weird starting issue...

[David T]

Rest pressure serves two purposes. The first one is to prevent vapor lock by keeping the fuel under pressure to prevent it from boiling till the motor cools off. The other purpose is to provide enough pressure to operate the injectors because the CSV will not operate if the engine is hot so the injectors must start working right away and it takes time to get the pressure up high enough and longer if you aren't starting at "Rest Pressure". When the motor is shut off it eventually reaches ambient temperature. If it is summertime and the car is out in the hot sun, you might never run the CSV to restart the car. Deloreans originally came with a sticker on the sun visor that said to give the car 1/4 gas pedal to start. Most, if they are running well, do not need any pedal to start but some benefit from it. Another thing you can do is cycle the ignition switch on and off several times to get the fuel pump to run before trying to start the motor. Or try Dave's relay.

[painterdave72]

It only did it that one day it was really hot in the garage.. it has cooled off a bit since then and fires right up no issues first time... took it to a large car cruise today and ran great... so just a weird anomaly.....lol

[Ron]

But if your injector lines are not primed full of fuel and your ambient air temp is 100 deg then your coolant temp is also 100 deg.

When the engine is 'cold', yeah. The injector lines should always be full (but not always pressured up, which is what I think you meant...).

Then you do need the CSV unless you crank fast enough to pull on the air plate.

It cranks fast enough to pull the plate down hot or cold. (Guessing 8-9 CFM going through with stock cams.... The DPI cams might have lower vacuum while cranking, but not that much.) You can pull the coil wire and watch the plate wiggle up and down. Remember, when roughing the CO in, how little you have to turn the CO screw backwards to make them stop spraying. Or how a slight push during warm up at idle will kill it.)

I'd lean towards it being the tune, not priming every time the key is turned on, possibly in conjunction with the cams, or, something odd like a vacuum leak that shows up when dead cold (if it persists) or a hiccup, especially with the problem showing up at 100F ambient.

FWIW, if it was after an hour or so, only, I suspect leaky injectors flooding it. Not a "hot start problem".