As I let my car idle it is gradually going up in revs around 3000 before I shut it off. Is this because of my new (maybe higher pressure and flow) fuel pump? Or is it something else. All help appreciated.
Original Post
Replies sorted oldest to newest
I'm assuming you already checked around the carb for a vacuum leak. Are you stuck on the fast idle cam? Is your choke open all the way? The choke on your car needs heat from the exhaust cross over passage in the intake manifold to open. Later cars had an "electric assist". There should be a little metal tube connecting to the choke housing. If the choke is fully open and your off the fast idle cam (located next to the choke housing) then I'm guessing maybe something to do with the distributor advance. Try disconnecting (and plugging) both vacuum lines going to the vacuum diaphragm on the distributor and see if the problem goes away.
Too much fuel pressure would most likely cause the idle to go down. Besides, if the fuel pressure was more than the float and inlet needle could handle, you would have gas squirting out the top of the carb through the bowl vents.
Here's a picture showing the adjusting screw for fast idle. The cam has a series of "steps". The screw shouldn't rest on any steps when the engine is warm and the choke is fully open.
Too much fuel pressure would most likely cause the idle to go down. Besides, if the fuel pressure was more than the float and inlet needle could handle, you would have gas squirting out the top of the carb through the bowl vents.
Here's a picture showing the adjusting screw for fast idle. The cam has a series of "steps". The screw shouldn't rest on any steps when the engine is warm and the choke is fully open.
Attachments
Images (1)
If this is a sudden change to the norm, 1) look for vacuum leaks (use a vacuum gauge also), 2)look at the automatic choke, 3)verify that the advance in the distributor is operating correctly.
I had one instance with an Accell distributor where the advance springs stretched themselves out.
I didn't realize what had happened and readjusted the idle to approximately normal idle speed by turning the distributor.
I never looked for the distributor to advance as the engine speed rose and had to bring it to a mechanic who took all of about 5 minutes to find it. Ofcourse he needed to test drive it to find the problem. When he came back he said, "you have a broken distributor".
I had one instance with an Accell distributor where the advance springs stretched themselves out.
I didn't realize what had happened and readjusted the idle to approximately normal idle speed by turning the distributor.
I never looked for the distributor to advance as the engine speed rose and had to bring it to a mechanic who took all of about 5 minutes to find it. Ofcourse he needed to test drive it to find the problem. When he came back he said, "you have a broken distributor".
Happy Easter. Thanks so much guys, where/how do I check for vacuum leaks around the carb - do you mean the various lines or where the carb actually mounts to the intake (clearly I'm in over my head but I'm having fun learning)? I will look at the choke but I have to admit I haven't figured out how it works (or if it works). It sounds like my fuel pump swap is not the problem? Interestingly I just put the air cleaner/filter on and hooked up the vacuum line to the air cleaner, maybe I will disconnect that line and see if it idles easier though I don't know why that should help. The vacuum retard at the distributor should be a possible culprit right. I just put the bulkhead back in - but I think it is coming off again.