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Dead Car

My 78 930 was acting up the last time I drove it which was a month ago. The tachometer was not working all of a sudden and it was missing on the low end. I thought it was the coil so last night I replaced it with a blaster 2 to test with. It will crank with either the old coil or the blaster for about 2 seconds now and then quite. I can crank it again and it runs 2 seconds and then quits. I have ruled out the coil. I checked the rotor and cap and they look good. I unplugged the finned box on the driver side of the engine bay to check the connections there and plugged it back in and they did not make a difference. It still runs for about 2 seconds then quits. Anybody have an idea? Oh, I also put new plugs in it about a month ago.
Old 10-02-2009, 05:23 AM
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If you have CIS gauge set, I would hook up and check pressures. Sounds like lack of fuel pressure...

I had the same problem a couple weeks ago...
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Old 10-02-2009, 05:34 AM
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Make sure your battery is fully charged and/or use a jumper to make sure. With a dead battey or bad alternator, it won't run right or at all. A wacky tach is usually a sign of electrical, but...
Old 10-02-2009, 05:41 AM
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I had a red relay go bad but I replaced that and they are jumped so they run when i turn the key. The last time I checked I was 13~13.5 afr and 10.5~11 at 0.8 bar so it should be getting plenty of fuel and the battery is fully charged.

Is it starting on the cold start then switching over? Is this why it works for 2 seconds?

Last edited by rufporschecar; 10-02-2009 at 07:28 AM..
Old 10-02-2009, 06:24 AM
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I still can not figure out what is wrong with the car. Anybody got an idea?
Old 10-07-2009, 06:46 PM
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Originally Posted by rufporschecar View Post
I still can not figure out what is wrong with the car. Anybody got an idea?
Know anyone with a spare CDI ignition box you can borrow? Need to rule that out.

The wacky tachy has me wondering poor power connection or ground. Check 'em all (at the battery, the ground strap from the body to the tranny, etc). Intermittent power loss is my guess, if not the CDI.
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Last edited by mark houghton; 10-07-2009 at 07:05 PM..
Old 10-07-2009, 07:02 PM
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As stated above, wacky tack points to alternator, so make sure battery/tach are good. Also make sure both pumps are working, and maybe just jump them to make them run, then try starting the car. Ck system pressure with key on and pumps jumped. Ck voltage to dist from CDI, there is a procedure in the manual. I know you should not do this, but I did it when I was testing my CDI, pull the coil wire, and see if it sparks when someone is cranking. My CDI make the whine, but the spark was so faint that it would not fire the car. You do risk damaging the CDI testing it this way, but I took the chance. Ck the yellow relay, these can be very intermittent as the solder joints sometimes fail. Well, thats all I know!
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Old 10-07-2009, 08:45 PM
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Usually the CDI either works or it doesn't, with the ignition on it should make a faint hum sound if it is working properly!
It could be a dodgy relay, to test that the fuel pumps are both working the easiest way is to reach around the back of the fuel head/metering plate assembley and disconnect the wire/connector there, reach around the left hand side, it's one of those simple clip type connections. With this disconnected and the ignition turned on your pumps will run without the engine running. It's also a good way of getting the fuel system pressure up before you start the car, as hard starting can be down to leaking injectors, bad accumulator etc, although that shouldn't really affect the car starting from cold.

If when you disconnect the wire and turn the ignition on you can't here the two pumps running, then it's either dodgy relays or broken fuel pumps, it's a 10 minute test that requires no tools
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Old 10-08-2009, 02:07 AM
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Did you check the pos leads at the starter? Power goes from the alt, to the starter, and to the battery. If the leads are dirty or loose, it won't run right.

Replaced an alternator before I figured that out.
Old 10-08-2009, 06:32 AM
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I have the intercooler off and can try to crank it and it makes a small fire in the throttle body behind the plate. Does that tell you anything?
Old 10-10-2009, 04:59 PM
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rufporschecar,

Did you ever find the problem? My car started doing the same thing today, cost me a tow home.

