It may be that the wrong holder assembly either prevents the pump from drawing a suction, or causes some serious suction restriction in that particular tank. An extreme case of that would cause the pump to overheat and die. The latter is the guess I'd favor, tho' I have no expertise whatsoever here.
Jim, "Mo' coffee!"
'06 Tiger CX 'C Minus' on a Silverado 2500HD 4x4, 8.1 & Allison (aka 'Loafer's Glory') www.tigervehicles.com
I've been told that some assemblies are "not serviceable" what that means is, they don't trust your average guy to work on it. If it's all plastic that's been eaten up by modern fuels, it probably can't be fixed. If it we me, I'd drop the tank and take it to a shop and have it modified to accept an off the shelf fuel pump. Or have an assembly fabricated that can be repaired. It can be done, guys do it to race cars all the time. But, then I'm just that way and most people just trade vehicles.
krell wrote: Problem isolated, but not repaired yet. Armed with a wiring diagram downloaded by mechanic friend, I see the fuel pump relay is controlled by the PCM (Powertrain Control Module). The power source to the relay is hot all the time and there is a direct connection to the pump in the tank and the ground wire returns along the same path all the way back to the grounding management connections. Under the van, adjacent to the fuel filter, there is a seven pin connector where you can test the circuit. The power and ground to the plug is ok. The last time the engine did not start, I opened the connector and tested toward the pump. I measured about 65 ohms when the reading should have been closer to 2 ohms. I concluded that the pump stopped at a bad spot or there is a high resistance open in either the power or ground conductor. The pump is not grounded locally, but grounded up front. Watching the meter, I tugged on the wire harness at a point where it disappears into the chassis near the fuel tank. The resistance dropped to about one ohm. Engine started after that. When the mechanic replaced the first fuel pump he had to cut off the original four pin plug and splice on a new pigtail/plug assembly that came with the new pump. The new intermittent problem is likely due to a bad splice or a crushed wire when the tank was re-installed. I tested the old pump and it was defective, so the mechanic probably created the second problem. It happens. At any rate, I am done with my RoadTrek and the constant parade of normal and abnormal troubles. Next week it's going back to where we bought it and we'll be driving off in a new RV. Hopefully the problems we have are going to be the normal RV aches and pains.
Problem isolated, but not repaired yet. Armed with a wiring diagram downloaded by mechanic friend, I see the fuel pump relay is controlled by the PCM (Powertrain Control Module). The power source to the relay is hot all the time and there is a direct connection to the pump in the tank and the ground wire returns along the same path all the way back to the grounding management connections. Under the van, adjacent to the fuel filter, there is a seven pin connector where you can test the circuit. The power and ground to the plug is ok. The last time the engine did not start, I opened the connector and tested toward the pump. I measured about 65 ohms when the reading should have been closer to 2 ohms. I concluded that the pump stopped at a bad spot or there is a high resistance open in either the power or ground conductor. The pump is not grounded locally, but grounded up front. Watching the meter, I tugged on the wire harness at a point where it disappears into the chassis near the fuel tank. The resistance dropped to about one ohm. Engine started after that. When the mechanic replaced the first fuel pump he had to cut off the original four pin plug and splice on a new pigtail/plug assembly that came with the new pump. The new intermittent problem is likely due to a bad splice or a crushed wire when the tank was re-installed. I tested the old pump and it was defective, so the mechanic probably created the second problem. It happens. At any rate, I am done with my RoadTrek and the constant parade of normal and abnormal troubles. Next week it's going back to where we bought it and we'll be driving off in a new RV. Hopefully the problems we have are going to be the normal RV aches and pains.
With our 17' boat in tow, I can still pass other vehicles on a 7% grade at 4,000 ft. altitude. I've driven 18% grades and I know I can go fully loaded up a 12% at 9,000 ft. Fuel starvation is not and never has been a problem. In the tank and in the fuel lines there is not a trace of dirt. Just last week when I replaced the fuel filter, I back flushed it and then inspected the filter medium only to find that I could have left it in there a few more years. The original fuel pump and gauge sending unit assembly shows no signs either. Pay attention class... the problem has to be electrical. The repair shop that I brought it to is the same one that my former employer sub contracted fleet vehicle repairs to. I know their work. When trying to start a vehicle and the fuel pump doesn't prime, smacking the bottom of the tank where the fuel pump sits often brings it back to life. This is how they were able to drive the van into the service bay after the tow truck dropped it off. Each time, even with the first and second replacement pumps, I was able to start the engine. A string of bad pumps? A coincidence that banging on the tank starts the pump? The RoadTrek has been at the mechanic for four days now and not a peep from them. This can't be good. I am still hoping that someone else had this exact same problem and a solution. This forum has been an invaluable aid in dealing with all things RV because someone else has "Been there, done that."
* This post was
edited 03/13/10 03:09am by an administrator/moderator *
Banging the tank fixes it? Again I don't know Chevy vans specifically, but most fuel injected vehicles, when you turn the ignition key from off to run, you can hear the fuel pump run for a few seconds. There's a relay that controls that and it's different than the fuel pump relay. But it's not located near the tank. I wonder if there's a grounding connection that's gotten corroded? That's the only thing that comes to mind that banging could fix. The negative lead to the fuel pump wouldn't be grounded to the tank itself, it's could be grounded to a mounting strap.
The BCM energizes the Fuel Pump Relay only for a few seconds until the engine is running. This makes it tough for one person to diagnose an intermittent trouble. With my wife turning the key to the run position, I would position myself close enough to the fuel tank to hear the pump start and stop. When I did not hear the pump, I tested from the relay socket to check for continuity to the pump. By the way, a normal pump will draw about 8 amps or so when running. About the same power as a small coffee grinder.
We're trading in for a 2009 Navion IQ CL. If RoadTrek had a unit with an "Ideal" floorplan on a longer chassis minus the slide, I think that would be close to what I envision. If you study the Navion IQ floorplan compared to the RoadTrek 200, you will see a similar concept. The rear dinette has a panoramic view to the rear and sides perfect for those million dollar views. When the bed is made up in the rear (wife and dog still snoozing), I can get up work in the galley and sit up front with a cup of coffee and do whatever. The new rig is going to be 4 feet longer, two feet taller and just a couple of inches wider. With a van camper, I've grown accustomed to being able to go just about anywhere and park anywhere. We'll see if I'm back in a "B" in a year or two.
Krell: I have no mechanical experience and to make matters worse, am a redneck from the Ozarks. Bought a new truck in 02 and within a few weeks started having problems with the fuel pump. within the first year the dealer replaced the fuel pump seven times, at no cost to me. His mechanics are all factory trained but were never able to determine the reason for the pumps going bad. Some only lasting over night. One never made it away from the dealership. Vehicle manufacture got involved - still no answer. Truck never failed to crank. Never suspected andy trouble with the battery. While waiting for a wrecker to pick up the vehicle for the another fuel pump a decrepit old meechanic stopped by and after hearing my tale told me to check the battery cables. The ground cable was loose. He explained to me what this was doing to the fuel pump by the fire arching and a few other terms that I did not understand and we tightened the cable, the wrecker arrived, took truck to dealer, new fuel pump installed. That was in Jan 04, still have the truck and have not had any further fuel pump problems
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