Porsche 928 Non Start
#1
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Hey, forum PLEASE HELP...I need someone to walk me through a check list of what to diagnose ... PLEASE HELP...ANYONE in San Antonio who can come out and help. ![surrender](https://rennlist.com/forums/graemlins/surrender.gif)
What happened? Driving the car, never notice any problems. Parked the car at school, after class the car would not start. I was abel to start the car and nurse it home. It had a very rough idle and could not hold its idle unless I had the gas pedal pressed down.![bowdown](https://rennlist.com/forums/graemlins/bowdown.gif)
![surrender](https://rennlist.com/forums/graemlins/surrender.gif)
What happened? Driving the car, never notice any problems. Parked the car at school, after class the car would not start. I was abel to start the car and nurse it home. It had a very rough idle and could not hold its idle unless I had the gas pedal pressed down.
![bowdown](https://rennlist.com/forums/graemlins/bowdown.gif)
![Confused](https://rennlist.com/forums/images/smilies/confused.gif)
#2
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Where to start? I don't know, but generally, battery good?, put a meter on it; grounds, relay (fuel pump), spark? Plug wet? Have you done anything to it recently?
#3
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My 82 sounded like that when I first got it. Mine was the vacuum line from the Aux air valve had slip. in the video it sounded like the flapper is continuously shutting. Try to hold it open with a long hose and see if it will run on its own. If it does check all the vacuum lines, manifold connections, seal between flapper and throttle body and temp 2 sensor. You can jumper the sensor to rule it out.
#4
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My 82 sounded like that when I first got it. Mine was the vacuum line from the Aux air valve had slip. in the video it sounded like the flapper is continuously shutting. Try to hold it open with a long hose and see if it will run on its own. If it does check all the vacuum lines, manifold connections, seal between flapper and throttle body and temp 2 sensor. You can jumper the sensor to rule it out.
#5
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Aux air valve is located on the passenger side of the throttle body in front of the Cold start valve. There is a vacuum hose that goes from there to the throttle body. Thats where mine was leaking yours maybe a different line will you need to check all the vacuum lines. Try taking out the air filter and then open the flapper and put a long piece of hose in it to hold it open. To jumper the temp 2 sensor just put a wire between the 2 connections on the plug Sorry i cant post any pics my daughter took the camera to school for a class.
#6
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SO many variables........hard to say exactly where....BUT I just solved a similar issue that was the AFM (air flow meter)....the air temp sensor was reading incorrectly and it sounded very similar to what you describe.....
Have you tried starting it cold....is it harder or easier to start cold?
Have you tried starting it cold....is it harder or easier to start cold?
#7
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SO many variables........hard to say exactly where....BUT I just solved a similar issue that was the AFM (air flow meter)....the air temp sensor was reading incorrectly and it sounded very similar to what you describe.....
Have you tried starting it cold....is it harder or easier to start cold?
Have you tried starting it cold....is it harder or easier to start cold?
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#8
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Okay, I am poking around the AFM housing. I removed it and stuck my hand down that hole where that AFM sits. There is dirty oil and it smells like a hint of gas. Is that where the smoke is coming from? Should there be oil in there? Please help...
#9
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My 82 sounded like that when I first got it. Mine was the vacuum line from the Aux air valve had slip. in the video it sounded like the flapper is continuously shutting. Try to hold it open with a long hose and see if it will run on its own. If it does check all the vacuum lines, manifold connections, seal between flapper and throttle body and temp 2 sensor. You can jumper the sensor to rule it out.
![typing](https://rennlist.com/forums/graemlins/yltype.gif)
![surrender](https://rennlist.com/forums/graemlins/surrender.gif)
Will post a video shortly...
#10
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#11
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#13
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Check all the vacuum lines. There are also a couple of plastic caps that are plugging off ports on the side of the throttle body make sure there still there. Mine were cracked and brittle so I replaced them with heater core plugs from the auto parts store. There is a good write up on here how to check and clean the AFM. https://rennlist.com/forums/928-foru...rebuilder.html
Also check the plug going into the AFM and the big oring.
Mine smoked bad too when I did the hose down the AFM. The temp 2 sensor is the one between the center fuel pressure reg and the oil fill on top. Just unplug it and place a wire in the connector. I am sure there is a pic posted on here if you cant find it.
Also check the plug going into the AFM and the big oring.
Mine smoked bad too when I did the hose down the AFM. The temp 2 sensor is the one between the center fuel pressure reg and the oil fill on top. Just unplug it and place a wire in the connector. I am sure there is a pic posted on here if you cant find it.
#14
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#15
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Check all the vacuum lines. There are also a couple of plastic caps that are plugging off ports on the side of the throttle body make sure there still there. Mine were cracked and brittle so I replaced them with heater core plugs from the auto parts store. There is a good write up on here how to check and clean the AFM. https://rennlist.com/forums/928-foru...rebuilder.html
Also check the plug going into the AFM and the big oring.
Mine smoked bad too when I did the hose down the AFM. The temp 2 sensor is the one between the center fuel pressure reg and the oil fill on top. Just unplug it and place a wire in the connector. I am sure there is a pic posted on here if you cant find it.
Also check the plug going into the AFM and the big oring.
Mine smoked bad too when I did the hose down the AFM. The temp 2 sensor is the one between the center fuel pressure reg and the oil fill on top. Just unplug it and place a wire in the connector. I am sure there is a pic posted on here if you cant find it.
Man when I saw all that smoke I paniced inside, I was like NOW what....I love this car and I hate to see it down, and I beat myself over not knowing enough about these cars.