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3.6 Conversion Expertise needed
Here's the sum up. I'm new to the Porsche world, I have a '74 911 with a 3.6L conversion that I bought 2 months ago. Due to a cold start issue and a fuel smell I took the car to a mechanic. In his analysis the idle control motor was missing, when he attempted to replace it the idle ran extremely high. His theory was that the PMS lightened flywheel was causing the high idle. In a previous post others had mentioned the throttle cable and air leaks being a possible culprit to the high idle behavior, nothing was found in these areas. The car was returned to me with the Idle control motor still removed and no resolution to this issue.
Now I have a new problem. I drove the car home and the idle seems a little more sporadic now, I'm blaming the fact that to fix the fuel smell the tank was vented back to the motor and into a container that periodically opens to the intake to allow the fumes to be burned off. Yesterday I took the car to the gas station and filled up with gas and upon pulling out the car stalled and then wouldn't start. The car cranked and eventially turned over and ran very rough all the way home, stalling 2 more times. Upon arriving home I noticed several wires that are not connected now.  View of the engine compartment  Disconnected prong near intake  Disconnected wires that appear to be coming from the left bank of injectors  Same wires. I'm hoping someone can tell me what these wires should go to and where they should be connected to. I don't know much about this type of engine, or fuel injection for that matter. Most of my experience is with a '70 beetle, oh things were so much simpler then.
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There truly is no substitute 1974 Porsche 911 3.6L 1974 Porsche 914 2.0L 2017 Porsche Macan S 3.6L |
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05-09-2004, 08:54 AM
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The first picture it should be color coded the the plug on the right side of the motor, only plug missing, the last pictures the smaller plug is not used the black plug goes in the plate above the green and white plug and i believe connects to the wire harness, my 3.6 is out or i would go look, Kevin
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05-09-2004, 11:38 AM
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The 3 wires on the left are most likely from the heater fan(now missing) and can be tied out of the way. The one at the top I don't recognize.
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Bill Verburg '76 Carrera 3.6RS(nee C3/hotrod), '95 993RS/CS(clone) | Pelican Home |Rennlist Wheels |Rennlist Brakes | |
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05-09-2004, 03:46 PM
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The gray connector connects to Idle Stabilizer Valve. The other wires very likely go to heater blower and it's various sensors.
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05-09-2004, 04:21 PM
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When I trace the wire casing back that appears in the 3rd and 4th pictures it comes from the 3 fuel injectors on the left side, the fuel injectors on the right side have an identical wire set that seems to trace to an identical plug on the right side of the most forward distributor. However, I'm unable to find a plug on the distributor for any additional wires. This is a '95 993 3.6 if that helps. I guess my main concern should be the car is now undriveable, it was running fine before I arrived at the gas station and suddenly on departure began having problems, which seemed fuel related. A lot of vibration, uneven idle and then it would stall on acceleration.
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There truly is no substitute 1974 Porsche 911 3.6L 1974 Porsche 914 2.0L 2017 Porsche Macan S 3.6L |
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05-09-2004, 06:24 PM
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plug it in and start it, your mechanic may have neot pluged it in all the way, and the blakc square plug bolts in the plate above the white and green wire plugs you will see the hole and bill is right the smaller plug was for the fan, Kevin
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05-09-2004, 08:18 PM
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Wondering if I can get a consensus on the use of a single lightweight lower pulley on a 964 engine or should one keep the heavy harmonic balancer going to a single pulley? Timmins recommends keeping the heavy harmonic balancer. Although if you are going lighter on the front (clutch) of the engine, could it hurt to lighten the rear also? Thank, MGH
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05-10-2004, 02:23 AM
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The large grey connector as mentioned is for the idle stabilizer motor. The other wires are again as mentioned above for the heater blower motor.
As I mentioned in your other post your car should not run very well with the idle motor removed and before diagnosing everything else you should ensure it is functioning correctly and replace it. Again re-install the idle motor before trying to fix the problem. The high idle is not caused by the lightweight flywheel as many members of the board have done the swap with no issues. It looks in the picture like you have a small breather filter on the oil tank rather than routing it back to the intake boot, is the hole in the intake boot plugged? You may also want to try disconnecting the tank venting valve since it may not be hooked into the gas tank system properly, most conversions just have this left open to atmosphere. Also not sure what manufacture your air filter is but if too restrictive it can cause major running issues. Might want to put the factory airbox back until your running issues are corrected. I would say if you are unable to diagnose the problem yourself to find a different mechanic who is willing to work on the car. You need to get everything hooked up as it should be and start troubleshooting from there. There is a good section in the 993 factory workshop manual on going through and diagnosing the various sensors etc. hahnmgh63 I would recommend against using the lightweight lower pulley on a non-993 engine. The crank was changed on the 993 and I think it was Bill who posted a not so nice photo of a 964 crank broken in 1/2 due to the removal of the balancer on a 964 crank. Todd
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05-10-2004, 06:21 AM
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Connect the idle motor connection. As said above, the dissconnected wires on the left side of the motor bay are for the heater blower motor. Tape them up out of the way.
I second what Todd said about the vent line. Do you have a vent line running from the rear top of the motor to the oil tank? It doesn't look like it. The 3.6 has a line with a restrictor in it. Without out the restirctor I know from personal experience that the idle is sporatic and the motor may have a difficult time starting. That is the first thing I would correct after plugging in the grey connection. As for the lightened lower pully, why would you want to change it out? You are not going to gain much and it is designed as a balancer. There is a pic of a crank posted by Bill V. that shows what can happen when it is removed.  IMO, the PMS lightened flywheel is not hte cause of the problem. I have had no problems with mine.
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05-10-2004, 08:17 AM
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Quote:
The 993 doen't need it as they got a much beefier(stiffer) crank
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Bill Verburg '76 Carrera 3.6RS(nee C3/hotrod), '95 993RS/CS(clone) | Pelican Home |Rennlist Wheels |Rennlist Brakes | |
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05-10-2004, 01:54 PM
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It was the Reference Sensor - once replaced car's running smooth again
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There truly is no substitute 1974 Porsche 911 3.6L 1974 Porsche 914 2.0L 2017 Porsche Macan S 3.6L |
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05-25-2004, 10:06 AM
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Iroc Outlaw
914
1976 Porsche Carrera 3.0
1995 Porsche 993 Carrera Coupe
1978 Porsche SC Targa 3.6
