7.3 No Start
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7.3 No Start
Im new to these forums, so please forgive me if this has been asked a million times, i have a 1990 ford truck with the 7.3, as of last week it will not run, the motor has around 100,000 KMs on it after a rebuild and has been running great, i would assume its a fuel problem but where do i start? do these trucks have two pumps on them? if so how do i know which one is bad? Thanks for any help.
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Joined: Nov 2003
Posts: 21,285
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From: Nutter Fort, WV
Hotrod, Welcome to FTE.
Yes there are two pumps, a lift pump and an injection pump.
There are many other possible causes for not starting.
Lets see what symptoms we have and what we can rule out.
I am going to assume that the engine cranks but does not start.
How long since the last fuel filter change?
How much fuel in the tank?
How long does the "Wait to Start" light stay on?
Does it smoke when trying to start?
What color is the smoke?
Lift pump test.
Remove schrader valve (looks like a tire chuck) from the fuel filter housing.
slide a pressure gauge hose over the fitting and have someone crank the engine.
You should see from 5 to 7 PSI fuel pressure.
Now remove the gauge and put the hose in a suitable container.
Crank the engine for 10 seconds and the pump should pump about 1/3 pint of fuel in the container.
Yes there are two pumps, a lift pump and an injection pump.
There are many other possible causes for not starting.
Lets see what symptoms we have and what we can rule out.
I am going to assume that the engine cranks but does not start.
How long since the last fuel filter change?
How much fuel in the tank?
How long does the "Wait to Start" light stay on?
Does it smoke when trying to start?
What color is the smoke?
Lift pump test.
Remove schrader valve (looks like a tire chuck) from the fuel filter housing.
slide a pressure gauge hose over the fitting and have someone crank the engine.
You should see from 5 to 7 PSI fuel pressure.
Now remove the gauge and put the hose in a suitable container.
Crank the engine for 10 seconds and the pump should pump about 1/3 pint of fuel in the container.
Last edited by Dave Sponaugle; Mar 1, 2006 at 07:56 PM.
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Joined: Aug 2005
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From: Katy, Texas
Check your IP, your tank, your fuel lines(leaks), your injectors, filter, anything that has to do with fuel...I suggest starting from the tank and moving forward cuz checking the injectors and all that might be a little work and then u find out it was just a leaky fuel line....so start from the back and move forward checking your injectors last. If your fuel system checks out then move to your air intake and then maybe sumthing more serious like inside the engine.
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Originally Posted by cookie88
Hello Hotrod. Welcome to Ford Truck Enthusiasts.
More information would be useful. Will it turn over? Crank and not start? Etc.
More information would be useful. Will it turn over? Crank and not start? Etc.
Thread Starter
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New User
Joined: Mar 2006
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Originally Posted by Dave Sponaugle
Hotrod, Welcome to FTE.
Yes there are two pumps, a lift pump and an injection pump.
There are many other possible causes for not starting.
Lets see what symptoms we have and what we can rule out.
I am going to assume that the engine cranks but does not start.
How long since the last fuel filter change?
How much fuel in the tank?
How long does the "Wait to Start" light stay on?
Does it smoke when trying to start?
What color is the smoke?
Lift pump test.
Remove schrader valve (looks like a tire chuck) from the fuel filter housing.
slide a pressure gauge hose over the fitting and have someone crank the engine.
You should see from 5 to 7 PSI fuel pressure.
Now remove the gauge and put the hose in a suitable container.
Crank the engine for 10 seconds and the pump should pump about 1/3 pint of fuel in the container.
Yes there are two pumps, a lift pump and an injection pump.
There are many other possible causes for not starting.
Lets see what symptoms we have and what we can rule out.
I am going to assume that the engine cranks but does not start.
How long since the last fuel filter change?
How much fuel in the tank?
How long does the "Wait to Start" light stay on?
Does it smoke when trying to start?
What color is the smoke?
Lift pump test.
Remove schrader valve (looks like a tire chuck) from the fuel filter housing.
slide a pressure gauge hose over the fitting and have someone crank the engine.
You should see from 5 to 7 PSI fuel pressure.
Now remove the gauge and put the hose in a suitable container.
Crank the engine for 10 seconds and the pump should pump about 1/3 pint of fuel in the container.
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Originally Posted by bassproguy07
Check your IP, your tank, your fuel lines(leaks), your injectors, filter, anything that has to do with fuel...I suggest starting from the tank and moving forward cuz checking the injectors and all that might be a little work and then u find out it was just a leaky fuel line....so start from the back and move forward checking your injectors last. If your fuel system checks out then move to your air intake and then maybe sumthing more serious like inside the engine.
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Originally Posted by PLC7.3
How fast is the starter turning the engine, if you can count RPMs its not fast enough. You need 2-850CCA batteries minimum and both fully charged to boot.
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Originally Posted by bassproguy07
Just throwing this out there....how sure are you that its Diesel in the tank and not gas or sumthing ealse
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Originally Posted by Dave Sponaugle
Hotrod, Welcome to FTE.
Yes there are two pumps, a lift pump and an injection pump.
There are many other possible causes for not starting.
Lets see what symptoms we have and what we can rule out.
I am going to assume that the engine cranks but does not start.
How long since the last fuel filter change?
How much fuel in the tank?
How long does the "Wait to Start" light stay on?
Does it smoke when trying to start?
What color is the smoke?
Lift pump test.
Remove schrader valve (looks like a tire chuck) from the fuel filter housing.
slide a pressure gauge hose over the fitting and have someone crank the engine.
You should see from 5 to 7 PSI fuel pressure.
Now remove the gauge and put the hose in a suitable container.
Crank the engine for 10 seconds and the pump should pump about 1/3 pint of fuel in the container.
Yes there are two pumps, a lift pump and an injection pump.
There are many other possible causes for not starting.
Lets see what symptoms we have and what we can rule out.
I am going to assume that the engine cranks but does not start.
How long since the last fuel filter change?
How much fuel in the tank?
How long does the "Wait to Start" light stay on?
Does it smoke when trying to start?
What color is the smoke?
Lift pump test.
Remove schrader valve (looks like a tire chuck) from the fuel filter housing.
slide a pressure gauge hose over the fitting and have someone crank the engine.
You should see from 5 to 7 PSI fuel pressure.
Now remove the gauge and put the hose in a suitable container.
Crank the engine for 10 seconds and the pump should pump about 1/3 pint of fuel in the container.
Ok so let me get this straight, the lift pump is in the tank and the injection pump is on the motor? can an inline pump be used on these like on the cummins in the dodges?