I have an 88kw Perkins engine, actually it's a part for part exact equivalent made by a company called MWM International, but it's identical to the Perkins engine. The problem is if the unit is running and then shut down and then started right back up again within a few minutes of being shut down it won't start. The fuel stop solenoid is not opening. The only thing that gets it going is to let the motor sit for an hour or more or it can be restarted immediately if I bleed the fuel system between the primary and secondary pumps (at the fuel filter). When I bleed it only pure fuel comes out, no air, and a short spurt comes out till pressure is bled off. The pressure seems like just the normal pressure from the primary (lift) pump. But it's relieving that pressure that lets the fuel stop solenoid function normally again. My theory is the secondary (injection) pump probably is making suction against one side of the solenoid's plunger, and the primary (lift) pump is making pressure on the other side so the natural forces are against the solenoid opening, but the fuel solenoid must be designed to overcome that. For what ever reason it isn't.
I've even tried replacing the stop solenoid with no improvement.
Before I ordered the relacement fuel stop solenoid I tested the voltage to the original one to make sure it wasn't an electrical problem and the voltage is fine. The original stop solenoid only had one connection for the +12 volts and it was grounded through the body of the solenoid. The replacement has a separate ground connection. I'm using the replacement now so I know it's getting a good ground. But the problem continues.
Originally I was assuming the fuel stop solenoid was bad so I replaced it but have the exact same issue.
Does anyone know why a fuel stop solenoid would fail to function properly besides the solenoid itself being bad?
Solenoid valves are composed of several parts such as the solenoid coil, electrical connector, bonnet nut, seal cartridge, O-rings, end connector, body and union nut.Very frequently, they're activated by an increase in the vacuum produced by the engine, a factor that's directly proportional to how hard the engine is exerting itself.
Well, solenoid valves sold by HyVac come in two primary types those rated to 29.5" mercury vacuum & those rated for 10-6 Torr which is greater vacuum. They come in two primary adjustments 'normally open' & 'normally closed'. They all operate using electro-magnetic energy to drive a piston or diaphragm.
Thanks! That's really great information. I'm not sure why our machine with suddenly not work properly with the standard equipment solenoid stop valve and require a more powerful one, but I think I'm in a go ahead and get one of the solenoid valves you mentioned.
Since a brand-new solenoid stop valve did not fix the problem, I'm assuming that the problem must be related to the fuel injection pump. We are having some other problems with the injection pump. The speed regulation is way out of spec and the machine doesn't sound as smooth as it used to be, so that combined with the fact that the solenoid is working strangely makes me think that something has changed with the dynamics of the pump.
The biggest problem, is that the machine takes a Delphi fuel injection pump that apparently is obsolete and no longer available from any source, neither from Delphi, nor the manufacturer of the engine in Brazil or any of the representatives in all of the countries that I have tried. The only option is to have the pump rebuilt. We had a spare that was in transit to be rebuilt and was lost. The machine in question is in the Amazon jungle, and the process of sending the pump out to be rebuilt and then sending it back into the jungle would probably take a month. And on the time that would be required to actually rebuild the pump, and we'd be down for long time. We have only one generator. So for now we'll just keep limping along.