rev-2-9k

My car is having the following problem. When i start the car there is a period when the car is warming up. It does not happen at dead cold, it does not happen when the engine is fully warmed up. In this range when the engine is at idle, the car can't figure out how many times to turn. It cycles back and forth between about 900 and 1.5 k.

I have the car at mazda now being looked at. Any one want to guess what might be wrong?

I have no ECU or intake on the car.

I am thinking I might have a leak after the MAF? Coolant sensor going bad?

Spin9k

Got FLASHed? That went away in mine after the 'L' flash, if I remember right. It would go up and down RPM-wise like that for 20-30 sec after starting. Is that what you have?

rev-2-9k

i have what i believe to have M flash. (done in late march)

my dealer just called and is looking for ways to blame my oil and or gas. 93 octane and 5-20 castrol.

djvelocitee

I had the same problem this mornig. It was 6 degrees outside this mornig. (6:00am) and i started my car and let it run for 8 mins while i was back in my house for some OJ. I drove about 5 mins at speeds no more than 45 to get to the highway and it felt fine.......
Then i started to merge onto the highway and started to give it a little more gas and it sputtered....I thought for a second my foot slipped off the pedal or something so i didnt think much. Then 45 seconds later, i switch to 6th and it just was not running smooth. It was all bouncy and it had NO power. From 1500 - 3000 rpm it felt like a moped....struggiling to get up a hill. Just the day before i filled the tank with Mobil Super so i know there shouldnt be condensation in the tank.......
so i drove 1 hour to work and i noticed it was running fine.....could it be that it took 40 mins just to "warm" the car up from my house?
i dunno.....
~Brian

rev-2-9k

so i got a new set of sparc plugs the latest flash and mazda is ordering me a new throttle body. whatever "tech" line they use with mazda says this is the problem. my guess is that it was not sealing properly when closed.

wakeech

a hunting idle can be caused by lots and lots of things, which is why your dealer is anxious to get rid of you on bullshit reasons (like your gas or the oil, neither of which would affect it at all, as i'm sure you'd know). getting the new MAF (which is in the throttlebody unit, i'm assuming?) might be the trick, as there's been so much talk of wacky maf units (some better than others, one of the factors in the wildly varying stock power results).

Boneknot

same problem here. glad to here its not just me but this is becoming a widespread problem with the cold start. mazda better come up with some good answers....

rev-2-9k

maybe i am using the wrong term. i do not mean MAF i mean the drive by wire unit made of aluminum just up from the MAF. i believe it is the butterfly valve inside not sealing.

brillo says he had the same problem, maybe when the part comes in next week i will get better that 160 miles per 13 gallons.

i have noticed that the car actually idles "off" fully warmed up as well. so my initial observation of it only happening when cold was wrong. it just happens more often when cold.

rev-2-9k

well the first time they replaced the sparc plugs, then they ordered me a throttle body. the third time they replaced the clutch posistion sensor. they assure me 100% that they fixed it now. they have proof the car thought it was in drive mode not neutral. it was in neutral. i have my car back and it has not acted up yet.

socalightning

Rev-2-9k, did the new clutch position switch fix this problem for you? I was thinking it was ignition related at first and was going to replace the plugs, wires and coils. Changing gas and additives to clean the chambers did nothing to improve the idle.

My car now at 22k miles, is experiencing this hunting idle. Tonight it was really bad as I drove my car cold from one building in my office park to another (still cold) and then parked. I noticed the idle fluctuate to 1500 or so and then drop back down with a worrysome vibration. It did this over and over, but when I depressed the clutch it stopped and idled regularly. ...I released the clutch and the fluctuation returned. I repeated this a few times wondering what the clutch position has to do with the idle speed when I'm in neutral. I then shut off the car to continue my errand.

For about the last 3-4 weeks, I've noticed a similar, but less severe, hunting idle about 10 minutes after cold start, usually when I'm stopped at a traffic signal. The idle would go up and down between 800 and 1500 or so exactly 3 times and then idle regularly - no vibration though till tonight's episode (the engine temp was much colder tonight).

Mike Z

Recently my 8 started to have an erratic idle with the clutch out only. With the clutch out and car in netural, it would idle up & down between 900 and 1500 rpms, but as soon as I put the clutch in it goes back to a smooth idle at 950 rpms.

Has anyone else experienced this and if so any solutions??

mikeb

have you got any mods on the car?

Mike Z

Yes, Racing Beat Back Cat Exhaust, SR High Flow Cat w/Casper fooler, SR Ultra Light Pulleys, Magncor spark plug wires, Fusion Grounding, Hyper voltage system & K&N Typhoon Intake with a S&B PowerStack cone filter, Royal Purple in crank, trans, diff & K flashing.

The car is fast, the mileage is fair 13 - 17 city 20 - 23 freeway doing 75.

It was running smooth at idle until about 2000 miles ago, it started the erratic idle only in netural with clutch out and not all the time, With the clutch in it idles between 950-975 smooth with little to no misfire.

