An RX8 in Belgium - R3 wheels fitted

[*thomas*]

The car currently sits at 102 624kms (approx 65000 miles). Time for an oil change.

Last year I overfilled the engine with oil due to the oil pressure light staying on... After draining the engine and filling it with approx 3,5 liters (on the dipstick, the oil sits at 1/4 bellow MAX level) the light doesn't want to go out. I was already considering to change-out the oil pan which will also include a new switch.

Cleaned the inlet and airbox from oil residue from last time and changed the airfilter and cabin filter.







A few weeks ago, I also installed a white screen washer bottle. The black ones look ugly and are a pain to read the level properly.

[warpc0il]

It's not that uncommon for the oil level switch to fail, often associated with a slight leak.

If there's no sign a leak, check the switch with an ohmeter (or bulb and battery) to earth, as the other case of the light staying on can be damage to the loom - basically the sensor wire earthed.

Sent from my SM-G398FN using Tapatalk

[*thomas*]

It's not that uncommon for the oil level switch to fail, often associated with a slight leak.

Thanks. Funny thing was that last time after adding (too much) oil, it went out and stayed out.

Still will change the oil pan. It's a bit rusty and ATM I'm trying to make the car's underside look good again.

[*thomas*]

I finally took the rx8 for a spin today, first proper ride in 6 weeks due to - well - being busy I guess... The oil pressure light went out after about 5 miles (I checked the oil before leaving, it was just below max). After half an hour, I decided to hit the rev limiter on the freeway entrance, but the car would not go past 7K rpm (it's a 192bhp, but it normally revs up to 8K on the tacho) and you could feel it wasn't happy. Tried a second time (in second gear), but same result.

Fuel had been standing for those 6 weeks, so I put in some fresh fuel, drove around a bit and tried the hit the rev limiter at a very steady rate. After a few miles, all was well again. Up to those 7K rpm, the car felt the same (and normal) during the whole drive, so I don't know what was going on.

[warpc0il]

It *might* be something as bizarre as a soft tyre, so DSC/TCS senses a difference in wheel rotation speeds and backs-off the power.

This can seem random until you take into account road conditions, bends, etc.

OTOH it's more likely to be something engine related, and again it could be something random, like a sheet of paper towel left in the intake, or a coil breaking down, or the fuel pump, or ... not really enough detail for a guess.

[HarSc]

...like a sheet of paper towel left in the intake...

This has simply never happened to anyone, I have no idea what or who you're talking about...!!

[warpc0il]

I have nothing against that scenario, since I once saved £100's buying a used Honda CBX550 from a dealer, with "a blown engine" only to find a piece of old towel sucked from under the seat into the airbox.

Took me moments to fix, and that bike ran really well for a few more years before I traded it in to another dealer, for a nice profit

[HarSc]

I have nothing against that scenario, since I once saved £100's buying a used Honda CBX550 from a dealer, with "a blown engine" only to find a piece of old towel sucked from under the seat into the airbox.

Took me moments to fix, and that bike ran really well for a few more years before I traded it in to another dealer, for a nice profit

Hah! I thought you were having a poke at Chris originally, didn't realise it's actually not an uncommon scenario

[warpc0il]

okay, I might have been having a slight poke at Chris too...

[Lemon]

I have nothing against that scenario, since I once saved £100's buying a used Honda CBX550 from a dealer, with "a blown engine" only to find a piece of old towel sucked from under the seat into the airbox.

Took me moments to fix, and that bike ran really well for a few more years before I traded it in to another dealer, for a nice profit

Hah! I thought you were having a poke at Chris originally, didn't realise it's actually not an uncommon scenario

remember that Misubishi sold an Evo from the factory which had a mislaid 10mm socket in the valvetrain and it was only discovered when the car went in to the dealer for replacement rocket cover gaskets.

[*thomas*]

It *might* be something as bizarre as a soft tyre, so DSC/TCS senses a difference in wheel rotation speeds and backs-off the power.

This can seem random until you take into account road conditions, bends, etc.

OTOH it's more likely to be something engine related, and again it could be something random, like a sheet of paper towel left in the intake, or a coil breaking down, or the fuel pump, or ... not really enough detail for a guess.

Just checked (cold) tyre pressure before leaving the driveway, so that's a no.

The car ran fine up to 7K rpm, just the last 500-1K rpm (on the tacho) were 'unobtainable'.

