QuestionI read your response to the vapor lock issue with these cars. I put on an
electric fuel pump from Checker or AutoZone back by the frame rail. After a
few months, I noticed my mechanical fuel pump is leaking around the gasket
holding the halves of the pump together and the last time I tried to run the
car, it kept quitting at lower rpms. I barely made it home. Any suggestions?
It was not a high-oressure pump, but maybe my mechanical pump has been
hurt.
AnswerIt seems you may have two separate problems:
1. The electric pump may be putting out too much pressure - you can use your vacuum gauge on the pressure scale to check it - anything over 5 PSI is too much, and could cause the gaskets to seep.
If the pressure is really high, I suppose it could injure the mechanical fuel pump by damaging the diaphragm, but that would take quite a bit of pressure, I think. More likely, the modern fuels have damaged the original fuel pump. If the pump has not been replaced in the last 5 years, you can be pretty sure the modern fuels have ruined it - current rebuilders are using much better compounds to prevent this. Don't replace the fuel pump with anything made or rebuilt earlier than about 2004. (This caution also applies to any rubber fuel hoses - you need to replace them all with current production fuel line rated for use on fuel injection cars - the old SAE 30R9 spec is now obsolete, although most stores will sell it to you if you are not aware of the difference. The new minimum spec is SAE30R11 - it is very expensive, but it won't fail and crack the way the older stuff does.
One other thought - if you do suspect the mechanical fuel pump has failed, pull the dipstick and smell it, to see if there is any odor of gasoline in the oil pan - if there is, do not run the car until you change the oil and oil filter. One of the common failures of fuel pumps will allow gas to get into the oil pan via the crank arm opening. This will cause rapid wear of the bearings and camshaft, and could even result in an explosion.
2: As for the quitting at low RPMs, that sounds like crud in the carburetor has plugged the low speed jets - you may clear them out by removing the idle mixture screws and using a spray-can of carb cleaner (Gunk is a good brand). Stick the straw into each mixture adjusting hole and give it a good squirt. This may dislodge the crud, but it might return or migrate to give trouble somewhere else. Check your fuel filter to see if there is any debris in it - if so, it is probably debris from the fuel pump failure or the hoses, or possibly even dirt in the fuel tank. If the fuel system is contaminated, you may have to kit the carburetor and flush all the lines and the tank.
Dick
