My RX-8 has started exhibiting really poor starting when it is bang up to temperature. It takes a good 20-30seconds of cranking to start her up when its right up to temperature, say I go on a reasonbly long journey and then pull in to get something it wont start after. If I give it like 20-30 mins to cool down a bit it will start fine and it starts fine first thing in the morning or when cooled.

I have taken it to a garage and had everything checked electrically (was suspecting temperature gauge giving wrong fuel / air mixture) and its all passed fine. We did a compression test and its running at 5.5 which is down.

Now I can pretty much attribute these problems over time to filling up with fully sythenthetic oil, 0w-30. I read a long thread on here but couldnt really make any conclusion to whether that would cause a problem, but I guess compression is generally only lost in the apex seal with these things right? I just figured that by poutting in fully synthetic I was diong the engine good as its the best stuff on the market, but I guess its a different engine to the norm.

 

Although in the 'states synthetic is not recommended as ~"Mazda has no long term data" it's not a requirement to go dino.

Poor starting when hot is often a low compression issue. See enclosed.

 

Thanks for that, can I ask do those bulletins only apply to cars in America? This is a car from England. I took the bulletins into my dealer and they knew nothing about them.

I wanted to elaborate on my findings so far, it should be noted that this car has flooded quite a few times lately and hasnt been out on a long journey since flooding. Because I have been working away for weeks at times it sits on my driveway and when I get back the battery has been dead and I have now changed the battery which has solved that issue.

Speaking to the technician at mazda directly he said that 5.5lb for compression if testing from cold isnt uncommon, especially as I had been having flooding lately. What he suggested was buying the new uprated starter motor, he said he had done a load of RX8's lately with the new faster starter motor that actually cured poor starting when hot?

I notice no lack of power and despite the problems starting in the past few months (which I can only attribute to a. fully synthetic castrol edge 0w30 oil and being left on the drive / flooding) the car isnt driving any differently to it did 12 months ago once I had the coil packs replaced.

 

That's a good question. I always assumed TSB's were universal, but perhaps regional.

Regardless, it's not unusual for dealerships to have no knowledge of TSB's, much in the way their sales staff often don't know much about their vehicles. When I bring in a TSB printout, which I always try to do, they always ask if they can keep it and hand it to the tech.

Much as in modern medicine, one must be participatory in the care of one's vehicles, and the moreso the better.

 

I'd ask for a properly performed compression check on a WARM engine. Testing when cold is pretty much useless,engines also have LOWER compression when warm.
Don't blame the synthetic oil. The lack of power may be minimal (3\5% of loss) so it's possible to have a slightly worn engine and not noticing much of an effective power loss.
I'd also check the starter and fuel pump but in your case it may really be a compression issue.

 

I have the same problem. Furthermore it only happens during the warmer months of the year. For example I havn't had any problems all winter. But this past couple of weeks I have had a problem restarting the car if it is up to operating temp. and I shut it off for a minute and attempt to restart it. I had the same problem last summer. I took it to mazda last summer when I was having this issue and had my compression. They assured me my compression was fine even though the numbers were lower than those posted in the service bulletin. Others have to be experiencing this same problem. It is annoying to sit there and have to go through the deflood process every time you take a short road trip.

 

Huey and bse50, could it also be an ignition (coils, spark plug wires, spark plugs) issue? No cel. Only when engine is warmed up. No mention of engine sputtering or losing power intermittently. I lean toward simple spark plug replacement. What do you guys think?

But I want to ask the OP: When you say it starts "fine" first thing in the morning or when cold, do you actually mean it ALWAYS starts right up on the first crank in the morning/cold? Or does it occasionally hesitate for 2 to 3 seconds and you have to keep the starter cranking for a while or even do multiple cranks sometimes?

