kraji

today morning i started my car and when i was letting it warm up my rpm was going crazy.

for example it would slowly go down then all of sudden it goes up slrighty then
it goes down again it did that like couple times before it got fully warm.

should i worry about this?

yiksing

Normal, just don't rev the car too high up until the oil in the transmission and engine warms up.

LiveToRev

As yiksing said, it is normal. Mine does the same thing as well.

NgoRX8

iTrader: (1)

hmm... I didn't even know this. Mine just goes up on crank and then goes down and down till about 750 rpm.

tiggerlee

^ditto here.

Raptor2k

Mine goes up when I crank it...when it's cold it idles around 1400 for a few mins, when it's warm it idles around 850, 14k miles.

Astral

normal...my car does this, and stays up there longer when it's colder...

Glyphon

i have no idea how my car behaves because i just crank it and then drive. no "warm up". i just keep it below 3k until its been at normal operating temperature for a few minutes.

Rotor Kreuzer

Hmmm, my JDM '03 8 has never done that before. 28k km and all it does is keep going down (after cranking) to about 800rpms after 5 or so mins.

spork

I crank it usually shoots up to 2000-2500RPM, then as you wait a short while, it'll settle to 1500, then 1250. But if you wait another 10 seconds, it'll rev itself up to 1500 for a few seconds. Then it'll drop back down to 1250 and stay there for a while. (This is a span of like 2 minutes).

I used to wait for it to be stable at 1250 before I started driving. Now I just wait until it hits around 1500 (about 30-45 seconds).

After I drive the car a bit, it'll idle between 750-900RPM.

KYLiquid

its only been about as cold as 42*F here when Ive driven the 8 into work, even so when I start the car and its below about 50*F it will idle at 2k rpm, then after about 1 min drop to 1500, then about 3 mins drop to 1000, then after 2 mins drop to 800 and stay there. If its over about 50*F it will start at 1500 then drop to 1000 in about 5 mins, then drop to 800 in about 2 mins.

I usualy only idle the car for about 3-5 mins then drive slowly till about 5 miles/15 mins have elapsed, then slowly work the revs up. With in 20 mins/10 miles Im fully on. Of course it doesnt get very cold here, and my car usualy stays in the garage so its amb temp is always around 65-70*F

KYLiquid

also as a note, its fine to let the car warm up by letting it idle but it will warm up faster with driving, since you are using a little more RPM and putting the car under load. Also when the car just sits and idles, it doesnt warm up the trany, diff or tires like driving does.

Start the car and let it run for a min to build oil pressure and get oil into all the parts of the motor, then just drive....go easy, but drive till its warm.

JRichter

I start the car (rpm usually goes to 1200 rpm for a few sec.), wait 10 seconds (or until the rpm drops to normal idle), then drive off keeping the RPM's below 4000 until the temp guage climbs to normal.

It takes for ever to warm up if it just sits and idles, not to mention how much gas it wastes.

ucfracerx8

I start it and let it settle down to about 1400 before I move it. When it cranks, it is about 2k, sometimes a little higher as it gets cooler, worst is when it has sat in the parking lot at work all day and with the wind blowing and it hits the upper 40's (this is Florida) it will be as high as 2.5k for a few seconds and then start dropping, must be its way of saying, damn I'm cold!

After it drops to 1400, off I go, slowly of course keeping it to 3-3.5k until it indicates full temp, then by the time I get to my road change she is ready to hit the BEEP

kraji

no no what im saying is when i crank it up it kicks up and revs but as it slowly goes down the neddle jumps up again for few sec and goes down again for 3 or 4 times when i start it

Macius8

iTrader: (3)

I have a similar question. I hope you dont mind if I ask it in this thread since its similar. Tonight just outside of chicago its like 5 degrees out. When I turned the car on the rpm shot to almost 5k. Now is that normal? They started dropping off rappidly after a couple seconds. I noticed that when it get colder the rpms usually are higher when starting the car, but holy shiet 5k? I know ur not supposed to rev the engine when its cold cause it may cause damage, but i wasnt reving it. Now tomorrow morning its supposed to be below 0, should I worry about staring it?

KKMmaniac

kraji:

I wouldn't worry too much about this; mine has done a strange, RPM up to about 2000, then drop way down, (and backfire) and back up, and drop, and so on, cycle-thing when cold, (~5 F) until it warms up.

However, last night leaving work, (about 5 F) it did (or tried to do) what Macius8 is describing. Damn RPM shot up to near 4k before I shut it off. I tried again: same thing. Then I remembered when it happened last year, I found if I started it in gear with the clutch in and let it out a little to scrub off some RPM as they raced upward, the revs would stabilize at a low RPM.

No, I don't think this is normal, and it's got to be incredibly bad for the engine. I'm one who believes in careful warm-up procedures and I don't let the RPM get much above 3k before the temp gauge shows normal. (and this behavior really pisses me off!)

I took it to a dealer last year, and they said they reprogrammed the PCM, and that should solve the problem. Turns out, there is no record they did anything.

So, maybe try the clutch thing for now (with foot firmly on the brake: be careful you don't launch the car into something or someone!) and maybe your dealer has a better answer. It sounds like it could be caused by some kinda interlock with the clutch or something.

(BTW: Also try doing a search on the subject; I know some of us discussed it last year)

Astral

Dunno, I wouldn't worry about it. Remember that the ECU limits the revs to 6K when cold. If it was really detrimental to go above 3K or 4K, they would've probably limited it lower.

In my opinion, 3K is a really low limit for cold driving... that's 33% of the redline. On my old 6500rpm redline Protege, 3K is 46% of the redline. So that's more like 4K for the rotary. I try not to rev above 4K when cold.

So if the PCM shoots up to 4K, or even 5K for a second... I would just let it run its course. It's a no-load situation anyway, so it's not putting out as much power as it would be under full-throttle 4K in 2nd gear. I think the no-load is less stressful on the engine there.

KKMmaniac

Astral:

I thought the ECU limit when cold is 4500 RPM but I don't remember where I read that.(owner's manual?)

I agree under no-load conditions the engine may more safely rev high when cold, but I don't know that percentage of the redline is necessarily a good rule of thumb.

At any rate, I haven't heard that everybody driving in colder temps is experiencing the same thing, so I'm thinking it may be considered abnormal.

KKMmaniac

"I thought the ECU limit when cold is 4500 RPM but I don't remember where I read that. (owner's manual?)"

Sorry...I stand corrected!

Astral

I think the manual only says "before the real redline" or something to that effect. I think I read from the forum 6K somewhere... so actually I'm not all that confident about the number.

How recurring is the high revving for you? I haven't started the car in 5 degrees yet. I think 22 was the coldest so far. It revved to like 2.5K.

dwill9578

If it's super cold then mine will spin to about 2k, otherwise stays below that for a few until I drive off. My car really seems to hate the cold more than other cars I have owned. It makes many a strange noise let me tell you. Pretty much loose insulation in doors and other creaks from the body. It kinda bugs me all the little nosies that arise when it gets cold. I hope my next car will handle the cold a little better.

Astral

When I had my Protege serviced at a Mazda dealer, I talked to a Mazda tech about the RX-8. He said: "too many weird noises in the winter" and that a lot of people would complain about a squeak here or there.

bluesunlion

Totally normal.

kraji

thanks fellas ;D