a vaccum leak.
3rd motors a charm I hope
Joined: Apr 2003
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From: Central New York
that seems to be what happens with power fc cars. Mine did the exact same thing. When it first happened, i thought something was wrong with the car, until i heard another fd doing the exact same thing. Sure enough, he had a power fc. From there, thats all i heard about was that.
It sounds like your car is revving more than most peoples with a PFC. I would look for a vacuum leak.
Which temp sensor are you talking about? Why do you think its bad? The air intake temp sensor and the ECU's water temp sensor hold a lot of weight in controlling the afr's of the car. So either of them could possibly play a role in your idle problem.
Which temp sensor are you talking about? Why do you think its bad? The air intake temp sensor and the ECU's water temp sensor hold a lot of weight in controlling the afr's of the car. So either of them could possibly play a role in your idle problem.
Last edited by Cgotto6; Feb 26, 2006 at 11:17 AM.
Originally Posted by FJDRX7
set up the idle in the TB, the screw one, the ait on bottom and the rev, also put a jumper wire on tne test plug between ten and ground, set up the idle to about 900, take the jumper out and the rev should be at 1000, easy
Also just noticed that this guy is in the UK so at any rate he couldnt do the jumper wire. Theyre cars dont have the diagnostics box.
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From: York, UK
Originally Posted by fastcarfreak
that seems to be what happens with power fc cars. Mine did the exact same thing. When it first happened, i thought something was wrong with the car, until i heard another fd doing the exact same thing. Sure enough, he had a power fc. From there, thats all i heard about was that.
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Ahh du ma! El Es Juan!
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From: Bay Area, California
Originally Posted by FJDRX7
set up the idle in the TB, the screw one, the ait on bottom and the rev, also put a jumper wire on tne test plug between ten and ground, set up the idle to about 900, take the jumper out and the rev should be at 1000, easy
Read section F on the Mazda workshop page F-16 under ignition timing, see the note and point #6, and yes you will read codes this way if jump from ground to ig, so read and get educated in the car first
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From: west side
Originally Posted by leylandracer
Its at the paint shop now for a full re-paint, so ill have to wait to check things over. Cant be norm though???with the power fc, started the car it started doing the reving thing so i left it for about 10 minutes, then it settled down fine untill i got to the end of my drive when it started again, the paintshops about 8 miles away and it was still doing t when i got there!!!! fine under power though its just on idle and on light throttle, It isnt a UK car its a Jap import
7th heaven
Joined: Jul 2004
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From: Washington
Car shouldn't idle like that, I have a pfc and I had to tweek a few settings to get it to idle correctly. Now it's dead on, it will only vary by 10 - 20 rpms. Sounds like that mechanic doesn't know or is too lazy to hunt down the problem.
Crispy Beef
Joined: Oct 2004
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From: UK
I had the same problem with the idle too, I will point out that I have a standard ECU...
The revving was caused by the original LIM gasket blowing (I think they were paper-like ones or something). Also had a couple of leaks in the vacuum system too, they were all sorted out and idle was great afterwards and is fine to date.
The revving was caused by the original LIM gasket blowing (I think they were paper-like ones or something). Also had a couple of leaks in the vacuum system too, they were all sorted out and idle was great afterwards and is fine to date.
Just chipping in on behalf of the PFC...
I had one installed late last summer and have had no fluctuation on idle until lately...and i think it's a primary injector leak. Even then it's only a couple hundred rpm and goes away after about 20 seconds. But i've had over 5k miles with the PFC and no problems whatsoever.
I had one installed late last summer and have had no fluctuation on idle until lately...and i think it's a primary injector leak. Even then it's only a couple hundred rpm and goes away after about 20 seconds. But i've had over 5k miles with the PFC and no problems whatsoever.
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From: York, UK
I know what you mean when you say hunting, but its more like somone bliping the throttle? not just hunting between 1000-2000rpm Somone off the forum mentioned this;
If you go into etc on the commander then snesor/switch check, you can confirm if any of the values are way out, i.e. if the number are highlighted. VTA1 and VTA2 are the ones to look for. You could also try resetting the ecu by disconnecting the battery and pressing brake pedal for 20secs. Once hooked back up the apexi will relearn the idle and that may sort it out.
Maybe worth a try? The Fd will be away at the paint shop for at least a couple of weeks so ill have to wait.
strange though, one of the lads at the paint shop had to drive it indoors when i had gone, he said it was fine until he was about to swith off and it started again, weird?
If you go into etc on the commander then snesor/switch check, you can confirm if any of the values are way out, i.e. if the number are highlighted. VTA1 and VTA2 are the ones to look for. You could also try resetting the ecu by disconnecting the battery and pressing brake pedal for 20secs. Once hooked back up the apexi will relearn the idle and that may sort it out.