Could be a coil going bad. Plugs have 5K on them, leads also. Engine never started this good (hot and cold). Will see if it behaves badly on the next run.

I'm guessing it was fuel related. We have 95 with 10% ethanol and 98 with 5% ethanol. I normally use 98, but the last two I used 95 (fuel prices were insane). So could be that the ethanol was going bad (?). Just guessing.

[qwakers]

could be a failing fuel pump. thats the behaviour i got when my oem fuel pump started to fail.

[*thomas*]

could be a failing fuel pump. thats the behaviour i got when my oem fuel pump started to fail.

Is there a way to make sure it's the pump?

[qwakers]

you could flow test it but other than that, no not really.

this is a direct replacement.
https://www.aemotorsport.co.uk/shop/aem ... fuel-pump/

[*thomas*]

Ok, so an update.

I took the car for another spin yesterday and the exact same happened. Did most of my run at engine speeds below 5 or 6K and on the way home, wanted to hit the limiter => same problem (car doesn't want to rev freely up to 8K). Only when doing this very gently, the car climbs up to 7,5K on the tacho, but I could tell it was holding back.

To me, this also feels fuel related and takes me back to when I had 2 stroke bikes. When they were jetted improperly, they would also 'cut out' at high rpm but could also be 'forced' to climb further when going at it very easyly.

[warpc0il]

You could try a plug cut but the logistics can be a bit tricky with our cars.

Basically you run the engine to the point that it's not performing properly, then put it in neutral, switch off the engine and pull up.

Remove the spark plugs and check the condition of the business end.

If it's running lean then they will be nearly white.
If it's a lack of sparks then they'll be dark and wet.

This approach tells you "what" but not "why".
e.g. lean running could be a vacuum leak, stick injector, fuel pump,...

Note, when switching engine off, make such that the key doesn't come out, or you'll have the steering lock engage

[*thomas*]

Just a quick update. I didn't drive the car since my last post, but have changed the coils yesterday and this cured the problem.

Car is running sweet as it ever did.

[DrewR3]

Just a quick update. I didn't drive the car since my last post, but have changed the coils yesterday and this cured the problem.

Car is running sweet as it ever did.

Good news thomas. I am glad you found the issue. Please keep up to date with forum news as something that may interest you could be on the horizon.

[*thomas*]

I haven't driven the RX8 all that much during the last few months, but every time I wanted to take it for a spin, I needed a jumperpack. Time for a new battery. The old one was the wrong size/type/strenght, so after reading into it on the forum I went with the Varta E23. It's a tight fit, but it fits.

Out with the old.



Cleaned out the case.



New one in place. Note that the cable routing is finally as it left the factory. I tought I needed a new postive battery terminal clamp (is that a 'word'?), but seems the angle at which it was installed was the problem.

[*thomas*]

With the new battery installed, the car now starts flawlessly every time. How I managed to run it for so long without the proper battery is a mistery.

Yesterday I finally finished a job on the car that I had been postponing for over a year. In June of 2021 I wanted to replace 4 suspension arms from the rear suspension (the ones that enable you to do a proper wheel alignment). Sadly, the bolts that secure the arm into the knuckle were badly seized on both sides. They sheared off and it was impossible to remove them. I gave up and the dealer from which I bought the car made sure I could drive it for the time being.



In the mean time, I sourced two rear knuckles from ebay (which was harder than it seemed) and trough last winter I rebuild them with the bearings, silent blocks, wheel-speed-sensor and heat shields and wheel bolts.









Cheers

[PaulAV]

Will be carrying out the same type of job on mine this summer, along with replacing the differential and subframe. Some of the bolts require drilling out(already changed the camber and toe control arms)

[*thomas*]

Strangely, all the bolts that connect the arms to the subframe were corred, but spun freely.

It was only the 'pinch' bolt on the knuckle that caused all this drama. In the end, I'm glad I did all this work and I plan on replacing the 2 remaining suspension arms on both sides, together with new brake calipers. These never stick, but they are just so corroded it annoys me.

[PaulAV]

The pinch bolts actually have a straight knurl/spline on the plain section so they don't turn, I had to drill them out, with decent drill bits it took 20 minutes per side

[*thomas*]

I tried drilling them out 'in situ', but after several atemps, I gave up. I should've removed the whole knuckle from the car and do the job in the garage.

[*thomas*]

After reading up on it on this forum, i've ordered a bottle of Cataclean.

Also needed new 2 stroke, so grabbed some bottles of Castrol Power RS 2T.