Died like it was turned off

[ccc]

Went out today and I visually inspected three harness fittings. I took hold of them and turned them over, looking for corrosion. I then tugged on the grounds to see if any were loose from the anchor bolt. I pushed on the plug that goes into the FSD. I connected the hot wire I use to manually start the fuel pump, I lit up the glow plugs for 8 seconds and hit the key. The truck started up on the first turn. It sat and idled for about 5 minutes. It missed a few times during that time. When it did, it was a single miss and a small puff of smoke. Then, the truck died abruptly and wouldn't start again. I put the remote harness back on and an external FSD (that I THINK is good) but it isn't starting. ECM?

[DmaxMaverick]

How's the fuel condition? Got a full filter?

[ccc]

I think it's okay but since I don't know, I will change it....Thanks Dmax.

[DmaxMaverick]

The fuel filter is ALWAYS the first suspect. However, I meant, is the filter bowl full? If it isn't, something is preventing fuel flow at some point. IIRC, you did have some (better) success running with an external supply and gravity flow???

[ccc]

Yep, fuel bowl is full, and I changed the fuel filter. It started on an external "thickend" fuel but it also ran on the regular line. I have purchased another truck so the pressure is off to fix this but now I really want to figure out what is wrong. I have a bone yard pump that I use to see where things attach and how it should look. Attached is a picture of the front of the pump with the red and black wire attached. My question is this. If I take this harness off and place it on the truck in place of the one going to the pump, all the circuits will be complete with the exception of the red wire that goes to the front of the injector pump. Should I be able to detect any kind of amperage or voltage when I crank the motor?

[ccc]

Okay, get this. I went out today and the truck started on the first crank. It ran for three minutes and then "died like it was turned off!" So, I pulled the inlet line to make sure it was pumping fuel, it is. There isn't a fuel shut off solenoid on it at this point, I have a dummy one on. I even changed the pmd to a spare, via remote harness. I did notice that the glow plug light just flashes on and right back off with the spare pmd (and I don't know for sure it is good.) So, I took a harness off the spare pump I have and put it in but did not hook up the red and black lead the normally would go to the front of the pump. I then took the red and black leads and connected them to the corresponding leads on a meter. When the switch is turned on the meter twitches on DC current or Ohms, but I don't get any signal movment on the meter as it is cranking. Don't know if that means anything. SO, at this point, I know it is getting fuel, I have a new fuel filter in, I put two new batteries in, I have a dummy fuel shut off solenoid in and the truck occasionally starts! Oh one last thing, there is a solenoid, I think it is the oil pressure soleniod below the fuel filter in the valley and there are three wires coming out of it but it looks like there should be four.

[phantom309]

I did notice that the glow plug light just flashes on and right back off with the spare pmd (and I don't know for sure it is good.) So, I took a harness off the spare pump I have and put it in but did not hook .

There is a problem with the power feed to the ecm,.if you disconnect the batteries, the glow plugs cycle on and off really quickly 1st time after the batteries are reconnected,.,. The 2nd time you get a normal glow cycle,.
I can change pmd's and harness and it doesn't interrupt the power to the ecm,.
I,m wondering if you have an ignition key switch problem,.? your description of how it simply shuts off is another indication ,..when these 6.5's run out of fuel,. they stumble and miss before they quit,. just like most diesels do with fuel issues,.
Yours is a power feed problem INMHO.

Nick

[ccc]

Thanks Nick, it sure does seem to be electrical. It's like a connection that I need is connecting sometimes and other times not. I can see where the switch could do that. I was sitting in the truck and I may have moved the wheel as I timed how long the truck ran - that could account for the stopping I guess. Other than that, I need to find someplace that has a connection that is barely making contact and I have checked all the electrical fittings I can find.

[ccc]

Just wanted to thank everyone that has helped in this marathon. I haven't given up, but since the truck sits outside I am weather dependent and it has been cold! I haven't done anything on the truck except for one thing. I did send my two spare FSD's to a fellow member in Fla that put them on his remote harness to test for me. He has the exact same year and model truck. We found out that one was good and one was bad so he sent the good one back to me. At least when the weather breaks I will be able to hook up a FSD that I know is good! It feels good to know that ONE thing works anyway. I am pretty sure I have tried that already but I will do it again and if that doesn't start the truck, I am going to have to figure out how to trouible shoot the electrical signals as phantom309 suggests. My gut tells me he is right on the money. Again, I appreciate everyone's help and patience, what a journey!

