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Help: The engine of the car is turning but it doesn't fire up. Brand new battery in car. Will start with spray to carb. Removed panel to fuel pump and only felt a little movement. Is the fuel pump supposed to have some kind of whistle or suction noise? I only feel the a thump in the fuel pump when touching it. Checked the fuse and relay and looks good. I don't smell any gas when trying to start the car. I last used the car 14 months ago.
The fuel pump definitely makes noise while running. But a 79 does not have carbs. It may have been modified somehow.
Bottom line is if that is a cis pump and it has 12 volts you should here singing.
With cis it runs constantly after starting and runs the fuel out and back through a loop.
I have no idea how that works with carbs.
You sprayed carb cleaner into your carbs, or into the air-box? (which you shouldn't do, you could get a nasty back fire and crack the box).
I bought a '79 SC that sat for 4 years without starting. Old, bad gas clogged up my pump and seized it up. I doubt that after only one year your gas was as bad as mine, but it could have been bad enough if your fuel pump was tired in the first place. As stated in the above post, if your 79 is stock, and we are talking about a CIS (fuel injected) car, then check to make sure that you are getting 12v to the pump.
However, there is a BUT. I was trying to narrow it down when I had the problem, and when I checked the pump with a multimeter, I was getting 12v, but the pump was near dead. If you are savy enough(and this is very simple), try this...
-Pull an injector out of the intake manifold, and place it in a glass jar of some sort, be as delicate as you can when pulling.
-Unhinge those two rubber straps and take off the air filter and cover to the air-box (be very clean when opening the box, don't do it outside with wind and debris). On the top side of the airbox - inside- you will see a metal, alloy arm. This arm is "connected" to the fuel distributer on one side (right), and on the other side is a flap that allows air into the motor (left). These two work in conjunction, and when air is sucked through the air box and up past the flap, the CIS system will adjust the fuel mixture accordingly.
-So now that you know where said flap is, you can test to see if you are actually getting fuel to the injectors.
-With the key in the ignition, turn it all the way, without cranking the engine over. Leave it there for half a min. With the key still in that position, head to the back of the car, to the air flap arm inside the airbox.
-Now, you want to LIGHTLY push up on the flap, be gentle with these components. Hold it there for a few seconds, and if your pump is working properly, you should hear a whirring noise, and you should start to see fuel coming out of your injector that you have placed inside of the jar. If not, you are going to have to work your way back.
Keep in mind that it might not be the pump that is the problem, it could be another part of the CIS system that isn't working properly. But my guess is that after sitting for just over a year, it is most likely just the pump (hopefully). There are others on this forum that are MUCH more knowledgeable about this stuff, MUCH more lol. I'm sure the will chime in soon. They can point other problems that might be present, but this is how I did it. 3 months ago, this was my first Porsche, and I had zero knowledge of these motors until I started reading manuals and researching.
I'd say pump even more so now. Do the temps vary greatly throughout the year where the car sat? That'll make the gas in the tank and pump much worse. You should really consider draining the tank after you narrow the problem down.
do you have a Bentley manual? There are several procedures to check out for a no start car
be sure to keep the battery charged up so you don't run it down
if the fuel is only 2 years old it may still be good... but maybe not; why not eliminate that as an issue - you can also check the pump for flow rate & pressure
the rubber fuel hoses need to be replaced every 10, 15, 20 years with hose that is rated for ethanol mixes AND for CIS pressure levels - this is a good time to avoid an engine fire by replacing them
use a quality brand like Gates Barricade or whatever is their newest for that spec.
and be sure the clamps are good - not some garden hose clamp a PO stuck on there
and... the rubber brake hoses also need to be replaced every 10-15 years; the brake fluid every 2 years
tires are not safe past 6 years, no matter what the mileage (even if they have really round shoulders!!)
my gas was in my car 2 years while I rebuilt my engine .. fired up no problem . likely the pump
you should be able to lift the air plate with the ignition on and you should be bale to hear the pump down the street .. this is what I did after two years.
disconnect the nylon fuel lines from the injectors ( 13mm I think ) put the lines into a container . one each side .
disconnect cis box at the back , turn the ignition on and take the air filter out .. reach under and gently lift air plate, you should have old fuel and air purging out of injector lines . . if not get a pump.
Just finished putting a new bosche fuel pump and turned the key half way and didn't hear a peep from the fuel pump. Its taken sometime to remove and replace fuel pump and doesn't seem to have power to pump. Am I missing something? Tested fuse. any other suggestion? Any help would be appreciated.
10-13-2016, 08:13 PM
1979 911 Fuel pump question
