Herblenny

Here is my problem....

I'm having cold start problem at 80-90 degree warm alabama weather.

Car: 2004 GT with 20-24K on the reman engine.

Car will crank over but takes awhile to catch/fire. Once it cranks up, idle is rough, then it will either smooth out or dies. If it dies, on second crank it would start up fine some of the time and other times, the idle will hunt and dies. I should also state that this has gotten worse past 7 days.

When engine is warm, most of the time, no issues.

I've replaced the coils less than 5k miles, New plugs 500 miles prior to the coils, New wires, cleaned out the TB, Map sensor, clean air filter, added fuel injector cleaner in the tank, etc..

Once the car runs, its smooth all throughout the power range and RPM and idles perfect after driving the car.

Personally I don't think its compression, but I guess I could check that as I have my own mazda compression tester.

nycgps

iTrader: (1)

Add a few oz of premix into the tank, see if it helps

if it does, your motor is no good

if it doesnt, it might be something else.

RXtreme8

Herblenny,
What was the outcome from your issue?

I am experiencing nearly the same problem. After sitting overnight or all day, I fire it up cold. Runs real rough like I lost an apex seal. But after a minute and half it's like someone flipped a switch, and instantly the idle is smooth. No smoke or anything coming from the exhaust but it did smell rich.

04 GT 6spd. 75k miles on original engine. 20W50 Castrol GTX for past year.
The coils, plugs and wires were replaced with last spring. Stock ECU and injectors. Air pump, TB coolant lines, and EGR still intact.

I popped the hood and tried listening (while painfully watching the engine convulse) and while the idle changes slightly when the air pump shuts off, it does not seem to be linked. I think I heard a noise that resembled a valve opening just before the engine went smooth. I also recall yesterday hearing what sounded like water suddenly start flowing through the heater coils in the dash.

I poked around, can't find any vacuum leaks. My coolant levels were low a few weeks ago and had to add. I normally drive it pretty hard I think and regularly clean her out with a full sweep on 2nd gear. The only thing that's changed about the car in past month (besides the oil) has been the driving style. Was on a 3k mile road trip for the holidays, steady 4k RPM for hours on end. And got laid off too, so my daily mileage dropped from 35+ to 5.

Once she's warm, everything feels normal. Fires right up and pulls strong all the way up to 9k. Haven't visited the dealer yet, because until I find another job I can't afford a mystery labor bill.

Anyone have ideas?

RXtreme8

In the interest of preparing for a dealer visit and compression check, I reinstalled the OEM intake yesterday. While I was at it I cleaned the Throttle Body again. It looked pretty clean though since I'd cleaned it over the summer and installed a oil catch can. I also double checked the coolant levels. After sitting for several hours at this point, I fired her up and she stumbled again, and ran a little rough. Not as bad as before though (but the engine hadn't been sitting overnight). Then it cleared.

I let it sit all afternoon/evening, and fired her up around 8pm last night.... to my amazement, no stumbling, no rough idle when cold. This morning I fired her up again to drive home, and again this afternoon to go to a store. No stumbling, no rough idle when cold. WTF!

Even though the TB was clean, I sprayed a health dose of Carb Cleaner up in there. Wiped down the butterfly anyway, and wiped down around the edge where it seals.
Could the TB have been sticking when cold?

Do the RX-8 TB's have thermowax like the 7's?
Could it be something with my coolant system? So that as soon at the thermostat opens, coolant flows, and the idle goes smooth.

I don't know.

Go48

Maybe you inadvertently cleaned the MAF sensor when you were spraying the intake? If your aftermarket intake had an oiled filter, that is definitely a possibility.
See: https://www.rx8club.com/showthread.p...&highlight=maf

Bastage

iTrader: (1)

Check your cat. Back in August I was experiencing similar symptoms on occasion.

I had a hunch that there was a piece of catalyst material loose in the pipe that was sometimes impeding the flow of exhaust gases. I removed the cat and shook it and proved my hunch. A piece about the size of a racquetball was actually moving around in there. The piece was just big enough to actually clog the pipe.

I fixed the problem and have not seen the issue since.

RXtreme8

No, the cold air intake was on the ground next to the OEM air box. MAF was still secured in the CAI.

I probably should do a formal cleaning of the MAF though as I have been using K&N dropin in the airbox for 6 months, then K&N cone on the CAI for last 6 months; could have accumulated oil residue from the K&N's.


UPDATE: Problem returned this morning. Have at appointment Monday morning with a trusted dealer (Mazda of Wesley Chapel). Getting a compression check so I can free that worry from my mind.

RXtreme8

The only reason I'm hesitant to spend the effort of removing the cat, is that the problem only presents itself during first minute to minute & half after a cold start (engine sitting more than 5 hours). After that it feels fine, no apparent power issues. Warm start is fine too.

RXtreme8

Update:

For those who have been listening in on my plight.
I dropped my car off this morning at Mazda of Wesley Chapel.
Got a call back this afternoon and it's official.
The motor is toast!
They are ordering in a 'new' one (as in rebuilt I'm sure). Should take 3-4 days to arrive, plus a day to replace.

The problem... blown water jacket! Dealer techs said they pressure tested the coolant system and water came out the spark plug holes. I had 74k miles on my motor.

Hence my coolant shortage a few weeks ago. Apparent and audible air bubbles in the water lines. And most recently the white clouds of smoke with a hint of coolant flavor that started on Thursday.

Some of the guys got to witness my cloud of white smoke when leaving the Daytona 24 event. It was wicked this morning leaving for the dealer. I took pics.

Not really sure why this would have caused the water jacket to start leaking. The water pump was replaced under warranty about a year & half ago.

Engine replacement is being covered under 100k mile manufacturer engine warranty. I only have to pay for fluids and shop supplies. Said because I have over 50k miles, they aren't offering a courtesy car.