Uplift fuel pump problems / No Start Conditon

[ShawnB]

I am not getting the uplift pump to come on. I tried putting a 12 V jumper to it through the connector under the hood like the manual states with no luck. I also measured the voltage at the pump connector (by the pump) when the key is on and it is 0 V. Does it make sense to have a electrical problem to the pump and also a bad pump? Very puzzling......

[steve-r]

what year is your truck?
pre 96 - fuel relay does not power LP at key on, only during crank cycle.
96+ - fuel relay should power LP during wait-to-start.

if you are successfully getting 12v to the LP and its not running, replace it.

[ShawnB]

sorry 1992. I will check power at the LP while I crank it over...Thanks!

[ShawnB]

The LP did not come on during cranking. Replaced LP and it now comes on. But still no start. The LP also remains running after I turn the ignition off. Could that be a relay or ignition ship problem? One other thing I noticed while the engine is cranking; the GLow Plug light flickers?

[BUZZ]

Your LP runs for a few seconds do to oil pressure. The oil pressure switch controls LP operation. IF your engine will not fire are you glow plugs working? Might check the GP controller and the plugs them selves.
Buzz

[ShawnB]

I have checked the complete glow plug system. The old glow plug controller was defective and replaced it with one I new worked off another one of my trucks. I thought the LP pump was only suppose to run while in the run or start mode of the ignition switch. It seems to run while the ignition is off?

[BUZZ]

How long does it run 5 seconds or so?

[ShawnB]

continuously! you have a FFR roadster? I had one that I built in 1998 but sold due to change in jobs...

[Heilander]

I just finished repairing a dead lift pump problem this week. I made the mistake of not following through the entire troubleshooting procedure - prematurely concluded that the LP was bad & bought a new one - turns out it was the OPS. I did, however, learn a couple of things - 1. connecting an ohm-meter to the LP terminals will indicate an open circuit which could lead one to falsly conclude that the windings are burnt out.
2. If 12V is connected in reverse polarity, the pump will do nothing (unlike a simple DC motor that would run backwards),which also could lead to a false conclusion that the LP is bad.

Follow this link dedicated to common stall/no-start problems, if you haven't done so already, & go through every step.
http://www.thedieselpage.com/members/tt99-9.htm

BTW, what made you check the lift pump operation in the first place?

[ShawnB]

I will check out the link! thanks! I checked the LP after completely checking the glow plug system. Then I dtermined that I was getting 12 volts to the LP connector, but no operation if I put 12V directly to the LP. My manual told me it would then be a faulty LP. Now, you can hear the LP running after I attempt to start it, but when I turn the ignition to off, it continues to run...hence I am thinking ignition switch?

[JohnC]

The lift pump circuit is independent of the ignition switch. It is always live. The two ways the pump is energized are 1) through the oil pressure switch in the presence of pressure and 2) through the fuel pump relay when the starter is energized.

Once the oil pressure is up, the pump can run on for several seconds to as long as 30-40 seconds if the oil is cold and thick.

If the puump runs continuously then either 1) the oil pressure switch is faulty (test by unplugging sender) or 2)the relay is faulty (similar test)or the wiring is faulty (You're on your own...)

[BUZZ]

Hey Shawn,
Unplug the OPS and see if it stops, would eliminate the ops or condem it.
Yes I have a FFR car hull # 1273, sounds like you had a Vintage car as well. Love it. Giant kick in the pants to drive. Viper quality acceleration for a fraction of the cost.
Good Luck
Buzz

[ 01-07-2005, 04:19 PM: Message edited by: BUZZ ]