Help! Carb/intake swap good, bad &...

[Slartibartfaster]

Finally finished de-smogging my 79 and installing an 1800 intake and weber dfev...fully expecting to somehow break a perfectly fine car. Imagine my surprise when I pushed it out of the garage, found my fire extinguisher, crossed my fingers and turned the key..and it started!
First drive... wow, what a difference! Fantastic, usable power across a much wider rev range...felt like I'd freed the little beast from it's chains. Thinking I really need to upgrade tires and brakes now...but then... I noticed it was idling at about 2500 rpm...hmm, no worries, that's just a screw adjustment, right? Took it on the highway to stretch it's legs then when I hit the off ramp it starts to stumble and stalls at every stop on the return trip.

10 minutes of joy, then frustration hits me in the face. Now it won't idle at all, just stalls. Tried the Redline kit instructions for baselining the idle and mixture in case something had vibrated loose...nothing.

Wonder if this has something to do with the distributor vacuum line (spliced) or the charcoal canister setup. I have the bottom hose from the canister going to the vapor port on the weber (above the fuel inlet) but plugged the hose coming from the top of the canister - this was connected to my old carb but there is nowhere for it to go on the DFEV. Argh...so close!

[Vandrid]

I just did this exact swap on my 79. Along with quite a few other things so I know what you are going through.
A few things I would check without seeing your exact set up: make sure all ports and holes you don’t need are plugged, did you mess with the timing? May need to adjust your dizzy. Is fuel getting to the carb? If so is your float adjusted correctly? ( I thought mine would be out of the box but it wasn’t even close.) I would also get a new vacuum line, I bought one at a car shop for about $6 to remove that splice. I also completely blocked off my charcoal filter because there is no need to connect the thing anymore with the new carb.
That’s where I started on mine. Hopefully you get it running, I know the pain of being so close but not working.

[bobplyler]

Is the choke stuck?

[Slartibartfaster]

Thanks for the responses - Choke is working fine..I'll replace the dist vac line and then get to reading about carb floats...I'm learning as I go. Could something have changed during my drive that would make it stutter and stall?

A couple of additional thoughts that may or may not matter..
-The car has an electric fuel pump that the PO had installed due to low pressure at the carb years ago
-It seems important that the driveability and stalling problems started only after the car had been well warmed up and driven at speed.
-Before the carb/intake swap everything ran perfectly, slow, but otherwise correctly.

[Vandrid]

Hmm... don’t know about the electric fuel pump thing. Mine has a mechanical and I’ve never worked on anything else.
Does it run when it’s cold? If it does then I’m thinking you have a bad mix and aren’t getting enough gas when the choke lets off.
Things to check would be fuel pressure in the line going to the carb, jet sizes and mixture screws.
If it’s not running when cold then we have a different bag of worms.

[Slartibartfaster]

Okay, I did put a fuel pressure gauge on it today and got a steady 2.5ps in between the filter and inlet so that seems ok. It started and idled about 2k so I drove around the block. With in a couple of minutes it was bucking and sputtering then stalled whenever I pushed the clutch in. Will reset the mixture screw again. I also noticed that there is an audible suction noise but couldn't pinpoint the location, so I think I might have an air leak somewhere. I'll see if I can find it with the carb cleaner trick if I can get time tomorrow.

[Vandrid]

2000 rpm seems high, even with fast idle, but you can easily adjust that, not really the problem here. Does it only sputter when trying to drive or anytime after it starts warming up?
I still think you have an issue with the mix or the ignition timing

[Slartibartfaster]

Hmm... decided today that I'm not going to get to the bottom of this without opening up the carb and checking float level, jetting, etc... don't know if this is the cause of my issues but I'm pretty damn sure that I shouldn't be finding metal shavings inside my brand new Redline Weber 32/36 DFEV, right? So much for "genuine Weber" quality.



This is only some (most) of what was in the float bowl, along with some very fine sand like brass particles collected in the corners. And the internal little fuel filter was compressed/flattened as shown inside it's tube..WTF?!

[Slartibartfaster]

Figured it out with a little help from the Redline Tech line...
The primary idle jet (and holder) was missing.. I guess it was loose and vibrated out on that first test run. I pulled the secondary idle jet out and tried it on the primary side and it idles and revs with no stalling/farting etc. now. Grr.

On the positive side, I am now MUCH more familiar with my Weber now that I've opened it up. Oh, and the float level was off as well!

Now to figure out what jet size to order...

[Vandrid]

Metal shaving lbs are very bad!!! Hope none got in the engine. Glad you are sorting everything out. I’m not good on jet sizes but you can find the info you need on the forum. Best of luck and hope you get it back up and running soon