79 Fiat Spider - New Dfev Weber - tough Idle

[harvfiat1]

I installed a DFEV Weber Carb on my 79 Fiat Spider. The best part of the install has been the very strong running under heavy foot and load.(once kicked in to the secondary all systems perform well) I did use the stock dual plane intake. There are 2 holes that almost fit the carb. The bigger hole in the intake is 36mm and matches the secondary on the carb
while the smaller hole is 28mm and a little small for the primary opening on the carb which is 32mm. I fitted the cylindrical electric fuel pump and have a fuel regulator set at 2.5 psi.

I have read that the proper intake should be a single plane from an 1800. Is not switching out the intake an achilles heal for my idle circuit and runability in general?

I was attempting to setup the idle and mixture screws according to factory instructions. My biggest problem is trying to maintain an idle of 850 rpm. When the cooling fan comes on it tends to pull the idle down to a stall. Maybe someone out there has experience in this area and could comment on where I should be headed on this issue.

The tech folks at weber carbs direct said to put a regulator on it and run at 2.5 before starting with any rejetting.

Harvey

[vandor]

Check the plugs to see if it's idling lean or rich. I would also look at the ignition system and make sure everything is ok.
Check for vacuum leaks.

The intake manifold will limit the performance, but should not affect the idle.
I doubt it's a fuel pressure problem, but check it with a gauge - if it's way too much it could be a problem.

FWIW, if you got if from WCD then it's not a real Weber.

[VaSpiderman]

Just installed a DFEV on my '79 and it is working great. Is currently on the dual plane intake and fed with an electric pump. Did spend a little time eliminating some potential vacuum problems. . . Agree to look there for your problem.

[harvfiat1]

It seems that vacuum leaks seems to be the common
Item to track down so that is where I will start the
Debug. The only vacuum lines in use are to the brake booster
And distributor advance and there are no leaks in the
Hoses. All other vac connections are plugged.
I need to recheck the pollution valve towards the front
Of the intake that I thought was plugged up
Properly. Beyond those items I could look at the
Intake manifold gasket. Any other vacuum
Connections where leaks might manifest.
Harvey

[harvfiat1]

Thanks to all who contributed to my idle fix. The culprit
Was the seal on the smog fitting towards the front of the intake.
The solution was to cut gaskets for the bottom of the casting
That covered the holes in the intake.
Idling is really great.....can't get too much of it.

Thanks,
Harvey