Community Forums

rotorflying · 12-25-2016, 12:35 PM

06 damon astoria 3465 300 hp cumming freightliner chassis
I just purchased in florida (Zephyrhills) Picked it up with a full tank 100 gal and drove to Macon ga (475 rgest area). about 40 miles before the rest area noticed the engine would surg going up a hill. pulled in to res area and shut off engine. shortly were ready to go and the engine would not stay running. the fuel gauge showed slightly less than 1/2 tank. Long story short, replaced both fuel and water separator and engine would still not stay running. The generator ran fine so I know there was more that 1/4 tank of fuel. I ended up adding 20 gal of fuel and the engine would stay running, so I topped it off and was able to drive 122 mile back home. Can anyone say why I needed more than a half a tank of fuel to keep the engine running?

twinboat · 12-25-2016, 12:37 PM

Could the fuel pickups be switched ?

Stranger things have happened.

Unplanned Tourist · 12-25-2016, 12:38 PM

Bad lift pump? Fuel that is.

rotorflying · 12-25-2016, 02:03 PM

what and where is the lift pump

twinboat · 12-25-2016, 02:37 PM

The lift pump is mounted on the engine. It is used to bring fuel from the tank to the high pressure injection pump.

Some only run for 30 seconds after starting the engine, then the injection pump takes over.

A few, as I understand, run full time to supply enough fuel to keep the engine running and recirculate some fuel to keep the pump cool.

In either case, the engine stays running once started.

Adding 20 gallons of fuel and having it run well, after not starting, is not a symptom of a bad lift pump.

A slightly loose connection pulling air into the fuel lines, a switched pickup or a bad pickup tube with a hole at the level of fuel you were at, are more likely.

rotorflying · 12-26-2016, 08:02 PM

Is there a way that the lift pump could be in the fuel tank itself? If the problem were a pickup in the tank would I have to drop the fuel tank to repair?

twinboat · 12-26-2016, 08:17 PM

No ! The lift pump is on the engine.

Possibly. Look for fuel lines to the top of the tank. If there is some clearance, they may be able to be removed.

If either one can be removed, you can check the length. One goes 1/2 to 3/4 of the way to the bottom of the tank. The other will end an inch or two from the bottom. The long one belongs on the engine fuel line.

rotorflying · 12-26-2016, 08:45 PM

I really appreciate the feed back. when the road tech replaced the filters he noticed a place in the fuel line, along the frame rail that looked like a bracket and a brass or copper insert in the line. like something was removed and replaced with the fuel line insert. could that have been the pump or a filter (screen)? Do you know where the low pressure pump would be located?

twinboat · 12-26-2016, 09:00 PM

Some chassis had small screen type filters along the frame rail. Could have been removed.

The low pressure pump is the lift pump. Located behind the fuel filters near the starter.

rotorflying · 02-20-2017, 07:25 AM

It has been a while, but after a few weeks at the freight liner dealership. It has been determined that the fuel tank was rusty and the pickup tubes had holes in them. not allowing the fuel to be picked up after the fuel level dropped these holes. Tank removed and cleaned, coated and bad pick up tubes replaced. Very costly. but no obvious way to check with out dropping the tank.