Quote:
Originally Posted by 67ragtp
Jody,
The vacuum port Im using is the big one at the bottom of the throttle plate. Its got a small piece of hose then a vacuum "Y" fitting is connected to it, one side goes right to the MAP sensor and the other goes up to the regulator.
If it were a fuel filter limiting the pressure it would still be low when I disconnected the vacuum line from the regulator- is that right?
The under hood temp was very high, could very high fuel temps cause this?
Could I run the car with out the vacuum reference, it was tuned this way, would the idle A/F be richer with the small additional pressure running with out the vacuum line?
Thanks Rich
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when the fuel temp gets high enough the pump starts to cavitate and fuel pressure drops, until it won't run at all if it escalates enough. You'd know in advance if you pay attention as the pump gets louder.
If the car was tuned without it you would have thrown the idle and cruise tuning off some by adding it, unless you re-tuned for the reference line. The line would have dropped pressure in those situations.
You might try no line and see how the fuel pressure works out when the fuel temps get high. If it has the same issues (which I think it might) then you need to do something to control fuel temps.
Jody