1988 911 hard-start on cold motor condition
10-25-2002 | 02:06 PM
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From: Boston, MA
1988 911 hard-start on cold motor condition
Hello fellow 911 nuts! Great forum, I love this stuff. I need your collective expertise:
I have a 1988 911 cab, 65K miles, tune-up 1K miles ago (three months), ran flawlessly until three days ago. Now, on a cold motor it is hard to start. The motor turns-over properly, but it won't start. I know it's getting fuel because I can smell it after two minutes of trying to start it. Sometimes it will almost start just as I'm releasing the key, then immediately die. It will generally start after 4 or 5 minutes of trying.
I know what you're thinking- DME Relay. I already replaced it. No help.
It's got new ignition wires,plugs, cap and rotor, all OE or better quality.
Who has a good theory? Any and all help is appreciated. Many thanks... <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />
I have a 1988 911 cab, 65K miles, tune-up 1K miles ago (three months), ran flawlessly until three days ago. Now, on a cold motor it is hard to start. The motor turns-over properly, but it won't start. I know it's getting fuel because I can smell it after two minutes of trying to start it. Sometimes it will almost start just as I'm releasing the key, then immediately die. It will generally start after 4 or 5 minutes of trying.
I know what you're thinking- DME Relay. I already replaced it. No help.
It's got new ignition wires,plugs, cap and rotor, all OE or better quality.
Who has a good theory? Any and all help is appreciated. Many thanks... <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />
10-28-2002 | 10:53 AM
#2
The only things that I can think of to check before taking it in to have someone look at it are...
Try checking the grounding strap for the motor. Very weird things can happen if it isn't tight. It attaches to the rear of the intake plenum on the driver's side. Farther forward on the driver's side is the 3 connectors for the head temperature sensor and the 2 crank sensors. You might check them to see if they are loose. I would check the wires leading forward to the crank sensors. Make sure the wires are ok and that the sensors at the flywheel are clean and are at the correct gap from the teeth on the wheel. I don't know what the correct gap should be (someone else help out!?). If it starts ok when it is warm it might be the cylinder head temperature sensor. They are a common source of problems and there is an upgraded part to replace it. The last thing I would check is spark intensity. Perhaps the coil is weak? Take a spare plug and widen the gap to 2.5mm (or .100") and hook it to a sparkplug cable with the body of the plug grounded on the engine. It should show a strong blue spark.
Other than these little bits, I think you will need to take it in and have someone look at it. It could be the DME but I doubt you have a spare that you can swap it with.
Good luck,
Wayne
Try checking the grounding strap for the motor. Very weird things can happen if it isn't tight. It attaches to the rear of the intake plenum on the driver's side. Farther forward on the driver's side is the 3 connectors for the head temperature sensor and the 2 crank sensors. You might check them to see if they are loose. I would check the wires leading forward to the crank sensors. Make sure the wires are ok and that the sensors at the flywheel are clean and are at the correct gap from the teeth on the wheel. I don't know what the correct gap should be (someone else help out!?). If it starts ok when it is warm it might be the cylinder head temperature sensor. They are a common source of problems and there is an upgraded part to replace it. The last thing I would check is spark intensity. Perhaps the coil is weak? Take a spare plug and widen the gap to 2.5mm (or .100") and hook it to a sparkplug cable with the body of the plug grounded on the engine. It should show a strong blue spark.
Other than these little bits, I think you will need to take it in and have someone look at it. It could be the DME but I doubt you have a spare that you can swap it with.
Good luck,
Wayne