Weber DGV: Not Idling: Problem Solved

[Aaron Datsun]

Situation:

  - The car is not idling, it revs just fine, but it will not idle it immediately dies. It was running and idling great.

  - I just fueled it up for the first time since I bought it (it did have old gas in it for sure) and the next day it stopped idling

  - Any help would be appreciated. I have tried to write a detailed synopsis up to this point, I am starting to get a bit frustrated.

 

 

Specifications

  - L20B: Newly rebuilt

  - Weber DGV (32/36 Redline)

    -- Can get jet sizes, but the car was 

  - Fuel Filter: New

  - Timing set per stock: Verified with timing light

  - Choke was fully engaged and open

  - All tests were performed without a filter on, or the crank vent hooked up

 

What I have done already: 

  - Checked all jets: They are clean (even pushed air through them)

  - All Emulsion Tubes Checked

  - Pump discharge nozzle: The top was loose, tightened after removed and cleaned

  - Checked the accelerator Pump it seems to be working

  - Checked fuel level in the float bowl: Sitting about half way, first time I took them off the gas looked nasty and old

  - Tried adjusting the idle mixture screw (currently set at factory default 1.5)

  - Idle Stop set WAY to high (should be idling at 1300 RPM how far out that is)

  

  - From the Trouble Shooting Guide:

    -- Read through all the first steps since the car starts and runs and won't idle I don't think they really apply

    -- It stalls, hesitates or dies: Step 5C (per the instructions do that then move from there)

    -- 5C: Test Fast Idle (couldn't perform, to warm) though the car does run for about 5 seconds then dies

    -- 5D: Automatic Choke: Choke assembly warmed up to fast, but it opened on its own

    -- 5E: Nothing noted wrong here

    -- 5F: Not Equipped

    -- 5G: Cannot get it to idle so I have done it from everywhere from 0-3 turns (half turn increments)

    -- 5H: Checked the idler jets

    -- 5I: I have two vaccum sources (one needs to be blocked), the other is on my vacumm advance for the distributor it seems to be working (I do not have a vacuum gauge)

    -- 5J: Float boal looks right (it was here where I noticed the nasty fuel, which I sucked out and replaced with clean fuel), I did not change the float levels

  

 

What I haven't done: Use a small cup of gas that I know to be fresh to see if it is the old and new fuel mixture

 

Edit below to make the problem solving and solution in one post for easier searching later

 

- Did not run off of the new gas

- Took a feeler gauge (Shim) to the bottom adapter plate it slid right in. So I took off the carb, all the adapters, put locktite on the bolts and reinstalled. It is idling perfectly now!

  -- Credit for the fix goes to Datsunaholic

 

Links to resources:

- Jetting Chart (Not my jet sizes) http://2.bp.blogspot.com/_dlt8k_lxV9c/TAPyQcSHX5I/AAAAAAAABTU/LLA_52-qdR8/s1600/3236dgv+jetting+001.jpg

- Tuning Guide: http://www.carburetion.com/Weber/adjust.htm

- Trouble shooting Guide: http://www.3fowlers.com/Weber%20Trouble%20Shooting%20Guide.pdf

 

[datzenmike]

Does it have an idle cut solenoid?

[Aaron Datsun]

Does it have an idle cut solenoid?

 

 

There are no electric solenoids on the carb. I just checked again the definitive answer is no (this was edited to be more clear)

[racerx]

Run some gas from a can

[datsunaholic]

Did you remove the carb, or just open it up in place?

 

- The manifold adapters, particularly the 2-piece ones have a nasty habit of having the bolts back out.  Especially the ones that go into the manifold, and then they push the adapter up and cause a vacuum leak.  Engine will run (lean) but only above a certain RPM, won't idle.  I've had this happen numerous times.  In fact, the truck I just got a few weeks ago, the prior owner gave up on it b/c it wouldn't idle.  The adapter plate was loose.  I tightened it up, only to have it loosen up 200 miles later.  This time I put blue loctite on the bolts, which usually does the trick.

