Won't start...

[First]

This morning my '02 Duramax stopped running 30 seconds after starting it. Now it turns over fine, but will not fire. The check engine nor any other light is on. I did run it very low on fuel yesterday, but ran it for approximately an hour after filling up with no problems. Any suggestions? This is my first Diesel and have had great luck until now.

Thanks for the responses,

First

[DmaxMaverick]

Welcome aboard!

Sounds like the pump lost prime. When you ran it low, it may have got a gulp of air. Not a big deal when the engine is warm and running, but that air bubble could have migrated to the pump as it cooled off, and caused the loss of prime.

If so, you should be able to cure it by priming. Pump the filter primer until it is very hard to push. That should force out the air and prime the pump. Any time it runs for a bit then dies, try this. If it runs after that, air was the likely suspect. This is very common after a filter change. A plugged filter will exaggerate a problem with any air that gets into the system.

[First]

Welcome aboard!

Sounds like the pump lost prime. When you ran it low, it may have got a gulp of air. Not a big deal when the engine is warm and running, but that air bubble could have migrated to the pump as it cooled off, and caused the loss of prime.

If so, you should be able to cure it by priming. Pump the filter primer until it is very hard to push. That should force out the air and prime the pump. Any time it runs for a bit then dies, try this. If it runs after that, air was the likely suspect. This is very common after a filter change. A plugged filter will exaggerate a problem with any air that gets into the system.




Thank you very much! I'm very new to a diesel, so I'm unsure of how to pump the filter primer. Can you give details?

Again, Thanks.

[DmaxMaverick]

There's a plunger on top of the filter assy (filter assembly is just outboard of the passenger side valve cover, to the rear). It's a cylindrical thing sticking up on the outboard side. It's spring loaded, so push it down, and let it up. It should start out easy to push, then get harder as you go. Don't get discouraged if it takes a lot of pumping. Most take about 20-30 strokes, but if it takes 100+, it wouldn't be abnormal. Next to the plunger (inboard) is a plastic screw. Be very careful with this. It is the bleed port. If you pump it up to hard, you can open this to let out the air (this way, you aren't pushing the air out through the HP pump). Open it 2 turns, then pump until you see fuel escaping. Close it (just a little more than hand tight), then pump the primer until hard. It is not required to open the bleeder, but it will speed the process. Use a nut driver or socket on the plastic screw, not a screwdriver (crack the slot, and you're stuck). It is O-ring sealed, so it doesn't have to be very tight, and NO sealer/tape is required.

[First]

There's a plunger on top of the filter assy (filter assembly is just outboard of the passenger side valve cover, to the rear). It's a cylindrical thing sticking up on the outboard side. It's spring loaded, so push it down, and let it up. It should start out easy to push, then get harder as you go. Don't get discouraged if it takes a lot of pumping. Most take about 20-30 strokes, but if it takes 100+, it wouldn't be abnormal. Next to the plunger (inboard) is a plastic screw. Be very careful with this. It is the bleed port. If you pump it up to hard, you can open this to let out the air (this way, you aren't pushing the air out through the HP pump). Open it 2 turns, then pump until you see fuel escaping. Close it (just a little more than hand tight), then pump the primer until hard. It is not required to open the bleeder, but it will speed the process. Use a nut driver or socket on the plastic screw, not a screwdriver (crack the slot, and you're stuck). It is O-ring sealed, so it doesn't have to be very tight, and NO sealer/tape is required.


Thank you. I plan on working on it Saturday morning. I'll let you know how it goes.

[First]

Well I tried. It started three different times, but it only ran a minute or two. I loosened the screw until nothing came out but fuel while pumping (three seperate times). However I noticed there was a steady stream coming out of the bottom of the filter every time I pumped the prime. In fact it was a fairly large amount. Could the o-ring at the bottom of the filter be bad? I'm just guessing. Any way I never could get the prime to build a lot of pressure, even after 250+ pumps. Should I change the filter? If so how is the best way to accomplish this? Sorry to sound like a beginner, but tis is my first diesel and I'm officially stranded. Thank you so much for the help!

First

[DmaxMaverick]

That would certainly explain why you have starting/running problems. You can stop looking for a cause.

If it's coming out the bottom, it could be the WIF sensor O-ring, but I doubt it. Could be the upper O-ring, and fuel is running down the filter to the bottom. When they cut, they leak right away. It could be the water drain valve, or a cracked WIF sensor. Try tightening the drain valve (plastic tab sticking down with a hose nipple on it, finger tight only--no pliers). Under the circumstances, I suggest you remove the wheel and fender liner so you can get your eyeballs on it. Have someone pump it while you watch for the leak source. Hose down everything real well with water afterward. Fuel will dissolve the coating on the frame if you don't get it off quickly.

If it ran fine for a long time, then it just began not starting, the WIF sensor is probably cracked, or debris (or something) impacted the drain valve. If everything is tight and you still have this issue, you'll have to pull the filter and get a closer look.

If you have a lot/unknown miles on the filter, now is a good time to change it anyway. Might as well, you're in there.

[First]

With the stream I'm seeing it definitely looks like a crack. I'll buy a WIF sensor and replace the filter. No secrets to changing the filter is there? I'm sure I should fill it with fuel and prime it, right?

[DmaxMaverick]

No secrets. If you don't have a strap wrench, get one (cheap item at Autozone, etc). It makes the job much easier. Be sure to unplug the WIF sensor before starting the change. It'll be the pair of wires attached to the bottom of the filter/WIF sensor. Just follow the wires to the connector. Careful to not get it fouled in the wrench, or it will break the wires at the sensor. Do not fill the new filter. Use the primer pump to do that, just like we discussed above. Otherwise, you may be pouring unfiltered fuel into the clean side, and it makes a mess trying to get it installed. It helps to use some gear oil or dielectric grease in the top O-ring groove to keep it in place during the install. Don't overtighten the WIF sensor. It only needs to be snug enough to seat the O-ring, and maybe a little more. Same with the filter. There are some options for a special wrench that fits the sensor, www.kennedydiesel.com is one. I give the filter a little bump with a strap wrench after it's hand tight, but some folks do well with just hand tight. Mine leaks if I don't.

[First]

I changed the filter and WIF sensor. I then primed the pump to get all the air out and it cranked fine. It did run rough for about ten minutes, but ran smooth shortly after this. I drive this truck a lot. Is there anything else I should do as routine maintenance? I of course change the oil every 3,000 miles and have changed the transmission fluid and filter when I bought the truck. Again, when something goes wrong with a diesel I'm unsure of where to start. I'm also thinking of upgrading the air filter and intake system just to help the motor breathe better. Again thank you very much for your help. You were a blessing.

First