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So, I have had this thing for about 3 months or so. In the beginning, I disconnected the electric choke and just left the choke wide open, because it didn't work and constantly buzzed at me. I have been letting it warm up for a few minutes before driving, and have not had a problem.
Last night, I was tooling around and getting some Buffalo Wings and Rings for my wife, when I decided to open it up on a stretch of road. When I reached Geo Metro speeds, I backed off and finished the drive home, which was less than half a mile.
This morning, when I started it up, it did not want to idle properly anymore. It idles around 400 rpm and wants to die all the time now. When I give it gas, there are no stumbles or misses that I can feel. It runs nice and smooth, but drops down to 400 rpm again when I brake. In neutral it tachs at 500 rpm and acts like it wants to die.
I am at work right now, so not near the car (I swapped it out at lunch). I just want to get a few ideas of what to look for when I get home.
It's an '81, with a '79 carb and distributor on it.
Did I maybe blow a vacuum hose off somewhere when I gunned it? Something come loose in the carb, like a dirt clod, maybe? Float stuck? Time to replace the L81 with an LS3, maybe?
No shortage of possibilities, but I would srt by looking for a vacuum leak. Lots of vacuum lines on these cars. I have had similar symptoms when the intake gasket failed. I would start by disconnecting the vacuum lines and plugging them one at a time to see if it makes any difference.
So, from what you guys are hinting at, this isn't a "Oh, here's your problem" deal.
Looks like a weekender project, then.
As an aside, while checking the timing out, what should it be set to? I imagine when the cam was put in by a previous owner (L48 clone cam) the timing was set to stock. I have read it should be set to around 11 degrees at idle, some websites saying 13 degrees.
Last edited by DVAST8R_88; Aug 1, 2017 at 03:42 PM.
Reason: Spelling
So, from what you guys are hinting at, this isn't a "Oh, here's your problem" deal.
Looks like a weekender project, then.
As an aside, while checking the timing out, what should it be set to? I imagine when the cam was put in by a previous owner (L48 clone cam) the timing was set to stock. I have read it should be set to around 11 degrees at idle, some websites saying 13 degrees.
I would plug the vacuum advance, and try 36* at 3000RPM. Then see what it is at idle.
So, from what you guys are hinting at, this isn't a "Oh, here's your problem" deal.
Looks like a weekender project, then.
Assuming the pistons go up and down, the valves open and close, and the compression is good, your left with spark and fuel.
Could be a plug wire slipped off, or a fouled plug.
Could be lack of correct air/fuel.
Gotta divide and conquer.
Just for grins, check your distributor lock down and make sure the distributor didn't move slightly when you were on it.
But this could be the perfect opportunity, "Honey while I was out picking you up Buffalo wings and rings the old motor went out, so now I need to replace it".
How could she argue with that?
LS3 time for sure.
Last edited by OldCarBum; Aug 1, 2017 at 07:09 PM.
Just for grins, check your distributor lock down and make sure the distributor didn't move slightly when you were on it.
But this could be the perfect opportunity, "Honey while I was out picking you up Buffalo wings and rings the old motor went out, so now I need to replace it".
How could she argue with that?
LS3LS-X time for sure.
Anyway, I didn't get to look at it last night other than to make sure the choke wasn't doing anything weird.
I went home a bit ago for lunch and checked things out. I didn't have a problem until I punched it the other night, so I was checking out the carb.
Moving things by hand, there felt like there was some binding near wide open throttle. It would go, but not smoothly. I worked the throttle back and forth through the full range a few times, with the sticky feeling near the end each time. I made sure the throttle plates were closed and started the car.
After a minute or so of feathering the gas pedal, things fell back into rhythm. It runs and idles just like it has since I got it.
So, secondary throttle plates maybe not closing all the way after I opened them up? Maybe?
I have put more miles on it in the last 4 months than the previous owners did in the past 5 years. Maybe the carb needs a good cleaning, or replace the carb to manifold gasket? Both?
Regardless, it is running just fine now.
My work computer won't pull pics off my phone, so I have to wait till I get home to post my latest pic.
Anyway, I didn't get to look at it last night other than to make sure the choke wasn't doing anything weird.
I went home a bit ago for lunch and checked things out. I didn't have a problem until I punched it the other night, so I was checking out the carb.
Moving things by hand, there felt like there was some binding near wide open throttle. It would go, but not smoothly. I worked the throttle back and forth through the full range a few times, with the sticky feeling near the end each time. I made sure the throttle plates were closed and started the car.
After a minute or so of feathering the gas pedal, things fell back into rhythm. It runs and idles just like it has since I got it.
So, secondary throttle plates maybe not closing all the way after I opened them up? Maybe?
I have put more miles on it in the last 4 months than the previous owners did in the past 5 years. Maybe the carb needs a good cleaning, or replace the carb to manifold gasket? Both?
Regardless, it is running just fine now.
My work computer won't pull pics off my phone, so I have to wait till I get home to post my latest pic.
Imagine gratuitous Corvette picture here.
I would send it off to Lars for a refresh. Best $$ you'll spend.
I got myself a large spray can of carb cleaner and went to work. I really hosed down the outside of the carb first. The thing was covered with bronzish looking crude. Then I sprayed into the venturies and worked the throttle plates back and forth for a while. Then, I sprayed exactly one crapload down the vent tube into the fuel bowl and let it sit for a few minutes.
I also discovered that the port at the rear/top of the airhorn was open and sucking air. I put a cap on that.
Not only is the idle problem gone, but I have seriously improved the throttle response.
I may still send it out for a rebuild when the cold weather comes, but for tight now, I am pretty happy with the results.
And Suddenly... crappy idle!
