Engine Sputtering and Dies

[jfnichol]

I've been trying to figure out the issue with my A4 since November. I got it running really well for 1 day. The next day it sputtered and would not stay running. The following day it would not start at all.

I rebuilt the carb, changed the fuel pump, and cleaned the fuel tank and lines. Also added an inline fuel filter. Now it will start and sputter until it dies a minute or so later. I brought a mechanic in and he seems to think the carb is not working properly and flooding the engine with fuel. He told me if it was working properly the fuel pump would stop pumping once the it got the right back pressure. All 4 spark plugs are black and dry.He recommended getting a carb.

[Dave Neptune]

First welcome to the MMI Afourian Forum.

When you got it "running good" what had you done and how long did you run it?

Dry plugs are indicative of lack of fuel. Black plugs indicate a rich mixture. And if the carb were flooding you would have fuel dripping out of the carb. Leave the carb alone for now if it ran I doubt it got plugged up again so fast.

Check to see if the choke cable slipped if so she may start.

Be sure and close your water valve until she starts to run to avoid water incursion.

You mentioned the fuel lines too. I would go over each connection from the tank to the pump. If one is a bit loose the pump could just be sucking air.

A good thing to check is fuel pressure especially if you don't find a loose connection. A gage is cheap in lets you know about fuel delivery with just a glance.

Dave Neptune

[sastanley]

Fuel pumps on A4's do not ever quit pumping. Tell your mechanic "thanks" and save your money in the future.

+1 on a cheap fuel pressure gauge. You can get an inline one (after that last filter and just before the carb) for about $15 on Amazon. I like the Mr. Gasket 1561. It will tell you if you are getting the adequate 3PSI of fuel pressure.

+2 on the welcome. We'll get it running!

[JOHN COOKSON]

DO YOU HAVE AN ELECTRONIC FUEL PUMP?

. Now it will start and sputter until it dies a minute or so later. .

The fuel pump is not working. You are getting gas to the carburetor while cranking.* When that gas is used up the engine dies.
If you have an electronic fuel pump short across or bypass the OPSS and see if the engine runs normally.
*There is wire that is co joined with the wire to the fuel pump that comes from the stater so the fuel pump operates while the engine is being cranked. Once the engine starts the oil pressure goes up and the OPSS should close.

ex TRUE GRIT

[roadnsky]

I'll repeat what John said...
What fuel pump did you add? Can you give us more specific info on that?

Can you expound on the carb rebuild and what you did?
(Specifically, if you got the float setting correct)
Also, are you SURE that the inline filter you added is installed in the correct direction? (DAMHIK)

IF you want to try a simple test, you can use a 1-gallon gas can and use gravity flow to feed the carb temporarily.
IF it then runs, you can work back from the carb thru the fuel system step-by-step until you find the issue.
Very likely, when you do find it, you'll slap your forehead and say "Doh!"