Post by Dennis D on May 20, 2007 12:15:41 GMT -5
The problem with my Strada that I first thought was the vacuum fuel switch that I replaced with a manual petcock, and then thought was with the automobile fuel filter.... turned out to be vapor lock. I thought vapor lock couldn't happen on a line that's near vertical, but I'm certain that's what it is, because when I reached under the cowling to turn off the petcock, I touched a frame crossmember near the engine(which the fuel line also touches). It was so hot that I could have burned myself on it if I didn't pull back quickly. Waited a minute after the engine was shut off, and it was already cooled down to just being quite warm. That's about all the time it takes to be running again when it shuts off, too. What led me to believe it was originally the vacuum switch is that it never happened til I was about .7 gal low on fuel, so I thought the fuel "pressure" couldn't push through a vacuum switch that was just barely or partially opening. It was sorta like that, but what I'm now sure was happenning was that vapor lock developing in the near vertical line wouldn't stop the fuel flow til the pressure from the weight of the fuel got below a certain point. I was at a real loss for ideas once I replaced the vacuum switch. I initially thought that removing the vacuum switch fixed it because I tested it with the underseat storage removed... which would have allowed the frame to stay cooler. Then there were some cooler days then when I ran down to near empty with no problem. After I touched that hot frame piece and rerouted the gas line, I ran for 15 miles in the same temps it's been stalling out at(constantly), with less than 1/2 tank full, so I'm sure that was really it. Never woulda figured it out if I hadn't accidentally almost burned myself feeling for that manual petcock I installed.
With the vapor lock taking place in a near vertical line, it doesn't have to cool much to get fuel pushing through again. I've been hoping with each thing I thought was the problem, that really was it.... this time I'm sure! The thing is, I created this problem myself by taking excess fuel line out and running as direct as possible as is often recommended. Just goes to show that by trying to head off some problems before they show themselves, it's possible to create problems. I sure had no idea that frame crossmember would get so hot! So for those who are experiencing similar problems, check to see if the line is touching a frame member near the engine compartment.
With the vapor lock taking place in a near vertical line, it doesn't have to cool much to get fuel pushing through again. I've been hoping with each thing I thought was the problem, that really was it.... this time I'm sure! The thing is, I created this problem myself by taking excess fuel line out and running as direct as possible as is often recommended. Just goes to show that by trying to head off some problems before they show themselves, it's possible to create problems. I sure had no idea that frame crossmember would get so hot! So for those who are experiencing similar problems, check to see if the line is touching a frame member near the engine compartment.
