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MG MGA - MG won't start...help

OK, OK, it's my neighbor Cindy's car, and it's a 78 midget with a 1500 CC engine. If no one on this board can help (and I know you can) I will post on the Midget board as well, though I don't know those guys (and they are therefor suspect, though some of you are probably "them" as well...).

Car had a tune up about a month ago -- new plugs, distributor cap, and ignition wires. About a week ago (she has driven since the tune up) the car decided not to start. I checked for spark with a spare plug on the block, and it's there. Car had one of the motorcycle type glass and chrome fuel filters, which have been panned pretty well on the BBS, but I could see that it was getting no fuel. I removed the filter (in case it was somehow to blame), which changed nothing. Pouring gas directly into the carb (a Weber DGV conversion) gets it running for a few seconds, so it's still looking like fuel delivery problem.

This car has a "later" style mechanical spring and bellows type fuel pump just below the starter. Dumb question -- does it also have an electric SU fuel pump near the gas tank? I thought the mechanical pumps were pretty reliable, whereas the SU needs "regular" maintenance (which this one, if it's there at all, has probably never had). Her Hayne's or Chilton's book shows both, but not for the same version of the car, I don't think, though it's not clear. I couldn't get my fat @$$ far enough under a Midget to see the area near the tank, and I didn't have a lift handy.

What's interesting to me is that, again according to the drawing in the manual she has, the "later" style engine with the mechanical spring and bellows style pump is supposed to have a bunch of charcol canisters and emmissions stuff that is absent here, whereas the earlier stle engine with the electrical SU pump does not. Is this a mix and match car and engine?

Could it be anything other than the fuel pump? The manual said something to the effect of "if the carb doesn't provide sufficient vacuum, the bellows pump will not allow fuel to pass" -- paraphrasing here as I don't have the book handy. The wiring on this car has been reworked to the point that I am scared to even start trying to figure it out.

Suggestions, as always, gratefully accepted. At least on the MGA (MGA content here), you can get to the fuel pump without crawling under the car -- especially on my "A", which has no body at the moment!

Thanks...

JIM in NH
'55 MGA 1500
AJ Mail

The MG Midget with the 1500 engine does not have a BMC engine. It is a Triumph 1500 engine. It should have a mechanical fuel pump, camshaft driven, not an electrical SU pump.
Does the pump have a operating lever under it? If so, can you see the fuel pumping in the glass bowl? Remove the fuel line to the carburetters and see if you can pump fuel, either with the hand lever or turning the engine with the starter motor.
Triumph engines normally have an "anti run on" system that uses vacuum to lower the fuel level in the carburetter bowls. This has hoses that go from the carburetter back to the combined vacuum/emission system.
If the emission system is partially removed ensure that these hoses are not still sucking on the carburetter bowls, but the bowls are vented to the atmosphere.

Mick
Mick Anderson

A slight correction, I always word this incorrectly.
Anti run on systems do apply vacuum to the carburetter bowls, but that raises the fuel level in the bowl, it does not lower it.
Raising the fuel level in the bowl then lowers the level at the jets.

Mick
Mick Anderson

Have you checked to see if the car has the 3 main properties

1)Fuel to the carb's
2)Spark to the plugs
3)Air to the intake
Jones

A further correction to Mick's: the applied vacuum doesn't change the fuel level in the bowls, it simply counteracts the vacuum normally applied at the jet, so no fuel flows.
The statement from the manual, if quoted correctly, is balderdash, likely a Chilton.
Likely cause for no fuel from the mech pump is an airleak in the line from the tank, typically at one of the short rubber connectors, which crack with age. You can check the pump itself by removing the line from the tank and either putting a vacuum gauge or a finger over the pump inlet while someone cranks the engine over - if the pump is working, vacuum will be apparent. It is possible that the DPO has lugged up the tank vent in his changes, but not likely since the car was working.
FRM
FR Millmore

Car has air (it's a Weber with a K&N type filter right on top), and spark (see above), but not fuel.

