D16A6Turbo

If I start my car after it's been sitting overnight, it's easy to start...If I start my car after it's been sitting for about 4hrs or so, it's super hard to start up. What do you guys think the problem is?

Note: when it's easy to start in the morning, I've notice the system has been depressurized (no pressure in the lines). When it's hard to start up I have a bit of pressure in the lines still...

Any help please...

speed

sounds like the engine is flooding with fuel.Do you notice a gas smell when you go to crank it after say it sits for 4 hours?

Speed PHreak

Try adjusting the startup pulse in your Zdyne. I think I've got mine set to 60%. Sometimes an inline fuel pump can over power the stock fuel pressure regulator. Do you have an adjustable FPR with a pressure guage? I've got my static pressure set to 40psi.

Also make sure the pulastion dampener opposite the FPR is in good working order, it helps with startup becuase it holds the pressure on the rail by preventing backflow through the fuel lines.

HTH

~Steven

D16A6Turbo

Speed, nope, no gas smell.

Spead Phreak, is the pulsation dampener on a D16A6 attached to the end of the stock fuel rail (same side that leads to the fuel filter). Is it that plastic looking thingy? If so, when I put my Venom fuel rail on, I elected not to install it, maybe I should try to put it on. Yes, I've got an aeromotive FPR set to 42psi static pressure...what's strange is that the car starts perfect when the pressure has dropped over night and the guage reads zero...my cobra blower buddies that run in-lines sometimes run a manual switch to turn on the in-line after the car has started, I think the pump is throwing too much fuel at the injectors at initial start-up. I've played around so much w/ the binhacker start-up pulse (trying all kinds of percentages) that I don't think it can solve it. So, I may switch over to the 255lph and hopefully it will solve the problem...

Speed PHreak

Sounds like a good start on your problem. I don't see much use for the aftermarket rails though, your fuel system is happy when it has the pulastion dampener on it. That little thing does a good many things. It keeps the fuel pressure from backing off after you turn the key and the pump initially primes the system before startup, and as you would have guessed it also retains pressure on the system for a few hours after the engine stops running....these are just for ease of starting issues mainly. The KEY reason the thing is there is because it's like a shock absorber for you fuel system.

Picture this, your fuel pump does not flow at a constant rate, it varies up and down slightly, because of how the pump works. It pulses fuel at a fairly fast rate, while it seems like a constant steam free flowing. Also if you think about it your fuel injectors place pulses in the opposite direction of the fuel flow. Whenever an injector opens it has fuel sprayed out of it, but what happens when all the sudden they close? You get a tiny shockwave the goes against the flow of the fuel. Now it may not seem like much, but left unchecked the pulses from the pump and injectors can build up a sort of ressonate in the fuel system. This can cause spikes and drops in your fuel pressure, cause a chaotic turbulence in your fuel system and even cause damage to components.

Food for thought but not having it 99% of the time won't hurt anything. Just sharing a bit of the useless knowledge that floating around in the ole brain

Steven

D16A6Turbo

Thanks for the info, when I get the chance, I'll install the dampener...

The venom fuel rail, for me was more of a function and ease of accessory installation rather than just to have it in there. I've got 3 items which I hang off of the rail (makes it pretty and clean, also have you noticed how small the fuel rail passageway for the D16A6 is...remember, this motor stock is 108hp...

1. Aeromotive FPR
2. Underhood manual fuel pressure guage
3. Electric sending unit for cockpit mounted electronic fuel pressure guage.

Guess what, I've made a strange discovery regarding my tough start-ups. I found that if I depress the throttle while I'm cranking it, the car starts up alot faster after it's been sitting. This leads me to two conclusions:

1. I'm so rich at start-up that the throttle being open allows more air to be mixed w/ the fuel.

2. I'm so lean at start up that depressing the throttle at start-up gets more fuel into the mix. (this one I'm not really buying because the car starts perfectly when the fuel pressure is zero.

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