 

the OP said that he replaced the coils in the last year... i guess that they changed the plugs as well
Anyway I would lean towards a low compression, the results that they gave him with a cold engine...
Then there's the usual catalyzer, fuel pump, reflash to consider but that's another story. Since the OP is blaming the synthetic oil i won't tell him to try with some heavy premix to see how it goes!

 

Although the OP got coils replaced, he also stated he has flooded his car "quite a few times lately," something I had missed earlier. Given that he's flooded his car at least a few times lately, I'm leaning even more toward fouled spark plugs. I'll bet his spark plugs will be noticeably "caked" with crud.

Also, the OP should check out the many other Hot Start Problem threads, notably this one: https://www.rx8club.com/rx-8-discussion-3/hot-starting-trouble-169432/

In that thread, focus on Pyre and jiggawha1. For Pyre, it turned out to be spark plugs. Unfortunately for jiggawha1, it wasn't that simple.

 

Hot starting issues are common here because of the horrible scheduled maintenance. Oil changes every 20.000kms and other ugly facts.
Anyway it's usually a low compression issue since short trips don't let the coils and fuel pump fail but literally kill the engine. Add the fact that the recalls concerning the OMP were only seldom performed and you have a winner. Just take for granted what he says about the cold compression, there's no point in going any further!

 

for me ... new battery helped.

 

Hmm, thanks all for the help so far.

On the coil packs / spark plugs, whilst the coil packs were replaced the spark plugs were not. They are said to be in clean / good looking condition.

I'm not blaiming the oil per say, I mean I'm really just back tracking on what changed recently to introduce the problems. So I guess it probably isnt the oil by what people are saying.

So from here I guess I need to get it booked back in to the mazda dealership and have it diagnosed there. To think the inspection and compression test actually ending up costing as much as it would have at Mazda, only Mazda were fully booked and from teh off seemed more expensive....yet in the long run they would have been cheaper and done the job properly.

My only concern about Mazda is they are absolutely selling to every customer to buy the new uprated faster spinning starter motor, and they are pushing me down this path. Only a new starter motor is not cheap at all and I wouldnt want to find out it was something else having spent the full money on it.

I'll have to get it booked in for next week and go from there, maybes try the new hotter spark plugs (RE7C-L) as first fix if the compression is okay according to Mazda.

Thanks, ill check the other threads.

 

I didn't realize you had the old starter (and potentially also the older battery?).

Although both no longer offered free, you still want to upgrade. The faster spinning starter (and more powerful battery) can often overcome the heat-induced low compression.

Note also that the voluntary emissions recall 4206F as well as upping the OMP output (ECU setting; more oil to the apex seals) also included the new sparkplugs.

MSP16 and 4206F are typically Mazda-required precursors to further troubleshooting starting/compression issues.

So, you've got some variables to eliminate.

 

Just wanted to update on this, managed to get a new starter (the new longer / faster version) on the cheap and give it a try, turns out I know someone at mazda :D


Anyway, unbelievable difference. I still cannot believe that a new starter has comletely cured the issue, everytime I start it up now it confuses me as it starts on the absolute first stroke. It sounds like a right powerhouse when it starts and makes me smile a little

Totally differnet car for starting with the new starter, its never started as well as it does now and the new starter is about a million times faster. Even in the good weather at peak temp it fires off the first key if you stop and start it 2 seconds later.

 

Good news. Tell us how much the starter cost you, please.

 

Hmm.. This happens to me as well. After the car is driven for a long time. The battery is brand new though. I also feel like the car is heating up from inside.

 

Normally they are like £350, I paid a fraction of that. It was from a friend who works at Mazda, his mechanic mate had an almost new starter that had been replaced as part of warranty diagnosis but it turned out not to be the starter so I've had it

Anyway, thanks again everyone for the help. I'm actually turning to the dark side today, picking up last of the new (nearly new) honda S2000 and trading the rx8 in.

 

Many of us looked at the S2000 before going with the RX8, so nothing negative about the reverse.

 

Totally agree with you there.