Thread: Won't start. I have fuel pressure spark and the engine cranks

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  1. #1 Won't start. I have fuel pressure spark and the engine cranks 
    Florida Tuner Z34Phoenix's Avatar
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    Won't start. I have fuel pressure spark and the engine cranks. Car is at a shop as I broke down on way to my honeymoon.

    Had spare PCM no change
    Engine cranks over
    Has 40+ psi fuel pressure
    Injector test light blinks during cranking
    Spark boots will spark to ground so I know it is sparking
    Fuses are good
    Timing belt turns and still looks good


    The car was running fine. No signs until I started to go from a traffic light. At first the car hesitated like it was the tranny slipping I thought ... Then I noticed it wasn't the trany as toms were falling. And kept falling till the engine died.
    only thing I can think is I had gotten 8 gallons of gas to fill my tank about 15-20 min before. Any ideas?

    96 Z34 (RIP LQ1 14.81@92.3) L36 Swap 14.9@91.5 www.cardomain.com/id/z34phoenix
    Topswap: P&P All,Si Valves,L76's,LW Pushrods,SD's,DHP PT PB 13.91@99.8
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  2. #2 Re: Won't start. I have fuel pressure spark and the engine cranks 
    Turbo is the way to go. BillBoost37's Avatar
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    To start, a motor only takes fuel, spark, compression and timing.

    If you have fuel and spark, is it possible the plugs are wet?
    I drink..so consider that when reading my posts.

    2010 Audi A6 Dual IC's
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  3. #3 Re: Won't start. I have fuel pressure spark and the engine cranks 
    Florida Tuner Z34Phoenix's Avatar
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    Don't think... As it was running fine till it died for no reason. I'm thinking it is related some how. My freind suggested flooded but I pulled the fuel relay and cranked it over a bunch and it didn't help any.

    My thinkIn is it is a crank sensor or one of the two cam sensors... Cause maybe the spark isn't firing at the right time?

    96 Z34 (RIP LQ1 14.81@92.3) L36 Swap 14.9@91.5 www.cardomain.com/id/z34phoenix
    Topswap: P&P All,Si Valves,L76's,LW Pushrods,SD's,DHP PT PB 13.91@99.8
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  4. #4 Re: Won't start. I have fuel pressure spark and the engine cranks 
    Turbo is the way to go. BillBoost37's Avatar
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    You'd get popping and farting from it if timing was off.

    Wet plugs won't fire. Pull a front one and check it out.

    "It was running fine til it died.. " LOL yup. They usually do. I know it sucks and you need it running. Pull a plug and give it a quick check.
    I drink..so consider that when reading my posts.

    2010 Audi A6 Dual IC's
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  5. #5 Re: Won't start. I have fuel pressure spark and the engine cranks 
    Florida Tuner Z34Phoenix's Avatar
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    Update... mechanic called me saying he saw some dust in the timing belt and thinks it could have jumped timing... wants to change the timing belt... but said since i put an under drive pulley on it he doesn't have the timing marks to do the belt change.

    i asked him to check the crank and cam sensors and get me an estimate for the belt change... he said the engine has compression. im about 2 hours away so i cant look at it... im assuming he pulled the plugs when he did the compression check and would have looked at those too... just doesnt seem like a physical timing issue... more like a spark timing issue to me.

    my opinion on it right now... i don't want to spend the money on a timing belt job and find out it still wont start. or risk it being timed wrong and then do damage to the engine. if it isnt something like a sensor i will just have to pay to have it towed. and if it is needing a Timing belt or there is damage inside the engine then i wont have much choice but an engine swap....

    96 Z34 (RIP LQ1 14.81@92.3) L36 Swap 14.9@91.5 www.cardomain.com/id/z34phoenix
    Topswap: P&P All,Si Valves,L76's,LW Pushrods,SD's,DHP PT PB 13.91@99.8
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  6. #6 Re: Won't start. I have fuel pressure spark and the engine cranks 
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    Crank sensor all the way man
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  7. #7 Re: Won't start. I have fuel pressure spark and the engine cranks 
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    Crank sensor has 2 hall effect sensors in it. 3x and 18x if one fails the motor will not start but you will have spark. The pcm fail safes only if it goes out while driving. It will use the cam sensor and one of the 2 crank signals to keep running. It may jerk and stall but on the road the motor keeps spinning at 1500 rpm do the computer has time for trial and error trying to sync up the crank signal with the cam signal. But when the engine is off its not able to failsafe from what I know. It might if you hold the ignition to start for 30 seconds straight but that's hard on the starter. But on these 3800s you can have spark and still have a bad crank sensor
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