getting spark and fuel of shrader valve .. still wont start

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Apr 27, 2011 | 06:57 PM
  #1  
Well im getting spark to my wires and fuel is coming out of the shrader valve on the fuel rails. My car just cranks over but wont fire... any ideas?
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Apr 27, 2011 | 08:35 PM
  #2  
Re: getting spark and fuel of shrader valve .. still wont start
im pickin up a compression tester tomorrow and fuel pressure tester tomorrow..think its the compression or fuel pressure?
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Apr 28, 2011 | 09:56 AM
  #3  
Re: getting spark and fuel of shrader valve .. still wont start
what car is this for? what engine?

you list a 96, but this is the Ls1 section. Your car would have a Lt1 originally.

2 somewhat different beasts when trying to diagnose a no start.

and to answer your question, Its less likely to be a compression issue. The fp could be sending some fuel to the rail but not enough for the car to start.

also, is the spark triggered at the correct time? guess it could be a crank or cam sensor. (do lt1's have those?). but then the plugs would probably be pretty wet.

let us know what the fuel pressure is when cranking.
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Apr 29, 2011 | 07:40 AM
  #4  
Re: getting spark and fuel of shrader valve .. still wont start
sorry i clicked on ls1 not lt1. it is a 1996 lt1 a4.
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Apr 30, 2011 | 04:55 PM
  #5  
Re: getting spark and fuel of shrader valve .. still wont start
Scan it for codes - loss of the low res signal from the Opti will prevent it from starting. Sets a code, but does not turn on SES light.

Check the fuel pressure with a guage. The fact that fuel squirts out of the Schrader valve does not prove there is adequate pressure.
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May 6, 2011 | 04:21 PM
  #6  
Re: getting spark and fuel of shrader valve .. still wont start
Verify you have spark using a spark checker (about $10 at any parts store). The spark should be able to jump a 3/4" gap. A weak spark could be a bad coil.
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