Sputtering after 2 hours of driving

[AllensRiviera]

A little history: I have a 1800 fuel injected engine. My bus has all new fuel lines, vacuum lines, and ignition system (cap, rotor, points, plugs, wires). It has a new fuel pump and a fuel filter with 200 miles on it. I have drained the tank and no sediment came out. The engine has good compression. The AFM screw is adjusted correctly. The points are correct. The timing is correct. The TS2 has less than 1000 miles on it.

The problem: Today I was driving home from The Dalles after spending a weekend at RendezVW in Maupin Oregon. I had no problems until about milepost 15 just outside Portland. I am driving and I start to notice an occasional sputter or "kick" with the engine. As we get closer to Portland it gets worse and worse. I pull over in Portland to take a look but everything looks ok. I try to drive again but the sputtering gets much worse. I can tell the engine is losing all power for brief moments. The engine soon dies and won't restart. From past experience I know that if I unplug the fuel pump electrically the engine will run. I unplugged the fuel pump and try to start it. I can get the engine to run but it is a low, rough idle. I turn the engine off and reconnect the fuel pump and start the engine without problem.

But it will only drive for a minute or two before experiencing the severe sputtering again. We could not get home and the bus is currently on the side of the road. We are home safe but I am worried about my bus. What should I try? I have heard that the fuel pressure regulator could be failing and causing too high fuel pressure. Does this seem accurate?

Thank you.
-Chris

[dtrumbo]

I have heard that the fuel pressure regulator could be failing and causing too high fuel pressure. Does this seem accurate?

Hi Chris! First, I'm glad you and the fam made it home safe. No wonder Claire wanted to ride home in our bus! Ha, ha, just kidding, I couldn't resist!

Now to the problem. I finally understand what you were describing when we were talking about it at Maupin. A funky fuel pressure regulator might explain the situation. If you can get the bus to a place where you can safely work on it, you should measure your fuel pressure. On the left side of the engine there is a port on the fuel rail where you can attach the gauge. I don't have my Bentley handy right now, so I don't know for sure what the numbers should be and I wouldn't want to steer you wrong. Somewhere on this site I recall Colin describing a procedure for checking the regulator. It had to do with measuring it with the engine running and then shutting it down and watching what happens next.

The whole "unplugging the pump and it will run for awhile" thing had me baffled, but perhaps by doing that, you're bleeding off excessive pressure and it will run until it builds up again. Good luck and come back to us with charts and graphs.

BTW, if you need a fuel pressure gauge, this looks like it will do the trick.

http://www.harborfreight.com/fuel-injec ... 92699.html

[AllensRiviera]

Claire was really good about the whole thing. At first she kept saying the road was bumpy. Then, during a particularly hard lunch, she looked up surprised and said "Whoa!". It was a good tension reliever.

Update: I got the bus home!

AmSkeptic aka Colin checked out my bus and made a few adjustments. He fixed a vacuum retard problem, adjusted the idle screw and adjusted the air fuel mixture. His official assessment is a funky temp sensor 2. He suggested I clean the head where the sensor seats. He had 4 gauges hooked up and could wiggle the wire and get different readings. I will get the sensor installed this week but drive time will be short until next week.

Public Thank You to Colin for the very gracious offer to help and diagnose.

[AllensRiviera]

A new problem:

Last week we took a camping trip to Detroit Lake, about 2 hours away. The bus was fully loaded with 2 adults, 2 kids, 2 dogs, and camping gear for 4 days including a loaded cooler and food. The bus drives great and we did stop for gas in our neighborhood, after about 10 minutes of driving. Once we stopped at the campground I did not try to start it again. However, on the way home we had to stop for gas after an hour of driving. The bus would not restart. It cranks over fine but won't run on its own. I tried about 5 times. The next minute I reached under the bus and disconnected the electricity to the fuel pump. I went to turn over the bus and it starts running after about 10 seconds of cranking. It died after about 15 seconds of running on its own. I reached back under the bus to reconnect the electricity. I started the bus and then drove it home another 60 miles away.

I have had the same issue before and am able to cure it the exact same way each time. Do you have any idea what this could be?