87 starts hard cold if tank not full

[mint87]

car has 45K miles, just changed the fuel filter, but it still cranks a lot to start when engine is cold. Unless, I have a full tank of fuel!

What should I change next ? There are no codes, and I don't hear the fuel pump running when I turn the key on.

 

[fore]

this is the point. You may had a bad fuel pump relay or your fuel pump just die. Don't forget check the fuel pump fuse in the fuse box on passanger side.

 

[WhalePirot]

The car would not run if the fuel pump and relay did not work. It needs 32-47psi to run properly. That don't happen by gravity.

There is a 'sock' on the pump inlet, inside the tank. It can clog. The pump is rather easy to extract, through the filler door. The tank has a polyethelene liner inside the metal. I don't know if it can warp and cause your 'more full' issue.

You can install a fuel pressure gauge to verify that you have enough pressure and that the pump runs for 2 seconds when the key goes 'on' and that the pressure holds at 40.5-47psi when the pump stops.

The '87 still had a clod start valve. The fuse is "C INJ", located behind the warning light display panel; a lt blu wire. This adds fuel only when coolant is below 35C/95F, for 8 seconds max. A bimetal switch lowers that time if coolant is warmer. If conditions call for it, the fuel pressure will drop more than 3 psi, if the cold injector is working when you crank the engine.
mike

 

[mint87]

thanks thats good info. Newbie question on fuel pressure check though... where's the best place to hook up the gauge for that ?

 

[WhalePirot]

only place to connect is near the distributor; a tap on the fuel rail.

the test gauge is $45 from TPIS, pn 100-147.