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Registered
Join Date: Jul 2015
Location: Seattle, WA
Posts: 421
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SC died while driving!
My engine suddenly died yesterday and now will not start. The engine just cut out when shifting (? if this has anything to do with it I doubt). Now it cranks but won't start. (I had it towed home).
I checked the fuel pump as per Bentley, and it seems to be operating (noise heard when sensor plate is lifted and key is on). I don't smell any gas however. Next, I checked the voltage across terminals 86 and 87a of the relay socket, and there's nothing. The fuse is fine and tight in the panel, and the wiring seems in tact. How could the pump be operating if there's no voltage to the relay? What could be causing the missing voltage?
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82 911SC Targa |
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11-04-2016, 07:36 AM
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Location: Seattle, WA
Posts: 421
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OK, I realized I should be checking the voltage at each terminal, not across the two, and it's fine. So what next?
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82 911SC Targa |
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11-04-2016, 07:41 AM
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Member 911 Anonymous
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Did the alternator light come on prior to **** down?
What is the voltage reading on the battery? If you have an external Voltage Regulator, I would pull that to see how worn it might be.
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'85 Carrera Targa Factory Marble Grey/Black * Turbo Tail * 930 Steering Wheel* Sport Seats * 17" Fuchs (r) * 3.4 * 964 Cams * 915 * LSD * Factory SS * Turbo Tie Rods * Bilsteins * Euro Pre-Muff * SW Chip on 4K DME * NGK * Sienes GSK * Targa Body Brace PCA/POC |
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11-04-2016, 07:47 AM
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76 911S Targa
Join Date: Oct 2010
Location: Idaho
Posts: 1,150
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Engine needs fuel and spark. You checked for fuel but you have not checked for spark. Do that next.
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76 911S, 2.7, Bursch Thermal Reactor Replacements, Smog Pump Removed, Magnecors, Silicone Valve Cover Gaskets, 11 Blade Fan, Carrera Oil Cooler, Turbo Tie Rods. |
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11-04-2016, 07:57 AM
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RETIRED
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Fuel and spark check...
Lift the flap in the air box to actuate the fuel pump. You should hear also hear a high pitch whine from the CDI box.
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1983/3.6, backdate to long hood 2012 ML350 3.0 Turbo Diesel |
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11-04-2016, 07:58 AM
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What the ?
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Check your ignition coil...I had the same thing happen twice with my SC both times bad coil. The new Bosch coils are junk.
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SCWDP 73 1980 SC Harley Davidson Road King 9/11/01 FDNY/343 Never Forget! |
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11-04-2016, 08:17 AM
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Registered
Join Date: Oct 2006
Location: MYR S.C.
Posts: 17,321
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check fuse 18
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86 930 94kmiles [_  _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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11-04-2016, 09:34 AM
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Warren Hall Student
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Just because the fuel pump is running doesn't mean you have gas. You may be out of gas. The fuel senders on these cars stick all the time. Turn the key on, pull an injector out from a runner and lift the sensor plate to see if it sprays. If it sprays then check spark.
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Bobby _____In memoriam_____ Warren Hall 1950 - 2008 _____"Early_S_Man"_____ |
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11-04-2016, 09:41 AM
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Registered
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Location: Seattle, WA
Posts: 421
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No spark! How do I test the coil? I don't see anything about this in Bentley.
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82 911SC Targa |
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11-04-2016, 10:09 AM
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Registered User
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Mine did the same thing. +1 Bad coil.
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11-04-2016, 10:19 AM
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Designer King
Join Date: Mar 2004
Location: Toronto, ON Canada
Posts: 5,499
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Check the round black connectors under the dash.
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Paul Yellow 77 Sunroof Coupe/cork interior; 3.2L SS '80 engine/10.3:1/No O2; Carrera Tensioners; 11 Blade Fan; Turbo tie rods; Bilstein B6; 28 tube Cooler; SSI, Dansk; MSD/Blaster; 16x7" Fuchs/205/50 Firestone Firehawk Indy 500s; PCA/UCR, MID9 Never leave well enough alone |
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11-04-2016, 12:17 PM
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Registered
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Location: Seattle, WA
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I've measured the resistance of the coils. Primary is 1.0 Ohms, Secondary is 714 Ohms.
The tech tips section of our host's site says: "When measured with ohm meter the primary coil windings should give reading of 0.3-0.6 ohms. Secondary coils should be near 600 ohms."But it does not specify the year. Another post here says that Primary should be .4 - .6, and Secondary should be 650 - 790. Do I have a bad coil? Is it possible the coil is bad even if the resistance readings are in spec? If it's not the coil, then what?
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82 911SC Targa |
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11-04-2016, 12:25 PM
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Ignition signal test........
Quote:
Connect an inductive timing light and crank the engine. Look for a strong ignition signal. Or use the spark plug test. The ignition coil could be bench tested using a voltmeter to measure resistance of the ignition coil. Tony Last edited by boyt911sc; 11-04-2016 at 12:28 PM.. |
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11-04-2016, 12:26 PM
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Registered
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Location: Seattle, WA
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Paul, what connectors are you referring to?
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82 911SC Targa |
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11-04-2016, 12:26 PM
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Registered
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Location: Seattle, WA
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I pulled a plug wire, attached a new plug grounded the attached plug, cranked it over and no spark.
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82 911SC Targa |
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11-04-2016, 12:27 PM
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Registered
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Location: Seattle, WA
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Also, I'm getting voltage to the CDI.
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82 911SC Targa |
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11-04-2016, 12:40 PM
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Designer King
Join Date: Mar 2004
Location: Toronto, ON Canada
Posts: 5,499
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I'm not sure if my pm response went through. There are about 3 or 4 round black electrical connectors that plug into the steel part of the dash under the steering wheel. From memory, they are similar to the ones that are behind the fusebox, and are about the diameter of the fuses themselves. They sometimes just pop outof place.
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Paul Yellow 77 Sunroof Coupe/cork interior; 3.2L SS '80 engine/10.3:1/No O2; Carrera Tensioners; 11 Blade Fan; Turbo tie rods; Bilstein B6; 28 tube Cooler; SSI, Dansk; MSD/Blaster; 16x7" Fuchs/205/50 Firestone Firehawk Indy 500s; PCA/UCR, MID9 Never leave well enough alone |
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11-04-2016, 01:01 PM
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Registered
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Maybe your CDI box is the issue. Are you hearing the distinct whine when the ignition is ON but engine isn't running?
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1974 Targa 3.6, 2001 C4 (sold), 2019 GT3RS, 2000 ML430 I repair/rebuild Bosch CDI Boxes and Porsche Motronic DMEs Porsche "Hammer" or Porsche PST2, PIWIS III - I can help!! How about a NoBadDays DualChip for 964 or '95 993 |
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11-04-2016, 02:39 PM
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Registered
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Location: Seattle, WA
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CDI is whining!
What else can be causing no spark?
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82 911SC Targa |
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11-04-2016, 04:13 PM
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To recap, my engine died while driving. Now it cranks but will not start. The fuel pump makes noise when I lift the sensor plate in the air box. I'm not getting any spark. The coil appears to be near enough to spec to not be this issue (the primary coil is reading a tad high). The CDI is whining when the ignition switch is on.
What else could be causing no spark? The distributor pulse generator? (What's that?) There's one more test as per the manual that I can run on the CDI cable, but I need another pair of hands.
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82 911SC Targa |
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11-04-2016, 04:24 PM
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Marble Grey
Da cab
73' Porsche Targa
81 
81 
1974 Porsche 911 Targa 3.6
