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MG MGB Technical - Engine dies while crusing along.

This has happened about a half dozen times now in the past 3 months. Three of those times was on the way to work today. I am putting a new clutch in my jeep so the 79B is now my daily driver.

Most of the time it has happened while traveling about 40 mph. It dies, I pull over, turn the key and it starts right back up no problem. Twice it has happened after rounding a corner and beginning to climb an incline while traveling about 15 mph.

I looked at the Tach at the time of the stall. and it had not dropped down to zero. Therefore, I believe it is a fuel problem. The car has not been running as great as it used to prior to my carb rebuild in order to pass emissions last December. I have noticed it missing when the revs are up to about 35 to 45k. I'm thinking it might be running too lean,(would this cause it to stall while crusing along), Since I had to lean it out quite a bit to pass e-test.(and it also has better pick-up during hard acceleration if I pull the choke out). I have the timing set at 15 deg. BTDC at 1500 rpm. with the vac. advance disconneted and plugged. I also switched to a grose valve at the time of the carb rebuild.

Any suggestions would be much appreciated as always.
John.
John F

Could be dirt in the carb. Also could be the Grose jet -- these
have a tendency to stick open, causing overly rich running
and stalling.

The carb may just need a thorough cleaning
(how's your fuel filter?) But buried in the archives is a long thread
about a similar problem (cuts out when turning at low speed) that
was due to a clogged charcoal cannister. This causes a vacuum
to build up in the evaporative loss control system connected to
above carb fuel bowl, hence cutting out.

Maybe clean out the cannisters and check all ELC lines before
getting into the carb again.
Ronald

John,

thunder of hooves? think horses not zebras..

check the fuel pump: integrity, wires, fuel lines, and fuel filter as well as the fuel vents from the carbs

rn
RN Lipow

Thanks for the sugestions,
I have not been into the Charcoal canisters yet. Although that was something I wanted to get to eventually. I started to unhook some of the hoses to them at one point but it looked like a little more work then what I wanted to do at the time, especially the bottom hoses. After I unhook the hoses how do they open up? Do they unscrew or do you just change the charcoal by shaking it out? Are they completely full of charcoal? Anything else go in?

Are there any advantages to the Grose jet over the regular needle? I can always go back to the needle. There was a new one with my carb kit. I'm pretty sure all the carb passages are well cleaned. I blow it out well when I rebuilt it not too long ago. Actually, the car is idleing better then ever since the rebuild.

I was hoping I would not have to mess with it too much until I get the jeep going again (it will take me a while to change it's clutch out). I am down to my last
vehicle now and I need to get back and forth to work.

RN: I'm pretty sure the fuel pump is good. It pumped well when I disconnected the fuel line at the carb. But if it is intermitant it might be hard to determine.
After the engine dies it always starts right up again.
The filter is clean. (it is a clear inline filter).
What do I check for at the carb fuel vent. Only one as it has the ZS carb.
John F

I am with RN Lipow,

Had a similar problem, my recommendation is to
change (unless you have done so already) the rubber
lines (especally the one from the tank to the pump).
A leak in this line may not yeild a puddle of fuel,
but air drawn into the line through a crack can
cause a loss of pressure (stalling) and in the long
run can ruin your pump.

The lines are cheap, and as cracks may hide in the bend near the pump I would recommend you just replace
them. Mine looked pretty good, but was cracked at the
radius on top. Plus, if they are not yet cracked, you
have just eliminated one more cheap and easy thing to
trouble shoot.
Craig Amos

You could have an HT problem, perhaps the coil, and still not lose the tach. The car will usually sputter a bit before failing with a fuel problem.
George B.

Craig: I will check and change the fuel hoses you speak of tonight. Now that you mention it. I have been noticeing a smell of fuel when I open the boot lately. I have changed some cracked lines to the fuel seperator back there in the past, and thought maybe one was loose or cracked in a different spot.

George: I do have a new Lucas sport coil. That I haven't installed yet. After reading all the archive postings about the sport coil. I was not sure there would be any advantage to changing from the std coil. I was going to switch the coil out later this summer. I'm still thinking about how is the best way to by-pass the balast resistor wire that my current coil uses. I think I just need to attach the white wire that is hot when the ignition is switched on. Comments please.
John.
John F

This thread was discussed on 25/04/2002

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