4.9 FI 1995 fuel pumps run in both tanks but do not shut down after 30sec...reg is good i believe...have spark no start.....please where is engine computer or PCM located it is not behind either kick panel and i do not see it visible under dash......The Haynes manual seems to have every thing *** backwards..THANKS

 

what about timing? if the timing is the problem it's not gonna matter what fuel and fire you've got. And is the spark at the coil or the plugs?

 

spark at plugs will temp start with ether(sp)

 

but not with gas? if you've gotta use starting fluid to make her start, and she won't run on her own, then it's a gas probem. What's the pressure at the fuel rail?

 

I have heard that the switching valve that selects either tank can fail and cause the fuel to be pumped from tank to tank. Does this have a third pump (higher pressure) that the in-tank 'lift pumps' feed? Possibly mounted on the frame about under the drivers seat. Maybe.
Either way, I'd get a fuel pressure gauge and hook up to the Schrader on the fuel rail. I doubt you have pressure... Are all the fuses good? Did you check the 'rollover' safety switch?

tom

 

Is the rear tank empty and are you starting on the middle tank?

Put some gas in the rear tank and if the sensor is good, it will start up. The way dual tanks are wired, "startup" is at default (maintank) for all the power needed to crank it. Then it switches over to middletank if that is what you are using.

Found out this bit of info with my E100 300/dual tanks after replacing the manual fuel pump (van is "stock" with no computer). Had my middle tank (Full) switched to use as my rear was empty. But it would not start. Checked everything....but it still would not start. On a vanning site, another long time van owner with dual fuel tanks told me this:

So, I put four gallons of gas in my rear tank (still had my middle as "on" to use) After a few pumps with the gas pedal.... before turning the ignition on....started right up.

As my rear tank does not register on the gas gauge, I generally use my middle tank as my main (it registers) until I can get a new sensor. Generally keep some gas in it as "backup" but forgot to the last time it needed filling.

Now I make sure to that rear tank does not go below a quarter.

 

On a late model 300 EFI engine (95) there is no main selector valve as such. Each tank has a separate Fuel Delivery Module (pump) that incorporates the features of the early models. Which ever tank is selected is the one it will start with, there is no default tank. There is a Shuttle Selector Valve in each pump that prevents the return of unused fuel to that tank unless the tanks pump (FDM) is energized. There was a recall on these pumps, the pump check valve would leak and the gas from the active tank would go into the tank with the bad pump. The fix was to change the pressure regulator and pump or put check valves in the pump lines, I know I did it. The dash tank switch selects the pump you want and turns it on and switches the gas gauge to that pump.
Get a fuel line test gauge at Autozone and see what pressure you have.I have looked at the wiring diagram for a late model and it doesn't look like there is anything to stop the SELECTED (only the selected pump will run) pump from running after 30 seconds, however I didn't go into all the subsystems.

stractor