bglz42

Strange! Ran 500 miles this weekend, unhooked the boat trailer and went to fuel up. Parked it Sunday night. Went out to start it this morning, cranked fine but no start. Checked the fuel solenoid and it's firing fine. (The truck's NEVER failed to start in 175k miles of driving...) I'm guessing I lost prime somehow...?<br><br>Thanks in advance!!<br><br>1996 Reg Cab, auto, 3.55

JFellman

Sounds like loss of prime...the Water in Fuel sensors on the filter housing have been known to let air in and also the infamous rubber fuel lines at the back of the engine can be the culprits.

Smokee

Yep, I would bet on the rubber lines. Run your hand along the lines between the starter and the fuel solenoid to check for dampness. A small liquid leak can be a large vaccuum (intake) leak.<br><br>You have a hot engine and fuel, shut the truck off, the fuel cools and contracts in a closed system, and voila, air is sucked in.<br>george

bglz42

Thanks guys!! I had replaced the rubber return line 3 years ago when I first bought the truck (100k miles). Maybe it's gone bad again... definitely sounds like an air leak.

kd460

Regarding the water in fuel sensor, short of replacing, what is the fix? A little sealant? Does it leak from where the sensor threads in or is it the guts of the sensor (where the wires go into the plastic nut) where the wires thread through and is surrounded by plastic filler? Thanks, Kevin D.

JFellman

The WIF sensor from what I understand can leak where the wires penetrate...one guy used some stiff grease to seal it temporarily until it could be removed and sealed with epoxy or sealer of some sort...probably be better off getting a new one unless you trust your repair job and verify with a pressure test.

bglz42

Thanks for all the input! I went home, pumped the plunger a million times and it fired up! Suspected the fuel filter, so I installed a new one. Fired it up, no problem. Then ten minutes later, no start condition again. <br><br>I noticed some fuel on the plunger. I pulled it off, cleaned it and greased it and re-installed it. (Looks a little scored and worn.) Immediate start. <br><br>This morning, it has leaked down again and would not start. So, I'm still suspecting the plastic plunger assembly. I'll also recheck my return hose. From what I could see, it still looks good. No visible cracks, like on the original.<br><br>Can the plastic plunger assy be purchased separately, or do you have to buy a whole lift pump? Any other ideas? <br><br>Thanks SO much for all your help!<br><br>Jim

kd460

I just went to the cummins dealer to locate the rubber plunger cover and according to cummins NO DICE! &quot;Need to buy a new lift pump&quot; just for a rotten rubber cover! Anybody got one from a dead lift pump?<br><br>Anyways, if they don't sel the rubber button, then I would guess they don't sell the plunger mechanism. Looking at the cummins parts book, I do not see it listed or exploded in the diagram. If it looks like it can be removed, I wonder if it is just an O ring or a sealing washer? <br><br>Chances are you will probably be buying a lift pump though.<br><br>Good Luck, Kevin D.

bglz42

???

What a drag! This is a wear item, and should be replaced!

The plastic plunger just screws out, there is a spring behind it so watch out...

It's sealed by o rings and a &quot;teflon&quot; looking seal on the plunger itself.

I'll second that request... if someone has replaced a lift pump recently, I'll buy your old plunger/boot assy!

I'm not 100% sure that my problem is the plunger, but it's definitely leaking. I guess it's not my lift pump itself because I'm leaking no fuel anywhere. Just a slight seep on the plunger.

Jim

kd460

I guess you could try matching up the O rings and give it a shot. If you can find viton O-rings then that would be a better option. Cant help ya with the &quot;teflon looking seal&quot;. <br><br>If it's seeping, then it's probably sucking air while you drive, any miss or stumble? The seepage is probably the reason you are losing prime. When it runs have you noticed any performance issues or rough idle? Good Luck, Kevin D.

bglz42

No running issues at all! Runs like a champ, always...<br><br>Went home last night, after it sat all day. No start. Diesel still seeping from plunger. I removed it, and will go looking for a o-ring today. <br><br>Timing could not be worse! I'm taking my boat to the shipyard today for haul-out. I'm adding a swim platform to it, so I REALLY need my truck!! Oh, well... Murphy strikes again...<br><br>Thanks for all the help!<br><br>Jim

Pete Miller

Engine that won't start could be a fuel line failure also. There is a fuel line that runs under the engine, near the bell housing that needs to be replaced every so often. The fuel line gets an air leak, loses pressure, end the truck won't start. Are you leaking fuel?

bglz42

Well, I replaced the o-rings in the primer, no leaks there anymore. But still no start...<br><br>I had been able to start it by pumping the primer a zillion times then cranking a zillion times, but last night (when I strted to look for fuel line leaks) it would not start at all. I'm planning on replacing the rubber return line again, this morning. Does the other line (inlet?) need replacing too sometimes? I am seeing some diesel leaking, but I haven't been able to track it down yet. I'm hoping that I pump enough pressure into the system to cause it to leak, without running. <br><br>This is so frustrating, because this truck has not missed a beat in 175k miles, and suddenly it just won't run. Thanks for all your help...<br>Jim

bglz42

Ok! Officially at WITS END!!!!! :'( :'(<br><br>Been working on the darned thing since 6:00 am this morning... found that my return hose was toast. Many cracks in it. Replaced.<br><br>Now it still won't start. I've pumped it thousand of times, no start. I've cranked it until I'm scare to crank anymore. <br><br>Observations... I cracked the nut on the top of the fuel filter (fuel line out). Pumped. A few little bubbles but no a lot of pressure.<br><br>I cracked the number one injector line. Nothing when I crank or pump.<br><br>Do you guys think this is another problem, besides the cracked return hose? Or am I just not getting prime for some reason... (it sure ain't for lack of pumping that d*mn plunger! I have a monster blister now!!)<br><br>Thanks!!<br><br>Jim (getting desperate now!)

BoldtsWagon

Just a guess for the next places to look. Maybe a new lift pump or you got a hole in the plastic tubing in the fuel tank suction assembly.