DOA

[Sscottdvm]

Thanks seebeltp

That's my next step. I did replace the fuel pump just now, took me three hours. A few people have mentioned the " dual points". I have to learn how to do the timing. Have a manual , wiring diagrams and voltmeter. I really think it's a vapor lock issue. I get spark when it won't start. It will start for 30 seconds when I pour gas in the carbs then dies 15 seconds after using up that fuel. Once it's cold again starts and drives fine. Hey, maybe I'll get lucky and the pump for some reason won't start the car when's it's hot and been sitting for an hour

[architect]

Thanks seebeltp

That's my next step. I did replace the fuel pump just now, took me three hours. A few people have mentioned the " dual points". I have to learn how to do the timing. Have a manual , wiring diagrams and voltmeter. I really think it's a vapor lock issue. I get spark when it won't start. It will start for 30 seconds when I pour gas in the carbs then dies 15 seconds after using up that fuel. Once it's cold again starts and drives fine. Hey, maybe I'll get lucky and the pump for some reason won't start the car when's it's hot and been sitting for an hour

So I had the same problem.. replaced all electrical components (went with fireball / new blue ignition / sparks / wires / everything) and replaced the mech pump with Facet fuel pump.

It would drive like a champ, then all of a sudden, after sitting for a few weeks, it would run for 10 seconds then die. I went through all the hoops and could not figure it out.

check your fuel pressure. I ended up having to replace my steel lines. My theory is the pump pushed all that crap thru the lines and my fuel pressure dropped significantly. The tank had crap in it, the lines were dirty.. and I could not keep my fuel filter clean for the life of me... So I threw in the towel and replaced it all!

I decided to run a fuel reg with gauge, and all new stainless lines (which lead to a new tank, new sender, new everything from carb inlet to fuel cap). GOOD LUCK! it wasn't that bad, and now I know my carb is getting fresh clean gas... at the correct pressure.

[Sscottdvm]

I sure hope I don't need to do all that. I replaced the fuel filter when I got the car and it still looks clean. My problem is ONLY when the car has sat for about an hour and the engine is still warm sitting in the sun. Never happens at night, I'll test it out today. Run it for 20 mins then let it sit in the sun for an hour, that usually causes the problem. Next step timing check and maybe that electric fuel pump.

[architect]

I sure hope I don't need to do all that. I replaced the fuel filter when I got the car and it still looks clean. My problem is ONLY when the car has sat for about an hour and the engine is still warm sitting in the sun. Never happens at night, I'll test it out today. Run it for 20 mins then let it sit in the sun for an hour, that usually causes the problem. Next step timing check and maybe that electric fuel pump.

Ah. If your filter is clean, totally ignore my post above LOL.

But I am curious about the heat. I'm in Texas.. and trying to mitigate any issues heat will drive. (Subscribed)

[Sscottdvm]

My solution at this point is don't take it out on warm, sunny days. Not a great solution but better than waiting for 1-2 hours until it feels like starting again.

[seabeelt]

Sounds like it starts fine on the starting or advanced points. It does t want to start on the running points. Could be a relay issue or a points issue

[Sscottdvm]

Have no idea if the points are the problem but if it's warm and I just stop for a few minutes it starts and runs. If it sits for an hour or two, it starts runs for 30-40 seconds and dies. Sometimes can start it up pouring fuel in the carbs. Sometimes need to wait 1-2 hours. Can the dual point set up cause this kind of problem?

[seabeelt]

Well that amplified things some. it's Possible depending on how long the car ran before you shut it off and if all systems shift from starting to running points Have you found the relay under the dash ( under the glove box) Is there a relay in the socket or is it jumpered out?. I'm now leaning more towards a carb issue if the relay is in place and if you can hear it click. It could be that the car is cooking off the gas in the carb bowl. It could be leaking when warm when things expand through any number of places

As a double check, identify which set of points has voltage when you first start the car. The other set will then be the running set. ( you should be able to tell from wire color but that's not guaranteed given the age of these cars ). Run the car at home until the car reaches temp. Radiator fan should cycle on and off three or more times. Now check which set of points has voltage. If it's the same set, the relay didn't switch over to the other set. If it did switch over you can probably eliminate that for the moment

Let the car sit to recreate your non start condition and turn the key and recheck the points voltage. If still good on the running set, you can then progress to a fuel issue

Have you checked the actual timing yet?