I will check the line from the tank to the pump, and from the pump to the carbs for leaks (that's why I removed the pretty but ineffective filter), install new filters between the tank and the pump, and the pump and the carb, check that the pump is pumping (dump a temporary supply line from the pump into a can of gasoline vs. the actual gas tank).

I have been reading the archives as well on this...

Thanks for the advice so far...keep it coming!

JIM in NH
AJ Mail

With these ideas you have, pumping fuel through a hose disconnected from the carburetter, putting the inlet hose into a can of fuel etc..... be sure that the car is in the open air, or air fan forced through your garage. Be careful that ignition sparks do not contact fuel vapor.

Mick
Mick Anderson

Hi AJ. An engine needs spark, compression, and fuel to run. Since the engine runs briefly when gas is poured down the carburettor, I would say that there is definitely a fuel delivery problem. I would remove the main fuel inlet line where it enters the carburettor, then crank the engine for a short while. Fuel should spurt out the fuel line. (no smoking or open flames please)If it doesnt, then either you have a defective fuel pump, a clogged or broken fuel line, or perhaps a plugged tank vent. Blowing air through the fuel and or vent lines should confirm if they are clear or plugged. You might also want to try starting the car with the gas cap removed. If a negligent gas attendant put the wrong type of gas cap on the car, that can cause tank vent problems and prevent the car from starting. Personally, my money is on a defective fuel pump. Best of luck, Glenn
Glenn

Jim. I agree with all that has been posted. The first place to start is to remove the fuel line to the carb, install a long piece of fuel line and run it into a plastic bottle, then crank the engine over to see if fuel is being delivered. If there is no fuel, remove the filler cap and try again. One thing that has only been mentioned in passing is the venting of the fuel tank. It is vented through a hose running from the tank to the charcoal cannister. If this hose becomes blocked, as I have seen happen, the fuel pump may not be able to pump the fuel from the tank. One indication of such a problem is a "whoosh" when the filler neck cap is removed.

If the fuel pump does not pump when the cap is on, then, does not pump when the cap is removed, it is a blocked line or a bad pump. Simply removing the line from the pump and blowing back through it will tell you if it is plugged or not. If it is, you need to find out where the plug is--it could be in the hard line, the rubber hoses or the fuel filter. If the line is clear, check the line from the pump to the carb. If it is clear, attach a line to the input side of the pump, put it into a gallon can of gas, try to pump the fuel and see what you observe. If no fuel is pumped, replace the pump.

Les
Les Bengtson

Thanks for the answers guys...

I will probably be able to investigate further today and will dutifully report back on the findings, and hopefully, the resolution of said problem.

JIM
AJ Mail

A fuel pump is about $43 from World Pac, 2 in stock local. Should not be hard to find. Problem in order of probability 1 bad pump 2 air leak in lines and fittings between pump and tank 3 plugged condition of same lines and fittings. good luck.
R J Brown

If you put a vacuum gauge on the inlet of the pump and crank the engine, you should see it pull a vacuum if the pump is working.
R. L Carleen

Is there gas in the tank? I have been fooled by a fuel gage that quit working, causing me to check all kinds of things before actually checking for gas in the tank.
Ed Bell

Ed's question is the first one to ask. My neighbor tried and tried to start his truck the other day, and finally had it towed, only to find that it was out of gas.

Long ago when I was doing computer support, we fixed a lot of problems, just by asking them to make sure the it was plugged into the wall socket.

Jeff Schultz

Found the problem!

The 1/4" fuel line was broken near the bottom of the car in the transmission tunnel area.

The DPO hadn't secured the clips on the lines that attach them to the firewall so they were free to vibrate and eventually the rubber cracked where it slips over the metal line.

I put the two fuel filters in and reassembled it all with new rubber.

I did check the pump to see if it was pulling vaccum, and it is.

Car now runs. Tomorrow, when it's not dark, and hopefully not raining (will it EVER stop raining in New Hampshire this year? Maybe when it snows...) I will reattach the clips if I can figure out where they go, and make sure there are no kinks in the new lines, etc.

Thanks for the help.
AJ Mail

This thread was discussed between 20/06/2006 and 24/06/2006

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