engine revs spike 3-4 times before levelling
#1
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engine revs spike 3-4 times before levelling
When I start my 8 in the morning, revs are smooth @ ~1500-2000 for a few seconds, then I get 2 or 3 peaks to 3000 (approx. 1 second period of each peak), then smooths to nominal idle of 900 rpm.
My dealer tells me to expect the car to rev @ ~2000 for a few seconds steady, then down to idle revs. But I see these spikes that he can't explain.
Anyone else notice this phenomenon? Any insights as to what is happening and if it represents a problem?
My dealer tells me to expect the car to rev @ ~2000 for a few seconds steady, then down to idle revs. But I see these spikes that he can't explain.
Anyone else notice this phenomenon? Any insights as to what is happening and if it represents a problem?
#2
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Re: engine revs spike 3-4 times before levelling
Originally posted by bgparsons3
When I start my 8 in the morning, revs are smooth @ ~1500-2000 for a few seconds, then I get 2 or 3 peaks to 3000 (approx. 1 second period of each peak), then smooths to nominal idle of 900 rpm.
My dealer tells me to expect the car to rev @ ~2000 for a few seconds steady, then down to idle revs. But I see these spikes that he can't explain.
Anyone else notice this phenomenon? Any insights as to what is happening and if it represents a problem?
When I start my 8 in the morning, revs are smooth @ ~1500-2000 for a few seconds, then I get 2 or 3 peaks to 3000 (approx. 1 second period of each peak), then smooths to nominal idle of 900 rpm.
My dealer tells me to expect the car to rev @ ~2000 for a few seconds steady, then down to idle revs. But I see these spikes that he can't explain.
Anyone else notice this phenomenon? Any insights as to what is happening and if it represents a problem?
#3
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My rpm estimates are from memory so your numbers could well be more accurate.
Why do you say "no problem"? I've never had a car go through this periodic rpm cycle on startup before .... I hope it's no problem, but so far, I'm just ignorant of what is causing it to happen.
Why do you say "no problem"? I've never had a car go through this periodic rpm cycle on startup before .... I hope it's no problem, but so far, I'm just ignorant of what is causing it to happen.
#5
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Not to 3K, but does happen to mine. Of course every little thing different in a new car is cause for concern, but it only does it maybe 3 times, then it's over. I'm mentioning it when I take it in anyway. Doesn't seem as if a new car should exhibit this 'erratic' behavior.
Maybe a little ECU tuneup would solve it.
Maybe a little ECU tuneup would solve it.
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Mine does the same thing early morning (when you hear it 'purr'ing)
I don't think its anything abnormal, my Toyota used to do exactly the same thing. Basically it all depends on engine coolant temperature (I think)
The cycle goes like this:
1. 2K for like 5 secs
2. 1.5K & 2K ~ 2.2K spikes (pretty fast)
3. Then goes down to 1.1K until the engine is fully warmed up.
As I said before, I have experience from my previous car. It used to do the same thing (except for the spike)
I don't think its anything abnormal, my Toyota used to do exactly the same thing. Basically it all depends on engine coolant temperature (I think)
The cycle goes like this:
1. 2K for like 5 secs
2. 1.5K & 2K ~ 2.2K spikes (pretty fast)
3. Then goes down to 1.1K until the engine is fully warmed up.
As I said before, I have experience from my previous car. It used to do the same thing (except for the spike)
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Someone else mentioned this "spiking" after a cold start and said he used regular gas and it went away. I tried the same thing and the spiking also went away. I now use regular gas since I notice no difference in performance and the engine runs very smooth and quiet.
Word of warning though. I only have 2800miles on my RX-8 so if the compression improves as the engines breaks in, I may have to switch back to premium, especially if I hear pinging or other noises.
Word of warning though. I only have 2800miles on my RX-8 so if the compression improves as the engines breaks in, I may have to switch back to premium, especially if I hear pinging or other noises.
#11
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So you're saying that I shouldn't be such an old woman ...
Thanks for the feedback, I'll quit worrying about it. I will mention it to the dealer when I go in to get the newly released basepan installed.
Thanks for the feedback, I'll quit worrying about it. I will mention it to the dealer when I go in to get the newly released basepan installed.
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FWIW, I've been using 87 octane for about the last 6 or 7 tanks and still have the up/down surge during initial warm-up (like this morning around 60 degrees). and another FWIW, Shell doesn't seem to increase mileage.
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