Engine/Transmission (1994 - 1998) wierd power issue

[bradyw]

Ok i had an other thread about low power issue in 911 thought i had fixed it but now a new one. Ill start with what ive done. Ive put new fuel lines removed heater cleaned pre filter put new lift pump and overflow valve. My fuel pressure was low but after all that it was up to 24 at idle and 29 at 2300 rpm now its around 25 max. Heres what iv noticed the last two days in the morning at 5 am it runs outstanding power all the way lthrough but at 4 pm it is about half power, let me add it has no smoke so i looked it up on here and was thinkin a shutoff silenoid so i checked the fuse link and and pulled the relay and cleaned the contacts now it wont pull up but will stay up the boot seems to be fine. Im going to get a new relay and try that but why does it run perfect in the morning and not in the afternoon i also need to get a boost gauge but with no smoke iv read it probaly not boost. thanks

 

[budnate]

next time no power go lift the fuel solenoid up and see if it moves up to full open... sounds like its hanging up and not opening all the way

 

[MLee]

Have you cleaned the solenoid and cylinder? they do rust and get crud in them. make sure the boot is not binding the movement of the cylinder. As mentioned manualy lift to see if you are getting full travel.

 

[Missouri Mule]

The fuel shutoff solenoid relay is for starting only ( sends power to start coil in solenoid). The hold up coil in the solenoid keeps it running. You need to check out if hold/run coil is working as suggested above.

 

[bradyw]

Today i got the new relay from a automotive electrical place 70amp. And nothing. I tried it a couple of times and nothing. I plugged it back into the old one and it fired up. I will pull the silenoid and clean then trace my wires and check for breaks anything else. Thankx for info. Ill lift up on the lever again to double check

 

[Dieseldemon]

Check the blue wire on the drivers side battery for a bad connection +

 

[bradyw]

Ok ive crazy busy at work havent had the time but this is whats up now i thought when when i saw the fuel shut off lever hitting my needle valve that was it but i rotated it and still no better fuel psi is still 24-25max 19 at idle over flow valve wide open still runs great in the morning and half pedal in the afternoon iknow im good to the lift pump when i installed new lines it took only about ten pumps to get fuel "what next" ill try putting gauge on filter inlet see if its different thankx

 

[bradyw]

Whats up no ideas. I tried once again to pull up on the shut off valve and couldnt get it to move. Is there any vacum lines or maybe the afc line or i read a little bit about gov spring. when it cool in the morning its good afternoon half pedal thankx