Cold Start Issues

[sKenDread]

08 231 West Midlands

[sKenDread]

Hey Huw,
Just wondering. What starter motor do you have. My one had the N3H1 model. After a grumble this weekend looking back at my ignition and resetting the leads etc
It still didn't fire up.
I threw a N3R3 model in on Saturday. Didn't test untill this morning. He fired into life after 2 cranks!
I still think in my case it's probably still masking the low compression. But he's definitely crankinh/ turning over completely different!



08 231 West Midlands

[MARKTHOMASBRAND]

Anything sorted yet Huw

Regards,Mark.

[Rotary Potato]

Anything sorted yet Huw

Regards,Mark.

Nope ... although with the warmer weather, I now have to leave it longer before it won't start straight away.

At the midlands meet on Thursday, it was left for just over 2 hours and fired straight up. It really does need to be absolutely stone cold to be playing up, and once it plays up it's just as bad whether it's been left 3-4 hours or a week. It can also be reliably started by cranking for 6-7 seconds, pausing for a few seconds then cranking with the accelerator fully depressed. Fires up every time - so that's just become my cold start routine.

The above behaviour is what makes me think it's electrical in nature, not mechanical, but Ben wants a test to ensure no coolent leaking into combustion chambers, so that's the next step.

It's always fine once fired up, so solving isn't a high priority at the moment. Will eventually get over to Nick's and sure we can make some progress then.

[MARKTHOMASBRAND]

Thanks for the update

I think it's bothering me more than you

Regards,Mark.

[Rotary Potato]

Thanks for the update

I think it's bothering me more than you

Regards,Mark.

Quite probably.

It's a second car, and i now feel that I can always rely on it to start (eventually! ), there are more important things in life to worry about.

[Rotary Potato]

Sooooooo ...

The plot thickens.

After being sat all week, I went to start the car. Waited for the pre-flight checks (as always). Foot on the clutch (as always). Turned the key. It span pretty quickly, sounding like it might catch (as always). It didn't catch and after a second or so started to slow down (as always). At this point I decided to floor the accelerator (that's new) and the car fired right up.

That's a record for a stone cold start since the remapping - under 3-4 seconds.

The trick will be to try and repeat this again going forwards.

[warpc0il]

I wonder if the throttle body is sticking.

The PCM would only demand a small movement on starting but, if it were to stick shut, the larger movement triggered by flooring the accelerator may have released it.

Just a thought.

What year is your car? Mazda included a number of additional PCM checks with the '06 upgrade, which includes better tracking of the throttle position and throttle actuator performance.

[Rotary Potato]

Thanks for your thoughts Dave.

It's a 56 plate PZ.

What is the earliest point that pressing the accelerator would move the throttle? Could a pump of the accelerator pedal pre-cranking test your theory and unstick it?

[13Black]

Should be totally linear.

You can take the intake off, switch ignition on and ease the pedal on and it will open it up. Have a friend or wife (or none of the above) press it while you watch or vidya.

[rx_sjo]

Should be totally linear.

Linear in plate movement or torque delivery? DBW strategies are rarely mapped 1:1 between pedal and plate. I've not seen the RX8 calibration though so could be wrong.

[13Black]

Haven't checked in a while, but from what I remember the map wasn't too squiffy.

When I video'd it last year it seemed pretty smooth from fully closed to fully open. Can never get the pedal movement that smooth anyway.

[Rotary Potato]

Righty tighty ... managed to repeat a stone cold start using the method described above - let it spin for a couple of seconds, then mash the throttle to the floor & keep it there.

Warm starts are still 100% on the button.

It's not a 'fix' but it definitely makes the car more liveable with.

[ChrisHolmes]

You say the starting speed slows after a few seconds cranking which suggests to me your battery or your starter is the problem. Battery age is irrelevant , my Bosch failed after 14 months! I can see you have done checks and also done the jump start test so maybe it's the starter, or battery connections, or earthing to the engine and or coils.

[Rotary Potato]

You say the starting speed slows after a few seconds cranking which suggests to me your battery or your starter is the problem. Battery age is irrelevant , my Bosch failed after 14 months! I can see you have done checks and also done the jump start test so maybe it's the starter, or battery connections, or earthing to the engine and or coils.

Thanks for your thoughts Chris.

When I say 'slows down', it's still plenty fast enough to start a car (dropping from a peak of 290ish down to 255ish).

It also doesn't explain why the car fires right up when I floor the accelerator while it's cranking more 'slowly'.

[kopite72]

Didnt want to start a new thread, I've noticed in the last few days that the car is taking a bit longer to ' catch' when I go to start it from cold.

My battery is new ( 4 months or so old, E23), I also checked it with a multimeter and its good but I've noticed its taking an extra crank or two ( not of the key, the starter motor) to catch which is mystifying to me as the starter motor is spinning at circa 290 ( I tested this also)

Anyone have any ideas? I'm a bit baffled,ill try and get a vid up tomorrow just to give ye an idea...

[osman]

Having the same issues
Have rr bridgeport and map too, only starts cold when accelerator is pressed
Car does it when warm sometimes too
Was the issue figured ?

[ChrisHolmes]

Having the same issues
Have rr bridgeport and map too, only starts cold when accelerator is pressed
Car does it when warm sometimes too
Was the issue figured ?

Have you spoken with RR, also do you mean Rotary Revs or Ryan Rotary?

[osman]

Rotary revs
I've shot an email off
They suggested coils but car runs fine with no misfires

[warpc0il]

What does a live monitoring of the OBD show the Intake Air Temperature to be?

If the IAT sensor fails, or there's a bad connection between it and the PCM, you can't start the car "normally" from cold...

[Nanotrox]

Rotary revs
I've shot an email off
They suggested coils but car runs fine with no misfires

Have exact same problem as you no misfires (no CEL or codes being thrown) rebuild 25k ago by I think it was Hayward Rotary? with the previous owner and I have problems hot and cold starting, using the accelerator helps a hell of a lot with cold and hot starts RR said likely coils same as you after I've get a new battery, battery connectors and N3R3 starter. I'm waiting on a set of RRs D585s to come this week (second hand) just to see if it fixes the problem and if it does I can let you know if it fixes it. If mine isn't fixed I'm heading down to RR on 16th of Jan for a compression check and 60 point health check.

Be good to get an update if you get yours checked out / fixed before mine since our problems seem very similar.

[PaulAV]

I had a cold and warm start issue, it was taking longer than normal, replaced the battery and starter motor, no joy, removed coils and leads and cleaned the connectors and terminals put them back in and it made s massive difference. I also opened up the terminal on the leads at the coil end to ensure there was a good connection.

[boosted]

Dont forget the clogged fuel pump filter issue. B4 the car starts the fuel pump is primed for approx a second or 2 to 4bar .

If this filter is dirty..you wont get 4 bar. Easy check is prime by ign 2 on off four times and start..if better suggest dirty filter or dieing fuel pump.

Sent from my SM-N950F using Tapatalk

[osman]

Thought I'd update this
Elm came up for p0103 and p0113 so maf issues as Dave mentioned
Will swap it for a spare maf and update