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Old 07-11-2016, 09:34 PM   #13 (permalink)
Aviator44
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Join Date: May 2014
Location: Pensacola, FL
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Drives: AAM Twin Turbo 370Z
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Quote:
Originally Posted by phunk View Post
If you have a return fuel system on your turbo car, usually fuel pressure will not hold more than a few seconds after the pump is off. Aftermarket regulators are not designed to hold pressure.

To crank from zero pressure rather then a primed system should only add an extra 2 cranks or so until it starts.

If the car starts hot, but doesnt start cold, (assuming plugs are good and nothing strange is going on) it is most likely an issue in the calibration. Getting a perfect tune that starts quickly in every circumstance can be harder than it sounds with many computer systems. In my Z, I used to have a random problem with hot starts that I never fully worked out in UpRev, but it would cold start E85 1000cc injectors dead middle of winter 0 degrees out like it was factory stock on a summer day. My mustang is tuned by one of the best tuners in the industry for that platform and it has intermittent issues with cold starting where sometimes it doesnt even start on the first cycle.

Its worth chasing it a bit, to make sure nothing is actually wrong physically with the fuel system or plugs etc. But if you get it nailed down to the ECU calibration, it may or may not be easily correctable.
Thanks for the reply! The car is still running non-return. I've been meaning to get a return kit for awhile, but never got to it.

The car has the starting issue regardless of temperature. The only time It doesn't have the starting issue is when I start the car immediately after turning it off. I'm assuming the quick restart isn't giving the system enough time to lose pressure. If I wait 10 mins or so, the problem is back.

I should also note that the car has nearly 20K miles being boosted. The tuning has always been spot on and it still is once the car is running. The car has always started fine in the coldest Ohio winters and even on the hottest summer days since moving to Florida. The problem just randomly started a few weeks ago.

I have your mini fuel gauge. I've noticed that while the car is cranking, fuel pressure increases a little bit each crank until finally reaching 40-50 psi after 10 cranks or so, then the car fires. It's like the system is unable to instantly provide the necessary fuel pressure anymore.
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Last edited by Aviator44; 07-11-2016 at 09:36 PM.
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