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89 S2 poor fueling maybe?
Hello everyone, Im looking for some help with my car. It was running great, it would start instantly. Then it started cranking longer, then it would crank really long and start with a big cloud of black smoke. Now, it only starts when I hold the throttle wide open. It also has a bouncing idle which sometimes causes it to stall. Also, three of the four spark plugs are carbon fouled. They only have about 3,000 miles on them.
One more thing, if it sits for two days, it starts like it used to. What I am thinking is that the injectors are just old and have an intense leak. Thats why it only needs the throttle wide open to start after it has just ran. The injectors are just leaking fuel into the cylinders. After a while I think the fuel evaporates out of the cylinder and then there is no flooded like start up. I am just spitballing, thank you so much! |
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12-30-2016, 02:48 PM
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Registered
Join Date: Sep 2011
Location: Florida
Posts: 1,949
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Fuel pressure regulator gone bad causes black smoke like that.
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Mike A 9TECHNIK | TRANSAXLE ÄRA 1986 944 (Street); 1986 944 (Track); 1986 951; 1989 951 (3.0L 8V); 2000 996 Cab. |
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12-30-2016, 03:00 PM
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I had poor running and one black plug. Turned out to be one leaking injector (even though I had had them serviced at Witchhunter). I bought a refurb from our host and all was cured. I did actually notice a weak spark too - replacing the coil had a nice improvement to the power.
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1987 944 Summer 2006 E90 Winter |
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12-30-2016, 03:09 PM
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Registered
Join Date: Jul 2014
Posts: 405
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May want to check the DME coolant temperature sensor also.
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12-30-2016, 08:49 PM
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In the Fires of Hell.....
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Fuel damper can also cause a delayed/hard start. I would think about replacing both of the fuel components (damper/regulator) if one of those units tests bad.
Get a fuel pressure gauge and the correct fitting for the fuel rail to test.
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PCA Instructor: '88 951S - with LBE, Guru chips, 3Bar FPR, 1.3mm shimmed WG, 3120 lbs, 256 RWHP, 15 psig boost |
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12-30-2016, 08:54 PM
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944 S2
Join Date: Nov 2015
Location: Middle of Ohio
Posts: 599
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Fuel damper! I had the exact issue on my 91. Easy to check. Just pull the vacuum hose off and see if it leaks fuel. Mine did. I pulgged it and sure enough the car started right away. It was dumping raw fuel directly to the intake.
Good luck. |
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12-31-2016, 01:05 PM
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+1 on the fuel damper, been there done that.
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Red 84 w/25,xxx miles Stone Gray 89 S2 w/90,xxx miles |
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12-31-2016, 08:48 PM
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Wow you guys are good. It was the damper. I pulled the vacuum line off and there was a solid stream of fuel coming through. Thank you everyone!
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01-03-2017, 09:19 PM
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Porsche 944
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