long crank time [Archive] - SaabCentral Forums

: long crank time


grouchy
30-10-08, 05:24 PM
Ive had a 96 SE a year now, and had the usual repairs. (belt and pulleys, alternator, brakes, seat motors, cabin air sensor)
Now I have to crank it 10-15 seconds before it catches. I think the fuel line check valve is bad, and I need to cut a hole in the rear floor under the seat to acess the valve from above the gas tank.
Long ago I saw a thread on this forum by someone who posted pictures. Can someone point me to this thread I need to know the location in the rear floor where to cut a hole.
I assume it's the fuel return line check valve that is leaking. Any hints or links to how to do this?

grouchy
1996 Saab 900SE
1998 Audi 2.8 quattro
1992 Cadillac Allante
2007 Dodge dakota xlt
2008 Honda civic
1977 Honda gl1000
1966 Honda ct90
2008 Shoes size10

Eric in Lockport, N.Y.
30-10-08, 10:22 PM
http://www.saabcentral.com/forums/showthread.php?t=119759

john bernard
30-10-08, 11:21 PM
Why do you think it that a check valve is causing a long crank time( I agree that it could) and more particularly why do you think the problem is caused by the return check valve( I wouldn't suspect that valve so much as the other) . I suppose there are a number of other possible causes of long crank time. Shouldn't you make some tests of fuel pressure and pressure retention before you go any further?

hkayssi
30-10-08, 11:29 PM
I have to agree with John here, there are many other possible issues like the wrong spark plugs are used, a clogged fuel filter or a clogged prefilter on the fuel pump itself. A sticky Evap valve may cause that too. Start by checking the fuel pressure before starting up. Does the car startup easily if you turn it off and restart just moments after it catches the first time?
You never mentioned if the car is a 4 cyl or 6

grouchy
31-10-08, 06:58 PM
thanks. the car is a 96 900se 2.0L turbo. this happens if the car sits overnight or longer and its cold. after that it'll start all day

your right, I need to check the fuel pressure. is there a schrader valve somewhere?

john bernard
31-10-08, 09:50 PM
No, sadly, the 4 cyl cars don't have a Schrader valve altho the 6cyl cars do.
I am not familiar with the 4cyl cars, but among the "special tools" is an adaptor available from Kent-Moore ( 1-800 345-2233). One member reported that he cobbled up his own adaptor, altho he didn't go into any details. Perhaps someone reading this can help,or perhaps you can do it. You need to "T" into the system between the fuel rail and the fuel pressure regulator, with the fuel gauge connected to the tee, but not interfering with the flow of fuel.Or perhaps it would be more convenient to T into the other end of the rail where it connects to the fuel supply line. The controlled pressure zone begins at the pump and ends at the fuel pressure regulator. After the fuel passes thru the fuel pressure regulator it is carried by the return line to the return check valve and the fuel tank. The return line check valve is not in the controlled pressure part the fuel supply system.
When you are cranking the engine, the fuel pressure should rise almost instantaneously to about 45 lbs/sq. in. and hold at that pressure until you stop cranking or the engine is shut down. When the engine is shut down or you stop cranking the fuel pump stops, of course. After a shutdown period of
30 min. the pressure should be between 45 lb. and about 22 lbs.
If when you are cranking the fuel pressure rises very quickly to about 45 lbs and holds there while you are cranking then I think fuel pressure is not the cause of your long crank times.