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85 928 won't stay running?
Hi,I'm new to the 928 world.I purchased a 85 928.Flushed the fuel tank,replaced the fuel pump.It starts for a few seconds,then stops.Getting fuel and spark.Any ideas?I haven't been able to find too much info on line,any thing will be helpful
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09-21-2011, 04:35 PM
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Network Native
Join Date: Jan 2007
Location: SoCal
Posts: 10,349
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Well now you have found a lot of info.
 Relays, fuses, and grounds are common sources of trouble, replace the first two (not that expensive) and clean the latter. Google of 85 928 starts dies, got a few hits, here is one. Help! 85 928 Starts & Dies - Rennlist Discussion Forums |
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09-21-2011, 05:06 PM
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Location: Texas
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How did you check that fuel was getting all the way into the cylinders? I'm thinking that either your injectors are not firing or that your injectors are gummed up. Jumper your fuel injector relay ( a wire from terminal 30 to both terminal 87s) to remove that unknown factor from your fueling equation and try to start it. If it starts and runs, replace your injector relay.
If not, clean your injectors individually (I use Berryman's B-12, a mityvac, a battery charger and some leads)) and try to start it again.
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John Curry (Drift King) 928OC member Grand Prix White 1994 GTS AT (The GTS) Black 1989 GT (The GT) and Cobalt Blue 1989 S4 AT (The Blue Car) 1986 Euro AT Indishrot 1984 Euro S AT (The Stepson) and Black Metallic 1984 Euro S 5 speed (The Schwartz) Last edited by stepson; 09-22-2011 at 02:28 PM.. |
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09-22-2011, 02:24 PM
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When you say a few seconds, do you mean a few seconds, or just a handful of explosions, then stall?
You may be running on the cold start injector only, which runs off battery power, and is not computer-controlled. Sounds like you have prssure, but no injector pulsing. I strongly recommend buying a fuel injector noid test light. I wouldn't go any further without verifying injector pulsing. A noid will cost around $30, and will provide loads of data in an instant. Very easy to use. Test on a running car first to verify that it works properly, and to learn what you're supposed to see. Also, verify/scrub all grounds, especially computer grounds. Extremely important.
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1982 Porsche 928, Auto, 4.5 http://i72.photobucket.com/albums/i166/hethaerto/928Mist2.jpg?t=1305333945 |
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09-22-2011, 02:28 PM
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(1) Injector Relay (2) 14 Pin connector (3) entire fuse panel clean up
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09-22-2011, 03:56 PM
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1981 Porsche 928 "Euro" Auto Gunsmoke Metallic Flat - Black Interior 1983 Porsche 928S "US" Auto Light Bronze (Copper) Metallic - Brown Interior **SOLD** 
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09-22-2011, 04:09 PM
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Dunno which is worse, no advice or six flavors.
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09-23-2011, 05:07 PM
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Good point, but all no starts must begin with ground scrubbing/replacement/verification, no matter how wild the suggestions are.
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1982 Porsche 928, Auto, 4.5 http://i72.photobucket.com/albums/i166/hethaerto/928Mist2.jpg?t=1305333945 |
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09-23-2011, 11:38 PM
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My first test would be to jumper the FP Relay. The fuel pump and injectors are powered by the ignition switch during cranking then by the relay inthe run position. So with a failed relay it can run till you release the key from the start position then it will stall.
Also there is no cold start valve on an 85, the LH just increases the pulse width on the 8 injectors to compensate for the cold engine. |
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09-27-2011, 02:40 PM
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1991 Porsche 944S2 Can
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