I've been reading posts on this site to fix many of the issues that came up with my first truck build but this one stumps me and everyone that has tried to fix it.

I have a 1983 w250 that hadn't ran in 20 years and dropped a new motor in it but kept original trans. I've had it running for almost a year now but haven't been able to properly drive it because it won't idle low and because of college. The current and only problem I have with the thing is no matter what I do it refuses to idle below 1000 rpm. I've changed carb gasket, studs, timed it just right, messed with different A/F mixtures, new coil, and checked plugs to make sure all cylinders are firing. It idles nice at 1000+ and got her to rev to ~5000 but wont go lower. It doesn't sound like it bogs down or anything it just hard shuts off when turning down the idle screw and picks right back up when you turn it back and crank it.

It's a 318 LA with rollers, rv cam (don't have the part number with me right now), weiand intake, and edelbrock 1906 carb. At the 1000 rpm the vacuum sits at 15 cold/ ~16 warm.

If anyone with more experience could help me out would be a blessing because I just want to see her back on the road since it's just a nice truck.

Thanks

 

Sounds like it's for sure getting too much fuel... but why? That is a strange one. Does it have an IAC? This could be the culprit, as well.

 

If the intake is a spread bore style..... Check and make sure the 1906 is not Leaking/Vacuum leak on the spread bore side. It will be ever so slit, so you really have to look.... I think your fighting a vacuum leak?

 

vac leak was my first thought but man, that's quite a leak to not go below 1k idle? still, for suuuure a possibility.

 

Just my 2 cents worth..

 

I'm headed off to the store to buy walmart out of break and carb cleaner but I wanna run some other ideas that I hope aren't the issue. Since I'm using the old trans is it possible the torque converter is locking it up and need to be run around to break loose what might be in there? Another one I'm really hoping it isn't is because I trusted Mabbco motors to build a good long block could the valve timing be off? The vacuum gauge I checked with sits smack in the middle of the "late valve timing" bit, could this cause the issue?

Thanks for the replies I love mopar but being young dumb and busy means I gotta learn from people who play with their toys more.