CarburetorsCarb discussion and questions. Upgrading a Third Gen carburetor, swapping TBI to carburetor, or TPI to carburetor? Need LG4 or H.O. info? Post it here.
Welcome to ThirdGen.org!
Welcome to ThirdGen.org.
You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join the ThirdGen.org community today!
I am trying to figure out why my car is idling at 1900-2100 rpms. Its a steady idle but it is obviously way too high. I have an L69 carb on an 87 LG4, since the car is an original L69 and I swapped a whole host of L69 parts from the original motor to this one its sort of a hybrid of the two motors. I didn't touch the wiring harness though.
So far I've replaced a bunch of the valves, (were stuck or old), ditched my smog pump as that siezed up, plugged my AIR tubing, plugged a couple other openings, no Cat converter, and the timing is good, idles smooth, has power, etc etc etc. So where the hell is the high idle coming from? I can't figure this out. I don't want to drive the car the way it is now. Previously it would die as I come to a stop. But it drives great. What am I missing here? I also have a new choke on the carb as well. Carb might be all original from the factory.
This ad is not displayed to registered members. Register your free account today and become a member on ThirdGen!
Sponsored Links
Registered users do not see this ad. Click here to register for free!
You didn't mention any attempt at adjusting the idle speed. Most likely the fast idle cam isn't dropping down (see "Is the choke opening?" above). It could be help up by the choke not opening, or not dropping down when the choke opens due to stickiness (gummed up, dirty, jammed, damaged, etc.).
You didn't mention any attempt at adjusting the idle speed. Most likely the fast idle cam isn't dropping down (see "Is the choke opening?" above). It could be help up by the choke not opening, or not dropping down when the choke opens due to stickiness (gummed up, dirty, jammed, damaged, etc.).
Well as I said previously the car does have a new choke element on the carb. So startup is much better than it used to be. However, I can't tell if the choke is coming off the fast idle cam. I think a friend and his dad will come by and give me a hand with it. Is the plunger on that side what you are talking about? Also I told the mechanic that the car was running rich previously and idling high before too. He may have adjusted some things but it was idling at 800 after whatever he did. The vac lines were the problem before.
How to verify choke operation:
With the engine cold, remove the air cleaner. Plug the port for the vacuum line that goes to the air cleaner. Open the throttle a little, the choke butterfly should snap shut. This should cause the green weight on the passenger side of the carb to move up (that is the fast idle cam). Start the engine, the choke butterfly should open slightly (pulled open by the vacuum break, aka "choke pull-off"). As the engine warms, the choke butterfly should continue to slowly open until it is vertical after 3-5 minutes. After the choke is fully open, blipping the throttle should cause the green weight to drop back down.
If any of these things does not happen, you've got some sort of choke problem (even if it has a new choke thermostat). The one most closely related to your described problems is the green weight dropping down after the choke is open and the throttle is blipped.
Ok, I found the green parts you were talking about on an LG4 carb I had laying around, then compared it to the L69 carb to find the weight. I didn't follow exactly what you told me but what I did (air cleaner and etc were already removed) was hold a finger over the vac port, then threw the choke all the way open. The choke butterflies went vertical when I did this. Moving my free hand over to the other side I pulled the throttle. When I did that the choke snapped shut. (I'm trying to avoid running the motor unless I really have to because I'm not sure if my car is charging either, but that is a problem for another day I want to get it idling lower so I'm not working on a motor that is idling like its doing 80 on the interstate).
Because of the snapping shut I'm assuming (if I understand it correctly) that the choke is working right. Naturally I should probably fire up the car to be 100% sure.
