Re: HELP! car dies when hot.

Posted by JeromeSolberg On 2023/4/5 21:26:35

Well, three things:

1) atmospheric pressure is 14.7 psi. That's the most the pump can "pull" if the entire system was beyond perfect, but in the real world it cannot even do that. See what comes out at 10 psi, because the pump won't be able to pull a super-strong vacuum, and 10 psi is probably about what it can effectively pull. That might help determine if there is an obstruction. If you can simply use a vacuum pump or vacuum gage on the line itself, that would be a good test.

2) You could simply plug the pump into a vaccuum gage (instead of the bucket) and see what it's doing. That would tell you whether there is a seal or check-valve in the pump that is bad. Could be you sucked up some crap into one of the check valves and it isn't working effectively. One reason I have one of those cheapy see-through in-line fuel filters before the pump, though I know everyone hates those.

3) The starter doesn't crank the engine very fast, but still, could be a bad pump.

4) I know you were putting the pump on where it hadn't been installed in a long time. If for some reason you installed the pump "too far away", e.g. with too thick a gasket or a plate or something else, the effective stroke of the pump will be reduced, and therefore it's effective pumping power. It should still be able to pull a vacuum but it won't be able to pump very much fluid volume, and it will take a long time to pump up to it's maximum vacuum.