RB26 not warm starting - issue resolved

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Afternoon all,

Posting for others in case they run into the same issue.

Problem: R33 GTR running Nistune ECU - cold start was not a problem, once warmed car would struggle to start again if you turned it off. Sometimes with throttle. 

Symptoms: Cold start was fine. Warm start once at temp was not. We let it cool down + had a battery booster pack (was low due to trying to start) and it started.

Actions taken:

• Replaced CAS as had a rough idle when at lights + started once it was cooled down. Adjusted base timing (removing TPS). Did not resolve the issue. 
• Looked at Nistune and saw that battery voltage was dropping to 7- 8.5v when trying to warm start.
• Replaced with Supercharge Gold Plus MF55B24L battery ($160 from Autobarn wih 40 month warranty) which has a CCA of 490 - you just have to unbolt the rear strut and move it out of the way. Note that the battery is too tall, so factory brace won't reach.
• Post battery replacement - minimum voltage seen when cranking > 10v and no issues seen starting.
• I also found that during testing using Nistune my O2 sensors are not responding (they are dead) showing 0v - will replace them.

Summary: insufficient battery voltage to crank when warm.

Hope that helps someone in future to check if they are having a similar issue.

Links

[Dose Pipe Sutututu]

Did you try adding more fuel to the cranking table when warm?

With Nistune you're unable to set injector dwell vs voltage. It's just a fixed dwell so when you're cranking you might be under injecting fuel when your battery voltage drops.