So, I'm curious if anyone else out there is having the same experience? Otherwise, I can't complain, the car runs well and very strong, uses 1/2 qt per 1000 miles and has been very reliable. It has 15,000 miles.

socalightning

YES! ...I have the exact same problem only when it's cold - engine temp below middle of temp guage. It sometimes goes crazy up to 2500 and then back down with an engine shake. I'm having the dealer look at it AGAIN this week or next. Last week they didn't find anything wrong with the ECU - no codes and no CELs triggered except for a TPMS code which made no sense to me.

socalightning

Oh, and I only have an RB flywheel, SR pulleys, Royal Purple in trans and diff, ground kit, Nology wires and Green air filter (OEM panel). Have these mods since October/November and the idle problem just showed up a few weeks ago.
Mine is a GT 6-speed.

socalightning

...And "M" flash!

wintergrn

Similar thing here. On cold days with a "lukewarm" engine, the idle speed sometimes jumps up by 1000rpm, or drops low, almost sounding like a stall, but then recovering. It's on my list of things to mention at my first dealer visit. (See also: rattling rearview, rusting hubs, dipstick foam, tranny noise, orange peel, have I left anything out? :D)

No solutions yet, but my car is M-flash (has the MSP04 sticker), less than 1500 miles on it, still totally stock except for snow tires, so at least that rules out mods as the cause of the problem.

Mike Z

I just want to thank you guys for your replys. I'm also going to look into it further.

The only confusing thing with this problem is when my car does this erratic idleing, it runs much faster, it has the same response in power as it does when it is first warming up.

The cold start system let's any car run richer with more timing when it's first started cold till it warms up and then the on board computer (ECU) adjusts the air mixture, timing etc. to comply with emmissions standards set for the vehicle.

I'm guessing that our cars are somewhat malfunctioning, with the ECU reading them running colder and causing a confusion to the ECU, thus enriching the mixture and kicking in some timing but also confusing the car at idle. When my idle with the clutch out in netural is smooth, then the car still runs fast but not as responsive.

Let's keep this post going till we can find an answer to this problem or answer/solution.

socalightning

Here is another thread about this "hunting idle" as my dealer tech calls it...

https://www.rx8club.com/showthread.p...ht=bouncy+idle

I will post if I find a solution...

robertdot

Merging with other thread...

socalightning

Well the dealer was looking for the solution to this "hunting idle" (since last Tuesday) but now I'm told by the service manager that Mazda Tech tells them not to procede till I remove my mods and return the car the stock.

Removing the Green air filter element, nology spark wires and grounding kit is not a problem, but removing my aluminum pulleys and flywheel is beyond reason for me. It would cost me up to $1.5k to have them removed and to put them back in. These parts have been working just fine in my car for several months then I get this strange idle issue.

Has anyone else come up with a solution to this idle fluctuation when cold problem???? I told the dealer about the clutch switches but they don't seem to think they are the problem. ...And it also affects warm engine idle too (rough) and flattens engine response somewhat (especially below 4k)

tpryor

I was told last week that there seems to be a relationship between erratic idle and improper grounding of the system.

I ordered a grounding "kit" that tied the left fender ground, the right fender ground, the ECU ground, the engine ground, and the negative battery cable together (~$50). 20 minutes to install, and the idle has NEVER been smoother (cold, hot, doesn't matter). It's only been a week, but I think the tech "might" have been on top of this one.

He did mention that there is a rumor of a Mazda bulletin coming out about grounding issues in the near future.

My $0.02 worth.

socalightning

Thanks Tpryor for your 2cents! I heard something similar from my service advisor who mentioned that Mazda Tech thinks there is some issue like that - something weird like grounding loop issues and strange signals sent back to the ECU. However, I've have the grounding kit on my car already, since last June I think, and this problem just started up a month ago. BUT!!!! ....I did have the center radio stack out and reinstalled just before this problem came up so I may double check things in/under the dash for proper connections and ground - dealer left a rattle in there and I had to go in myself to find it. :D

spideRR

i just got my 8 used last week. my friend has one too and we were trying to figure out what all the comotion the engine was doing. First off, i'm not a gear head. I can wrench, but when it comes to technical stuff...it's over my head.

when she idles, it feels like the car is about to stall, but then it doesn't. is this the "hunting idle" question people are trying to figure out? is this normal? i also noticed a ticking sound at the same time when she idles. again, is this normal?

the car drives fine, it's a manual. I don't know of any engine mods, the seller didn't mention any. I opened her up to give her some fresh oil, i read on here too that she goes through a lot of oil. First gear launches are a little slow, some hesitation when i get on the gas for a quick launch. however, launches with slow, smooth acceleration there's no hesitation. I found my 600RR has the same problem unless i play with the clutch. Again, is this normal?

i scheduled an oil change at the dealership next weekend. I asked if the these two things were of a concern. the tech checked the VIN, and noticed the latest flash update was M and i think he mentioned the previous owner had the ECU/PCU replaced. I'm gonna have the dealership do a diagnostic while they change the oil. Again, any concerns i should be aware of?

You help would be greatly appreciated. Let me know if i missed anything?

zoom44

isnt he one of the guys from Monty Python? "always look on the bright side of life" and all that.:D