Maybe worth a try? The Fd will be away at the paint shop for at least a couple of weeks so ill have to wait.
strange though, one of the lads at the paint shop had to drive it indoors when i had gone, he said it was fine until he was about to swith off and it started again, weird?
As far as the VTA1 and VTA2 are concerned: I have read that the values from the power FC are way off. So I would not trust them, it's better to just go in and measure them yourself.
Check post #17
https://www.rx7club.com/showthread.p...&highlight=tps
I too have a PFC. Now my car was doing the same thing as yours. Except that the idle would swing from 900 RPMs to 1500 RPMs. I believe that my TPS has been out of wack since i got my rebuild done (I just realized what it was not too long ago). But it's a very slight annoyance, buckles at low speeds, idle hunts a little bit.
After changing my spark plugs and hooking up my PFC is when I started having all of the jumping idle issues. I thought something had come off so I checked and I didn't find anything. Which at that point I thought it was an amplified symptom of the TPS being out of wack.
Last night my car started to die on me. The idle would jump from 500 to 1500 RPMS and then sometimes just die. I went and poked around to see if anything was disconnected. The solenoid that sits right under the UIM (AWS) was disconnected. Connected that guy back up, started the car and my idle was back to 900 - 1500.
I continued looking because it just didn't sit right about my idle jumping. Finally I took notice that my map sensor hose was starting to come off. The hose was close to the end of the nipple and was actually pretty loose, thus compromising the effectiveness of the seal. Anyway I hooked that up nice and snug then zip tied it. Started the car and my idle was no longer jumping, took it for about a 1/2 hour drive and still no jumping idle, which before it did all of the time. It makes sense that while changing my plugs, I probably tugged on the map sensor hose without noticing. Since it never really came off, I never caught it.
My idle still hunts about 1K RPMs but it did that before so that's ok. Next is to get that TPS adjusted and I plan to use a multimeter and compare the readings to PFC.
Check post #17
https://www.rx7club.com/showthread.p...&highlight=tps
I too have a PFC. Now my car was doing the same thing as yours. Except that the idle would swing from 900 RPMs to 1500 RPMs. I believe that my TPS has been out of wack since i got my rebuild done (I just realized what it was not too long ago). But it's a very slight annoyance, buckles at low speeds, idle hunts a little bit.
After changing my spark plugs and hooking up my PFC is when I started having all of the jumping idle issues. I thought something had come off so I checked and I didn't find anything. Which at that point I thought it was an amplified symptom of the TPS being out of wack.
Last night my car started to die on me. The idle would jump from 500 to 1500 RPMS and then sometimes just die. I went and poked around to see if anything was disconnected. The solenoid that sits right under the UIM (AWS) was disconnected. Connected that guy back up, started the car and my idle was back to 900 - 1500.
I continued looking because it just didn't sit right about my idle jumping. Finally I took notice that my map sensor hose was starting to come off. The hose was close to the end of the nipple and was actually pretty loose, thus compromising the effectiveness of the seal. Anyway I hooked that up nice and snug then zip tied it. Started the car and my idle was no longer jumping, took it for about a 1/2 hour drive and still no jumping idle, which before it did all of the time. It makes sense that while changing my plugs, I probably tugged on the map sensor hose without noticing. Since it never really came off, I never caught it.
My idle still hunts about 1K RPMs but it did that before so that's ok. Next is to get that TPS adjusted and I plan to use a multimeter and compare the readings to PFC.
Last edited by Montego; Mar 2, 2006 at 12:37 PM.
I have the same problem after installing my PFC. Does not happen all the time, but tends to occur after I've done some hard boosting. I can get the the idle hunting to stop if I turn car off, turn car back on. Sometimes I have to do this more than once. I have not started to actually troubleshoot on my car but have researched the forum and FSM. Here are all of the forum articles I located related to idle hunting:
- https://www.rx7club.com/power-fc-forum-47/high-idle-479812/
- https://www.rx7club.com/power-fc-forum-47/hot-start-idle-433957/
- https://www.rx7club.com/showthread.p...ght=bypass+AWS
- https://www.rx7club.com/showthread.p...ght=bypass+AWS
- https://www.rx7club.com/power-fc-forum-47/power-fc-idle-control-470743/
- https://www.rx7club.com/power-fc-forum-47/still-having-idling-issues-please-help-479845/
- https://www.rx7club.com/3rd-generation-specific-1993-2002-16/strange-idle-50535/
- https://www.rx7club.com/power-fc-forum-47/help-fc-install-idle-16970/
I'm sure there is more. As someone mentioned, there is a section in the troubleshooting section of the FSM that specifically discusses idle hunting. I was trying to review a series of threads to look for common cause and map out my test strategy. I've got a draft, but have not begun the process yet.
