Idle issue

[studelover]

Would a bad fuel pump effect the idle of the motor while it is in drive? I think the fuel pump I have is going bad. when the car is in park it idles great as soon as I put it in drive after it warms up it wants to die. when it cut off it's hard to start and the filter bowl(clear) is empty. if not the pump what could cause this? I checked for vacum leaks at the manifold and carb base.

Studebakers forever!

[JDP]

Drive just loads the engine and causes the stall, not the pump.

JDP/Maryland
"I'm a great believer in luck and I find the harder I work, the more I have of it."
Thomas Jefferson

[GTtim]

I'd vote for the fuel pump getting weak with little or no fuel in the filter.

Tim K.
'64 R2 GT Hawk

[Studeman]

The fuel-pump should have no effect at all. once there is enough fuel in the bowl to start/idle the engine, just shifting it into gear wouldn't cause an "instant" cut-off of the engine. The description does not sound like it's "running-out-of-gas"...as a fuel-pump issue would cause....

I'm still leaning towards a vacuum leak, or other cause of a very lean condition in the cylinders. Such as: plugged idle passages in the carb, float level issues, intake manifold leaks, etc...




Specializing in Studebaker Restoration

[studelover]

Although this fuel pump is leaking gas,squirting oil I think your right about this not being the primary problem. I pulled the plugs this morning and all were sooted, after cleaning and installing the car great. I pushed it hard for a 1/4 mile up and down the street than again. It held idle when I stopped to turn around both times. When I got back to my driveway and put it in reverse the idle went way down and tried to cut off. I think it has something to do with the idle curcuit, there must be something clogging it. If I cut the car off and wait five min. all the symtoms disappear. It's like something is floating in there and can't get out. I have sent my original fuel pump out to be rebuilt, maybe I need to change the plugs and soak the carb.

Studebakers forever!

[studelover]

On the edelbrock 500 how do I check the float level? how would I truly clean the idle passages?

Studebakers forever!

[bige]

You could have a step up rod that is not sitting in the jet. It can happen easily if you put the top of the carb on with the rods installed in the top. If the rod is out of the jet you would get an extremely rich situation at idle and you can get a slow stall as the idle slowly drops because of too much fuel. Open the little kidney shaped covers, they don't have to come off completely just loosen the screw enough to rotate them around so the rod will pop out. Inspect the rods, if something's bent straighten it and put it back so that you can push it down easily about 3/8". It should move easily and want to jump out of the hole when you let it go. It takes a little fiddling to get the rod into the jet but much easier this way than when you put the top on with the rods installed.

If everything is good with the rods try re-setting the timing. Advance it a little and see if the stall goes away. If it does lower the idle down until it's about to stall set the timing again, then do a final adjustment at the recommended idle setting. It could be that idle and static timing are set such that the centrifugal advance is beginning to come in giving you an improper curb idle setting. Then depending on conditions as the idle drops the centrifugal goes away, retards the timing and then the idle drops further resulting in a stall.

If you still have a point distributor check the point dwell.

ErnieR

[studelover]

Those are great points to look for, I do have electronic ignition. I did advance the timing until it pinged then I had to drop it back some. I have another question I searched the forum and read about the plugs folks were using, they had a simular case where a guy could not get his car to idle. I am using the old style plugs and maybe they got washed out. I notice everything is fine until the motor gets good and warm could the plugs be just giving up and only work well when they are cool? I have noticed that f you let the car sit for a while everything goes back to normal. I have ordered some autolite 437 and they will be here tomorrow these are recommened for a 289 right?

Studebakers forever!

[studelover]

I also noticed that I have my vacume advance hooked up on the passenger side port. On a Edelbrock carb do most you have it there? THe other sidehas the vacume port, when I plug the Vac.advance on that side the motor revs higher.I always thoght this is why you disconnect the Vac. advance when setting the timing.

Studebakers forever!

[bige]

You have your vacuum advance connected correctly. It is suggested that you disconnect when you set the timing but if your idle screw is adjusted properly you wouldn't see a change connected or disconnected. In the 60's some GM vehicles ran full vacuum advance at idle and 70's Fords had a vacuum retard on their distributors so a general rule of disconnect covers all the bases.

My experience with bad plugs has been hard starting when cold and a high RPM miss when warm Cheap and easy enough to eliminate them as a cause by changing them.

Do you still have a heat riser and if so is it moving freely? If it's stuck closed you could be heating the fuel enough to boil and the vapors are then drawn into the carb richening the mixture at idle enough to stall.

ErnieR

[studelover]

The heat riser is moving freely.however I had a question on weather or not it is installed properly.

Studebakers forever!

[bige]

There's one I can't answer. When I took it off the Avanti I could see that installed incorrectly it could restrict flow even if it moved freely.

ErnieR

quote:Originally posted by studelover

The heat riser is moving freely.however I had a question on weather or not it is installed properly.

Studebakers forever!

[leyrret]

The fact it is fine when cold leads me to believe you are too rich at idle. How does it react to idle mixture adjustment screws?
Some after market carbs seem to have rich mixture at idle, especially competition models. I used wire to restrict fuel through idle
in my Holley to lean out mixture. Mine idled ok but using a fuel ratio gauge it was richer than necessary for best mileage.
Unlikely metering rod is at fault as you shouldn't be pulling fuel through main discharge at idle. Possible plugged air bleed could
be letting it siphon out main discharge after throttle closing, but this would likely flood engine after shut off when hot. It should also
be visible looking in carb throat. I assume choke is wide open.

[studelover]

Yes, choke is wide open. I installed some autolite 437's today and changed my valvecover gaskets, I am also in the process of changing that fuel pump leaking fuel and blowing oil. once I get that pump back from Antique cellar I will be able to run the car again.

How do I lean the mixture out. The idle screws are working they change the idle speed when screwed in and out. I am running a Edelbrock 500, There are not many adjustments that this carb can take or are there[]if someone knows another please let me know thanks.

Studebakers forever!

[farmhawk]

Go to Edelbrock's web site and look up the owner's manual for your carb. It will answer all of your questions about adjusting it. I run the vacuum advance on my edelbrock 500 off of the driver's side port and haven't had any issues with idle, I am also using an electric fuel pump.

Wayen K.
Libby, MT
61 Hawk (On the road, FINALLY)