i have a 330 cat in a 2004 tiffin alegro bus. it has 60,000 miles on it and runs great. my problem is after it sits for about 48 hrs it loses its prime and will not start. i have changed fuel filter and replaced fuel line from filter to pump. no sign of any leakage.i always keep at least a half tank of fuel in it.we fulltime so it dont sit to long. could use some suggestions
I don't have one of those, but I do have a couple diesels, and had a similar problem with one of them about two years ago. Turned out to be a tiny leak in one of the Injection pump seals. It did leak fuel when running, and then air when shut off. The fuel made it stinky, the air made it lose prime and fail to start. Obviously it only dripped fuel when actually running, otherwise it was sucking air.
For what its worth, the dealer wanted $1400 to replace the IP (PLUS LABOR). I found a shadetree mechanic who replaced the offending seal for $150, $25 of which was the seal kit, most of which was thrown away, as he only needed one part out of it.
Good luck finding the leak, as that is clearly what is happening. And don't forget to look in the crankcase for oil dilution. I've heard of IPs leaking that way, too, and in which case you won't see any evidence of a fuel leak on the outside, just more and more oil in the crankcase.
Air in the system indicates a problem anywhere between fuel tank, primary filter, and the lift pump.
Could be something as simple as a loose clamp, could be a bad O ring on a filter or hose with crack in it. If before the lift pump, there will likely be no sign of a fuel leak, as this is on the suction side of the pump.
Do you have the secondary fuel filter with manual primer pump? If so, how many strokes to prime it when this happens?
changed fhe fuel filter and replaced the hose from filter to lift pump. it only has one fuel filter. no secondary fuel filter. will start find with in 24 hrs. but 2 days no go but trys hard but wont make it
sunny jeep wrote: changed fhe fuel filter and replaced the hose from filter to lift pump. it only has one fuel filter. no secondary fuel filter. will start find with in 24 hrs. but 2 days no go but trys hard but wont make it
Sounds like a problem I had with my CAT 3126, 1998 model. After it sat for four or five days it would not start unless I used the primer pump. I just thought it was what it was supposed to do.
Took it to CAT for its yearly service, and the tech called and told me the HEUI pump only had about one half of normal pressure. Said he was surprised it had not thrown a code.
Replaced the HEUI pump and all is well. Starts immediately after setting for any length of time. Suggest you have your HEUI pump pressure tested.
CarlGeo
sunny jeep wrote: wants to start cranking at about 500rpms but wont.
Sorry, don't know what that means. Please explain "wants to start cranking at about 500rpms but wont."
If an engine (any engine) won't turn over fast enough to start (and with a diesel not enough amps to heat the intake manifold heater), fix the battery/wiring system FIRST.
If still a problem, then look at the engine.
What happens when you use the battery boost/combine switch?
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