Hey guys... I have an '89 305 5 Speed TPI Car... all stock engine... with adjustable fuel pressure regulator. No matter what I set it at... I am getting something like 10:1 and 11:1 on the A/F ratio... whether the Fuel Pressure is set at 41psi to 52 psi???

Any thoughts on why this car is running so rich? It does have a high flow fuel pump as well?? But figured Fuel Pressure is all that mattered for that.

Thanks for any/all input.
Dave

 

You should set the fuelpressure to max 46 PSI (without vacuum) and then it goes down to ~38psi on idle... .. higher than 46 psi will make it rich on an stock 305 with a high flowing fuelpump...
maybe 45PSI (qithout vacuum) will make it right ?

Or did you adjust it without vacuum ?

 

If you have a Holley AFPR it may have a torn diaphragm. Common problem.

 

THanks guys... if it has the 'torn diaphragm'... where can I get one 'quickly' and 'locally' to replace it with?

Thanks so much!

 

You have to order replacement diaphragms from Holley.

You can check to see if it's torn by starting the engine and removing the AFPR vacuum line. If it's torn, it will leak fuel out of the vacuum port on the AFPR.