Long start
Thread Starter
Cruising
Joined: Aug 2010
Posts: 12
Likes: 0
Long start
Hello,hope some one can help.
94 vette was getting a long start
replaced the fuel pump, i was getting no
pressure on the old one. new one in cranked
right up.Took it home sat for a few, went to
start same thing long start but it does start.I think i
replaced the fuel pump relay. At least it is where i
think it is located,under the dash on driver side.( it is
on a block of 4 other relays ?).
Thanks for any help.
94 vette was getting a long start
replaced the fuel pump, i was getting no
pressure on the old one. new one in cranked
right up.Took it home sat for a few, went to
start same thing long start but it does start.I think i
replaced the fuel pump relay. At least it is where i
think it is located,under the dash on driver side.( it is
on a block of 4 other relays ?).
Thanks for any help.
Safety Car
Joined: Nov 2008
Posts: 4,328
Likes: 15
From: Jacksonville FL
How long does it have to sit before it has its long start? Does it crank right up when you are running around or does the long crank occur each time? If you turn the key on, wait 10 seconds, then crank does it fire right up? If you advance the throttle a bit does it crank right up?Long cranks usually indicate leak down or low fuel pressure. The fuel pump is the main offender but since you replaced that you need to go on to other things like leaking injectors as indicated An indicator there would be a bit of dark smoke at crank up where the car is burning off excess fuel. Check all along your fuel lines for any cracks, loose fittings or anything that would allow air in. You should see dampness around these suspect points.
You should also check your TPS for correct voltage (0.54v), IAC for the right counts (20-30 I think). Cranking/running I think is also governed by adequate oil pressure. If the engine takes a while to build pressure or you have a bad sensor, that could play a role as well.
Good luck and keep us posted.
Thread Starter
Cruising
Joined: Aug 2010
Posts: 12
Likes: 0
Thanks for the feedback, okay this is where i am at,key on 20psi then drops (within 5 sec.)
to 0.Engine running 29psi stays there,take hose off fuel regulator does not idle up,still 29psi.
I applied 14 inches of pressure on fuel regulator as the shop manual says,no drop in fuel
pressure.If i push the accelerator id does drop.No dark smoke no fuel leaks or cracks that i can see.Thanks again.Bad regulator ?
to 0.Engine running 29psi stays there,take hose off fuel regulator does not idle up,still 29psi.
I applied 14 inches of pressure on fuel regulator as the shop manual says,no drop in fuel
pressure.If i push the accelerator id does drop.No dark smoke no fuel leaks or cracks that i can see.Thanks again.Bad regulator ?
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
When you turn the key to ON, do you hear the pump run for 2 seconds. If it does not, then the engine has to build oil pressure to close the second switch for the pump. Then the fuel pump will start as so will the engine. Just another item to check
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Pro
Joined: Mar 2013
Posts: 628
Likes: 13
From: Indiana
Every once in a while when someone installs a new fuel pump the new higher pressure of the pump pops the pulse dampener off between the pump and the exit tube. This sets or fastens directly to the top of the pump. Some times it rupture's it or an old hose. These are both inside the tank so you won't see or smell it. This can cause low fuel pressure and rapid pressure loss even though its a new pump because the pressure bleeds back into the tank. I have seen this on this forum multiple times and actually look for it when someone installs a new pump. The other thing that goes wrong with new installs is people get the sock on backwards and it gets pinched while putting it back together. I would pull the pump again and inspect it. It doesn't take long and may very well be the issue. The pinched sock just causes low pressure because the pump is starved. You should be getting high 30's to low 40's psi wise when turning the key on.
Last edited by Klyde; Dec 1, 2013 at 07:18 PM.
Le Mans Master
Joined: Jan 2006
Posts: 5,621
Likes: 206
From: Orlando FL
Every once in a while when someone installs a new fuel pump the new higher pressure of the pump pops the pulse dampener off between the pump and the exit tube. This sets or fastens directly to the top of the pump. Some times it rupture's it or an old hose. These are both inside the tank so you won't see or smell it. This can cause low fuel pressure and rapid pressure loss even though its a new pump because the pressure bleeds back into the tank. I have seen this on this forum multiple times and actually look for it when someone installs a new pump. The other thing that goes wrong with new installs is people get the sock on backwards and it gets pinched while putting it back together. I would pull the pump again and inspect it. It doesn't take long and may very well be the issue. The pinched sock just causes low pressure because the pump is starved. You should be getting high 30's to low 40's psi wise when turning the key on.
100%This is a good place to re-check and possibly find the solution. I think you will.
FPR has been eliminated and does not sound like it would be any kind of injector problem.
If fuel pressure is low, FPR will not operate properly and you will not see expected results.