Datsun Roadster Forum-311s.org

A little about the rodster. 1600. These were all installed at the same time. Weber dcoes 40s with a east coast electric ignition and a afr meter . Electric fuel pump at 6 psi
115 main
Impassioned tube f16
Air correct 150
45 f9 idle jet

I can start the car but is popping at the carbs and running lean at idle on the afr. If I try to drive it it dies and has no power. I give it any gas and won't move . And afr is lean. I adjusted the carbs and nothing. The moment I give it gas it just leans out and dies. I am stumped. Could it be a ignition issue?

srfjay wrote: ↑Sat Jul 09, 2022 6:14 pm A little about the rodster. 1600. These were all installed at the same time. Weber dcoes 40s with a east coast electric ignition and a afr meter . Electric fuel pump at 6 psi
115 main
Impassioned tube f16
Air correct 150
45 f9 idle jet

I can start the car but is popping at the carbs and running lean at idle on the afr. If I try to drive it it dies and has no power. I give it any gas and won't move . And afr is lean. I adjusted the carbs and nothing. The moment I give it gas it just leans out and dies. I am stumped. Could it be a ignition issue?

No help here, but best to have introduced one new system at a time. Water under the Bridge. Best of luck.

Yes that would be the right game plan. Unfortunately I bought the car missing the distributor. And carbs were missing peices.

How many turns out are your idle screws?

How confident are you that you installed the distributor correctly?

Idle screws are 1 and a half out.
And I would say pretty confident. I actually just rechecked everything tonight. I removed the distributor and put everything to top dead and reinstalled with the wiki instructions. And still rough. Idles fine but once any throttle leans out and dies. And popping out of the carbs . Which to my knowledge is a lean issue.
I am thinking maybe the generic electronic fuel pump might be a issue. Maybe try and rebuild the stock fuel pump and see if the issue continues.

Bwk2000 wrote: ↑Sat Jul 09, 2022 10:24 pm How confident are you that you installed the distributor correctly?

My very first thought. I ran my very first engine for 80 miles with the the plug wires crossed. The Mikuni's snarfed through the throats, but it more or less idled and I could get it to drive down the road but not well. So do check all ignition... firing order, timing, consistent spark, etc.

However, your meter says lean, so ignition system is less likely I think. The carbs will definitely backfire when lean, sometimes loudly. You should be able to adjust the idle screws out to where it is stupid rich, so are you saying you cannot richen the mix at idle? If so, you are not getting fuel to the carbs. Remove your main fuel jet (air, emulsion tube and main fuel) and look inside for fuel level, or insert a short clear straw/tube into the hole, cover the top of the straw and draw out to see the fuel level. No fuel no go, and an incorrect fuel level will be super lean. Alternatively you could have a huge intake leak, so spray around all gaskets, especially the intake manifold as I've heard the aftermarket options are very suspect (not flat, don't seal). Have you balanced the carbs with a flow tool of any kind? Keep posting, I love the Rs with dual Webers look...

1 3 4 2 firing order... make sure... been there done that...

If it is not firing the AFR would be rich no. Vacuum leak somewhere?

spyder wrote: ↑Sun Jul 10, 2022 1:01 am If it is not firing the AFR would be rich no. Vacuum leak somewhere?

Ya, that's what I was thinking, but ya never know! Changing the distributor at the same time confounds the issue...

srfjay wrote: ↑Sun Jul 10, 2022 12:48 am Idle screws are 1 and a half out.
And I would say pretty confident. I actually just rechecked everything tonight. I removed the distributor and put everything to top dead and reinstalled with the wiki instructions. And still rough. Idles fine but once any throttle leans out and dies. And popping out of the carbs . Which to my knowledge is a lean issue.
I am thinking maybe the generic electronic fuel pump might be a issue. Maybe try and rebuild the stock fuel pump and see if the issue continues.

Strange … Well, you could always disconnect the fuel line from the carbs and run a flow test to see if the pump is putting out enough gas. Probably a good time to replace the fuel filter as well.

Also, how old is the gas?

Is there a choke/ fast idle hooked up to the carbs ? Choke it some my 1600 Cold , doesn't start with out it
Take compression test . Note 1st pump reading mostly
All of the previous posts are important things to check of course
The a f m is good , butt after the compression test crank it and see if a fuel mixture comes out the compression stroke
With the high compression engines they can be fickle to start , cranking quick enough

Are you using a vacuum advance, and if so, where is it connected?

If all else fails, it may be time to go back through the build of the carbs to confirm it was done correctly. These may help:

https://racetep.com/media/old-pdf/40DCOE151.pdf

https://240260280.com/Tech/Carbs/Weber/ ... uning.html

https://lcengineering.com/weber-carbura ... ing-guide/

Trouble shooting guide is for the DGEVs but it is mostly still applicable.

Thanks guys for all the help. Also better when you have a different outlook on something.
So let's see . Fuel is fresh. Tank is clean. And no vacuum advance. I have the east coast distributor with the electronic advance. Spark plug order is correct from the wiki. No compression test yet. I can test that. No chokes . From what I rear most of the webers don't need choke.
Here is a couple pictures . Maybe something visual would help.