Paul
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Old 10-22-2009, 03:57 PM
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I am haveing a crazy tach issue myself...but I noticed I am in need of a new fan belt...cracked and partially loose....

Check their as well
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Old 10-23-2009, 05:58 AM
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I am not having the tach issue with mine, it works fine. Mine will start and run OK for a few seconds and then start missing and die. It's not a fuel issue, checked all the relays and the pumps are running fine, also checked with the electrical connection pulled from the air meter and no luck.

I think it is electrical. Will a bad coil or permatune run and then quit?

Thanks,
Paul
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Old 10-23-2009, 11:13 AM
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Paul

A bad coil or permatune can cause these problems. I'd start by checking the coil and install a new one. They are cheap. Then I'd replace the permatune with an MSD 6AL or one with boost/timing capabilities.

Vascott01: I'd change our that belt with the proper tension asap. That's what keeps the engine cool!
Old 10-23-2009, 01:20 PM
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I've had a mysterious issue lately myself, car starts fine runs fine then out of the blue engine dies as if i had hit the kill switch, there is still fuel pressure and the car will restart and stall over and over then like magic everything is ok and the car runs fine, My alternator is suspect as it is noisy until it warms up or the rpms under load are increased above 3000rpm. Could the alternator really cause the car to shut off like this.
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Old 10-28-2009, 07:22 AM
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If you're using one of the newer silver color bosch coils that was made in Brazil, they are junk and will leave you stranded eventually.

I love the gorgeous down to earth and fun Brazilian women but those oil filled third world coils they make for bosch often last only a few months and often leak oil and burn out mounted upside down on a hot fan housing that is vibrating at constantly varying medium to high frequencies.
...totally bozo place to mount an oil filled ignition coil upside down or right side up in my opinion but it works for a while.

The epoxy encapsulated MSD high vibration blaster coil is highly rated and will hold up mounted on the fan housing and I've heard Permatune also makes an epoxy filled coil of good quality and will last in that location.

The origonal german made black painted oil filled bosch coils from years ago are known to be much better quality and more reliable than the new ones from south america.
Old 10-28-2009, 07:59 AM
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Twin plug blasters, i dont think the problem lies there, my experience with coils is when they fail, they fail and dont recover.
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Old 10-28-2009, 10:07 AM
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To followup on my problem, the car would start and run for a few seconds then die. I thought I had an ignition problem after I ruled out fuel delivery. I bought a new MSD coil because the original coil broke at the terminals when I pulled off to check it. It didn't solve the problem, the Permatune ohmed out fine so I was back to re-checking things I had previously ruled out.

It turns out that I had a bad connection for the rear fuel pump relay. The way I found it was I pulled the plug on the air flow meter so the pumps would run when I turned the key on. With the pumps running, I wiggled the relays and noticed the rear pump making odd noises as I moved it. This is a socket/relay that I had overheat on me when the rear pump went out recently so I know it is probably not in the best condition. It was a new relay though. I cleaned it up a little more and spread the pins on the relay slightly and works fine.

Paul
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Old 11-05-2009, 08:25 PM
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How many points do i get?
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87 930, 993 turbo engine, RS Tuning 520PS/515lbf-ft, Arrow Rods, ARP hardware, Solid lifters, G50-50, RS Flywheel, 890nm Sachs clutch, RSR coil overs all round, 993 C4 calipers front, 930 fronts on the rear, Ruf Speedlines.....
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Old 11-06-2009, 05:16 AM
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Jonathan,

Good call. I should have known, every time I have had a starting issue it has been electrical, either fuel circuit or overboost.

It threw me off because I could hear the pump running, I didn't notice it was only the front pump. Odd thing is prior to replacing the rear pump, the front alone would allow the car to run and drive. With the new rear pump, the car will not remain running with it off.

Thanks,
Paul
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Old 11-06-2009, 09:11 AM
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