engine won't run well after changing oil/filter

[scuba0_1]

I like your last idea don't make it worse

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[jkishel]

You appear have a blockage or air leak between the fuel tank and the primary filter. The primary filter should not be low on fuel after bleeding, it should fill from the tank as you pump. Fuel is not getting from the tank to the primary filter. Check the fuel pickup and all fittings between the tank and the primary. The easiest things to check are the two gaskets in the primary filter housing; the ring gasket under the cover and the little o-ring around the T-bolt handle. Also check the hose clamps or fittings on the fuel line and check the fuel line itself.

[hellosailor]

"(couldn't unscrew by hand)."
A strap wrench or chain wrench is often useful, and will fit more than just one thing. A quick cheap improvise is to take a rubber glove, or a fabric work glove, and generously apply a thin layer of flexible glue to the palm and fingers. Then sprinkle with abrasive or sand (or even salt) and let dry. You'll get so much more grip you can often spin out things you "can't" get a grip on.

[fryewe]

Do you have an engine driven (non-electric) fuel lift pump? if so you may have a broken diaphragm in the fuel lift pump. Check your oil level and smell the dipstick for diesel smell. If its higher than it was at the completion of your oil change, you have found your problem. No way that fuel filter should be empty after 45sec of engine ops. It's draining out to somewhere...either to the bilge, the oil sump, or back to the fuel tank.

[rwidman]

There are plenty of things that would keep a diesel engine from starting but changing the oil and filter is not one of them. It would be very coincidental and unlikely that some other part would happen to fail at the very same time that you did what you did.

I'm thinking you accidentally knocked or kicked something loose and didn't notice it.

I suggest hiring a mechanic and telling him exactly what you told us here. Don't make things worse than they are.

[dlymn]

After priming, there should be no air at all in any part of the fuel system. This suggests an air leak or a blockage which induces an air leak under vacuum forces. Check the fuel tank tap is on then open each junction from the tank looking for flow. restore each join perfectly.

Did you go around tightening joints? You might have cracked a barrel nut.

[Mycroft]

I'm with fryewe, the fuel in the primary filter has to be going somewhere and the most likely candidate is back to the fuel tank. This means there's an air leak after the primary.

Engine running out of fuel after 45 secs seems to me that it's not even getting much fuel out of the secondary filter before it hits air. So the prime suspect IMO is the lift pump.

[Uncle Bob]

Originally Posted by Mycroft

I'm with fryewe, the fuel in the primary filter has to be going somewhere and the most likely candidate is back to the fuel tank. This means there's an air leak after the primary.

Engine running out of fuel after 45 secs seems to me that it's not even getting much fuel out of the secondary filter before it hits air. So the prime suspect IMO is the lift pump.

I would humbly disagree with this view.
If the primary filter is empty it is drawing air into the system before the filter, not after it. If the engine was returning fuel to the tank, or the leak was in the lift pump the primary would remain full.

[rwidman]

Originally Posted by Mycroft

I'm with fryewe, the fuel in the primary filter has to be going somewhere and the most likely candidate is back to the fuel tank. This means there's an air leak after the primary.

Engine running out of fuel after 45 secs seems to me that it's not even getting much fuel out of the secondary filter before it hits air. So the prime suspect IMO is the lift pump.

But what are the odds of the pump failing at the same time as an oil change?

[Mycroft]

Originally Posted by Uncle Bob

I would humbly disagree with this view.
If the primary filter is empty it is drawing air into the system before the filter, not after it. If the engine was returning fuel to the tank, or the leak was in the lift pump the primary would remain full.

Yeah? So where's the fuel going? That much fuel departing between the filter and the engine would usually be noticeable.

Originally Posted by rwidman

But what are the odds of the pump failing at the same time as an oil change?

It has to go sometime. Isn't it actually more likely since he pulled on the lever when there was nowhere for the fuel to go? Much more likely for the diaphragm or something else to give - opening up the air leak.

[Uncle Bob]

[QUOTE=Mycroft;1781351]Yeah? So where's the fuel going? That much fuel departing between the filter and the engine would usually be noticeable.




My guess is the fuel in the primary is bieng relpaced with air because of a leak at or close to the primary, the engine runs for a short time until air gets to the injection pump and shuts down.
It could even be the gasket on the primary filter.

[Mycroft]

I agree that it's being replaced by air. However, the fuel being replaced by air has to go somewhere.

[Stu Jackson]

Originally Posted by Mycroft

Something's def wonky. How would changing the oil filters cause the primary fuel filter to empty?

Because he said he messed with the fuel filter pump, that's why.

[twinboat]

The fuel he is pouring in, is returning to the tank, thru the return line.

The first time you moved the primer lever, on the pump, did it stick down? If so, it won't pump.

Now it sounds like the gasket on the fuel filter top may be twisted or cracked. There is a O ring too.

If the primer lever feels like it's not doing anything, give the engine a half turn to get the cam lobe down.

You should be able to pump the empty filters full, with the primer. I never fill my filters on my Volvo TAMD 40B.
I pump until the primer stops working ( 30 or 40 times ), wait a few seconds and start pumping , again, slowly for 10 or so strokes.

Good luck

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[Uncle Bob]

Originally Posted by Mycroft

I agree that it's being replaced by air. However, the fuel being replaced by air has to go somewhere.

I believe the fuel in question is bieng burned in the short runtime the OP is experiencing.

Originally Posted by twinboat

The fuel he is pouring in, is returning to the tank, thru the return line.

The first time you moved the primer lever, on the pump, did it stick down? If so, it won't pump.

Now it sounds like the gasket on the fuel filter top may be twisted or cracked. There is a O ring too.

If the primer lever feels like it's not doing anything, give the engine a half turn to get the cam lobe down.

You should be able to pump the empty filters full, with the primer. I never fill my filters on my Volvo TAMD 40B.
I pump until the primer stops working ( 30 or 40 times ), wait a few seconds and start pumping , again, slowly for 10 or so strokes.

Good luck

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Surely if the fuel was bieng returned to the tank the primary filter would not be empty.
My understanding is that the return line is to return the very small quantity of fuel not injected into the cylinders.

One thing that I would ask is which filter is the OP refering to as the primary. I have met someone that is adament that the primary is the filter fitted to the engine by the manufacturer and any filter fitted elsewhere is the secondary, I believe this was discussed on this forum as well.