Will Not Start

[jkmc17]

I have an 82' 911 with a 3.0L. I started the car the other day and it took longer than usual to fire off. I drove the car home and the next day it would not start. It will turn over but will not fire off. The spark plugs are firing and the fuel pump works. When I removed the fuel line from the fuel pump, it had a lot of pressure in the line. I feel that the problem is downstream of the fuel pump. Any suggestions other than maybe the fuel filter? Thanks

[twistoffat]

could be the fuel relay or possibly the spark is not sufficient. Hows your battery

[jkmc17]

The battery is fully charged. The engine will turn over very fast. The spark is very good also.

[twistoffat]

It still could be the fuel pump. Did you check the pressure with a guage on starting. Is the fuel pump humming okay when you start it. Can you get a spare relay to swap with yours to rule it out?

You may also have a plugged fuel filter; based on the spark though IŽd say its lack of fuel

[ossiblue]

You've confirmed spark so fuel delivery is the next step. I'll offer the following steps:

Unless your fuel pump has failed (or the relay which activates it), you should get some immediate firing of the engine due to the cold start valve. Since you don't, I'd suggest you first confirm the fuel pump is working.

Remove the relay and jump the terminals (I think they are #30 and 87, but others will need to confirm) so the pump will run with the ignition turned on. If it doesn't, then the pump is your problem. If the pump runs, then the relay is your problem--swap in a new one and see. If the fuel pump and relay check out, move on to test the cold start valve, followed by testing the fuel pressures, but be sure to ask questions of this forum if you are uncertain of any steps, and report any results so help can be offered on your diagnosis.

[jkmc17]

Thanks for all the info. I took the fuel pump off and wired it directly to a battery and it worked. I then placed it back in the car and left the downstream fuel line off and turned the engine over. There was a lot of fuel coming from the pump.

[ossiblue]

My thoughts only.

You've got spark and the fuel pump works. Still, I'm bothered by no immediate firing due to the possible cold start valve problem. You might try this: bleed the fuel system by turning on the ignition, removing the air filter, and gently lifting the plunger for less than five seconds--you should hear the injectors squeal. This will also shoot fuel into the intake valves so now, try to start the car and you should get some firing/running.

If no injector squeal, there is blockage or inadequate pressure. If the pump doesn't turn on, the relay may be at fault.

If injectors squeal and engine fires and dies, fuel delivery problem--clogged filter, low pump pressure, too high cold controlled pressure.

If injectors squeal and engine fires, runs but pops and backfires, lean condition from any/all items mentioned above.

If injectors squeal and engine runs smoothly, all is good except cold start valve/electrical circuitry.

Let us know what you find.

[jkmc17]

Will do. I will give it a try.

[jkmc17]

It looks like the fuel filter is clogged. There is hardly any fuel passing through. Got one order.

[RWebb]

drain the tank & repl./clean the brass mesh

[boyt911sc]

Originally Posted by ossiblue

You've confirmed spark so fuel delivery is the next step. I'll offer the following steps:

Unless your fuel pump has failed (or the relay which activates it), you should get some immediate firing of the engine due to the cold start valve. Since you don't, I'd suggest you first confirm the fuel pump is working.

Remove the relay and jump the terminals (I think they are #30 and 87, but others will need to confirm) so the pump will run with the ignition turned on. If it doesn't, then the pump is your problem. If the pump runs, then the relay is your problem--swap in a new one and see. If the fuel pump and relay check out, move on to test the cold start valve, followed by testing the fuel pressures, but be sure to ask questions of this forum if you are uncertain of any steps, and report any results so help can be offered on your diagnosis.

Larry,

To test the FP for SC's with ignition switch @ RUN, you need to jumper these terminals: #30 and #87A. Terminal #87 is for the starter (yellow wire). Hope this helps.

Tony

[ossiblue]

Originally Posted by boyt911sc

Larry,

To test the FP for SC's with ignition switch @ RUN, you need to jumper these terminals: #30 and #87A. Terminal #87 is for the starter (yellow wire). Hope this helps.

Tony

Thanks Tony. My cars don't have relays so I'm in the dark here.

[jkmc17]

Thanks Guys