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356-930 356-930 is offline
Acceleration Junkie
Join Date: Aug 2007
Location: Laguna Beach, CA
Posts: 263
Hot Start Problem

Originally Posted by Porschephd View Post
Do you have an accumulator in place and a check valve? the head will evaporate the fuel out in a matter of minutes (About 5-10) and will partially vapor lock making it hard to start. BTW wonderful looking build!
Thanks for your kind comment and help.
Accumulator (plumbed right thanks to your advice) is in the the fuel system, (shows in photo below MSD). Front fuel pump (under fuel tank) has a check valve and is working. Don't know about the pump near the engine.
If engine is warm/hot and shut off for only 15/30 seconds, it won't start. Wait 15 minutes, starts. It's also a start made by opening throttle body just a bit. No throttle or too much throttle and it won't 'catch.'
I suspected vapor lock but engine compartment is force fed with ambient air when ignition is on. No mater how hot the engine gets, fuel head, intake plenum and intake manifold are cold to the touch. They do warm up on soak but the start problem occurs long before anything on top of the engine takes on heat.
Perhaps something in the WUR? Pressures are in spec. Pressure holds within spec for 20-minutes after power shut off. Unfortunately, I know nothing about how the WUR operates.
Old 02-24-2008, 08:00 PM
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