Bought my rx8 a few months ago. All is fine apart from recently a few issues with hot start - takes a couple of goes - 20-30 seconds to get going. Was due a full service but decided to get a compression test done first - results not good. Cranking a bit slow which isn't the end of the world, but compression just below the minimum required. Average of about 5.5 on a crank of about 215. Conclusion - it's on its way out - am I right? General theme seems to be low compression means it's just a matter of time before the engine goes. How long do you reckon I've got? Dont do a lot of miles. Is it also wishful thinking to think that it's not all that bad and may just be a lot of carbon build up affecting the compression. A good carbon removal run using mazda a stuff or seafoam might help things a bit? Thanks.

 

Nothing will fix it but a rebuild. There's no telling how much longer it will run, but hot start issues and mpg loss will get progressively worse. Flooding becomes much easier.

Carbon removal at this point could be a bad thing if the seals wore unevenly due to carbon build up.

 

Your last resort could be seafoam. Does not mean its going to improved, but it could clean the carbon away. If not, then its time for a re-build or a re-man engine...good luck!

 

do a decarb , slap a upgrade starter on , keep battery and ignition in good order and you will get many 1000s of trouble free miles yet .

 

You can also add a little premix to the equation. It should help prolong its life a little, but in the end it will need to be rebuilt or replaced.

 

you could say that about anything ever built by man

The issue here is ... when is "the end" . I say it's a LOT longer than most allow it to be simply because they don't do the above ................

 

Out of curiosity how many miles does it have on it?

 

58000 miles. Runs great. I can manage my journeys so I never do a hot start (and I can get it started if I have to). On reflection power seems a bit down pulling away which Is to be expected but I don't really notice. At the moment I've just got a piece of paper telling me the end is near and not sure what to do about it! Going to run some seafoam through and see what happens.

 

Any misfires? I was running fine with hot start issues for some time, but the situation got worse, over a course of just a couple of days, to a point where the car would not run. Misfires under heavy load was the first real symptom besides the hot starts.

 

Again , an engine with low compression runs just fine (apart from a small loss in top end power )if everything else is good .
Low compression does not cause misfires.

 

i agree, if you can squeeze another 10-20k miles out of an engine before replacing it and follow that recommendation then your engine replacements will span out further.

the focus should be on the cranking speed and your ignition system anyways, replacing the engine won't fix those growing problems.