Hopefully this thread will help others too

 

Glad we were able to point you in the right direction! I cannot express how sensitive these cars are to clean spark plugs. Once they're fouled with gas, it makes starting the engine very difficult.

 

Wow that will do it. I don't super understand the injector situation. How did they diagnose it and if they know which one it is, can they not tell you what replacement to get? And if they didn't narrow it down to a specific injector then how do they know that's the problem?

 

Yes mazdaverx7... The spark plugs were dark n covered in gas and THEY WERE THE ORIGINAL ONES FROM 2008 !!! .. gonna replace them .. the shop insits on doing a compression check too idk why tho.. Never had any compression issues whatsoever... I mean when shes hot shes perfect only the cold start issue..

Thanks for all your replies mazdaverx7.. You are the G

 

Hey there Loki...
Yeah,, they have narrowed it down to one injector they showed it to me today its one of those yellow Injectors.. This particular is spraying below the required amount and they say tht this might also cause issues in the future so better replace it too..

Thanks for all you help ma man .. ALL HAIL LOKI

 

The yellow injectors should be completely off at starting both hot and cold. I dont think thats your issue. Seems like they are just throwing stuff at the wall till something works. What you really should do is replace all of the spark plugs, plug wires, and ignition coils with brand new factory replacements.

NEW. GENUINE. REPLACEMENTS.

You continue to mention issues and symptoms and what shops claim to find, but youve made no clear indication that you are following peoples advice and actually doing what were telling you and doing so with the quality components your car requires IF you want your car to potentially run again. Clean your airflow sensor with proper airflow sensor cleaner too.

 

Hey there RickySE3P , Thanks for the reply

Yeah ive replaced all the spark plugs with NGK laser iradium ones and the coils n wires r fine ( they were recently replaced and new ). And yeah the shops keeps telling me about low compression but then the test was done when the engine was bone dry n rid of any oil or anything and it wasnt devastatingly low jus a tiny bit low. And i asked the shop compression issues usually give hot start issues , but then he says no it mainly gives cold start issues. but im baffled cuz this forum and utube n even ChatGpt says the hard hot starts n hot stalling r the issues of comrpession n ive never had any issues when hot. matter of fact its perfect when its hot.

So till now the MAF was cleaned , sparks replaces , fuel filters replaced , the air filter with the box as it had a broken lock , the one clogged injector replaced, and he mentioned some oil tht he will use to rebuild compression.. The parts r to be fixed in the next few days n hopefully everything goes to plan.

 

Its a good practice to perform a proper compression test with a rotary compression tester to get a better understanding of how healthy the engine is. Snd in the event that the engine is low on compression, this will aid in diagnosing issues and prevent you from wasting money on parts and labor that are not needed. The test has to be done on an engine that's at normal operating temperature and should be performed with a rotary compression tester. Until that is done properly, I would not trust the results.

Low compression will cause hot start issues. The shop has this information backwards. One of my 8's runs amazing until it reaches normal operating temperature and then the engine begins to run rough and will go down on power and eventually stall and not restart u til it's completely cooled down. A compression test yielded low compression, which i knew but wanred to confirm.

these were the cold numbers:





And these were the numbers when the engine was at normal operating temperature. Its a huge difference and you can be fooled if you do a compression test on a cold engine:

 

Thanks so much for this extensive reply Mazdaverx7 , Yeah. its super hard to find a proper rotart comp tester here in Sri lanka so they have don it with th conventional one and it was done on s uper cold engine and with my experience i had no issues whatsoever with the car when its hot .. like i can turn it off n start it ryt back inly when it sits for days n i try to start it does it give me issuess..

Thats why i was baffled and because the shop has the theroy twisted i actually didnt care much about the compression cuz after the successful deflood i did i actually drove the car to ths shop which is in the capital Colombo abt 80kms away in the highway n i actually did drive it spiritedly n it had no issues with the idle or hot starts.. i was in some traffic idling and even stopped at a BK to get a whopper n it started ryt back up... n matter of fact since the cols start issues started i somehow got her started n had looong trips with no issue only when it flooded tht day did it refused to start at all..

and for the cold starts there is a def culprit we found ryt the broken spark plug. so imma jus get them replaced soon wihtin this week alr have gotten the parts he is waiting till the shop frees up to do the replacement..

Car rides fine no unstable idle no power loss no hesitations , Starts perfectly when hot never ever have it died on me , pulls nice sounds nice no smokes or anything no CEL, fuel consumption is normal ( LIKE A THIRSTY V8) .. so its safe for me to rule out a compression issue ryt..? The car has 30,000 miles only.. deffo feels like the shop is tryna include more stuff to the bill..

Compression wasnt even smt i was bothered abt .. even ran a thick *** oil n she was let to redline frequently..

 

So update apparently i need a new fuel pump too cause the filter inside is clogged n the whole unit comes as 1 assembly.
Was quoted aroung 900USD for the job
JEEZ. !!!

 

The fuel pump is simple to replace. It requires removal of the left rear seat bottom and is accessed through a cover on the floor board. Once the cover is removed, you will need to remove the fuel lines, which are plastic, so be careful. You will then remove the lock ring, which requires a special tool. The tool can be purchased for less than $100 U.S. Finally, with the lock ring removed, the fuel pump assembly will lift out. Beware the suction tube that runs to the right side portion of the tank. The pump can be replaced as an assembly or replaced as a single part. $900 seems a bit excessive to me.

 

Again,

If you have cold start issues, there is one of the supporting systems wrong with the car. Chase Fuel, Spark, Air, Flooding or Timing.

