Hot Starting Problem
 

Hi to all at rx8 club :Peace:,
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.:bowdown:
before i go shed a out a load of money on parts

Cheers D:wallbash:

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.

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.

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?

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

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. ;)

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.

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?

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

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

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

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

... 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?

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?

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.

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...

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

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.

the way you put your compression test results tells nothing.

Can u tell me where is ECT senor located?

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 :(

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/

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!:tear:

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

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

Your LTFT is plus 17 at idle?
If it's plus it means it's adding 17% fuel to maintain stoich ... I would say your car is running lean if you took the 17% away.
You might have a vacuum leak.

i am having all these same problems, will the warranty cover it now or does it need to die first? i can't afford a rebuild or a new engine. shit

Where do you live?
How old exactly is the car?
How many miles on the car?
Do you have receipts of your oil changes? (Sometimes not required but is very helpful to have, depends on dealer it appears)

Have you purchased any Rotary Karma lately?

I have no idea what rotary karma is. the car is an 04. 76k miles on it almost, just started doing this maybe a month ago, changed the coils and plugs maybe two months ago. i did buy some aftermarket coils could that be the problem? i don't want to spend 130 on new ones just to realize it didn't fix anything. i have no receipts for oil changes but i don't believe that should matter considering the year and the consistency of this problem.

i have noticed a decent loss in power recently tho so i'm suspecting i took too long to be concerned i may have low compression now which is just great. however it doesn't have too hard of a time starting, it started mostly after the people inspecting the car for state inspection flooded it out. mostly it just takes a few seconds but there were a few times where i had to try like 3 times to start it. i just got back from vacation in las vegas and spent money so now i'm stressing a bit haha

Rotary Karma was a joke, sorry. You know what "Karma" is right? I think at some point every rotary owner wishes they could buy some good "Rotary Karma" ... anyway ... a fail on my part.

Then warranty varies on your location. If you are in the UK you are screwed.
If you live in Canada you might squeeze in.

The Canadian warranty is 96 months or 160,000 kilometers.
I "think" the US warranty is the same except 100,000 miles.

Aftermarket coils will not give you low compression numbers, but could make your car run poorly.

LOL you don't believe that oil receipts should matter. Dude I agree 100% but I've seen many a compliant and plea for oil receipts on this forum.

The following is quoted directly from the Canadian Rotary Engine Core Limited Warranty Information Card

4. Your Responsibilities:
Maintenance:
You are responsible for properly operating and maintaining your Mazda Vehicle in accordance with the instruction described in your Owners' Manual.

Maintenance Records:
You must retain maintenance records to show that required maintenance has been performed.
The "Scheduled Maintenance Record" on your Warranty Information booklet should be filled in when scheduled maintenance is performed. Keep all receipts and make them available in case question about maintenance arise.

Good luck dude.
Keep us posted.

well i do change it every 3k-4k miles so i should be able to scribble that down in it a little bit. and i was just wondering if the aftermarket coils could of failed out that fast, i've only had them in for about 3k miles now and they are BSD coils. Apparently my rotary karma is fucked at the moment since my 2nd gear synchro is junk also haha. and thank god i live in Pa.

or could having my CEL on due to my cat not existing cause this? cuz it seems these are the same symptoms for many different things. I'm checking my coils after work so i'm kind of hoping its that

alright so i hopped in it today and had no issues with hot start. although i have noticed a trend. A guy i work with at the body shop said he noticed a lot of carbon build up on my exhaust tips and to check to see if its missing since it was flooded and then i told him it was doing it a little before that and that its hardest to start when the gas is close to E, and since i was close to it today i filled up and after that on my lunch break it was actually a little more difficult to start, and i know this all happened first when i literally just about ran out of gas trying to get the one kid i work with home before his house arrest time kicked on. everytime im close to E it starts hard on the first try or it takes 3. So I'm gonna change the fuel filter this weekend and check my plugs and coils since they shouldnt take long to get to and I'm pricing a compression test, even tho i squeeked the tires dropping from 4th to third today, which i am going to admit wasn't a good idea but i wanted to see what it was doing after i filled up but i shoulda just hammerd it in 4th cuz dropping to third it went up to 7 and although its not too close to redline, still makes me a little uneasy. But i feel the low compression would be more consistent and would not of lasted this long.

think these are some good steps to take before hitting the last resort?

The rx8s has the fuel filter built in the fuel pump assembly so if you want your filter changed you'll have to buy a whole new one my car is hard to start up when hot too I'm wondering if its either vapor locked or a valve bleeding fuel before it reaches injectors

9/ 10 times ... hot starts are a sign your engine is going ... loss in compression. Go get compression tested.

In the meantime, I recommend you start premixing ... it will help with compression somewhat.

This isn't aimed at anyone in particular, but why doesn't anyone read the stickies and hundreds of threads on this subject. On top of that people love to go and start replacing parts and spending money instead of getting a compression test.

