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not as smart as I think
Join Date: Oct 2006
Location: Northern California
Posts: 769
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3.2 hesitation
Thank you for taking the time to read my question. I am looking at purchasing a 1985 Carrera. On the test drive I noted hesitation in the car at around 2000 RPMs and again around 5000 RPMs. I am told the car sat for about 18 months before it was prepped to sell.
Anyone care to guess what the issue might be? My gut tells me it is probably just a fuel filter issue. The seller thinks it is a distributor problem. Either of which I assume should be easy to fix and would not scare me away. I appreciate your time and I look forward to your answers. Steve
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1978 911SC stock-SOLD 1985 911 Carrera Stock |
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THE IRONMAN
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Welcome aboard Steve.First of all...get a PPI for that 911 before to buy it.The car was stored for a 18 month period... It's look like a fuel problem for me...(contamination)
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1984 911 CARRERA RUBY RED TARGA SW CHIPPED-BURSCH CATBYPASS MONTY FREE FLOW EXHAUST <IN GAS WE TRUST> |
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not as smart as I think
Join Date: Oct 2006
Location: Northern California
Posts: 769
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Thanks for the input. I will probably bring it by my mechanic later this week. It was more something that was keeping me awake (note current time is 3:30 a. m. in CA) and since this is such a great resource I thought I would fire the question off.
Steve
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1978 911SC stock-SOLD 1985 911 Carrera Stock |
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Registered
Join Date: Jul 2006
Location: Honolulu, HI
Posts: 9,837
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Not to worry. My 85 was sitting for 3 years after a major service, 5 years prior to that. Added 10 gallons of premium (not much old gas in the tank) put in a new battery and she started up right away! Check to see if your fuel filter is fouled.
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The fun - '06 Carrera, '79 930, '06 S4 Avant, '16 i8 The mundane - '24 Tesla Model 3, '22 Tesla Model Y, '19 Tacoma |
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Registered
Join Date: Oct 2005
Location: Birthplace of Bix
Posts: 1,145
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My 85 stumbles briefly in cold weather, probably more of an oil warmup symptom than anything. I have the new fuel filter but have not installed it yet, when I do that I'll pull the injectors and have them cleaned and flow tested. By most accounts, the Motronic fuel management and delivery system is relatively trouble-free. Sounds like more of a routine maintenance issue in your case. What's the mileage?
I love my 85, BTW. A very good year for the 911. Regards,
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Joe 85 Carrera 64 Honda Dream - for sale 71 Hodaka Super Rat - keeper |
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Registered
Join Date: Jan 2002
Location: Long Beach CA, the sewer by the sea.
Posts: 37,722
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As a new Carrera owner and a new student of the DME engine management system, I can tell you this might well be a very simple matter of a sensor not worrking properly. Or, a corroded ground wire. Now, finding which one is not so simple. But, the head temperature sensor and other varible output sensors have simple tests for the range they shoud be in to function correctly. Others are on-off. If you do a PPI, make sure the person doing it is a crack tune up person. Might save you a ton of headaches in the long run.
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not as smart as I think
Join Date: Oct 2006
Location: Northern California
Posts: 769
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The car has 168K on it. The motor was rebuilt at 160K. It is really clean. I saw where it was parked in storage, no oil at all (unlike my 911 SC) and when I got under the car, it was totally clean too.
The car appears to have been well cared for (I saw the records going back 10 years) and that makes me think that it might just be bad fuel / dirty fuel filter. I really appreciate the food for thought. Steve
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1978 911SC stock-SOLD 1985 911 Carrera Stock |
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Large Registered Member
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Welcome to the Board Steve!
Milt is right on about all the sensors... Distributors rarely go bad in the Carrera's. I chased the IDENTICAL problem in my car for almost a year and a half. One of the more frustrating things was that the problem in the beginning was sporadic. In the end, it was constant at the same rpm range you describe. I replaced all sensors, plugs, plug wires, distributor, fuel pump, filter, swapped afm, entire airbox, DME from 2 different good running cars, dme relay, intake manifold gasket... Did I forget anything? In the end, it turned out to be 2 bad fuel injectors... I replaced all of them at 140k miles, and the car has never run smoother! It ran as well as or better than when I bought the car with less than 60k miles on the clock... My vote is either replace the injectors, or have them overhauled... They definitely don't last forever... You're definitely not throwing your money away replacing original 21 year old injectors!
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'85 Carrera Coupe, Marble Grey #118 JP/R6 '93 Lexus SC400, '00 Ford F-150 '70 911T- 2.7 (SOLD) |
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Join Date: Dec 1999
Location: Novato, CA
Posts: 4,740
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Anytime you throw a good part away is a waste of money IMHO.
It might be better to start with the basics like ignition and go from there. |
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Registered
Join Date: Oct 2004
Posts: 15,612
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A tune up is in order (valve adjust, new filters, new spark plugs, change oil) first. Then I'd recommend a can of BG 44K in the gas tank with premium fuel. From there, you can start to diagnose any remaining problems. Start with the easy stuff first.
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Registered
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The AFM also gets worn spots on the track and can cause hesitation, easy, cheap DIY fix on this board.
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DonMo 1984 911 Carrera Targa 3.2 liter, SSI's, Dansk 2 to 1, Steve Wong Chip Columbia, SC "Go Hokies" |
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