99 ISB, Won’t Start After Filter Change

[CVD]

I changed both fuel filters; now will not start. Priming via Cummins instructions didn’t help. I then vented the lines via the banjo bolt going into the filter canister, still cranked without starting.

Details:
After changing oil, I changed the fuel/water separator filter (Fleetguard FS1242). Did not prime it (I normally do, but was distracted). Since I'd not filled the filter, I decided to start the engine before going to the other filter. It started immediately, oil pressure came up. As I went to the back to look at the fresh filter (to confirm nothing was leaking), engine stopped.

I figured I had air in the lines, so I proceeded to change the main filter element (canister on top of engine, Fram CS8941). I did not fill the canister, as I was going to have to vent the lines anyway.

I then cycled the key on, waited 30 seconds, off, back on. Did this a couple times and tried to start it – no progress. So, I then turned on the key, ran back to the engine compartment, loosened the banjo bolt going into the canister I’d just serviced, fuel came out. This makes me think I do not have air in the lines (I immediately tightened the bolt). I was working by myself, a 2’d set of hands and eyes would have been nice.

I then went to the first filter (fuel/water spin-on), to see if perhaps it wasn’t full. As I unscrewed the filter, fuel immediately came out the top – it was full.

Suggestions?

[CVD]

Thanks to all, especially BarryG20. I loosened the #3, then #4 injector line bolts, bumped the start key to activate the pump, ran to the back, and waited for fuel to come out. #4 took a couple cycles, so it definitely had air in that line. Engine then started after cranking 6 - 8 seconds.

One last question, what torque should those injector line bolts be retightened too? Quick on-line search came up with 44lbs, which is quite a bit less than what it took me to get them off (may have been first time they’ve been loosened).

[wolfe10]

Remember, if the level of the filter head is higher than the level of fuel in the tank (so both how full the tank is and whether the front is higher or lower than the back of the coach are important) with the filter is removed, FUEL WILL FLOW BACK TO THE TANK, leaving you with 25+ feet of AIR in the fuel line.

Never understood why a diesel-compatible ball valve was not installed at the inlet to the primary fuel filter. Actually I do understand-- it would have cost a few bucks.

[lj2654]

I have never prefilled either filter and have never had an issue with starting afterwards. It has to be air somewhere. It may take quite a few cycles of turning over the engine.

[boogie_4wheel]

You will have to bleed the injector lines, just as BarryG20 said. The engine will run on the bleeding of the 3rd cylinder. The other 3 will self clear shortly after.

Just bleed the ones that are easy to get to; it's 1, 3, 4 on the trucks...

[BarryG20]

Have you bled the injection lines? If not try that. The injection pump may have fuel but if there is air in the injection lines you will have to bleed at least a couple of them. Just loosen one up at the engine, crank engine until you see fuel coming out . Tighten move to the next one and repeat. I never had to do more than three and usually two did it.

[Passin_Thru]

I always fill my filters 1st, put them on and then pump them til fuel comes out the bleed valve. May run rough but keep your foot in it til it picks it up and runs smooth. Doesn't hurt to use a injector cleaner to fill primary.

[path1]

And no gas soaked rag over intake.

After redoing my fuel system with 1/2 line and dry filters...took 5 times...turning over starter for 25 seconds...rest starter 40 sec then repeat.

I usually just loosen couple injectors but wanted to see how long priming the hard way.

[NEHOG]

SidecarFlip wrote:
There is always starting fluid...

I'd recommend NOT trying that.

[wolfe10]

SidecarFlip wrote:
There is always starting fluid...

Not if the engine has an intake manifold HEATER.

Ether and red hot wires do not play nice together!

[SidecarFlip]

There is always starting fluid...

[sch911]

I fill the filters before installing. Thought that was SOP.

[wildmanbaker]

Cliff, there should be a plug on the side that goes to the injection pump. Try loosing it about 2 turns, until there is some shake to it, and perform the same actions you did before. I believe the main filter is air-locked, and this will bleed it out. Be very carful when loosing and tightening Banjo fittings, as the will tend to leak with this newer diesel fuel.