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Hard start, Losing prime

15K views 13 replies 6 participants last post by  yinzer5.9 
#1 ·
It has done it to me three times over the course of two years...hard to track down.

So 99.9% of the time It starts on the first rotation of the motor, but as stated, three times it's taken some cranking to get going. The first time was shortly after I put in a new set of rebuilt injectors. Started and ran fine (run it pretty much daily) for about three days then one day, i drove it to work and after work it didnt want to start. Cranked for 20 seconds or so and pumped the throttle and it popped off and didn't do it since. Then about three weeks ago, same thing, drove to work and everything was good. Went out at lunch and cranked for 20 seconds or so pumping the throttle and it popped off and never missed a beat.

Yesterday I was cutting firewood and starting and moving a few feet and shutting it off quite a bit. Went to start it one time and it took about 20 seconds of cranking and it popped off and never missed a beat :confused013:

The only thing I can think of is maybe the copper sealing washers on the return line for the injectors? Might just pick up some new ones and put on to eliminate that, but where it is so random I don't know what the issue could be unless the FSS has a problem that could be that intermittent.

When it does it and finally starts there is no miss or anything like that that would indicate an air bubble in the system. When it pops off and goes, it just goes
 
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#2 ·
Any visable leaks? Look for dampness. Also check all the rubber lines between the tank and the lift pump. They can be cracked, but show no signs of a leak.
 
#4 ·
start by replacing your fuel line and maybe lift pump. I doubt it would be the return line washers, if they leaked, the only thing that would happen is that you'd get fuel leaks on your engine.

FSS might also be a possiblity...

conrad
 
#6 ·
My 92 just had this problem. A loose fitting at the lift pump was causing the hard start. There was no fuel leak but apparently air was getting in and letting the fuel drain back.
 
#8 ·
I'd start with checking the wire on the FSS to be sure it's clean and tight. You could always gut the FSS and try that for a while to see if it changes anything.

After the truck has sat for a few hours open the bleeder for the filter and manually pump the LP to see if any air bubbles come out.
 
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#9 ·
Well mine recently started to idle real low for a few seconds after I'd start it sometimes and recently it got to where it didn't want to start without giving it throttle and it got to where it'd do it every time the last few days. So I guess a lot more frequent than yours.

It could be getting small amounts of air built up in the fuel system once in a while.
If it does it again, without the engine running crack the bleeder above the filter and prime the LP and look for bubbles. You could barely loosen the injector lines at the injectors too and see if any foam comes out if them. Remember, be careful.
I would look at the FSS too though :thumbsup:
 
#10 ·
I'm honestly leaning toward the FSS. When it does it it cranks and cranks and doesn't even try to start. 0 fuel. Then all the sudden it fires and runs smooth as a kitten.

Maybe I'll look into bypassing the FSS and do a manual fuel shutoff. Any opinions on that. What are some negative issues of it?
 
#13 ·
Just remove the FSS, take the spring and plunger out and re-install the "gutted" FSS. People use a choke cable ect and hook it up to the manual kill lever.
 
#11 ·
had one do this, took the lift pump off and just by pumping it by hand it didnt feel right, replaced it for $45 and never had another lick of trouble
 
#14 ·
well thats hard to answer mine acted up 3 or 4 times before i changed the lift pump because i was worried about it taking out the injection pump, but yes it would start fine every day then one day i would have to crank it for 10 seconds three or four times for it to fire but then run fine, the trouble with injection pumps is they will supply themselves with fuel and eventually burn up without ever knowing the lift pump is bad, the first gen rotary pumps were way more forgiving then the second gen vp44 pumps though, but i would start there, run the primer arm a few times with your hand, it should be firm and have a lot of spring to it (like a primer bulb on a weedeater or pushmower) if the lever moves up and down freely with no return it is worn out and could be losing ur prime randomly
 
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