Hope this helps,
Richard
- https://www.rx7club.com/power-fc-forum-47/high-idle-479812/
- https://www.rx7club.com/power-fc-forum-47/hot-start-idle-433957/
- https://www.rx7club.com/showthread.p...ght=bypass+AWS
- https://www.rx7club.com/showthread.p...ght=bypass+AWS
- https://www.rx7club.com/power-fc-forum-47/power-fc-idle-control-470743/
- https://www.rx7club.com/power-fc-forum-47/still-having-idling-issues-please-help-479845/
- https://www.rx7club.com/3rd-generation-specific-1993-2002-16/strange-idle-50535/
- https://www.rx7club.com/power-fc-forum-47/help-fc-install-idle-16970/
I'm sure there is more. As someone mentioned, there is a section in the troubleshooting section of the FSM that specifically discusses idle hunting. I was trying to review a series of threads to look for common cause and map out my test strategy. I've got a draft, but have not begun the process yet.
Hope this helps,
Richard
Originally Posted by montego
As far as the VTA1 and VTA2 are concerned: I have read that the values from the power FC are way off. So I would not trust them, it's better to just go in and measure them yourself.
Check post #17
https://www.rx7club.com/showthread.p...&highlight=tps
I too have a PFC. Now my car was doing the same thing as yours. Except that the idle would swing from 900 RPMs to 1500 RPMs. I believe that my TPS has been out of wack since i got my rebuild done (I just realized what it was not too long ago). But it's a very slight annoyance, buckles at low speeds, idle hunts a little bit.
After changing my spark plugs and hooking up my PFC is when I started having all of the jumping idle issues. I thought something had come off so I checked and I didn't find anything. Which at that point I thought it was an amplified symptom of the TPS being out of wack.
Last night my car started to die on me. The idle would jump from 500 to 1500 RPMS and then sometimes just die. I went and poked around to see if anything was disconnected. The solenoid that sits right under the UIM (AWS) was disconnected. Connected that guy back up, started the car and my idle was back to 900 - 1500.
I continued looking because it just didn't sit right about my idle jumping. Finally I took notice that my map sensor hose was starting to come off. The hose was close to the end of the nipple and was actually pretty loose, thus compromising the effectiveness of the seal. Anyway I hooked that up nice and snug then zip tied it. Started the car and my idle was no longer jumping, took it for about a 1/2 hour drive and still no jumping idle, which before it did all of the time. It makes sense that while changing my plugs, I probably tugged on the map sensor hose without noticing. Since it never really came off, I never caught it.
My idle still hunts about 1K RPMs but it did that before so that's ok. Next is to get that TPS adjusted and I plan to use a multimeter and compare the readings to PFC.
Check post #17
https://www.rx7club.com/showthread.p...&highlight=tps
I too have a PFC. Now my car was doing the same thing as yours. Except that the idle would swing from 900 RPMs to 1500 RPMs. I believe that my TPS has been out of wack since i got my rebuild done (I just realized what it was not too long ago). But it's a very slight annoyance, buckles at low speeds, idle hunts a little bit.
After changing my spark plugs and hooking up my PFC is when I started having all of the jumping idle issues. I thought something had come off so I checked and I didn't find anything. Which at that point I thought it was an amplified symptom of the TPS being out of wack.
Last night my car started to die on me. The idle would jump from 500 to 1500 RPMS and then sometimes just die. I went and poked around to see if anything was disconnected. The solenoid that sits right under the UIM (AWS) was disconnected. Connected that guy back up, started the car and my idle was back to 900 - 1500.
I continued looking because it just didn't sit right about my idle jumping. Finally I took notice that my map sensor hose was starting to come off. The hose was close to the end of the nipple and was actually pretty loose, thus compromising the effectiveness of the seal. Anyway I hooked that up nice and snug then zip tied it. Started the car and my idle was no longer jumping, took it for about a 1/2 hour drive and still no jumping idle, which before it did all of the time. It makes sense that while changing my plugs, I probably tugged on the map sensor hose without noticing. Since it never really came off, I never caught it.
My idle still hunts about 1K RPMs but it did that before so that's ok. Next is to get that TPS adjusted and I plan to use a multimeter and compare the readings to PFC.
ok scratch the part where the idle jumping got fixed....
The FD is one cruel bitch. She behaves just long enough for me to be happy about a fix then it acts up again to ruin my parade (and to me make look like an *** on here lol).