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New to 12V, thought I was safe from lift pump issues.....?

3K views 38 replies 12 participants last post by  P.J 
#1 ·
My son just got a 94, nice and clean, 175K miles. Non leaker, runs (...ran) like a top with plenty of power. According to previous owner it is bone stock, I'm not 100% sure though, considering the age.

Drove it up for inspection today and about 10 miles into my trip it started losing power, I let off of the pedal and it seemed to pick up fine. Seemed almost like a gasser running out of fuel, the more I pushed the go pedal, the more it died.

Anyway, made it to where I was going, even made another short jut to pick up something.

On the way home it started acting up again, this time steadily losing power and eventually dieing totally. I got it started back up and have a light haze of white smoke. Made it home, by then it was running full blast again, pushing a whole 24lbs of boost (haha).

Whats the deal? Seems fuel related, just changed the filter last week, where should I look first.

(no F/P gauge yet)

Thanks in advance!
 
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#3 ·
Fuel in tank, fuel at pump, fuel at overflow valve? Pump primer with ofv loosened. Is there fuel and zero air?
 
#4 ·
I'll check, remember, it's totally intermittent though, seems like today it would start and run perfectly fine for a few minutes, then start acting up.

Can't get the thing to warm up for schit either, gauge is pegged at cold side, new stat yesterday afternoon......
(probably totally unrelated)
 
#6 ·
Whats the chances that the pre filter screen was causing all my issues? It looked super nasty, like solid black. Chunks jammed in there from way back in the day.

Took it out for a fairly long ride, much longer than my last two (where, I almost didn't make it back home). Flogged on it pretty hard, absolutely no hesitations, no signs of any power loss........

Thoughts?
 
#7 ·
Pretty common for the prefilter to be ignored for the entire life of a truck till it plugs up and causes problems.
With the fuel I run the filter has been spotless every 100k except the very first time.
 
#26 ·
bill, what fuel is it that you run? inquiring minds need to know...

thanks,

rande
 
#8 ·
when i first got my truck the prefilter was never cleaned. full of junk. that could of been your problem since its not doing it anymore.

as for the cold problem, it should get warmer faster if you plug it in over night. i dont plug in my truck. it takes about 10 miles or so to get to reg running temp. just turning it on and idleing it at 750rpm wont get it really warm like a gasser. takes a while for these engines to warm up
 
#11 ·
yup, temp sensor

also you can throw a piece of cardboard in front of the radiator, i have my rad blocked in the centerand have a solid grille cover and i cant get my engine over 180
 
#12 ·
i would be sure its not your thermostat as well. those things are known for going out. mines on its second one in less than 30k miles.
 
#17 ·
97 withe the the same problems, I changed my fuel filter and replaced my pre-filter yet needed to clean pre filter several times times after the change to clear the fuel system cause the truck sat for a while before i purchased it
 
#23 ·
I went through fuel system issues for a while. Every now and then, if its cold enough (usually less than 30) mine will do the same thing your does. When I crack the priming screw, I get air, but it doesn't suck air unless its REALLY cold outside, and even then, its not that often. And fuel heater is deleted and a new line between the prefilter and lift pump. But it hasnt been a major problem yet so I'm not worried about it.

My donor engine had 400k on it and it had never been messed with. Exhaust was completely stock, and tamper proof screw was still in place. And still is :doh:

Oh well at least I can keep my clutch for a while this way :stirpot:
 
#27 ·
There may be two screens in the tank-one at the bottom of the pickup assembly, and a filter inside it that you have to disassemble the unit to get to. I don't know if all of them have it, but my '98 12v did. It's fun and interesting to track down a fuel starvation problem when you don't know to check for the one in the pickup. I got very good at dropping my tank with a floor jack or two by myself before I found the 4th filter.
 
#29 ·
Im baaaaaaaaaaaack........

Same thread topic, NEW fuel supply issue. After a leaking fuel filter (and/or water sensor, which was brand new along with the filter, ugghh), I am not having major fuel issues. Truck was running like a top, got a new filter today, the one without the bung for the sensor. NOW, after a half hour of priming and messing around, it just won't run. After some crazy stumbling, it started, only came up to like 10psi, ran for about a minute solid, then slowed way down, then died.

I took the pre-filter back out, it has some chunky sandy looking stuff in it, nothing major though. I am deleting the prefilter/heater this week, guessing I am ordering a lift pump too....?

Any suggestions would be appreciated. The primer button leaks badly once you push it a few times, I read where that isn't supposed to introduce air, but also isn't supposed to happen either.

Since installing the gauge we haven't seen over 22 psi or so, even when loaded and hammering it on the highway.........????
 
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