If you have hot start issues, 90% of the time with Rx8's it will be compression issues. Which can be hidden if you do a cold compression test, which is the reason I don't trust the dealer numbers that people give.

 

Yeah but the thing is i they said the fuel filter has been clogged and tht needs the whole part to be replaced , and if the fuel filter is clogged shouldnt i have issues while driving..??... thinking if jus skipping it for now and replacing the other fuel filter along the fuel lines for now.. and since its not a rx8 specialist shop i feel more confident doing it from the rx8 master here in SL .. so gonna skip on tht for now ..

Thanks for the replies .. im gonna approve the job n pay n fix it up within a few days will update u guysss..

Who thought jus a broken spark plug will lead to a 700USD plus job..

Cant wait to hear the 7000rpm beeeeeeep again
[ i got an auto ]

 

Hey there mincvinyl..


No ion have hot start issues .. well havent experienced any ...
And yes ur right all of the spark plugs were old n one had a broken connection tip..

Will fix them n updateeeee

 

Typically the fuel pump assemblies only get replaced when you have issues going high rpm. Where the fuel pump fails to deliver enough fuel.

Granted I do not know about the fuel quality over there or weather conditions.

 

I also would just like to contribute again by saying that back more than 10 years ago I had a automatic Rx8 that I took to Mazda dealer to test for low compression, even though I didn't have any hot start problems...

The corrected compression on that engine was nearly even on all the faces, but the highest corrected compression value was so low that the numbers dont even show up on the compression chart Mazda uses to determine if the motor is failing. The highest compression value on that motor was 4.1kg/cm² at 250rpm.

Metals can expand, bend, and generally change shape as they heat and cool. While unlikely, it isnt impossible that your engine could have less trouble starting when warm.

 

I jus got a wierd random question that i couldnt find a proper answer.

I have seen many utube vids of ppl tryna deflood their rx8s over n over using the pedal to the floor method like i did and some places like in the Rotary Revs wesbite mentions that it can cause harm to the engine.. Is it true..??
I did crank it a loot..

Ik the oil layer washes off when mixed with fuel n the car is flooded but then does tht cranking can cause any significant damage enuf to cause low comp..??

 

900 USD for a fuel pump replacement is insane. Maybe it's more expensive where you are but parts and labour done at the dealer would be mmaaaybe 400? And they already did half the work by taking out the fuel pump to check the filtrr right? Right? They did actually look at it and aren't just guessing? And if it's a filter issue, fo you still have to replace the injector or that not a problem any more?

I have no idea what you're seeing on youtube. The gas pedal fully depressed cuts fuel, this is Mazda's procedure for clearing a flood. The fuel is already in there, there's no other procedure that makes it less of a problem. But it's just not a big problem to begin with, starting is low rpm, low pressure, you're not stressing the seals. Obviously don't do it every day, but there are far worse things for the engine.

 

Sooooo Guyssss
UPDATE !!!!

The car is fixed.. No more cold start issues matter of fact starts ryt up way faster than im used to and is super smooth n all.

Parts Fixed

• all 4 Spark Plugs
• 1 injector that was below par
• Fuel Filters
• Air filter
• Done a tune up

Culprit of the cold start issue

• THE BROKEN SPARK PLUG

So currently there is no issue until today when a CEL flashed out of nowhere while i was heading home ( it was fine all the way ) n the car was in some sort of limp mode. came home n cleared the codes and its gone .. Futhuremore ig theres some loose electrical cinenction wihtin the car cuz sometimes the ac n radio unit wont power up but will work once the fuses r shaken a little. and the windows decided not to roll up or down anymore.

And there is a slight whine like a supercharger when accelerating in 1,2 gears since the car was back.. i mean its barely noticeable unless u give all ur ears to it.. and from what ive read its normal.. maybe thts a haealthy engine sound i didnt hear till now cuz mine wasnt runnign at full power..

Thank you for all the help you guys gave to me with figuring this out even when the shop had sm ROTARY SCIENCE confused .
I wish this thread helps others too.. Will post n keep an update abt the CEL.. i do have an airbox tht has lost its locks n doesnt seal all tht well but it has never caused a cel till now ..

 

Glad to hear the car is fixed. You can go on the marketplace section here on the forum and look for a part out and buy a new air box that will seal. Sounds like you're on the right path, congratulations!

 

IM BAAAACKKK !!
So regarding the CEL

It occures only when i have to start the engine after stopping in quick succession like within 4,5 mins ( if i have to start the car like 5 times within 10 mins ) and it comes up n car goes into limp.. I stop the car turn it off lock the car unlock n start it n voila its out of limp mode.
I read the codes using a scanner n this is woot it came back with ,


Could this be a issue related to low battery voltage , i mean when i select only the OBD-II section within the scannign app n click Clear the CEL goes away prooving tht its a OBD-II related issue. There were no codes under ECM or tranny , once i clear them they dun come back until it happenes n it never happens unless i have to stop n start the engine a lot withing a short period of time n always happens after a cranking n start.

 

What other sections are there besides ODBII? All codes are part of ODBII..
Also why are you starting and stopping the car so frequently? I can see it maybe being a loose battery cable or similar wiring connection, but it5also possible starting and stopping each system very quickly doesn't let them boot properly or trigger some kind of anti-theft or dealer access program.

 

Hey there Loki,
Other sections include engine , ABS , tranny , SRS airbags blah blah but none of then have any issue.
all the codes were under the OBD-II section

Had to do some chores n decided to take the dorito machine out .. thats why there were many frequent stops..
Can a low voltage cause this issue if the battery is failing..

 

Yes abad battery or battery connection can cause all kinds of gremlins

 

Gonna get the battery fullt charged n see
Will update