Fuel pump failing? Or something else? Recently my car has been very hard to start when the engine is hot (starts right up when the choke is engaged / engine is cold...).. Could this be due to a failing fuel pump? Yesterday I spent 20 minutes trying to start it after refueling, when I finally bought a can of "start gas" at the local gas station and sprayed into the air cleaner it fired up almost instantly. When the car is running it has no issues at all, runs fine at all rpm's and with full power. If anyone could confirm this I would love to hear it I also have a new fuel filter which I am going to change also. Does anyone have the GM part# for a correct new pump for my ride? (see sig).
Whenever I have lost a fuel pump in my 455 (3 times), it has been an under power stumble, not a starting issue, that signalled it, although the car was hard to start. This could easily be the infamous "hot start" issue with GM cars, were the starter solenoid gets so heat soaked the car won't start. Also could be a battery cable, or even a carb problem. Fuel line, too (vapor lock?) Give us a run down on the engine's buildup, especially the fuel system. This could be as simple as the choke. Where is the fuel filter located, by the way? You can have issues if the filter is too far away from the carb
I don't think there is anything wrong with the starter (or solenoid), as they both work fine both when hot and cold. Fuel line or carb / filter / pump seems like more likely to be at fault.. the filter is the standard in-line one (at the carb fuel-inlet)... The choke is fine, it shuts off when the engine gets warm, no problems..
In all my hot start problems, the starter would crank and crank and crank and crank. It wasn't that the starter wouldn't work. Maybe I didn't explain it right I just got back from another operation and I feel lucky that I'm spelling words correctly I hope you get this sorted out and quickly beccause I know how frustrating this is and it must be hard to get parts over in your area. You seem very certain that this is the fuel pump, and I am not second guessing you, I'm simply pointing out alternatives to the pump being bad because this doesn't seem like a pump problem to me. I'm no expert but pump pressure should be greater at lower rpms, to my knowledge, and lower at higher rpm, so a stumble under load would indictae to me a bad pump. They are cheap and easy to replace so go for it, I hope this solves your problem
Indeed the starter cranks and cranks and cranks.... but I don't see how that could be wrong? Please emphasize.. I am not sure it is the fuel pump I just thought that was a likely fault
Bjorn, Sounds like vapor lock to me. When you shut the car off hot, it is possible for the fuel to boil in the bowl. This results in an extra rich mixture which will give you starting problems. Keeping the carb as cool as possible will help. Blocking off the exhaust crossover in the intake manifold, insulating the fuel line, using an extra thick carb gasket or heat shield will all help with vapor lock. Does the fuel pump have a vapor return line. This helps by constantly circulating cooler fuel through the pump and returning vapor and hot fuel to the tank. Does the car start hard when cold? I would also check voltage at the coil when cranking. Should be at least 9 volts. If it is less the switch in the starter solenoid is not supplying battery voltage to the coil in the crank position. Hope that helps.
Seems like the problem is gone now, after replacing the "low-voltage" wires that go to the coil from the distributor.. Thanks for all tips!