 

- The main jets aren't what lets it idle, so did you clean just those or did you also pull the side screws that cover the actual idle jets?  Since you don't have a cutoff solenoid it'd be a brass plug on the same side, in front of and below the choke heater.

[Charlie69]

It is either fuel supply problem or vacuum leak.

 

If you did not clean tank and lines and install new fuel filter you might have clogged the idle passage.  Blow compress air backwards through the idle fet port with the top of the Weber removed.

 

Check for Vacuum leaks.  Vacuum directly affects idle.

[racerx]

Did you remove the carb, or just open it up in place?

 

- The manifold adapters, particularly the 2-piece ones have a nasty habit of having the bolts back out. Especially the ones that go into the manifold, and then they push the adapter up and cause a vacuum leak. Engine will run (lean) but only above a certain RPM, won't idle. I've had this happen numerous times. In fact, the truck I just got a few weeks ago, the prior owner gave up on it b/c it wouldn't idle. The adapter plate was loose. I tightened it up, only to have it loosen up 200 miles later. This time I put blue loctite on the bolts, which usually does the trick.

 

- The main jets aren't what lets it idle, so did you clean just those or did you also pull the side screws that cover the actual idle jets? Since you don't have a cutoff solenoid it'd be a brass plug on the same side, in front of and below the choke heater.

...or sometimes people tighten them too much and caves in causing a vacuum leak

[Aaron Datsun]

Datsunaholic, I did all my adjustments with the carb in place. I will check those bolts today, could you tell the adapter was loose without removing the carb? Edit: Ding Ding Ding, I believe we have a winner.i just checked the gap with a feeler gauge, slide right in. I am about to head to Church, but when I get home I will pull it apart and tighten them. I will report back in my next post

 

Charlie69, I pulled the idle jeta along the aide and pushed air through them. I did not clean the tank, but I changed the filter before I fired the engine the first time.

[Charlie69]

Be carefull over tightening the base nuts may result in warping the base and causing vacuum leak. Only 12 ft lbs of torque

[Aaron Datsun]

Charlie69. I don't know exactly how many Ft-Lbs I put on it, but I used a small allen wrench and tightened that way. It is running WAY better. I also finished wiring up the electric fans.

 

Thank you RATSUN!

[Charlie69]

An easy way to check for vacuum leaks is spray starting fluid around the base of the carb moving around the base of the carb with the engine running. If the engine increases in RPM then there is a vacuum leak

 

The Weber manifold adaptors are notorious for coming loose and leaking. That is why we use red loctight on the bolts, studs, and nuts to help precvent this leaking.

 

I am happy your car is running better.

[edekalil]

Just curious, while y'all are talking about a 32/36 dgv, I just put one on my L16 in my goon. It starts and runs and sometimes idles. The jets say 160 and 175, is there a better jet setup I should use. I have a kit to rebuild the carb. The l16 it is on has been rebuilt with low miles on it sense the rebuild. Any suggestions on the jets I should use? I have not worked on one of these befor so I'm up for any tips.

[Charlie69]

I would disassemble that carb and soak it in a bucket of carb cleaner for a couple hours take it out rinse it good with your water hose and look it over real good.  if it is not clean enough to eat off of put it back in the carb cleaner and let it soak another couple of hours.  When you finaly get it clean the blow all the ports and passages backward with compressed air.  Make sure all passages are clear then proceed with the rebuild.

 

Put the carb back on the vehicle adjuct it and drive it then determine if the carb needs re jetted.  As dirty as your Weber is on the inside it cannot fuction properly.

 

I have had my last new Weber on my truck for 7 years now and next winter I will pull it of and put a kit in it.

 

Report back how it runs after rebuild.

 

Caution Do NOT soak it longer than a couple hours at a time, the acid in the carb cleaner will start breaking down the alloy.  This is also why you rinse it with water.

 

Check out the video links here.

http://community.ratsun.net/topic/61446-j13-engine-after-market-parts-and-all-other-520-521-cross-over-parts-with-mg-also/page-2?do=findComment&comment=1342518