Roof alignment problems

[quicksilverdon]

What do you do, run red lights?
You can't be making short hops with that mileage.
Happy for you and WELCOME.

[CruiserDan]

quote:Originally posted by bigtommy83

I think all GT's go through that cycle of not starting the first time or having an extended crank. Everybody that has a GT will probably confirm this. I noticed it especially happens on a cold start when the temp changes noticably. It also happens because of the returnless fuel system. It is really nothing to worry about. And it will be useless going to a dealer because they will say they cannot confirm it. Most times if you just leave the key on for a sec, like tun the key "on", count 1, 2, then start it. If you leave the key on too long, the fuel pump will time out and will have to build pressure again when you try to start it.

what do you mean it is because of the returnless fuel system? and when the key is turned on and the starter not run the fuel pump will run and prime the lines and feed more fuel that is needed into the injector for a widened injector pulse width.

It was bogging down from excess fuel by pressing the gas. Almost like a minor flood due to dual compensation for cold start.(increased fuel from both the ecu and the driver)

Dan

[bigtommy83]

It is a returnless system so whn fuel presssure is built to high, the pump is shut down. Instead of being routed through a fuel pressure regulator and sent back to the tank. Fuel pressure at the injector does not determine injector pulse width. That is controlled by the PCM. When you press the gas down it actually adjusts the timing by the PCM receiving a Throttle position signal so it does not bog down the engine. When you go WOT, it allows less fuel through the engine so it clears all the excess fuel that may be in the engine before dumping more. Kind of like a reset button. It's not like a carb that when you press the gas, it dumps a bunch of gas into the bowls and can dump down the intake and wash down the cylinders.

[CruiserDan]

i know that pressure in an injector doesnt affect pulse width it is all the ecu but there needs to be pressure to have enough fuel in the lines to feed the widened pulse width and i know its not like a carb where u step on the gas and it dumps fuel but the ecu compensates for a cold start by widening pulse width and when you step on the gas that feeds more fuel as well in a mini flood like action the combustion chamber recieves a rush of fuel much more than cold engine and spark plugs would need. Thus the hard start.

When you turn the key one in a car the fuel pump turns on and builds Initial pressure to supply the injectors with fuel. So there is no reason that a hard start would be caused by a returnless fuel system. I still see no explanation for that thought.

Dan

[bigslim]

Welcome to the forum.

[bigslim]

Sweeeeeetttt!!

[RallyDRock]

ok but you are opening the throttle valve and letting more air in to mix with the fuel so it all balances out, right. Wrong.
The PCM runs a pre programmed starting cycle. Injector pulse width in our speed density calculated vehicles comes from three sensors. Intake air temp, crank position, and throttle position. The computer then adjusts pulse width in open loop mode. once special conditions are met the pcm monitors the 02 sensor and enters closed loop mode.

So actually you are getting a lean condition of not enough fuel to start the vehicle when pressing the gas during starting.

Example: If a vehicle with electronic fuel injection becomes flooded, depress the accelerator. The computer recognizes this as a clear flood condition, cuts off the injectors and the open throttle valve lets in maximum air to lean it out and allow the vehicle to start.

[CruiserDan]

rally , this makes more sense to me now that i think about it, I would have to agree with you.


But still has no explanation as to why a returnless fuel system would affect it.


Dan

[CruiserDan]

quote:Originally posted by RallyDRock

ok but you are opening the throttle valve and letting more air in to mix with the fuel so it all balances out, right. Wrong.
The PCM runs a pre programmed starting cycle. Injector pulse width in our speed density calculated vehicles comes from three sensors. Intake air temp, crank position, and throttle position. The computer then adjusts pulse width in open loop mode. once special conditions are met the pcm monitors the 02 sensor and enters closed loop mode.

So actually you are getting a lean condition of not enough fuel to start the vehicle when pressing the gas during starting.

Example: If a vehicle with electronic fuel injection becomes flooded, depress the accelerator. The computer recognizes this as a clear flood condition, cuts off the injectors and the open throttle valve lets in maximum air to lean it out and allow the vehicle to start.

Also i really like your pt those breakes are sick and the rims too

[RallyDRock]

thanks Dan, the brakes are awesome when you really honk 'em but are about the same as stock around town only squeakier. Have to clean the brake dust off once and a while.

With the return line that i needed with the turbo, the fuel pressure drops after the pump cycles on/off (ign. on). with returnless system i would say that the pressure would hold at about 55-60psi for a while because it has nowhere to go but back up into the line and the tank. PT fuel pressure is constant 58psi. Mine right now is anywhere from 60 all the way up to 120psi @ full boost. I will be bringing it down a bit with the installation of 26lb/hr injectors.