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ggrecian · Joined: 20 Oct 2013 Posts: 29 Location: Pa

please forgive the elementary question.i am am amatueur mechanic at best.took off manifold gasket to fix vacuum leak.put it all back together now crank no start.firing order is correct.what could cause the car to get out of timing?could replacing manifold gaskets and trying to start it 1000 times after changing over parts and sensors cause the car to get out if timing?
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porschelover

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

Fuel? Spark?
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

larchie · Joined: 19 Jun 2003 Posts: 297

If this is for the same car questioned in your past individual threads on this forum on Oct 27nd, two on 28th, Nov 2nd, 3rd, 7th, 8th and 10th, then the two things which come to mind are ...

(1) By reversing the sensors and then re-installing in the proper order the speed sensor and reference mark sensor is accidentally picking up metal filings magnetically or the like and so not having the proper clearance for proper readings.
(2) Problems with the timing -- use ideola's troubleshooting help outlined in these threads:

http://www.924board.org/viewtopic.php?t=39217
http://www.924board.org/viewtopic.php?t=39232
http://www.924board.org/viewtopic.php?t=39292

on how to solve the ignition/timing issues, esp. with regard to the reassembly with the distributor.

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

Um, OPs car is a 2.5 with Motronic. . .

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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

ggrecian · Joined: 20 Oct 2013 Posts: 29 Location: Pa

Yea same car in previoua threads.thank you for guidance.Have fuel with adequate pressure (36psi)to the fuel rail.and have spark.sent away dme to be bench tested.trying to rule out timing issue in the meantime.
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porschelover

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

So, just to clarify, your car does not have a conventional distributor, and does not have adjustable timing in the conventional sense. The ignition rotor is attached to the end of the camshaft, and ignition timing is controlled by the DME. If you are getting spark and fuel pressure, you likely have a crank speed/reference sensor problem. The most common culprits are wrong installation (plugs reversed) or a wiring fault at the connector. This assumes that you did not disturb the sensor bracket and mess up the gap.

If you don't know the history of the sensors, I think best practice is to replace both. The cheap replacement is Facet 12141710668. Both sensors are the same part.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

joecitizennn · Joined: 12 Sep 2005 Posts: 2096 Location: no mans land