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MGB '77 MGB runs for a bit, then shuts down

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Wizardd

Wizardd

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Was able to get it running after sitting for at least a couple of years, got the dwell set and the timing is as close as I can get it w/o timing light. Starts and runs (seems a bit rich, I think) but will suddenly die as if it's out of fuel...will restart easily after it cools down. Any ideas on what gremlin to chase first? Am new to these cars...just aquired it from brother and sis-in-law.
 
Just a thought, but if you have a spare, try another coil.
Also, did you replace the points and condenser or just set them. It could be the condenser, but try coil first.

Hope this helps.

Dave :savewave:

Let us know what happens. Welcome to the forum. Lots of good knowledge here
 
before condenser, check the obvious - is the gas flowing? is the float stuck? Is the gas fresh. More likely after two years that something is gummed up somewhere along the fuel system.
 
Ah-ha! moment? Maybe...or not, will let you know! Think maybe the fuel pickup tube (am guessing it must have a screen on it?) is being fouled by who knows what. Will drop the tank, drain it and have a look. Since it's been sitting for so long, it may be clogged by 'varnish'...and maybe other trash. when it shuts down the fuel pump gets noisy, as in no fuel in it, I took off the filler cap, disconnected the hose from the pump to the tank and blew air into the hose in hopes of unclogging the pickup, added more fuel to the tank (in case it was simply low on fuel) and the results are the same. Thanks for the input, will post results later.
 
Hi;
I agree,probably fuel related in some way.Also check the float bowl vent line for airflow.If you have old gas in the car change out the old fuel filter for sure if you haven't already. You could unhook the fuel line from the carb(s?) and attach a tube to the line and pump the tank out into a gascan and refill with good fresh gas,this is a good test for your fuel pump too, to make sure its consistently performing etc.
Also check your fuel tank vent line for being plugged,a buddies midget had that problem years ago and we ended up running a wire down it and probing and blowing through it with compressed air till it blew the crud out.
The vent line on my 74 sticks up close to the carbon canister on the passenger side,it comes up out of the tunnel and gets joined by a rubber vacuum hose to the carbon canister.The other end is inside the trunk on the right side up near the top of the inner fender ,there is a seperator tank there with the vent lines running to it.Not sure how your 77 is rigged but should be close.
:cheers:

Good luck and keep us posted

Mark
 
Long day of it! Checked tank pickup...found it wasn't necessary to drop tank...just raised passenger side with floor jack and it was right there on other side of leaf springs...no problem there. Checked quite a few other things, too. Seems to be a problem with the ignition switch but that's not the issue...pump still seems to 'run out of fuel' for a few minutes, then will restart with no problem but now suspect crankcase breathing system...will pursue that further tomorrow. I have the hose from the valve cover removed (the one to the vapor cannister), removed valve cover and ensured the 5/64th inch hole isn't clogged. There is a hose going from the cannister to the carb (I think or the air filter?), there's a square hole in side of filter (Factory?)...is there supposed to be some sort of fitting there to accept one or more hoses? Car has Weber downdraft carb. I'm slowly running out of ideas here! Thanks for any input!

Vance Roberts
 
Ah! A new day...with a bit of rain interferring with my next step! Am preparing to attempt adjusting the valves...rather ugly there but not prepared to pull the head and have it hot tanked just yet...that'll be for another day. Cross fingers and hope it goes as smooth as it's supposed to be!
 
Vance -

Not sure if it has already been suggested, but have you tried running with the gas cap off? If it runs OK, then you have an obstruction to deal with.
 
Yes, I've tried that too! Didn't solve the problem, very frustrating!
 
Hang in there - no doubt it'll be something simple, and you can do the Homer dope slap!

~~Like I do all the time!~~
 
Valve adjustment went smoothly and quieted the engine...but didn't solve the 'running out of fuel' problem...am wondering, has anyone ever experienced an intermittent fuel pump problem? It's almost as if it gets heated and loses it's ability to suck up the fuel...seems that it should either work or not work, but...??? It's an aftermarket pump BTW...just have it laying there, two hoses, two wires...will permantly attach if/when the problem is resolved.
 
Wizardd said:
...am wondering, has anyone ever experienced an intermittent fuel pump problem?
Click to expand...

It's an MG for crying out loud.
Self answering question
 
Lol...so I'm beginning to understand! The pump however, is not MGB...it's aftermarket...am convinced at this point that the impellar must be losing suction after running for a bit. Will break down an get a new one soon. Perhaps I can then get on to the other issues I want to do on this vehicle.
 
Anything you install on an LBC takes on the characteristics of the mother ship.
Therefore...
 
A Facet brand low pressure pump from any autoparts store will work.
 
check the float in the carb - it may be binding
 
Make sure the pump isn't sucking air! I had that happen and the culprit was a cracked suction line between the tank and the pump. After setting, enough fuel would move up to the carbs and it would run for another short period and then shut down. Just a possibility. PJ
 
After extensive testing, looking for blockages/vacuum buildup in tank, etc. I'm convinced the problem is the pump...it simply gets noisy as it ceases to pickup fuel...though I'm surprised that it's an intermittent problem. I would have bet money that a pump would either work or not work...glad I didn't bet the farm, would have had to buy a farm to pay off the debt!
grin.gif
 
A quick trip to A-Z or Advance for that Facet will end the messin' 'n guessin'. :wink:
 
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