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Weird cold start issue; Truck starts fine, idles for a bit, then dies, then starts

TheDjost said:
The fuel shutoff solenoid is redundant. It mechanically closes the fuel flow to the injection pump. But since the injection pump is electronically controlled, it if perfectly capable of shutting itself off and stopping fuel from going into the cylinders. It was necessary on mechanical fuel pumps.

The solenoid is very simple. If it gets power, it lifts a rubber plunger off it's seat to permit fuel flow. If the voltage is too low, or there is some other problem, the plunger will not lift high enough to let the fuel go by... thus stalling the engine.

This is not proven, but I think that the rubber plunger sticks to the seat, and when you start the engine, the prime cycle from the lift pump gets in a little fuel throuth the space between the rubber sealing face and the plunger shaft. This allows the engine to idle for a couple seconds. When that is all used up, the engine stalls. The vibration from the running engine unsticks the plunger frome the sealing face, but the negative pressure from the fuel pump is holding the solenoid closed. When the engine stalls, thee pressure releases and the plunger is free to lift off it's seat, so it starts up fine on the second try. Like I said, this is just my hypothesis on what may be happening.

The problem can be in the solenoid or electrical, but for now it runs fine with the plunger removed.

To remove the plunger, just unplug the connector, unscrew the solenoid from the injection pump and remove the small circlip that holds the plunger in there. Reinstall the solenoid and reconnect the harness to make sure the computer doesn't throw a code. It's a 5 minute job if have snap ring pliers with small enough tips. I didn't so it took me 10 minutes since I had to wrestle the snap ring out of there with the wrong tools.
Click to expand...

You are talking about removing the plunger from the vertical steel film canister sized cylinder that is screwed into the top of the IP, yes? Looking at the AllData vehicle diagrams they refer to the vertical solenoid as the Engine Shutoff Solenoid (ESO) and the solenoid between all of the injector lines as the Fuel Solenoid.
 
Yes, it is the ESO/FSO, same thing. The cylinder on the IP functions as an engine shutoff by using a solenoid to shut off fuel input. The FSO and FS would be different items as you say.
 
I know this is old but its low coolant level. If this happens again unplug coolant sensor and start truck to see if it stays running
 
mgray said:
So this has now happened a few times(like 3), and only this winter on cold starts(around 0c/32f). So it's not even that cold.

Truck will start strong and quickly on the first try, idle fine for a few seconds, then bog down and die like it's running out of fuel. I never push on the pedal to see if that makes a difference. I just let it die, then start it back up. Sometimes it takes a few try's to start again, but it will start again relatively quickly, then continue to run normally after. Sometimes it will start right up the second time I try.

I live in Vancouver, so temps don't really get too low, -5c on cold days, -15c on really cold days, but those are rare.

This issue I think has happened at temps above 0c, like 5c or so as well.

Doesn't really sound like fuel gelling as I don't think it's that cold, and she always starts strong and quick, it's just like 10-20seconds after start, it will run rough like it's running out of fuel, then die. Again, only about 3 or so times it's done this.

PMD is Heath, and this issue is only on certain cold starts, never hot. GP's are Bosch and I think the previous owner did them 3 years ago? Anyways, I don't think it's the GP's either as she always starts strong.

It's like something is restricting fuel or something after initial start.

This is the first year I've added 2 stroke oil, and I don't add much, like 230ml(I fill up a Stanadyne performance bottle 232ml I think). I think this problem has happened since I started using it. Not sure if it's connected.

Any ideas? Thanks in advance
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Hi, l am going through with a same problem, did u find a solution for that..
 
Welcome gschd.
His was a bad lift pump. That does not mean yours is.

The first thing GM says to do it put a clear line in place of the ip (injection pump) return. That is the 1/4” diameter hose about 5” long out the front of the ip in an upside down U shape. Just get the clear line from any hardware store like Home Depot. Then have someone else start it while you watch or set up your phone to record on video while you start it. You are watching for air bubbles in it, and if there is constant flow.

What happens is there is fuel in the ip enough to start but an air pocket from lack of fuel flow so it runs out of fuel. If there is a spot that is before the LP (Lift Pump) that is open, it will suck air into the fuel line and the aerated fuel will not compress properly in the ip causing it to die.

Then if the LP is not working or is allowing fuel to gravity flow back to the tank from a bad checkvalve in the LP, you have same issue. Then also if the LP is not working, the ip primary will suck fuel from the tank but you can have same effect from lack of fuel supply.

with the engine running, open the water in fuel drain valve and the LP should push fuel out (I can’t remember rate right now), but is fairly quick to fill a quart bottle. If you open the drain valve and the engine dies- the LP is not working.

This is engine will run with a bad LP, but it ruins the expensive injection pump quickly- and brand new ones are no longer available.

Best long term solution is get a high end LP like Fass filter pump combo unit on there inplace of the garbage factory ones that never should have fed the ds4, and barely ok for db2. Then more importantly imo is get a steel “T” installed at the ip inlet for a fuel pressure sensor and mount the pressure gauge permanent on the dash so you can always see fuel pressure. Because you didn’t say what rig you have- db2 should have 2-5 psi, ds4 should have 8-14 psi.

