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Registered
Join Date: May 2006
Location: dorset england
Posts: 80
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sc wont rev above 4k
Hi folks
My sc will tick over fine, it will build revs up to 3.5 k anything afrter this and it splutters and backfires like mad and wont go above 4k, I have an msd 6al in place of the cdi rotor and cap are ko plug leads are fine. Any ideas? please please I really wouldlike to have the car running at least once this year. Thank you Gordon Last edited by gordoncoll; 10-08-2007 at 04:37 AM.. |
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10-08-2007, 04:33 AM
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Trotskyite
Join Date: Aug 2007
Location: Las Vegas
Posts: 219
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I just had the same issue with mine. The injectors were leaking, and the oxygen sensor wasn't working properly. Runs like a top now! Good luck, when I was looking on these forums for help there are a long list of possibles, seems like it can be one of ten things causing your problem.
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10-08-2007, 05:45 AM
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Do you still have a catalytic converter? Or did you ever have one? It could be clogged up.
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2021 Model Y 2005 Cayenne Turbo 2012 Panamera 4S 1980 911 SC 1999 996 Cab |
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10-08-2007, 05:50 AM
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Registered
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Location: dorset england
Posts: 80
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just the ten things? thats not too bad then
never had a cat uk car 1981 ssi exchangers |
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10-08-2007, 05:50 AM
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Hell Belcho
Join Date: Sep 2006
Location: Oz
Posts: 9,249
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Quote:
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10-08-2007, 07:19 AM
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Location: dorset england
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didnt need to use the tach adapter as the tach worked fine without it.
the backfires are inlet backfires not exhaust ones by the way. |
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10-08-2007, 07:22 AM
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Smart quod bastardus
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Check to see that the wires are in the correct order on the cap, sounds like you have some wires in the wrong order. Next check the timing advance itself, it may be out of time, too far advanced or retarded.
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1979 930 Turbo....3.4L, 7.5to1 comp, SC cams, full bay intercooler, Rarlyl8 headers, Garret GTX turbo, 36mm ported intakes, Innovate Auxbox/LM-1, custom Manually Adjustable wastegate housing (0.8-1.1bar),--running 0.95 bar max ---"When you're racing it's life! Anything else either before or after, is just waiting" |
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10-08-2007, 07:24 AM
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Alii&Maui
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Did you install the correct rev limiter pill? I think it comes with the 3000 or 4000rpm pill installed from the factory.
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1982 SC Coupe SCWDP#0087 KCSSL#0082 |
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10-08-2007, 07:25 AM
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Designer King
Join Date: Mar 2004
Location: Toronto, ON Canada
Posts: 5,499
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Have you checked your control pressures and mixture? Maybe your WUR is off and you are too lean, especially once warmed up.
Check the distrib. As someone said, is it advancing OK? If you turn the shaft @ the rotor, does it spring back?
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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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10-08-2007, 07:33 AM
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Registered
Join Date: May 2006
Location: dorset england
Posts: 80
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Quote:
the wires I know are on right, I cant get the car to time properly, the timing light is very imtermittent at 900 rpm on and off and on and off. I am going to put a cdi on it tommorow and see if I can time it using a cdi then go back to the msd, I am positive the wiring is correct. I will then look at the fuel metering heads and so on and so on. I have put the correct pill in it. Last edited by gordoncoll; 10-08-2007 at 07:59 AM.. |
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10-08-2007, 07:33 AM
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Registered
Join Date: Dec 1999
Location: TX USA
Posts: 9,804
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Gordon,
Your MSD box is having the 'classic' switchover-to-single-spark-mode' failure ... which occurs at 3000 - 3500 rpm. Evidently, the high-rpm, single pulse mode fails first, followed later by the startup and low-rpm mode. Sounds like your low-rpm mode is dying fast. All of the above info has been derived from postings on this board, as I don't do MSD, and haven't [won't, up til now] observed one in person while failing.
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Warren Hall, Jr. 1973 911S Targa ... 'Annie' 1968 340S Barracuda ... 'Rolling Thunder' |
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10-08-2007, 08:22 AM
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Registered
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Location: dorset england
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"Your MSD box is having the 'classic' failure ... which occurs at 3000 - 3500 rpm.
Evidently, the high-rpm, single pulse mode fails first, followed later by the startup and low-rpm mode. Sounds like your low-rpm mode is dying fast. All of the above info has been derived from postings on this board, as I don't do MSD, and haven't [won't, up til now] observed one in person while failing." where do i find out more about this?????? |
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10-08-2007, 08:29 AM
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Somatic Negative Optimist
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Gordon:
The distributor often gets neglected. If you haven't serviced the distributor, go here for an easy clean/lube: Distributor service (Clean and lube) real easy without removing the pinion gear! I assume you know that the SC-distributor rotates counter clockwise (CCW) with the corresponding wire arrangement.
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1980 Carrerarized SC with SS 3.2, LSD & Extras. SOLD! 1995 seafoam-green 993 C2, LSD, Sport seats.  Abstract Darwin Ipso Facto: "Life is evolutionary random and has no meaning as evidenced by 7 Billion paranoid talking monkeys with super-inflated egos and matching vanity worshipping illusionary Gods and Saviors ". 
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10-08-2007, 09:05 AM
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Registered
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Location: dorset england
Posts: 80
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distributor is fine, followed that thread quite recently. this just came on suddenly one day when driving, one min fine next dead. got it started by retarding the dizzy and limped home.
now it will start and run up to 3.5 4k then all hell breaks loose and it cracks and bangs like fury Gordon |
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10-08-2007, 09:20 AM
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Registered
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Location: dorset england
Posts: 80
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I assume you know that the SC-distributor rotates counter clockwise (CCW) with the corresponding wire arrangement.[/QUOTE]
funnily enough this is wrong in my Bentley book !! I do know it goes couter clock but I thnk thebentley describes it as clock, weird |
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10-08-2007, 09:21 AM
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Registered
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Probably not the issue here but, if you leave the 3mm allen key in the C/O adjustment slot, it wont rev past 4k.
BTDT
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10-08-2007, 09:40 AM
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10-08-2007, 09:51 AM
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Registered
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Location: dorset england
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tommorow I will be rewiring the msd after checking the car with a CDI, new leads rotor and cap going on tommorow, will also regap the plugs and clean them.
report back later how it has gone ! |
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10-08-2007, 11:40 AM
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Registered
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cracked air box or or intake rubber sleeve ripped
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10-15-2007, 07:11 PM
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GAFB
Join Date: Dec 1999
Location: Raleigh, NC, USA
Posts: 7,842
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Quote:
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10-16-2007, 06:22 AM
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1985.5 Porsche 944 2.5L Supercharged 
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