RX-8 Owners Club UK

Hi everyone, I have been poking about the site for a while now but finally registered.

I have had the pleasure of being given a 53 plate 231 and when given it I knew it needed a rebuild, as it had hot running issues, now I’m not a mechanic but have done bits of tinkering, but my friend who gave me the car ( as you can imagine very good friend to give me a car ) and we agreed if I buy the bits we would do the engine work together, as he originally got the car as he wanted to work on a rotary engine.

Now I have enjoyed this process immensely and learning what bit I have about the engines for me has been a real treat, and after many days and weekends of playing with it, and rebuilding the engine, it is now back in the car, but with a couple of issues, and wondered if you good people could help, as I cannot seem to find the answers from my searches.

As in the title this will be just a track car, and will not be going on the road, so in the near future will be fully stripped with seats and harnesses to go in, so anything not required is being removed.

The issue I have is the car would fire on its own, new starter is on order and this should sort that out, as after a short bump start it does fire, but if left to idle it stalls, after keeping the refs up to about 3k for about 4-5 mins the engine just cut off, but up until then seemed to run very well and Rev very much better than before the build.

Is there something we should be looking at as to why this is cutting out? We spent many days watching videos and following guides to build the engine as all the information we had, and everything went very well, it has had a bit of porting work, and decat with exhaust and associated sensors disconnected as these won’t have a home any more.

If anyone can suggest what we can try it would be greatly appreciated, the wiring of all injectors has been double checked, and all ignition coils and leads and plugs are all new BHR ones, and a few other bits like ultra light fly wheel and pulleys.

Have any of you good folks any suggestions as we have only run it a few times till it cut off after about 5 mins, so didn’t want to keep running it in case anything was untoward.

As some other sensors have been disconnected does it also need the a remap to get it to run better or does it just need a good running in?

Hi Ian & to the RX-8OC

Please check out the EVENTS SECTION's - Events Team

Hi Ian,
Others will come along with more experience than me... but until they do...

Firstly did you check the battery voltage and that the connectors are tight? The connectors can come loose or the wiring corrode. Low/no power could also have prevented the starter from turning and cause the PCM to re-learn the fuel trims as mentioned below.

Any warning lights and have you scanned for error codes?

Sounds like no idle could be a few things:
- PCM re-learning the fuel trims, which is normal. Got to drive it and keep the revs up when changing down the gears. It's a fine balance given you also don't want to rev too much when the engine's cold.
- Dirty MAF (easily cleaned with MAF cleaner)
- Stuck open SSV
- Low compression (sorry hope not, had to say it). A compression test is a handy guide if you've rebuilt it.

Have you checked all the relays and fuses in the engine bay? I believe there's at least one relay that effects idle and the fuel pump.
Haydn

Which sensors have you disconnected as being not required and are you seeing any error codes?

As above. Surely the first port-of-call would be to reconnect the sensors you have deemed not-needed as it appears they may well be needed.

Likewise, you say it's been ported. Do you have pictures of said ports?

Also did you take pictures of the housings and irons before re-using them? It is unlikely in a low compression engine that every single part (excluding seals) can reliably be re-used, so I think everyone with the skills to advise would want to see pictures of the components used.

Whilst the rotary engine is simple in it's functionality, building one isn't exactly a meccano kit...

Hi and Ian. Well done on what you've done so far and you won't be the first to have an RX-8 as a track car - maybe check the Personal Car Projects and Mods section viewforum.php?f=104 to see if you can find a couple of examples and read details of what they have done and to see whether any of them had similar issues.

I don't have the technical know how to advise on what may solve your current issue, so seems like a good place to start - also, if you join the club you will gain access to electronic versions of all the technical and workshop manuals.

Hi everyone, thank you for the warm welcome and advice, for some of the points raised above please see the replies below.

The engine has around 50,000 miles on and when I took it to Rotary Revs for the porting works, he was complimentary of the condition of the irons and said they were very suitable for the build, so hopefully it’s not these.

The battery is new as the car had been in storage for a long while, but did run ok with the hot start issue before the rebuild.

The starter motor is definitely struggling, and a new 2kw has been ordered and should be on maybe this week to see if this cures the starting on the key as a quick bump start and it’s away, it just won’t idle on its own.

Sensors that have been removed, apologise if my terminology is wrong as I’m not a mechanic, the air feed from the exhaust manifold, and the lambda sensors from the decat pipe.

The MAF sensor was checked and cleaned up I’m told and was in good order.

The only error codes that come up are related to the lambda sensors not being connected I’m told.

I will be having a good look over other people projects to see what ideas people have done, I have seen a couple and I am really excited to get this done and at some point in the future onto a track to drive it properly, as I’ve heard good things about the chassis and handling of the car.

If any of you good chaps have any other ideas or advice to look at it would be greatly appreciated, or do I just need to try and run it once the starter motor is fitted and works to cure the key start issue?

uummm, did you remove both lambda sensors or only the rear one? the front one is definitely necessary for the engone to run correctly...

I will have to check as I have no idea I will double check, thanks.

Well today the new starter was installed, and both lambda sensors are in, and still won’t start on the key, but is better on cranking, so still needs a bump start, then cuts out.

Having to bite the bull it and drag it over to Rotary Revs as we are at a loss, hopefully nothing major

Clutch switch or gearbox neutral sensor?

Ian Johnson wrote: ↑

Fri Jun 14, 2019 9:46 pm

Well today the new starter was installed, and both lambda sensors are in, and still won’t start on the key, but is better on cranking, so still needs a bump start, then cuts out.

Having to bite the bull it and drag it over to Rotary Revs as we are at a loss, hopefully nothing major

Could save you a lot of time and stress taking it to RR.

Would the clutch and a neutral sensor affect it running and idling? Apologise if it’s a daft point, as I’m not mechanically minded, would these affect is running and cranking?

Yes, regarding running and dying, as would a failing anti-knock or ESP sensor, the latter could also impact starting (or not) on the starter.
Could also be fuel pressure, throttle body, ...

If you don't have the kit to investigate then a trip to RR could save you a lot of messing about.

Other rotary specialists are available (see my signature )

I've run without a clutch switch for weeks and there's no downsides as bad as that - it just thinks you're in gear with the clutch up and kicks the revs up a bit sometimes. Strange but not debilitating.

Thank you for the other suggestions, I will ask my mate to see if he can have a look, but may be quicker to book it in, as for other rotary specialists, I would gladly let anyone look at it, but looking at your location, were as rotary I can do in about an hour, Cornwall would take me slightly longer

click the link, im in cornwall, ryan rotary performance, are not

Just had a check where they are, from Blackburn that would still be a good trek, but thank you for the recommendation, I do have my eye on a few of their parts once the car is running again, and funds recover from the rebuild

they have two places, the workshop is in rugby

Ahh I see now, will keep them in mind thank you