Cold Start Issues

[13Black]

PCM reset will be fine. You'd be hard pressed to accidentally change the map

I don't know if they change anything to do with the starting parameters with a FBP map, don't see why they would but could always fire RR an email?

[350matt]

Maybe silly question but if you have a scan tool does it say what temp the coolant sensor is showing?

as its this that has a very strong effect on fuel mixture

if yours is faulty then it can skew the fuelling

[Rotary Potato]

PCM reset will be fine. You'd be hard pressed to accidentally change the map

I don't know if they change anything to do with the starting parameters with a FBP map, don't see why they would but could always fire RR an email?

Thanks.

Will prob fire Ben an e-mail - better to be safe than sorry.

[Rotary Potato]

Maybe silly question but if you have a scan tool does it say what temp the coolant sensor is showing?

as its this that has a very strong effect on fuel mixture

if yours is faulty then it can skew the fuelling

Thanks Matt - I'll check in the morning.

The coolent temp needle (yeah, I know ... hardly last word in accuracy) seems to react as I'd expect. No idea if there's 1 sensor for the gauge and another for the ECU, but I'll see what it throws up in the morning.

[350matt]

there's only the 1 sensor but as you say that gauge is heavily damped and its difficult to say what its reading with it all cold as I suspect if it was -50 the gauge would be on its end stop as it would if it was 10 degrees

[Rotary Potato]

Ambient = 8 degrees

Coolent = 8 degrees

IAT = 11 degrees

I'll send Ben an e-mail today and go from there.

[350matt]

the other thing that can have a strong effect is to check for exhaust leaks before the O2 sensor as if this has been experiencing an exhaust leak then it will have been running very rich as the sensor will see the extra air pulled in as fresh / lean fuelling and be adding fuel to compensate.

this can lead to catalyst failure as the extra fuel can re-light inside and melt the catalyst

The best way to find an exhaust leak is to run the engine from cold and feel around the exhaust joints with your bare hands - you'll have about 30 seconds before it all gets too hot and you should feel any escaping gas blowing over your fingers

[boosted]

When it does start cold what's she idling at very start...all mine were about 2k if my memory ok and quickly drop to 1500rpm then slowly settle when warm 850..
Could be map.

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[Azimuth]

My method for finding exhaust leaks...

Spray WD40 into the inlet manifold, via a vacuum connection, downstream of the MAF, with the engine running.

WD40 produces a dense white smoke that's easy to see, without doing any damage.

[Rotary Potato]

the other thing that can have a strong effect is to check for exhaust leaks before the O2 sensor as if this has been experiencing an exhaust leak then it will have been running very rich as the sensor will see the extra air pulled in as fresh / lean fuelling and be adding fuel to compensate.

this can lead to catalyst failure as the extra fuel can re-light inside and melt the catalyst

The best way to find an exhaust leak is to run the engine from cold and feel around the exhaust joints with your bare hands - you'll have about 30 seconds before it all gets too hot and you should feel any escaping gas blowing over your fingers

Thanks Matt.

Surely an exhaust leak would also impact hot starts & running?

I'm fairly sure it's all good, but will double check at the next cold start.

[Rotary Potato]

When it does start cold what's she idling at very start...all mine were about 2k if my memory ok and quickly drop to 1500rpm then slowly settle when warm 850..
Could be map.

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Idles at 1600-1800, dropping fairly quickly to 1200 or so and down to about 1000 when warm.

[Rotary Potato]

My method for finding exhaust leaks...

Spray WD40 into the inlet manifold, via a vacuum connection, downstream of the MAF, with the engine running.

WD40 produces a dense white smoke that's easy to see, without doing any damage.

Thanks Dave, will give that a try.

My gut is still on something mapping/fuelling ... but makes sense to eliminate the easy to check along the way.

[boosted]

When it does start cold what's she idling at very start...all mine were about 2k if my memory ok and quickly drop to 1500rpm then slowly settle when warm 850..
Could be map.

Sent from my SM-N950F using Tapatalk

Idles at 1600-1800, dropping fairly quickly to 1200 or so and down to about 1000 when warm.

That's fine then....no one's messed with it since rebuild...coil leads in particular...leading at bottom trailing on top. Just ideas...

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[Rotary Potato]

Only time it's been touched since rebuild is by RR themselves for the mapping.

Not to say a lead couldn't have worked itself loose, but on a quick check all looked ok.

[boosted]

Well I'd just get it to Ben he will sort you out.

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[Rotary Potato]

Well I'd just get it to Ben he will sort you out.

Sent from my SM-N950F using Tapatalk

Ideally I'd like to solve this without a 2 1/2 hour trip each way to Leeds ... but yes, it is a nice last resort to have.

[ChrisHolmes]

Well I'd just get it to Ben he will sort you out.

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Ideally I'd like to solve this without a 2 1/2 hour trip each way to Leeds ... but yes, it is a nice last resort to have.

Consulting Ben should be your first resort not your last one!

[Rotary Potato]

Morning Chris.

Consulting Ben is definitely not a last resort. However the 5 hour round trip to Leeds definitely would be!

[Rotary Potato]

Ben has bet me a pint it's battery related and it'll fire straight up with a jump.

He thinks the strain of spinning the engine is meaning the coils don't have enough power to ignite the mixture, partially flooding the engine, hence why it then starts with fuel cut activated.

To avoid "doing a FrankenRex" I'll wait until the weekend when I'll have both daylight and time to help me steer clear of any sparky misadventures.

[13Black]

nJn7RPX.png

Is this going to become part of the RX-8 Lexicon?

Along with spring compressor whoopies being called 'Doing a Huw'.

[qwakers]

Along with spring compressor whoopies being called 'Doing a Huw'.

ive not seen that one... do Pray tell??

[Rotary Potato]

Along with spring compressor whoopies being called 'Doing a Huw'.

ive not seen that one... do Pray tell??

Had had a spring compressor slip off a spring about 18 months ago. Fortunately when it started to go I started unwinding the compressors. I'd got most of the tension off before it finally let go.

It smacked me in the face and put me on my arse. Apart from some smashed glasses and bit of a black eye I got away with a very close shave.

[Rotary Potato]

To share the stupids ...

[qwakers]

funny after it happened but not funny at the time im sure

[350matt]

good job you were wearing glasses to be honest

most vision glass is toughened these days so its takes quite a whack to break it