Do those two tests first. If you can do video and post on YouTube/ bitchute and post a link here, we can tell whats going on.
 
Will L. said:
Welcome gschd.
His was a bad lift pump. That does not mean yours is.

The first thing GM says to do it put a clear line in place of the ip (injection pump) return. That is the 1/4” diameter hose about 5” long out the front of the ip in an upside down U shape. Just get the clear line from any hardware store like Home Depot. Then have someone else start it while you watch or set up your phone to record on video while you start it. You are watching for air bubbles in it, and if there is constant flow.

What happens is there is fuel in the ip enough to start but an air pocket from lack of fuel flow so it runs out of fuel. If there is a spot that is before the LP (Lift Pump) that is open, it will suck air into the fuel line and the aerated fuel will not compress properly in the ip causing it to die.

Then if the LP is not working or is allowing fuel to gravity flow back to the tank from a bad checkvalve in the LP, you have same issue. Then also if the LP is not working, the ip primary will suck fuel from the tank but you can have same effect from lack of fuel supply.

with the engine running, open the water in fuel drain valve and the LP should push fuel out (I can’t remember rate right now), but is fairly quick to fill a quart bottle. If you open the drain valve and the engine dies- the LP is not working.

This is engine will run with a bad LP, but it ruins the expensive injection pump quickly- and brand new ones are no longer available.

Best long term solution is get a high end LP like Fass filter pump combo unit on there inplace of the garbage factory ones that never should have fed the ds4, and barely ok for db2. Then more importantly imo is get a steel “T” installed at the ip inlet for a fuel pressure sensor and mount the pressure gauge permanent on the dash so you can always see fuel pressure. Because you didn’t say what rig you have- db2 should have 2-5 psi, ds4 should have 8-14 psi.

Do those two tests first. If you can do video and post on YouTube/ bitchute and post a link here, we can tell whats going on.
Click to expand...
Hi, yesterday l took the truck to the shop
They changed the fuel fittings and bypass the water fuel separator filter and asked me to drive for sometime but problem still there. Thanks for sharing the info
I will try my level best to go through your suggestions. Thx
 
gschd said:
Hi, yesterday l took the truck to the shop
They changed the fuel fittings and bypass the water fuel separator filter and asked me to drive for sometime but problem still there. Thanks for sharing the info
I will try my level best to go through your suggestions. Thx
Click to expand...
Be sure to get that water/fuel separator hooked back up again.
From reading in this forum, it does not take much water to destroy an injection pump.
 
HOLY MOLY!!! NO!!!
Stop driving and hook that back up NOW!!!

Never have that mechanic work on your 6.5 again- he/she knows NOTHING about this. That is the dumbest thing they could possibly do. Way worse than driving around without an air filter- crazy worse. So many more options they could have done than that. That person was not even smart enough to bother looking up the manual- for a diy person that is a mistake but for a professional that is inexcusable. That could be the death nail for your injection pump. You can’t buy brand new injection pumps anymore. And doing that could ruin yours to the point you don’t even get the core charge for when you buy a remanufactured one.

Like- imagine if the filter is plugged up with something: dirt, water, whatever. Now bypass the filter would let whatever nightmare junk is plugging the tank to get to the injection pump and to the injectors. The filter on this is 5 microns. That is how easily these are damaged. Compare that to the diameter of a human hair, the largest circle in this picture.
DE981221-338D-43FA-BDC8-6137C1784076.jpeg
If you have basic tools, we can guide you through this. If you can’t/don’t work on your truck, thats fine but find a different mechanic.
 
Hello Dave and welcome to the forum.
If this is a gas engine, there could be a couple things happening.
The fuel pump relay switch could be bad or possibly the oil pressure sender unit.
 
daveob said:
I have a 98-6.5 C3500 that just dies after its been driving. I have new sender in back tank, 2- new carter lift pumps.
Click to expand...
The first and biggest question is after sitting a bit can you restart it and it runs fine, or if you pour cold water on the fuel injection pump will it fire back up? Which leads to the second question, is it the original PMD (black, cigarette pack-sized box on the driver's side of the Injection Pump, sometimes called the FSD) or is there a newer one on it that's preferably remote mounted behind the front bumper on a heat sink? These usually go bad when still mounted in the factory location on the side of the the Injection Pump and the number one symptom is the engine just dying for no apparent reason while driving, then after sitting a bit or pouring cold water on the Injection Pump, the engine starts right back up like nothing's wrong and will run/drive just fine until mysteriously just dying again.
 
daveob said:
I think it is my PMD. This morning in the cold around 14 F. I plugged in my other PMD after it wouldn't start and it fired up. Thanks
Click to expand...
I have had that be a bad wire/connector. I found in one case, it wasn't the pmd, but the fact that I moved the harness enough for connection to be made until it didn't
 
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