[Sscottdvm]

Michael
Unfortunately I think you're getting way beyond my skill level. Looked for the relay, there is a plate covering everything. When I turn the ignition I hear a click but think it's the seat belt light coming on. Opened the distributor and thinks look clean and unfrayed. How can you test voltage to the points while the car is running ?

[Sscottdvm]

Also, I've never seen this fan come on. Have even popped the hood while the car is hot and it never turns on. The car always runs at about 190 degrees on a warm day. In traffic it did get up to 200. Maybe the engine needs to get warner for the fan to kick in.

[nelsonj]

The fan should kick in just above 195. Pay attention to your engine temp. If it gets much above say 200 and the fan doesn't come on, something is wrong with the fan circuit. NEVER let the temp get to the red. If it's getting close, pull over, turn off the car and let it cool down. The fan definitely should be running if your getting close to the red.

Have you had the "no hot start" problem since you changed the fuel pump?

[Sscottdvm]

Its started fine but the weather hasn't been warm enough( only seems to happen when sits in the sun at the beach) or dry enough to drive much. The red zone isn't until about 250. Let it idle and it got to about 210, still no fan. I assume that could be anything from a bad thermostat, wiring, fan motor, some relay switch somewhere. Looking to buy another MG as my reliable weekend driver. Just need more garage space.
Think it's time to send it to my mechanic although he's too busy and won't touch it until the fall. Of course the starting problem won't be an issue then.

[nelsonj]

210 sound too hot without the fan coming on. You need to get that working properly but as long as you don't creep up to the red you are ok to drive, and it sounds like your car is working pretty good if the temp is staying in the mid range while driving.

I think there are only four wires to the fan - there is a sending unit/thermal resistor at the bottom, and then power to the fan unit. Check the board, I'm sure there is troubleshooting the fan post. Shouldn't be hard - and its usually just the sending unit (easy to replace, and if your fast you won't have too much fluid drain out in the process!)

Much better to identify these things BEFORE they become a problem. But again the fact the car is running at good temp if a very positive starting point.

UPDATE: I did some reading and the fan and horn are on the same fuse. Does your horn work? If "No", you likely need to replace the fuse that controls both.

If the horn works: Mark says "the easy way to test the circuit is to jumper the two wires to the thermo sensor. If the fan comes on then the entire circuit is good and you either have a defective switch or it's not getting hot enough".

Basically, the fan should always have power to it. The "thermoswitch" on the fan opens the ground when cold, and when the switch gets hot, it closes and connects the fan to ground. Then the fan runs. When the switch cools down, it opens the ground and the fan stops. Pretty simply. Thus, you should have power to the fan, and shorting/jumpering the terminals of the thermal switch should complete the ground circuit and the fan should run - regardless of the car's temp. If you have power to the fan, and it doesn't run with the thermoswitch shorted/jumpered, you may not have a good ground connection to the switch. You can use a volt/ohm meter and test for ground.

If you have power, you have a good ground and the fan won't start with the thermoswitch jumpered, then and only then should you conclude something is wrong with the fan. It seems the most common problem is a blown fuse (or a fuse that isn't seated correctly, or a bad ground connection to the thermoswitch (in which case you need to clean all the wire connections or add a new ground wire.)

Should be an easy fix.

[Sscottdvm]

Turns out the fan does actually work. Troubleshooted as a nelsonj suggested, turns out corroded ground wires to the switch. Replaced and comes on right at 190. While doing that noticed smoke coming from the corner of the radiator, guess a leak, put some bar's leaks in and no more smoke for the time being. May take it out in the sun today and see if it will start after sitting.

[nelsonj]

Glad to hear the fan was a quick fix. It's important to have that working properly. When everything is working, the cooling systems are reasonable and can handle any driving conditions I've seen (including stop & go in 100+ weather). But if anything goes wrong (such as the fan doesn't kick in while in traffic, or a leak in the radiator), there isn't much "fat" built into the system and you can get into overheating trouble quickly. If the gauge every starts to get close to the red, don't ask why, just pull over and let the car cool down. I have a 1600 that I needs to rebuild because I didn't take my own advice....

Peace.