For the love of god, go get a compression test and see where your engine stands before dumping $300 or more on coils, plugs, wires, starters, etc. A reputable dealer should be in the $100-$150 range for the test. Seems like a no brainer to me. I dont' know why people are afraid to do it. The worse case scenario is that it fails. If you're under warranty still and have a paper trail for maintenance, you get a new engine. Doesn't seem like that bad of an investment. If it passes, you can now rule it out and spend the money needed for tune-up parts. So you're out and extra $100 bucks, but now you have the piece of mind that your ticking time bomb of an engine has some extended time on it. Worth it to me. :dunno:

/Rant

There is no such thing as classic "vapor lock" on modern fuel injected cars. The mythical "valve bleeding fuel" *could be* a fuel pressure regulator, but this would be a very rare problem.

As previously mentioned, the most likely culprit is compression, then plugs/coils/wires, or weak starter.

How many miles? Auto or 6speed? Do you run it to redline 1x/tank full, rotaries love the 'abuse' Could be cat.converter clogged? Do NOT use any synthetic fluids in this car! Temp sensor could be bad. I drive an 04w/<62k, have no issues except hard cold starts due to age

Don't listen to this advice.

Due to age? :icon_no2:
That has nothing to do with hard cold starts.

My oil supply was inherited from a generous stranger.
I make my own oil.
I found this huge stash of oil in my garage left from the previous owner.
... etc.

All theoretical but some more believable / plausible than others; how do you provide a receipt then? What is the established bare minimum burden of proof? I know it's beating a dead horse, but it's always nagged me at how warranty claims get hung up on "receipts". The requirement to maintain a log is quite vague. Receipts in the traditional sense are very fragile things that fade over time (oops!). Fortunately Mazda has (recently?) provided a means for logging oil changes online @ mymazda.com .

Well all things considering I was gonna pull the fuel pump out but it turns out you need a special tool to pop out the white O ring so i feel its staying in, at least thats what i saw when i looked it up on google. so i am gonna try to de carb it, maybe that will do something. I am considering the compression test its only 110 here, but its not ever consistent. You would think it would happen everytime you the car warms up. but its not even every other time its like every 4 or 5 starts.

Dude .. if you are going to do the Seafoam thing ...
Do the ATF thing as well

Both are hail Mary's but what the hell why not.
https://www.rx8club.com/series-i-tech-garage-22/another-how-fix-compressions-any-rotary-engine-atf-170689/

It didn't help my compression but I will swear the car ran better

i mean i'm not doing it to help my compression, I'm doing it to try and clean up the injectors and the seals a little bit. I run a few ounces of seafoam in my bike every now and then so i already have it.

people are afraid of compression test just like people are afraid of AIDS test

not afraid of it, just would rather spend 100 dollars on something else. I saw that fuels pumps aren't real reliable, 76k miles on the clock you think its time to check it? i saw on here that that could be a problem. that or the sock on the pump is filthy because it only has a real hard time when i'm low on gas.

egg

If you're having starting issues and you aren't past the warranty yet, then get a compression test!!!

Same here 04 with 104k I bought the car off a B LOT should have had a compression should test done before i bought the car but i didn't and I regret it because I went to start the car today after its been driven about 5 or 6 miles and it would crank but not start. after I got off work I went to start a car when it was cold and the car fired right up when I got home (10miles) turned the car off and when I tried to restart it it just cranks worse case scenario the engine is shot is it hard to re build your own motor ive worked on many cars in the past but never a rotory and I have about 3k as a budget.

I couldn't tell you how hard it is because I've never done it, but there are some threads on this site that show you how to do it. Take a look and see if you can do it. There are also other options besides doing it yourself, e.g. places like Mazmart in Atlanta and Rotary Resurrection in east Tennessee that do high quality rebuilds. You can also get a "reman" engine from Mazda, but they are know to have quality control issues. Personally, I wouldn't buy one. Why spend at least $3k (if dealer puts it in too, it'll be $5-6k with labor) on an engine that may fail in 30k (could last longer) when you could spend $4-5k on an engine that will most likely last a long long time. Mazda only offers a 12m/12k warranty on their reman engines, so obviously they don't trust it either. Since you've rebuilt engines, I'm guessing you can remove and install the motor yourself and save yourself some serious dough. I have a reman with 48k and it already had entered low compression range at 30-35k, and is steadily getting worse. I'm not having starting issues yet, but my hot starts are getting longer and it's starting to shake more and more at idle. I'll be going to mazmart or RR next time for sure. You could also buy a low mileage used engine, but, again, it may not last long. No telling how long any engine will last, it's just a matter of probability :/
Some are just more likely to last longer than others :)

I would get a compression test before doing anything, though. It could just be a slow starter that's failing and/or a bad battery (04s had slower starters, mine did). Ignition system (coils, plugs, wires) could need replacing as well. Is the CEL on?