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Join Date: Jun 2005
Location: South Georgia
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Help Needed!!! '79 Sc

Well, the SC is threatening to strand me an hour away from home...

I commute to work each day from about 40 miles away. Most of the drive is through the country (plantation land), so I can run 75-80 without worrying about traffic. Anyway, I was about 5 miles north of town, starting up a gradual hill when I felt some hesitation. Had the peddle to the floor, but the RPM in 5th wouldn't get above 3000. When I leveled out, I continued to feel the hesitation and the car strated to sputter. I slowed down and found that as long as I drove under 2000 RPM, the car would stay under power, but above that mark, sputtering and coughing. I managed to get all the way through Tallahassee keeping the RPMs to a minimum. Now the car is in the parking area and I'm not sure it's going to get me home. By the way, at idle it runs fine. I should point out that the last few starts have seemed unusually sluggish - same sort of sputtering and the occasional mild backfire. I'm hoping this is a minor fuel filter issue, as I'm afraid I may have gotten some bad gas. Also, two tanks ago, I mixed in some fuel additive (STP).

Okay, I think that covers the symptoms. Now, what's the diagnosis? Can I fix the thing where it stands and get home with it? Any advice would be greatly appreciated!! Thanks guys!

Frank

Old 09-20-2005, 05:11 AM
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Unless you have a fuel filter and the tools to change it out, you are in a bad position. How old is the filter on her now? Is the fuel pump making loud noises or just buzzing as usual? What about your cap and rotor?
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Old 09-20-2005, 05:34 AM
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I don't know how old the filter is. I bought the car in June. The maintenance history has some gaps. I cannot find any reference to the fuel filter in the maintenance log I received with the car.

I did hear some noises along with thh sputtering, but didn't couldn't tell what they were. Sorry, I'm a novice - so I'm probably not giving you very useful information. Thanks for your feedback.
Old 09-20-2005, 05:47 AM
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79 sc

will the engine rev clean when it is not under load ? if so you might need to check your coil
when was the last time the fuel filter was replaced?
check your dizzy to see if you do not have a bad connection or a short
www.emeraldperformance.com
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Old 09-20-2005, 05:51 AM
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melted cat?
Timing off?
Vacuum advance off dist?
Plug wires tight?
Smell fuel?(Leak at front pan or engine bay- don't drive.)

CDI box whining consistently? My old one at a certain high temp would intermittently whine and the effect you have seemed similar to mine. This lead to the melting of my cat and paint on the rear bumper as it superheated my exhaust system with the unburned mixture. I'd let it sit for 20 min and it would function normally. Remedy was a new CDI box and coil. It was severe though.
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Old 09-20-2005, 06:01 AM
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If it backfires, doesn't that point to insufficient spark, not insufficient fuel? I would go with coil or distributor cap n rotor.
Cap and rotor can be found at your local autoparts store, cheaply, and only require a screwdriver to install in minutes.

Doug

Disclaimer, I am no mechanic.
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Old 09-20-2005, 06:04 AM
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I haven't detected a whine from the CDI box.

So far, I like the dist cap solution....I hope it's that simple. Some friends are meeting me at lunch to diagnose and hopefully fix the problem.

Thanks for the help folks.

Frank
Old 09-20-2005, 06:54 AM
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It's supposed to have a high pitched whine when you turn the key on. Some call it a whistle or squeal. It's hard to hear with the engine running. You can hear it when you just turn the key on before start.

Good luck.
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Old 09-20-2005, 08:06 AM
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So, this high-pitched whine is normal? And it's from the CDI box?

I've been wondering about this ever since I started troubleshooting my brake lights. Ended up to be a bad rear fuse block.

But most of my testing was with with engine off, and key turned far enough to allow brake light turn/signal operation.

-Tom
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Old 09-20-2005, 09:17 AM
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okay, new dist cap and rotor installed.....still sputtering.

I wonder whether this could be related to the recent gasoline shortage in this area. I filled up my tank with what was likely the bottom of the holding tank just before the local market ran out. Could I have gotten some impurities or water in the gas? Is that a possible explanation? I went ahead and bought some water remover and added it to my tank. ...the saga continues...will he sleep in the parking garage....will he make it home.....stay tuned...

