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  • zaken1 01/02/12 12:27 am PST

    The S10 4.3L pickup has had throttle body fuel injection ever since the first year the 4.3 engine was used in this model (1988); but the throttle body LOOKS something like a carb. A failing camshaft position sensor will often not send trigger signals to the fuel injector at low RPMs during cranking. As soon as the motor begins running from the fuel you poured in the throttle body; the rpms will go up to the point where the cam position sensor begins to function; so it then keeps running on its own. After the first start of the day; the engine has enough excess fuel in the manifold to prime the cylinders. It will then start by itself until it sits overnight and the excess fuel in the manifold evaporates. After that; it will need to be primed again before it will start the first time. Replace the camshaft position sensor to correct this problem.

    The cam position sensor is mounted on the distributor in this motor. Here's a link to a photo of that sensor: http://www.rockauto.com/catalog/moreinf
    o.php?pk=938110

  • sladd 01/06/12 8:39 pm PST

    We changed the cam position sensor,which was zaken1's answer, it didn't work, the truck still doesn't start. I also forgot to mention the truck sputters when it does run and if you turn a sharp corner it stalls out when the gas is between quarter and empty. It won't cold start without priming it. I don't want to put it in for a diagnostic test because it cost's $90.

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