[ccc]

Got a break in the weather, at least enough to work on it for a couple of hours. Here is the recap. I have a dummy shut off solenoid in (one that I have taken the guts out of) gone back to a tank on the top of the cab with a gravity fed line to the IP inlet. Charged up the batteries and hooked up the proven FSD on a remote harness (that I did a continuity check on) but no start. The weather is iffy for a while now so when it warms up a bit I will try again just to make sure it has cranked enough to clear any air I let in changing the lines. BUT, I am about done. I don't know what a harness for this engine would cost but that and the IP are about all I haven't changed and I am not changing the IP (just not good enough to do it.) So we are coming to an end to this saga one way or another. The next question is, what (besides what someone will pay you for it) should I expect to sell this for as a parts truck if I can't get this fixed soon? Thanks all for your patience and help.

[racer55]

Since you are not currently using the FSO,connect a volt meter to the leads for the FSO and watch the readings-it shares power with the PMD.

If you see 0 volts when it stalls I would concentrate on the connections of the fuel sol fuse and the ignition switch.

[brumpomatic2020]

Hello, I know this thread is old, what was the final solution to your problem OP?


I'm having the same or similar problem with my 99 6.5 ~214k miles, starts fine and runs fine...until sometimes, won't start or dies, then won't start. We have had this truck since 2010 but this year (2020) left me stranded a few times, had it towed to a few diesel experts, they cost a lot to diagnose, none could say for sure what the problem is.


When it won't start I notice the WTS light flashes for a second and the lift pump also runs for a second but truck will not start. If I disconnect one of the fuel lines from the injector there is no fuel coming out when spinning the starter.(when it does start WTS stays on for 5-10 seconds, I can hear the lift running and then it starts right up, runs great! fuel flows out of the T at 5-6psi)

So, this year I put in new batteries, changed the PMD (moved it to the bumper with an extension cable), tried another pmd in the bumper, (even removed the PMD extension and put a new PMD in original location next to injection pump), checked grounds in engine compartment, new fuel filter, new fuel sock, new air filter, cleaned the strainers in both fuel filter housing and injector pump, replaced the starter, replaced the OPS, fuel cutoff switch, ECT sensor, changed the fuses (ecm-I, ecm-B, etc), changed fuel pump relay, changed ignition switch, new glow plugs. No OBD-II codes.

Several times when it wouldn't start I tried disconnecting the optical fuel sensor in the injection pump, occasionally it would start in 'limp mode' (long time cranking to start, then barely runs), turn it off, plug optical sensor back in, starts like normal. Btw, with the optical fuel sensor disconnected there were 2-3 optical sensor or fuel injection timing related codes, those codes went away with the sensor connected.

People say must be the injection pump is worn out! Could be, but why does it sometimes start right up and run great... Not excited about spending any more $ on this truck to experiment, especially don't want to spend the time/$$$ on a new injection pump on a hunch.

...I read there's a piece of rubber hose behind the the fuel filter that connects the fuel filter to the steel line from the lift pump, it gets kinked then no fuel to the injection pump...I'll check that rubber fuel line. Thinking now maybe glow plug control module is bad, somehow signaling the computer to turn off the lift pump, never changed it, that would be an easy fix, perhaps that's a safety feature...also, I haven't replaced the glow plug wires, ever (just noticed the connectors are loose where they attach to the glow plugs)...I wonder if the ECM/computer is going bad or a connection to it or a bad ground someplace...Or the main fuel relay on the back of the injection pump is worn out or some part of the harness is bad/corroded?...


Want to be able to use this truck and rely on it again, it has been very good, any help would be appreciated!! OP...? Anyone...?

[brumpomatic2020]

I wonder if there's an air leak in the fuel supply...?

[a5150nut]

I wonder if there's an air leak in the fuel supply...?

put some clear line on the fuel return line to see if there are bubbles

[Yukon6.2]

Hi
I had a 98 that was giving me all kinds of electrical issues.
After i changed the ignition switch they went away.
From the time i got it,electrical gremlins haunted it.Went through 3 PMD's 2 were remote mounted.
This was a truck that didn't get daily use.