Danieljjvv

Hi all
i'm Currently having a hot start problem on my RX8.
when cold the car starts and stays in closed loop even when i'm driving.
it only goes into open loop on deceleration and when i shut the car off above 89 degrees celsius and stays in open loop (and does not start).
have to wait till the car cools to about 85 then it will start (in closed loop)
I did see a other post similar but a few thing is different.
after a few youtube videos and forum posts i'm still baffled.
things i have replaced so far.
Sparkplugs
Ls coil upgrade
Coil cables
All vacuum pipes
battery
starter 2.2.14 teeth

it has no idling problems
did have the compression tested
don't have a lack of power
my obd2 reads the o2 sensor as 15.0:1
please does any one have ideas?

wcs

iTrader: (2)

How are you determining if it's in Closed or Open Loop?


I would also try using OEM coils to see if that changes things for you.

Danieljjvv

I'm using a obd2 scanner to check the sensors and monitoring, that is how i see that it only goes into open loop on deceleration.

wcs

iTrader: (2)

So the ODBII scanner is actually reporting OL vs CL?
Ok well
On decel what you're seeing is a fuel cut.
Normal driving loads you should be in CL most of the time, so that's good.

When you do a WOT run the car should go in to OL .. see what your scanner says then



Have you checked the Maf?

The car will run in OL if the Maf is unplugged.

Perhaps the Maf is faulty?



What were your compression numbers?
Hot start issues seem to be compression.


Again, I've had issues as well with hot starts using non-oem coils.
Changing the DWELL map helped significantly.
So I wouldn't rule out the coils.


If you can post a 10 second idle log showing as many data point as possible might help.
In particular the following data is useful:

LTFT

STFT
Maf G/S

Maf volts

Battery volt
RPM
AFR
Coolant temp
Calculated Load


Posting your compression numbers would be the best place to start I think.
Sorry I can't be much more help

wcs

iTrader: (2)

Silly question but do you have a check engine light on?

Loki

iTrader: (1)

It should stay in closed loop when you're driving. That's what closed loop is. It will flip to open if you accelerate briskly.

I think the open/closed loop thing is leading you in the wrong direction. The car won't restart while warm is the real problem, which has 2 causes: compression or fuel pump. How's your fuel pump?

wcs

iTrader: (2)

Good point Loki.


I wonder what year and how many miles on the car too

Danieljjvv

After alot of research and checking problems on the OBD2 scanner I decided to take the car to our local rotary specialist and discovered the problem.
when I purchased the car, the dealer took the car to a electrician as there was faults on some of the wires.
​ it turns out that the wire running directly to the starter could not supply the starter with enough amps.and when the car was hot all the clearances tightened up and put more load on the starter which was under powered.
​​​​​​So the open and closed loop on the car has nothing to do with my startup problems.
so my advice would be when upgrading your starter take another look at wiring as well.
Cold (1°c)and hot (97°c) start with no effort.
How something so stupid can be sutch a pain.

wcs

iTrader: (2)

Thanks for the update, much appreciated.
Not everyone does update after posting an issue.


cheers