deedubs

Hi to all at rx8 club ,
I'm a noob and owned my 2004 8 for about 7 months now only issue i had was it had the old starter so replaced with new one, but now it seems that it starts fine from cold but when hot\warm will only start when left for at least half an hour, any ideas?
i've looked all over the net and haven't really found a solution.
ECT sensor?
IAT/MAF Sensor?
plugs?
coils?
leads?

also read about a hot start plug?

motor runs fine so i thought maybe not plugs, leads and coils.

anyway if anyone has had this issue or knows how to fix or diagnose it your help would be very very much appreciated.
before i go shed a out a load of money on parts

Cheers D

nycgps

iTrader: (1)

If your coils, plugs, plug wires, starter, battery, ECU, MAF, Throttle body are all in good working order ... then your engine is bad.

Actually, "Hard" hot start usually means your engine is bad.

All 04-08 RX-8 has 100,000 miles/ 8 years engine warranty. You got your car used so you might want to give MNAO a call to check your warranty status first.

Charles R. Hill

iTrader: (7)

What he means by "bad" is low compression, which seems to plague the '04-'05 models. We suspect low injection oil volumes from the factory.

Correct on the potential for warranty coverage but you need to call your dealer and register the "concern" as soon as possible.

deedubs

i haven't changed plugs coils or leads so would it be worth doing this or have i just got a bad engine (low compression) or could it be just oil?

Jedi54

iTrader: (7)

where do you live?
you could get a compression test done

Charles R. Hill

iTrader: (7)

Like Jedi says, I would get a compression test, first, as there is no point to throwing parts at the problem only to learn it is a common compression issue.

Get yourself a reman engine under warranty and then we'll take you to the next level with the performance.

Old Rotor

How many miles do you have? Have you ever run any engine de-carbon cleaner to improve compression? You might need this to clean up the carbon buildup. I would add a can to your tank with just a quarter left of gas. Give it a good work out in the high RPM range under load till its real empty. Most here get a can of Seafoam($8 Walmart) or BG44K about $15-20 at auto shops. Some times this has to be done a few times. If this does help then you might want to pre-mix after. Here is the "TSB" from Mazda that shows the best way to do it.

http://www.finishlineperformance.com...4-08-1924g.pdf

Mazda will do this free(if you have less then 8yrs or 100K miles) if you complain with these symptoms.

deedubs

90k miles never done a de-carbon will try this before i get a compression test as my local mazda dealer went under couple of weeks ago so i'll have to travel to get it tested. what do you pre mix with?

deedubs

Okay ordered sone BG 44K will try this first then go for a compression test

nycgps

iTrader: (1)

if Im you, I just gonna go straight to the next dealership and be done with it.

deedubs

i would but i havent lost any power when it is running it goes like hell which if it was compression would i not lose power
if the ect senor was faulty and was sending wrong signal to ecu starting hot engine with choke would i get the same symptoms and the fuel would cause a flooding type scenario
oh yeah i'm in the uk by the way and warranty only 3years 60k miles only USA got 8 year 100k miles extended warranty

nycgps

iTrader: (1)

well, didnt know you're from UK ... that sucks.

Charles R. Hill

iTrader: (7)

... and we have all forgotten to mention the possibility of a clogged cat-pipe, which usually happens when the coils start to get weak if they are not changed soon enough.

Have you checked the condition of your cat yet?

deedubs

haven't checked cat but its now on the list although i think i heard some of the cat rattling in one of the back boxes does this mean it gone and also would a clogged cat give these symtoms with bad coils?

Charles R. Hill

iTrader: (7)

The theory is that the coils begin to weaken, which places higher stress on the catalyst. This stress causes the cat material to overheat and destroy itself. Then the guts of the cat fall apart and clog the pipe. When one has an exhaust restriction, it will evidence itself as a loss of power, usually in the higher RPM ranges.

Old Rotor

There are lots of options for a good pre-mix I use MMO. Though it's off warranty. If all the service was done at the dealer I have read where Mazda is helping in some cases all you might have to do is cover labor. Good luck...let us know...

huggins14

hiya had the same problem with hot starting. changed starter motor no differance then had battery problem, changed the battery from the stock one in my rx8 and no problem starting anymore

elysium19

iTrader: (1)

FIRST thing to to is confirm that you're within the 100,000 miles / 8 year extended engine warranty period time.

SECOND thing is (if you are within warranty) just bring it to them and tell them you're having problems starting it, mostly when hot, and that it's flooded on you. That should prompt them to do their workup, which should include a compression test.

If you're within warranty, don't bother trying to diagnose/fix this yourself. From what you're reported, it's 95% surely due to low compression, and they should take care of it.

bse50

the way you put your compression test results tells nothing.

se3p_s

Can u tell me where is ECT senor located?

sophie_lee

Hiya first time RX8 owner bit worried...

I'm also in the UK having the exact same problem, Mazda seem to think it is a blocked cat, I had it hooked up to an ECU and it said it was the secondary air injector system... there is no rattling or weird sounds from exhaust or engine though????

I'm confused!!!! Please help!

SYMPTOMS ARE AS FOLLOWS!!

*recent loss of power last few days
*cuts out suddenly when you stop at traffic lights etc (when engine been running a while)
*wont start after long and short journeys (has on/off days sometimes starts sometimes takes ages, its getting progressively worse)
*starts first time in mornings even in coldest frosty/icy mornings if engine is cold etc..????
Hates starting when stopped if engine is warm.
*slight delay in acceleration lately with the loss of power
*engine when running sounds lovely and smooth!??

I am thing it could maybe be a temperature sensor? And the engine is flooding or running to rich? I am praying its not a compression problem as its not under warranty. It is a 2004 model and has 70k on clock its beautiful has the full spec, I mean everything built in sat nav, splitters , red/black leather, beautiful beautiful car please someone give me some hope very sad little girl I am

Brettus

iTrader: (2)

Sounds like classic low compression .
If you want to keep it going and avoid the cost of a rebuild then there are some things you should do .

Suffice it to say you need a 100% ignition system and a fast starter motor to mask the issue you have . You may also get some benefit from a de-carb.

Read this thread :

https://www.rx8club.com/series-i-trouble-shooting-95/starting-issues-start-here-222584/

sophie_lee

Thanks very much for the info the link is very useful also, covers everything i suppose its just a case of a process of elimination! just gonna test battery also now!

Mr.Rx8alex

i was hasing the same problems as you "not starting when hot" and what i did to fix it was seafoam my car i used
b13 carb cleaner aerosol can
used a glass jar and 1 clear rubber hose to the lower intake manifold (look up how to seafoam your 8)
anyways idk why but my car runs rich my long term fuel trims are 17 at idle causing it to bog and idle rough and it would die at stops i also noticed this happened because i didnt drive my car hard enough or constantly redlining also i tested my battery with a vat40 n my battery just barely kept 9.6v for 15 seconds so i replaced my battery now i dont have that bad of issues starting
When you have issues try to do this
try to hold the gas pedal all the way down and crank for 5 seconds dont over do it either you will overheat your starter (doing this will remove all fuel from your combustion chamber) also try redlining more often just dont push your car too much dont want to blow it up lol

hocknscary87

so I'm pretty sure my car is having the hot start problem, actually that is exactly what mine has being doing for over a month since right after i changed my plugs wires and coils. will they fix it without the engine being shot because mine is around the 8 year 100k mark and i have nothing else to drive and no way to fix it so if not I'm gonna sell it and just buy something else. which would suck because i absolutely love that car