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Registered User
Join Date: Jul 2014
Posts: 14
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Ignition
In a 82 911 SC 3.0 I have MSD 6AL-2 with programable timing ( #6530) . Iv'e had this running in the car for a long time. Now I find I should retard the timing from 15 degrees to 7 degrees for idle and start up ease. This car has PMO's also. After starting the car and using just a "basic strobe light" I notice the idle timing and as you increase rpm the advance curve move toward ATDC instead of BTDC direction. Weights in dist. are removed and totally locked. With a rheostat timing light, as you turn it from 28 degrees back to 7 degrees the pulleys marks move up to say beyond 35 degrees BTDC and more! It's as though something is backwards! But the car runs fine yet timing does not agree with what it should be before MSD and as stock. You all have any idea's here? You may call me if that's easier. Thanks, Rick 410-852-5794 (cell) Texas area
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02-02-2019, 05:30 PM
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Registered User
Join Date: Jul 2014
Posts: 14
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SOMEBODY help Rick out on this one!!
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02-02-2019, 05:31 PM
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Registered
Join Date: Mar 2001
Location: Marysville Wa.
Posts: 22,449
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Are the wires to the distributor plug swapped.
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https://www.instagram.com/johnwalker8704 8009 103rd pl ne Marysville Wa 98270 206 637 4071 |
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02-02-2019, 06:55 PM
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Registered
Join Date: Jul 2013
Location: South East England
Posts: 1,692
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^ Worth checking.
We see a lot of engines with miswired ‘mag’ sensors - swapped wires as John describes. The spark ends up being fired when the rotor arm is between the posts in the cap. On a timing light, this results in an offset of 15- 30 degrees depending on the sensor type. Rather than understand what is really at fault, we see folks try to workaround it by turning the distributor into it dialling it out on the electronic advance map. The engine will appear to run fine but will misfire under load. Often this leads to assumption of a fuelling problem. The real reason of course is that the spark has a big gap to jump in the cap which is harder for it to do under load. The sensor polarity must be set so the ignition box fires on the steep negative going edge of the mag sensor signal. Unfortunately this is difficult to see without a scope and is further compounded by some manufacturer information being incorrect (yes really).
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02-03-2019, 01:37 AM
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Registered
Join Date: Oct 2006
Location: MYR S.C.
Posts: 17,321
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is your dist. indexed correctly. you may be one tooth off.
check TDC in comp stroke and see if the rotor lines up to the #1 plug wire.
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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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02-04-2019, 02:59 AM
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