Looses engine power after driving 150 miles

[davebw31]

Ok broke down in Las Cruces, NM. Bogarts RV Service. Ran diagnoistic test and OB ll said bad Mass Air Sensor. They replaced sensor. They also did a road test with a meter for checking fuel pressure, which read normal in light and heavy throttle positions, anywhere from min. of 60.5 to max. of 65.0 psi. I drove for about 150 miles and it ran like a champ, not a problem up and down hills, stayed in 5 th even on the steepest hills. Then started down shifting at the smallest hill just like before I broke down in Las Cruces, NM. Pulled over and sat for about 40 mins. and it started right up and down the road I went for another 100 miles and started to do it again.

I think fuel pump is "going south" as it heats up and will not keep up with throttle position when I need more fuel getting up hills. It gets worse and then really slows down, like it is running out of fuel. I believe it is the in tank fuel pump. The RV service said there was no "lean" codes indicating a bad or weak fuel pump!

Help, I am in Campe Verde , AZ on my way to Grand Canyon.

Any help, advice is appericated!

dave b.

[M&EM]

Quote:

Originally Posted by davebw31 Ok Help, I am in Campe Verde , AZ on my way to Grand Canyon. Any help, advice is appericated! dave b.

Dave, how low were you on the fuel gauge at the times that your trouble started? Reason I ask is that the fuel pump may run a little cooler with more then 1/2 tank. It keeps more of the pump body submerged. If keeping above half tank does help your situation, I would guess pump. What is your miles on the coach?

Marty

[davebw31]

Marty thanks for your reply!

Yes I need to give more details.

2004 NRV Dolphin, model 5355 (36") 8.1 lt. engine
Miles 28,300
Recent PM items: New air filter, Oil changed at 25,000 miles, 2 qt. A/C filter
New Fuel Filter @ 19,000 miles and has the upgrade to adapter to use std. GM filter
Taylor Extreme plug wires @ 25,000 miles
Has Vanterra Air system ducted to both exhaust manifolds to keep temp down
Normal oil press. 41-43 psi. @ 2,400 rpm @ 65 mph
Normal water temp.

When fuel gauge gets down to just below 3/4 and just above 1/2 tank. Let it sit for 40 mins and pull fuel in it runs fine @ 65 mph. After a short time I notice more throttle pedal to get up small hills then start to downshift to 4 th gear.
No previous history, always ran like a champ
In-tow is a 24' Pace enclosed race car trailer
20,000 lb equalizer hitch
Deeper than stock alumn. finned pan with 4 qt larger capacity. Trans always @ 150-190 degrees and only on steep 6 or 7 % grades does trans temp get over 210*.
Have pulled this trailer loaded @ 10,000 lbs for 12.000 plus miles and never a problem on hills.

[onecb]

If it were me I would change the fuel filter again. I had one act exactly that same way. The only difference is mine set a code that said it was lean.

[Full-Timers]

Sounds like the common problem of hot fuel returning to the tank. The fuel returning from the Fuel pressure regulator is sent back to the fuel tank. This fuel is heated by the under the hood heat and dumps on the fuel pump when entering the tank. This affects the fuel pump. This can be exacerbated by the fuel tank being less than ½ full. This is the reason Workhorse came up with their overpriced 3 port fuel filter. The fuel is returned from the filter rather that the engine. To correct this problem the fuel pump has to be removed but not replaced. They can simply adjust the return line so it doesn’t dump onto the pump.

[pkmesser]

Quote:

Originally Posted by Full-Timers Sounds like the common problem of hot fuel returning to the tank. The fuel returning from the Fuel pressure regulator is sent back to the fuel tank. This fuel is heated by the under the hood heat and dumps on the fuel pump when entering the tank. This affects the fuel pump. This can be exacerbated by the fuel tank being less than ½ full. This is the reason Workhorse came up with their overpriced 3 port fuel filter. The fuel is returned from the filter rather that the engine. To correct this problem the fuel pump has to be removed but not replaced. They can simply adjust the return line so it doesn’t dump onto the pump.

OP indicates an 04 coach, which if the chassis is also an 04, hot fuel does not return to the tank from engine compartment, it diverts just in front of fuel filter back to tank. OP indicates he has the upgrade to allow standard GM fuel filter, which is consistant with the fuel being returned in front of the fuel filter, (front of filter= direction toward the MH front)

[davebw31]

Correct pkmesser, I have the 04 chassis with the three line fuel filter. I got the stainless adapter so I could use the less expensive GM fuel filter instead of the $$$ expensive WH filter, so fuel is returned to the tank from the filter and not at the engine like previous chassis.

[davebw31]

onecb: when Bogarts ran the OB ll code check there was no code for lean condition. Only codes for Mass Air Senser Default. I wanted them to change the fuel pump but they would not unless I paid for it (I have extended warrany policy with $200.00 deductable).

After they changed the Mass Air Senser we went for a road test and both OB ll and meter for reading fuel pressure read normal. So on the road I went and it ran like a schalded dog for 150 miles and almost to the 1/2 fuel gauge reading, it started loseing power.

I drove from Phoenix to Williams, AZ, as I had prepaid (non-refundable) two night RV park and train ride/bus tour of Grand Canyon. I am leaving tomorrow and will try to limp on the 200 miles to Las Vegas where there are two big RV/WH service dealers. I will just stop when the power starts to die, fill up the tank, and "truck on".

[txdutt]

I'm pretty sure my fuel pump just went south on us yesterday. Luckily I was able to get it off of I25 in Pueblo and park it next to a Love's Travel stop which gavet the tow truck plenty of room to hook it up. Basic symptoms were:

-hard start extended crank (really bizarre as usually you just had to barely tap the key to fire it up)
- noticed a gradual loss of power until it dropped off a cliff when I was trying to accelerate onto the freeway after leaving a rest stop
-would barely maintain 40 mph (temp gauge was exactly normal the whole time)
-when finally got to the exit, it sputtered and almost cut out
-idling very badly when unhooking our Jeep
-thought maybe it was bad gas but generator ran fine for the hour we waited on road service to come get it
- NO check engine light which really surprised me..
-should find out by Monday what the diagnosis is...getting my money's worth from the extended service plan!!