Hard start after sitting...

[im4darush]

Have a weird situation..when the car sits a while (few hours), it will instantly fire when you crank it, but then also instantly die. Then you have to crank it a few different times before it starts. Last time it took 4 attempts, each cranking about 3 seconds. After it starts it runs great. And also restarts great unless it sits for hours or overnight.

The car...new to me 86 GN. 29k miles. Out of storage with 2 year old fuel in the tank. Has the racetronix hotwire and an adjustable regulator. Shows 36 psi in the rail when key is on and not running. Have not looked what it is when running. It runs and idles well once started. Has a scanmaster but no numbers yet. I just got the car today.

I know the 2 year old fuel is not good, but since it runs good in general, I think the cold start is really something else.

Ideas?

 

[novaderrik]

does it hold pressure after you shut it off? it should hold full pressure for a long time.
if not, look at the fuel pressure regulator- pull the vacuum hose and see if there's any gas in it... if there is, it's junk.

 

[87geeinn]

X2 on giving the FPR a closer look. With engine off, put a mighty vac on it and pull ~15psi and see if it holds. If not, then diaphragm is bad and needs to be replaced/rebuilt.


Posted from the TurboBuick.Com mobile app

 

[SS502]

X2 on giving the FPR a closer look. With engine off, put a mighty vac on it and pull ~15psi and see if it holds. If not, then diaphragm is bad and needs to be replaced/rebuilt.
X3..
but also replace fuel filter. Like sucking through a straw if it's original. Driver side just behind the backseat against the frame under car for what it's worth.


Posted from the TurboBuick.Com mobile app

 

[im4darush]

Ok the fuel pump does not prime. 10 psi in the rail after sitting overnight. Turn the key and no action coming from the tank. Still 10 psi in the rail. It will fire after a good amount of cranking so I'm thinking fuel pump relay?

 

[RmvBfrFlght]

That or the ECM are the likely candidates.

RemoveBeforeFlight

 

[TurboTdr3.8]

Can a bad fuel pump cause fp to leak back also after you cut it off for a while too ?

 

[87geeinn]

With the new information provided, I'm leaning towards bad fuel pump relay. If the relay is shot, the fuel pump will engage but only after 4psi of oil pressure is built up. This is the factory bypass and would explain your long crank times to get the car to start. The occassions where the car will start easily and immediately die is because the car is probably just using up the residual fuel that is held in the system under pressure from the last time the car ran (which is one of the the jobs of the fuel pressure regulator).

 

[im4darush]

On the money. Picked up a new relay and all is well.