Impala Steve
Well Known Member
Hi Jim, I put a oil pressure gauge on it to measure. The readings at high idle cold start up was 50 psi. When the engine warmed up it went down to 25 psi. Is that a good reading?
1958 Impala oil light flashing at low rpm
- Thread starter Impala Steve
- Start date
25 at warm is good, try another oil pressure switch.
Impala Steve
Well Known Member
Should there be gray film/sludge on this oil filter? 
What James said above, 25 warm is good.
Impala Steve
Well Known Member
Hi SSpev, What brand of fuel pump do you recommend?
depends on what you want it to look like. you have options. Unless you have the vacuum pump on it.
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Impala Steve
Well Known Member
No don't have the vacuum pump on it. Thanks for the link I will look.depends on what you want it to look like. you have options. Unless you have the vacuum pump on it.
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Impala Steve
Well Known Member
Installed oil pressure sensor, started up the car and let it idle after warm up no light came on. Going to keep checking.
Impala Steve
Well Known Member
Update the oil light flashed again. Replaced the new sending unit. Any ideas? I did see some residue on the top of the fuel pump.
Impala Steve
Well Known Member
Noticed on the top of the fuel pump was some wetness. Does that mean the diaphragm failed?
Pull the dip stick and hold a liter to it, if it goes to flame easy you have fuel in your oil. A fuel pump can cause this, a over rice running engine can cause this also.
Impala Steve
Well Known Member
Update: Fuel pump has been replaced. The light is still flashing at idle. I plan on changing the oil to see if there is a difference.
Have you put a mechanical gauge on it to test it?
Once the oil was diluted with gas you'll need to change the oil
Do not continue to operate it with diluted oil. Hopefully the new fuel pump solved it
Do not continue to operate it with diluted oil. Hopefully the new fuel pump solved it
Definitely change oil. I have a pickup that uses some oil ( valve seals) so I use straight 30 weight oil and it seemed to help slow it down. Maybe you could try that to get the pressure higher at idle.. After all that's what was used back in the day.
Impala Steve
Well Known Member
Changed the oil with STP 20W-50 conventional with STP ZDDP additive. I adjusted the front carburetor screws turning them 1/4 turn inwards. Will turning the adjustments screws make a difference whether excess gas is getting the oil?
When you check the pressure with a mechanical gage are you checking at the same point as where the pressure switch is installed?Also those pressure switches are hardly a precision instrument and never were. Some manufacturers way of dealing with those issues back in the day was to put out a service bulletin that instructed dealer service departments to increase idle speed by 50 rpm.