This may sound crazy but I believe My shut down solenoid was causing a power loss. I changed it before I dynoed last weekend, It seemed that I gained power with the new solenoid.
Then I turned my fuel screw in 1 more turn, I thought I had it in all the way, but now Im at my limit.
Since then I have blown the rubber tip off my shutdown solenoid twice. I think I should just leave it alone and put a pull cable on it.
I also gained 2 MPGs after the solenoid deal and the fuel screw adjustment. Go figure,
I guess what I want to know is will a shutdown solenoid on a first gen affect power. If anyone has done testing, has anyone dynoed with a solenoid, then remove the plunger and see if you gain power.
I also cant figure how a gained fuel milage.
Any comments?

 

You are pushing enough fuel thru the system that the solenoid tip cannot maintain contact with it's seat....
Pull the solenoid out, remove the spring and stretch it about 1/8", no more. Then when your done put it back in.
You need to make sure you stretch carefully and equally too.
It's worked for me and I'm running higher pump pressures and timing to boot....

bob....

 

Unfortunately the last solenoid I put in which was last week, a big piece of the hard rubber tip is missing, looks like someone took a bite out of it. That is why it wont shut off, I just dont know how the tip gets damaged like that. Im guessing heat and pressure combination, but I dont know for sure.

 

Just gut the solenoid and put a pull cable on . . .

The MPG change could be related to a timing affect from the bad solenoid affecting flow and internal pump pressure. That is a stretch though.

 

The tip breaks/fractures because the tip is trying to stay engaged in it's seat and the fuel pressure is pushing against it.... the metal shaft that the tip is attached to is too short and, that allows the rubber seat to "****" in it's seat when fuel pressure pushes it back momentarily,..... at least that is my take on it.
I have been through 3 solenoids. On the last one, I stretched the spring as noted and so far, I have not had any more trouble... I did deliberately try to recreate the problem too, so far, no damage.
It may help you, may not, but it worked for me.
You might also try another "solution".... look at the spring, get a feel for it's tension and then find a similar spring to replace it with.... maybe a tough ballpoint pen spring???? I don't know becuase I'm still in good shape..

pastor bob.....

 

I was kind of curious if removing the rubber stopper would allow for better flow/more power also. It doesn't. I made before and after dyno runs and there was no difference. I have also gone through my share of plungers. The newer plunger design is actually different than the stock design. There seems to be some issues with the current design. I have been having problems with nearly stock rigs too. The local pump shops don’t have an answer, and I haven't heard back from Bosch yet.

Mike