hard starting

[Boydskyking]

I am a newbie in the 911 ranks and I have question.I have a 1980 911 SC and it is hard to start. It has got to the point where when cold it starts and pop and backfires.Can you guys give some ideas on where to start checking. I have ordered a kit from Pelican to check fuel pressure .


Thanks

[stlrj]

I would not rule out a cracked air box.

[ossiblue]

Classic symptoms of an overly lean cold start condition--usually from too high cold fuel pressure, or an air leak, or a combination of both.

You're doing the right thing, IMO, by waiting for the fuel pressure gauge set. In the mean time, you may wish to double check the valve adjustment so things are ready for your testing. Vacuum leaks are definitely a possibility but it is wise to begin your diagnosis with a complete testing of fuel pressures. Please post your results so we can offer help.

[Boydskyking]

I am the newbie that has a hard sarting and popping problem. This what I have done . Adjust the valves, new Plugs and wires with new plug ends.I received jy new fuel pressure tool from Pelican. I hooked it up between the control pressure regulator and the fuel distributor. I pulled the start relay and jumped the fuel pump. The pressure was 41 pds.I noticed that when the pump was turned on the pressure jumped to about 30 pds. and then slowly climbed 41 pds.My question is if the correct pressure should be between 65-75pds. I need 8 shims to bring it up to normal. Is this right and if so where do I buy the shims. Also I observed that when I turn the pump off the pressure drop to about 20 pounds in 10 minutes and then moved to 15 pds and stayed

[ossiblue]

Responded to your email before I saw your post. Not much to add except your residual pressure is ok. If you decide to follow my suggestions, post your results here for best responses.

[boyt911sc]

Originally Posted by Boydskyking

I am the newbie that has a hard sarting and popping problem. This what I have done . Adjust the valves, new Plugs and wires with new plug ends.I received jy new fuel pressure tool from Pelican. I hooked it up between the control pressure regulator and the fuel distributor. I pulled the start relay and jumped the fuel pump. The pressure was 41 pds.I noticed that when the pump was turned on the pressure jumped to about 30 pds. and then slowly climbed 41 pds.My question is if the correct pressure should be between 65-75pds. I need 8 shims to bring it up to normal. Is this right and if so where do I buy the shims. Also I observed that when I turn the pump off the pressure drop to about 20 pounds in 10 minutes and then moved to 15 pds and stayed

Boydskyking,

65-75 psi is the system fuel pressure. Are you checking the system pressure or the control pressure? 30 psi is typical control pressure. Close the valve while FP is running and you'll get the system pressure. Keep us posted.

Tony

[stlrj]

You might consider an ignition problem too. Moisture inside the distributor cap could wreak havoc or even bad ignition cables.

[Boydskyking]

I am the newbie that has a problem. First of all I did hook up the fuel equipment wrong and I am glad you mentioned it at the start. I hooked the guage up with the valve on the control pressure regulator side in the off position. I ran the pump and these were the pressure. primary pressure was 68 pds and the valve was opened and read the control pressure was 32 pds with the electrial conector off the control pressure regulator. I hooked the electrial wire back to the CPR and the pressure went up to 50 pds after a while. I think the reason I got 41 yesterday is that I didnt give the element time to heat up completely. I got the engine running but it runs really bad missing on both banks.I bought the car and was told that the compression was good but the engine didnt run. I think I will check the compression and if that checked good I am thinking maybe checking the fuel injectors what do you guys think

[Boydskyking]

I have also replaced the rotor button and the cap