carb swap problems

[SiDACRD|89LX]

Ok my car is an 89 LX. Problems it had were it would die if I hit the brakes, and my secondary was stuck 25% open after it would open first time. Would surge past 4G and I couldnt make it stop. Well I got a carb off an 88 LX and we swapped them last night. Well we marked the vacuum lines so they should be right, if not then its just 1 or 2 we are working on.
But the car is running hot now, idle just stays up near 4G, and the idle speed screw and all that doesn't make a difference. It also seems to have some smoky exhaust a bit now.

Anyone ran into these problems before with a carb swap and might be able to offer any answers? If we make any progress I'll post it up, but right now maintaining high idle and running hot are the 2 main problems. Thanks.

[SiDACRD|89LX]

We think we got the vacuums right now, Idle is at 1600-1900, with the idle speed screw backed out. Idle will go up if I screw it in, but it wont go below that range almost completely backed out. I think thats the only problem we have now. Anyone know of a way I can get my idle down? And please dont tell me to turn my AC on :P

edit: Idle was fixed, car still wants to die whenever I go out of gear and get on the brakes. I can keep it in a lower gear and gradually downshift to stop while using the e brake, but it will still wants to drop without giving it gas. sometimes it will stay at about 1000 and I wont have a problem, but the majority of the time, it will want to die. anyone know anything I could check? vacuums should be straight now so I dont really know. This problem happened with my old carb too but it would cut off way faster and as soon as you hit the brakes, so now its way better than before.

[steveko]

Sounds like a vaccum leak too me.

[SiDACRD|89LX]

well there isnt anything thats not hooked up, and we didnt change the vacuum setup at all. So unless it was something that was changed to begin with, and we didnt have to mess with it or we just kept it the same, then I dont know. I'm thinking I could just barely increase the tension on the throttle cable. Id only increase my idle rpms but 100-300 but it could help

[labeledsk8r]

well there isnt anything thats not hooked up, and we didnt change the vacuum setup at all. So unless it was something that was changed to begin with, and we didnt have to mess with it or we just kept it the same, then I dont know. I'm thinking I could just barely increase the tension on the throttle cable. Id only increase my idle rpms but 100-300 but it could help

you can get vacum leaks out of noware, there ruber hoseing thats around 20 years old it can rip itself apart.... i would look around you engine bay and follow every line looking for holes... you will be shocked that you might find a few

[SiDACRD|89LX]

We'd already found and replaced a few initially, then any that ripped while taking them off. I'll just have to look it over some more tomorrow. Were supposed to start putting my new tranny in my mustang in the morning so I'll have to wait for the rain to stop to check the vacuum lines since I can't pull it in the garage. I'll post up if I make any progress, until then I'm stumped.

[2ndGenGuy]

Did you get the carb from the junk yard? Good chance it's bad too, and why the car was at the yard in the first place...

[MessyHonda]

Did you get the carb from the junk yard? Good chance it's bad too, and why the car was at the yard in the first place...

yup i learned the hard way...best best is to get a carb from a wrecked car because the reason it went to the junkyard is because of body damage not mechanical.

[SiDACRD|89LX]

well the car I got it off of ended up getting towed because it was parked somewhere and the owner never claimed it. minus the battery and I think some radiator hoses the car probably would have started up.

[cygnus x-1]

You say it would die when you press the brakes? There are two things happening there. One is increased electrical load because of the tail lights. The other is a vacuum draw from the brake booster. Try removing the fuse for the tail lights and see if that makes any difference. If not, then try disconnecting the vacuum line to the brake booster and plugging both ends. The brakes will still work but will be very hard to push. Obviously don't drive very far without tail lights or power brakes. It's dangerous and the local law enforcement won't be impressed.

C|

[SiDACRD|89LX]

Thanks, I'll try that soon and let you know.

[SiDACRD|89LX]

well I turned up the idle and it helped alot with the car wanting to cut out when I stop. the haynes manual I got had a 3 step check for the brake booster and it said everything was ok. But I still think it might have something to do with it. For the time being that car is very driveable. needs a passenger side axle and then she'll be good as new. thanks for everyone that offered input

[cygnus x-1]

well I turned up the idle and it helped alot with the car wanting to cut out when I stop. the haynes manual I got had a 3 step check for the brake booster and it said everything was ok. But I still think it might have something to do with it. For the time being that car is very driveable. needs a passenger side axle and then she'll be good as new. thanks for everyone that offered input

The idle might have been it then. If it was too low the extra electrical load from the brake lights may have been enough to make it stall.

C|

[A20A1]

https://www.3geez.com/forum/showthread.php?t=46572

[SiDACRD|89LX]

well I thought the problem was fixed but its not entirely. I can take it out of gear while driving, idles about 1100, when I get on the brakes slowly, still idles until I get alot slower. If I slam on the brakes hard and/or turn sharply, it will cut out alot faster. I can give it gas and it will staying running, but that requires me to take it out of gear, give it gas, and use my left foot to brake. After a day its pretty easy, but I shouldn't have to do that everywhere. I really think its a brake related vacuum problem. I have a 1000watt system in my car with a boat battery, 500 watts @ 2 12"s doesnt even make my lights dim at all. It has to be something other than electrical. I can also pump the brakes as I slow down and it helps alot too.

I'll read through the link that was posted, but is anyone familiar with this problem?

[A20A1]

it is possible for the brake booster diaphragm to leak.