Frank
Old 09-20-2005, 09:44 AM
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Sound like a dirty gas tank pickup, do a search for SOUK's problem with his engine.
Old 09-20-2005, 09:51 AM
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I did a search using Souk's name and came up with a huge list of threads. Could you elaborate about the specific thread - so maybe I can winnow the list down to only a few? Thanks.

For what it's worth, the local shop has a fuel filter ($30) and pump ($300) in stock! I'm going to get the filter now, but due to the cost, I'm going to hold off on the pump until I know for sure that I need one.

Frank

Last edited by FrankF; 09-20-2005 at 11:32 AM..
Old 09-20-2005, 11:18 AM
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Update

Yesterday afternoon I managed to get the car over to my friend's shop, sputtering all the way. He has two older 911s and offered to help me figure out the problem. We checked the fuel filter and found that there was no pressure - no fuel spewed out when we loosened the top nut. We also removed the air filter and found it to be desperately in need of cleaning. Further, we turned the key on, but did not crank the car and listened for the fuel pump. Didn't hear anything. Then checked the fuse/relay box. When we removed the cover, the red relay for the fuel pump appeared to be barely seated. So we made sure all the fuses were good and firmly seated the relay. We put some adhesive form rubber on the top of the relay so it would be held in place once the cover was replaced. Finally, we cleaned the air filter with some mineral spirits and blew it out with the air hose. After putting everything back together, I cranked the car and it purred like a kitten. Sounded great! So, after a quick test drive down the road and back, it seemed like we had fixed the problem. But alas....

Half way across town, the sputtering and power loss started again. After about 5 stops to check the relay and make sure the pump was working, I finally made it to my friend's house, where the car now sits. Had to catch a ride back home to Ga.

So, it sounds like the pump is doing its job, but I'm still not getting sufficient fuel flow. Could it be the filter after all? If so, I do have one now and it was $13 instead of $30.

So, is there anything I need to be aware of before attempting to change out the fuel filter? How do I control the flow of fuel once I loosen the top nut, assuming there is some pressure this time? Is it necessary to drain the fuel tank to do this?

Thanks again to everyone for the helpful advice.

Frank
Old 09-21-2005, 05:10 AM
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Throw a rag around it, loosen nuts slowly and only a small amount will come out, easily caught by the rag. Use backup wrenches on the lines to keep from kinking expensive lines. Easy!!
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Old 09-21-2005, 05:23 AM
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thank you - for some reason I've been apprehensive about doing this.

I guess it comes from my latest DIY project last weekend - changing out the radiator on my 97 Volvo 960. That didn't go so well....
Old 09-21-2005, 05:25 AM
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A long shot but check the green wire going to the distributor. I too have a 79SC and found mine to be old and frayed. At one point it started arcing to the case (it is a coax) behind the distributor. It is possible that it is just breaking down and arcing under load.

Again a long shot but worth a look. I saw a good thread in the where John Walker recommends a splice and connector fix.

GB
Old 09-21-2005, 07:19 AM
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Does your friend have tools to check the pressure running and the residual pressure?
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Old 09-21-2005, 07:28 AM
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Frank,
Try loosening your gas cap. The venting for your gas tank may be plugged. Good luck.
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Old 09-21-2005, 07:57 AM
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Hey Frank,

I live in So GA as well but over on the coast, where you at ?

Todd
Old 09-21-2005, 09:25 AM
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GB,

When I replaced the cap and rotor yesterday, I did check all of the wires. I didn't see any bad connections, but I'll check again.

HK,

Yes, my friend has the tools to check pressure and we plan on doing that.

2.7,

Didn't think about that. I'll try messing with the cap - when you say the venting, do you mean the screen filter at the bottom of the tank?

K9,

Nice to see a fellow Georgian on the board! I'm over in Thomasville, about 30 miles north of Tallahassee. Ever do any weekend meets or get-togethers in your area? Any other Pelicans around here?

Thanks to all for the help. I hope to get the filter changed out this afternoon. Keeping fingers tightly crossed!!

Frank

Old 09-21-2005, 12:16 PM
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