Long crank when warm, not hot.

[liamfm]

Hi all,

2010 CX-7 2.3 T with about 96K on it. Around 65K it developed a hard start when warm (not hot, not cold, but after sitting for 20-60 min). Never threw a CEL, and the problem eventually just went away. Fast forward and we've been having the same problem since about 85K. It is basically a long crank 4-5 sec, when warm. This morning it did it cold as well (42*F). Once started it will restart fine, unless you let it sit for 20-60 min, then you get a long crank again.

No CEL at all, took to local mechanic and no codes lurking. Plugs have been replaced, but nothing else yet.

Can anyone point me in the right direction? I've read about sticking EGR valves, dirty throttle plates, etc.

The only thing I've noticed is that when doing a long crank I get the evap/gascap light on on the dash. It goes off as soon as the car fires, but the orange light stays on while cranking. I'm not sure that it comes on when the car starts properly, though that could just be that it starts so quickly.

I don't want to just throw parts at it, but I'm lost as to where to start.

Thanks in advance!

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[SaveMelMac]

Is it a slow crank? By long crank you mean the engine just turns over a few more times before it starts up?

[liamfm]

Fast crank, plenty of battery power, just longer time


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[Bob-o]

My 09 speed 3 does that too

[liamfm]

Originally Posted by Bob-o My 09 speed 3 does that too

I took the egr out today, soaked it in purple power, followed by hot water to flush it. It didn't seem stuck, but it was carboned up a bit. So far, the engine seems quieter, and starts instantly. Time will tell. Total project time, 2 hrs and 8 oz of purple power. On my Dodge with a Cummins, this is a 67.5k service. Same basic setup, but gas vs diesel. Maybe Mazda should have considered it a 70k service item.

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[davegutz]

I need to record my experience; this post fixed my problem too - EGR/Throttle Body dirty. It's a MS3 '07 totally stock () with 110,000 miles. I had the same symptoms except when I idled for 20 minutes to maybe reprogram the control it threw a P0300 general misfire once and a P0302 cylinder 2 misfire once. When it would crank too long - usually after 60 minutes warm restart - it would crank at about 1-1/4 seconds at 200 rpm before firing (what Versatune recorded). The steps I took to fix it:
1. fuel injector cleaner in tank - no effect
2. confirmed proper operation of coolant temp sensor using OBD tool
3. 'reprogram' by sitting idle 20 min A/C off and 20 min A/C on - no effect
4. Checked purge solenoid - fine
5. Replace all 4 plugs (0.028 gap denso itv20) and all 4 coils - no effect
6. Disassembled EGR, EGR tube, and Throttle body. Cleaned best I could using B12 Chemtool I got at AutoZone. - fixed it.

During the work I found the TIP solenoid vacuum signal from the turbo line was broken. It was all dirty indicating it had been broken a while. I plugged the line to the turbo hose and just went on because I read on this site somewhere that the vacuum feature is an anticipation device for tuners. Should be ok not to have it for my totally stock

It worked. After this I noticed idle was smoother and the engine was much perkier in general especially at low power. And when I waited an hour it started right up.

I drove it to check turbo. It felt fine and the Versatune log showed it holding 28 psi manifold pressure and it showed the ~1 sec lag I've been used to with the stock system.

It took 5 hours to disassemble down to EGR and throttle body, clean it, and put it all back together. This was my first time taking all this stuff apart. Next time should be much faster. I'm a fairly experienced DIY and this is a moderately difficult job. You will run into stuck bolts and rusted-away bolt heads especially in the battery stuff. The link here: https://corksport.com/blog/how-to-cl...ur-egr-system/

Good luck! Hope it works for you.

[Fstrnyou]

For others reading this:
When he says 28psi manifold pressure, it's either a typo or he's measuring absolute pressure.