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Join Date: Feb 2002
Location: Montana
Posts: 715
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big backfire and died
I've been chasing an issue for the last few months. Bouncing tach and idle issues. Changed the battery and had the alternator rebuilt. Tested coil (MSD) and changed spark plugs. AFRs are normal. I have not been able to drive it over the winter, but yesterday I took the car out and it ran good. Shut the car off and at idle it seemed to have a slight surge. I made it about a mile and was accelerating onto the interstate and when shifting into 3rd I had a big backfire and the car died and would not start. It cranks and sorta "hits" but will not run. I replaced the fuel pumps 3 years ago (the last time I was left stranded on the interstate).
I'll start my trouble shooting tomorrow but was wondering if anyone has experienced anything like this before and could share their fix/experance. Thanks
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1982 930, K-27, BL adj. WUR, Rarlyl8 Headers and Hooligan muffler, PK CDI, 22 and 30mm torsion bars, poly bronze bushings 30mm raised spindles and custom valved Bilstein shocks (by Elephant Racing), monoballs front and rear (by Rennline), Alton 17" Fuchs, Fred Cook fuse panel |
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03-16-2024, 05:52 PM
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Join Date: Mar 2012
Posts: 133
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Mine did the same thing and it was a failing CDI.
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03-16-2024, 06:40 PM
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Location: Montana
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Thanks, i was wondering about that. I have an MSD that’s about 10 years old. That’ll probably one of the first checks tomorrow.
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1982 930, K-27, BL adj. WUR, Rarlyl8 Headers and Hooligan muffler, PK CDI, 22 and 30mm torsion bars, poly bronze bushings 30mm raised spindles and custom valved Bilstein shocks (by Elephant Racing), monoballs front and rear (by Rennline), Alton 17" Fuchs, Fred Cook fuse panel |
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03-16-2024, 07:18 PM
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Thats a tough one. Funnily enough I thought - green wire.
Probably need some diagnostics to narrow the field down. Spark? If yes, are the plugs getting fuel - wet. smell of gas? Alan
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83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-) |
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03-16-2024, 09:38 PM
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Old Codger
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Big Backfire from exhaust indicates it was very rich at that moment - excess fuel in the exhaust. The no start condition is probably a result of the first problem, maybe blew the BOV hose off causing a massive vacuum leak?
Good luck!
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1981 Wide Body SC Turbo, Pacific Blue/Artic White Leather. 930/51 3.0 to 3.2, PP Twin Plug Heads, Twinfire Ignition, RUF Intercooler, 7006 Turbo, 044 Pump, 009 injectors, BL WUR, Powerhaus Headers, Zork, 930 4 Speed, Motec, Retroair, Euromiester, Innovate LM2. |
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03-17-2024, 02:24 AM
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Join Date: May 2005
Location: Loxahatchee, florida
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The shielded green wire from the distributor caused mine to do that a few times when it was going bad. Took forever to find since the problem was intermittent.
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88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's. 2019 Silverado 6.2L |
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03-17-2024, 10:35 AM
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Location: Montana
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Just to share i replaced the “green” wire when i had the distributor rebuilt about 10 years ago. But I’ll for sure check it as i go through the troubleshooting process.
Thanks for all the help and suggestions.
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1982 930, K-27, BL adj. WUR, Rarlyl8 Headers and Hooligan muffler, PK CDI, 22 and 30mm torsion bars, poly bronze bushings 30mm raised spindles and custom valved Bilstein shocks (by Elephant Racing), monoballs front and rear (by Rennline), Alton 17" Fuchs, Fred Cook fuse panel |
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03-17-2024, 02:51 PM
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Location: Montana
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First chance to troubleshoot the issue, no spark. now to figure out why. I'm starting to think the MSD box as the issue, but we'll see where this takes me.
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1982 930, K-27, BL adj. WUR, Rarlyl8 Headers and Hooligan muffler, PK CDI, 22 and 30mm torsion bars, poly bronze bushings 30mm raised spindles and custom valved Bilstein shocks (by Elephant Racing), monoballs front and rear (by Rennline), Alton 17" Fuchs, Fred Cook fuse panel |
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03-18-2024, 07:34 AM
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Location: Montana
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So here was the issue... The year old American made NAPA non-resistor rotor recommended for use with the MSD box blew a part. So I just decided to replace the MSD with a Parts Klassik CDI box and go back to the original Porsche rotor. I probably could have just went a different route but I'm not a fan of inferior parts.
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1982 930, K-27, BL adj. WUR, Rarlyl8 Headers and Hooligan muffler, PK CDI, 22 and 30mm torsion bars, poly bronze bushings 30mm raised spindles and custom valved Bilstein shocks (by Elephant Racing), monoballs front and rear (by Rennline), Alton 17" Fuchs, Fred Cook fuse panel |
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03-19-2024, 02:52 PM
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It is a major problem these days - sorting the genuine from the rubbish. And it causes so many headaches when you put in a new part - trusting it to be right.
