95 Astro Fuel Pressure Problems

[rushny]

Our van cut out on us last week and we have been unable to get it running again since then. I suspected the fuel system and began by replacing the fuel filter. That didn't help to get it started.

The engine turns over fine, has spark, fuel relay clicks in, pump can be heard and produces about 10 psi. It seems that the fuel is not getting into the combustion chambers. We have done the "pinch the return line" test and that yielded no increase (nor decrease in pressure). The pressure does not get up to the required 55- 61 psi.

We are trying to locate the fuel pump test connection in the engine compartment to see if it will build correct pressure. My research indicates that is should be a single red wire leading to a connector "on or near the fender" on the driver's side. We cannot find it there - at least, not a dangling test connector. Are we looking for the wrong thing?

We ARE able to locate a loose connector on the passenger side coming from the wire harness near the fuel pump relay with a gray wire. Today's project was going to be to try to trace this wire down and see if it connects to the fuel pump (pump has gray wire as does relay). Anyone know if it is before I waste more time on this?

I am also looking for the location of the "pulsator" and any suggestions as to how to test it.

Last year, we had a similar problem and replaced the fuel pump only to discover that the problem was actually a broken, corroded wire that caused the failure.

Reading the schematic, it appears that the "low oil pressure switch" may control the pump after start mode. Where is this and is there a test for it?

One final detail: there are no error or fault codes generated by the computer. "Check Engine Light" does not signal.

This problem is driving my Dad a little crazy. Any help would be appreciated. Thanks in advance.

[Kings-x59]

Here's a link on the oil pressure switch location and testing -
http://www.autozone.com/servlet/UiBr...3d80117d00.jsp

[Kings-x59]

Here's a thread from this forum that may be useful -
http://www.automotiveforums.com/vbul...light=pulsator

If you don't have a wiring diagram for your '95 there's one here-
http://www.autozone.com/servlet/UiBr...3d80119101.jsp

It appears you tested the fuel pressure. 10 psi isn't even enough to run the old Throttle body injection models. I've not heard of an electric test connection for the fuel pump on any year model.
If you find no problems with the wiring from the fuel pump, relay or oil pressure switch, the problem is most likely in the tank. The most likely culprit is the fuel pump. If it was just the pulsator, I think you'd be seeing more fuel pressure than 10 psi.

[rushny]

kings-x59: THANK YOU FOR YOUR HELP. THE LINKS ARE GREAT. WHILE I WAS READING AND STUDYING THEM, MY DAD WENT AHEAD AND DROPPED THE (FULL) FUEL TANK AND REPLACED THE "new" FUEL PUMP WITH THE OLD PUMP, CONNECTED EVERYTHING, TURNED THE IGNITION AND IT STARTED RIGHT UP! YOU WERE CORRECT, IT WAS THE PUMP.

THANKS AGAIN FOR YOUR HELP. IT WAS MUCH APPRECIATED.

Originally Posted by Kings-x59

Here's a thread from this forum that may be useful -
http://www.automotiveforums.com/vbul...light=pulsator

If you don't have a wiring diagram for your '95 there's one here-
http://www.autozone.com/servlet/UiBr...3d80119101.jsp

It appears you tested the fuel pressure. 10 psi isn't even enough to run the old Throttle body injection models. I've not heard of an electric test connection for the fuel pump on any year model.
If you find no problems with the wiring from the fuel pump, relay or oil pressure switch, the problem is most likely in the tank. The most likely culprit is the fuel pump. If it was just the pulsator, I think you'd be seeing more fuel pressure than 10 psi.