It watches the voltage drop.

 

Thanks
would you have an idea what this drop might be?
so I can check if this happening

regards
phil

 

You are getting into a rather long testing procedure and you might be ahead of the game if you rented a fuel pressure gauge, hooked it up so you could see the fuel pressure reading while driving and that would tell you just as much and more as to whether the pump is the problem. What ever the pressure is when you start and everything is fine, should not change much unless there is an electrical or pump problem. Even if the engine quits, the fuel pressure should stay the same if the pump is working properly..

 

Hi, when should their be power at the " inertia" switch as I have none when I try to start?

thanks
phil

 

There should be power to the inertia sw when the key is first turned on. It is for approx 2 seconds provided by the ECM.
After that it requires an RPM signal provided to the system by a pick up coil in the dist. which provides an RPM signal to the ign module and the ECM.which energizes the fuel pump relay.
If for any reason the RPM signal is missing the fuel pump relay drops out and power is cut from the inertia sw by the fuel pump relay

A fault anywhere in the circuit , relay, pick up coil in dist, possibly affected by temp can result in loss of power to inertia sw.and pump, Don't forget to confirm the pump ground connection.

 

hi,
Still testing have good earth for pumps
connection between pump and inertia (pink/blk) then to relay (org/lt blu). has power and clicks when ignition tried
how to identify (tan/grn) to no 22 on ecm connection tested for continuity?

pumps are working but not via ecm
would the purge canister have any influence?
looked inside ecm and no visable damage or on connector

thanks
phil









0

 

Canister has no influence on fuel pumps.
Do the pumps run when the key is on and that terminal of the diagnostic plug is connected to earth?
If so , relay is working.
Do you have power to the inertia sw when cranking the engine?
If not, pick up coil in dist may not be working and sending the RPM signal.

 

Hi,
I have looked at the pump relay and it seems not to be working ( blue and black) 4 poles two large and 2 small
Has no part numbers on it .
Would happen to know the number so I can get one ?
thanks

 

I don't remember there being 6 terminals for a fuel pump relay, are you sure you have the correct relay ?

Does your truck have i or 2 fuel tanks?

 

sorry I meant 4 pole but 2 were large and 2 were small in width with the connection blue and the other half black .
searched on net and could find a part number
so I can replace

phil