A good reason not to go diagnosing issues by changing out parts. Alan
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83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-) |
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03-19-2024, 03:03 PM
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Location: Montana
Posts: 715
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Just a follow up. I finally had time to remove the MSD box and replace it with the ************ CDI, coil, new rotor and cap. I had removed the distributor to get all the rotor parts out and forgot to ensure the #1 cylinder was TDC. I had a 50-50 chance of having it right when I put it all back together. Luck was with me as it fired tight up! Now if it would only quit snowing.....
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1982 930, K-27, BL adj. WUR, Rarlyl8 Headers and Hooligan muffler, PK CDI, 22 and 30mm torsion bars, poly bronze bushings 30mm raised spindles and custom valved Bilstein shocks (by Elephant Racing), monoballs front and rear (by Rennline), Alton 17" Fuchs, Fred Cook fuse panel |
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03-28-2024, 04:38 PM
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Location: Montana
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I guess there is some sort of issue talking about with the brand of CDI box I selected on the forum. I guess I missed what the issue was. Sorry for mentioning it.
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1982 930, K-27, BL adj. WUR, Rarlyl8 Headers and Hooligan muffler, PK CDI, 22 and 30mm torsion bars, poly bronze bushings 30mm raised spindles and custom valved Bilstein shocks (by Elephant Racing), monoballs front and rear (by Rennline), Alton 17" Fuchs, Fred Cook fuse panel |
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03-28-2024, 04:42 PM
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Join Date: Nov 2001
Location: top of 3rd
Posts: 4,336
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nice work!
had exact same rotor failure w/ my MSD... yuuuuuge backfire & dead roadside noon on the hottest July day ever for an hour++... goooood tiiiimez lol |
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03-28-2024, 05:57 PM
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Location: Montana
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Well back at it.... I was a little delayed in the test drive because I found a torn CV boot, so I repacked and new boots for both axels. Got finished and decided to get the timing exact. The car was running nice, timed it and made it about 1/4 mile from the house then a back fire when shifting to 3rd and died. No start. This is a little frustrating to say the least. So I'll be back at it tomorrow trying to figure out the issue. Seems to be an ignition issue. I've replaced plugs, cap, rotor, coil, CDI box and CDI wiring harness.
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1982 930, K-27, BL adj. WUR, Rarlyl8 Headers and Hooligan muffler, PK CDI, 22 and 30mm torsion bars, poly bronze bushings 30mm raised spindles and custom valved Bilstein shocks (by Elephant Racing), monoballs front and rear (by Rennline), Alton 17" Fuchs, Fred Cook fuse panel |
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04-23-2024, 05:00 PM
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Registered
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Also check your over boost sensor and its connection.
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87 930, |
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04-23-2024, 05:47 PM
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Thanks, that was going to be one of my first checks tomorrow
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1982 930, K-27, BL adj. WUR, Rarlyl8 Headers and Hooligan muffler, PK CDI, 22 and 30mm torsion bars, poly bronze bushings 30mm raised spindles and custom valved Bilstein shocks (by Elephant Racing), monoballs front and rear (by Rennline), Alton 17" Fuchs, Fred Cook fuse panel |
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04-23-2024, 06:10 PM
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What did you replace the coil with (suspect parts out there - including coils - and rotors).
Alan
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83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-) |
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04-23-2024, 07:10 PM
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Location: Montana
Posts: 715
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The coil came with the PK CDI (new wiring too). The cap was Bosch and the rotor was Porsche (the Porsche rotor was cheaper than the Bosch). I got burned by a Bosch coil several years ago and won't use one of their new ones. I plan on testing the coil because there seems to be issues with them, kind of sad how crappy some parts are these days.
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1982 930, K-27, BL adj. WUR, Rarlyl8 Headers and Hooligan muffler, PK CDI, 22 and 30mm torsion bars, poly bronze bushings 30mm raised spindles and custom valved Bilstein shocks (by Elephant Racing), monoballs front and rear (by Rennline), Alton 17" Fuchs, Fred Cook fuse panel |
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04-24-2024, 05:05 AM
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At least if it stays in the no start condition you can zero in on the issue. Nothing worse than coasting to the side of the road and sitting there for a while, only to have it restart and behave for another month or so. All trust goes out the window... BTDT.
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Ken 1986 930 2016 R1200RS |
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04-24-2024, 08:25 AM
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Join Date: Feb 2002
Location: Montana
Posts: 715
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Found another broke rotor, so it seems that my distributor needs rebuilding (again) or replaced. There is slop in the bushings/bearings allowing a little wobble and the rotor contacted the terminals inside the distributor cap. The distributor only had at most 25,000 miles over the last 10-12 years. Kind of foolish on my part not looking over the distributor closer the last time I had it out. But my old SC had way more miles on it without a distributor rebuild or replacement, so I just thought I was good. At least I learned something today.
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1982 930, K-27, BL adj. WUR, Rarlyl8 Headers and Hooligan muffler, PK CDI, 22 and 30mm torsion bars, poly bronze bushings 30mm raised spindles and custom valved Bilstein shocks (by Elephant Racing), monoballs front and rear (by Rennline), Alton 17" Fuchs, Fred Cook fuse panel |
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04-24-2024, 06:25 PM
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Turbo
1987 930
2013 KTM RC8R
1999 BMW R1100s
1987 BMW 535i
911 Turbo
