79jasper
Chickenhawk
Well it just depends how bad the clog is.
That's why I suggested trying air first. You could knock whatever it is out.
That's why I suggested trying air first. You could knock whatever it is out.
TRUCK STALLED A FEW TIMES THIS MORNING
- Thread starter bagpiperjosh
- Start date
bagpiperjosh
Full Access Member
yes usually, but today was above freezing and it was still doing it
SyicoIDI
Full Access Member
How long have you been running wmo? Wmo is acidic and wears on Ip and injectors. Try cutting your mwo to 50/50 and throwing some diesel treat in there for lube.
bagpiperjosh
Full Access Member
Ok, today i blew some air in the two lines on the fsv that were pointing towards the truck. I heard it bubble inthe fuel tanks. I test drove it again and it still stalls on heavy accel on hills. Around town seems to not give me any trouble. And it usually takes a few tries to get it running again. Once it does start, around town it seems to run fine again.. I am still stumped, and frustrated
79jasper
Chickenhawk
I would check what goose suggested.
bagpiperjosh
Full Access Member
Where is the metering valve? And how do i fix it sticking? Its a reman from conestoga with about 1000 miles on it
bagpiperjosh
Full Access Member
to me it seems like a sticky metering valve is unlikely. why would it run fine on full throttle then die out? it doesnt sound like it sticking, sounds like fuel is not getting to where it needs to under a heavy load. but does, under a light load.. and driving fast on a flat road it seems to be fine too
bagpiperjosh
Full Access Member
I'm wondering if its air intrusion. i pushed the schrader valve in on the fuel filter housing while the truck was at idle and no fuel came out of it, i also gave it throttle while pushing the valve down and still no fuel coming out. the first few times did seem to hiss though (but it was hard to hear)
Edit: my thought is, under normal driving conditions the air is settling somewhere where it doesnt get sucked into the engine. but when i get on it, all that fuel pressure sucks the air pocket into the engine thus causing it to stall under heavy acceleration. and why after a few restarts and giving it alot of pedal, it might get the fuel back in there and operate normally again
Edit: my thought is, under normal driving conditions the air is settling somewhere where it doesnt get sucked into the engine. but when i get on it, all that fuel pressure sucks the air pocket into the engine thus causing it to stall under heavy acceleration. and why after a few restarts and giving it alot of pedal, it might get the fuel back in there and operate normally again
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Sounds like no fuel pressure. Clogged line, bad lift pump, FSV clogged/not working. I would start at the filter and work back to see where the clog is or at the tank and work forward. But not pressure at the schrader valve means none to the IP!!
GOOSE
Happy IDI'er
I am sorry to have mentioned the metering valve. I did not know at the time that the ip was relatively new. This situation would apply more to a pump with tens of thousands of miles of WMO ran through it than a new pump. The metering valve is within the IP.
I still say you have a delivery issue. Does the fuel filter light come on when this situation arises? If you take a pair of vise grips and clamp the line between the steel fuel line on the frame and the lift pump, you should be able to start the truck and create this situation. The fuel filter light should come on as this blockage mimics a blocked fuel filter. If your truck stalls out and dies and the light does not come on, the warning light or sensor is not working properly. I would spend the $10 and get a new section of 3/8 fuel line and two new clamps and replace this section of hose to eliminate the possibility of a problem in this area. Next I would plumb in a low pressure gauge after the fuel filter and before the IP You should have 6-8psi here, at least 1 or 2 psi under heavy acceleration. Chances are, you do not as you said little fuel comes out when you depress the schrader valve on the filter head. Also, are you depressing the schrader valve when the truck is running or cranking over? When the truck is not running, you will simply relieve the system of any pressure that its under, nothing more will really happen. Ok, I re read and you did say that the truck was running.
You are describing the very EXACT symptoms my truck had on my trip from South Jersey to Jared's house in Central PA. There was a kink in the hose that connects to the lift pump. It was fine on the highway and around town. Bridges, hills or heavy acceleration would light up the fuel filter indicator on my dash and the truck would stumble and choke. The kink was under a vacuum and it would fully collapse under a heavy draw from the lift pump. When the pressure was relieved, it would partially open allowing enough fuel to pass for 1/4-1/2 throttle operation. The truck started hot or cold without issue, drove fine except under a heavy load. The only thing different is that my truck had no issue restarting.
I still say you have a delivery issue. Does the fuel filter light come on when this situation arises? If you take a pair of vise grips and clamp the line between the steel fuel line on the frame and the lift pump, you should be able to start the truck and create this situation. The fuel filter light should come on as this blockage mimics a blocked fuel filter. If your truck stalls out and dies and the light does not come on, the warning light or sensor is not working properly. I would spend the $10 and get a new section of 3/8 fuel line and two new clamps and replace this section of hose to eliminate the possibility of a problem in this area. Next I would plumb in a low pressure gauge after the fuel filter and before the IP You should have 6-8psi here, at least 1 or 2 psi under heavy acceleration. Chances are, you do not as you said little fuel comes out when you depress the schrader valve on the filter head. Also, are you depressing the schrader valve when the truck is running or cranking over? When the truck is not running, you will simply relieve the system of any pressure that its under, nothing more will really happen. Ok, I re read and you did say that the truck was running.
You are describing the very EXACT symptoms my truck had on my trip from South Jersey to Jared's house in Central PA. There was a kink in the hose that connects to the lift pump. It was fine on the highway and around town. Bridges, hills or heavy acceleration would light up the fuel filter indicator on my dash and the truck would stumble and choke. The kink was under a vacuum and it would fully collapse under a heavy draw from the lift pump. When the pressure was relieved, it would partially open allowing enough fuel to pass for 1/4-1/2 throttle operation. The truck started hot or cold without issue, drove fine except under a heavy load. The only thing different is that my truck had no issue restarting.
bagpiperjosh
Full Access Member
ok, im going to replace that foot or so of hose under there, it felt soft to me, so maybe that is the culprit, i sure hope so.i will let you know what happens after work.
gandalf
Senior Member
This isn't a hard thing to do, given the right filter head. I would assume that we're talking the '83 in your sig block, so the 'right filter head' is open to question. I'll paste in a picture here of how I did it on my '92. I went cheap on the gauge itself, and that needs to be replaced, as it seems to leak both externally and into the gauge face itself. Reading it under load is also a problem because of placement. I haven't yet found any volunteers.
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79jasper
Chickenhawk
Now it's sorta sounding like a lift pump. But as Mulochico and Goose said, start with the simple stuff.
Okay wait a cotton picking minute, I just read back from the beginning, have you tried changing the filter?
I know you said it has less than 1k on it, but your bad tank of fuel could've done it in.
Okay wait a cotton picking minute, I just read back from the beginning, have you tried changing the filter?
I know you said it has less than 1k on it, but your bad tank of fuel could've done it in.
bagpiperjosh
Full Access Member
ok.. SO FAR after replacing the fuel line next to the lift pump, it hasn't stalled on me again. the old like seemed to be too long, it did a loop before in went in to the lift pump. i only used about a 3" piece of fuel line to replace it. i will update again if anything changes if this fixes it, then good call goose! 
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