[Gmecm] Hard cold starting

[Jared Ryan]

Something just occurred to me.

The oil pressure switch is the old style, the kind that was used for the choke heater/relay setup back when the car had a carburetor.  I simply spliced the wires from the ECM harness to the connector.  The oil pressure switch may be as old as the car.  It simply has two blade terminals sticking up, and the pigtail has female blade connectors and a rubber boot to shield them.

When I do a lookup on the oil pressure switch for a '91 1500 pickup with a 350, it looks like it is threaded for the same port, but the connector is different.  It looks like a Weatherpack connector.  I do not know if the switches work differently, but they certainly look different.

The oil pressure switch evidently worked back when I had the 305, but I am going to try to rule it and its wiring out as a possible problem before I look at the tuning for the 350.


On Jan 13, 2012, at 10:28 AM, Eck, Joel wrote:

> Personally, and for testing purposes only, I?d pull the fuel pump relay and jumper from the power connector in the relay socket to the pin that feeds power to the fuel pump to test the oil pressure switch theory. The other thing I might do with that situation would be to install an indicator light which would illuminate while the fuel pump lead was powered. Either way should tell you if the issue is related to the fuel pump being powered or not.

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