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MG MGB Technical - white smoke, and a few more Qs

Ok, I got the MG running as you can see in the "IT STARTED!!!!!!" thread. Well, I changed the oil since it hadnt been changed in 8 years (doesnt really have anything to do with the prob, it was there before the oil change). Anyways, I run the engine, and the ignition light stays on (does this have to do with jumping the car?). Also, it runs smooth, but only with a little choke on, if I take the choke off it stays at like 1200rpm for a few seconds then just dies, but if I put my foot on the gas I can catch it before it dies, it obviously revs, and as long as my foots on, it stays running. The thing is, even with the SMALLEST amout of choke on, its at like 1500rpm... so I think the idle screws are adjusted fine seing as how it stays at 1200 rpm, but then just dies after a few seconds. Could this be because I just need to add gas, I put new gas in to get it started, but only 2 gallons worth, could this be a prob? Also, when the engine is running, theres no smoke, no smells, but a lot of black carbon stuff is coming out of the exhaust (like a semi-wet powder, is this just leftovers after sitting for 8 years?). When I turn the car off though a bunch of white smoke lifts off the valve cover and smells. There is no smoke while running, and I can see that the cams are being well lubed. Its only when I shut it off that this smell comes and the smoke lifts off for near probably 30 seconds. Also, is there a way to test to see if the oil pump is working? I THINK the cams are getting lubed, but not sure, the filter gets oil to it fine. Thanks soooo much people, Im getting an Interstate MT-26 tommorow morning!! no more harsh jump starting from here on out.
Bryan Corey

I'll address what I can: The ignition light means the alternator isnt chargig anything. Normally the light should come on when the ignition key is turned to the on position then go out after the RPM's reach 500 or so. the black debris from the exhaust may be caused by the carbs running too rich. Check your spark plugs and see what they look like. Properly set carbs will leave a brownish looking residue on the plugs. This may also be the problem with the idle. Do you have twin SU carbs? If the carbs arent synchronized you'll have a problem getting it to hold idle or it could mean they need a rebuild. Get it to idle steady then spray smoe carb cleaner at the ends of the throttle shafts.If the idle rises the throttle shafts need to be rebushed. Also idle should be around 900-1000 rpm. The white smoke may be oil leaking around the base of the valve cover. Is the smell like a buring oil odor?
william fox

I see nnow you have a Weber DGV. Make sure you dont have any vacuum leaks. I had a Weber that notoriously ran at high idle. It takes some adjusting but you'll work it out.
willia m fox

actually you were correct with the twin SU carbs. That really really seems like that would be it... the valve cover. Is there a seal there that could have worn out after 8 years? If so, Ill try replacing that and seeing if I get the smoke. Also, I dont know if its running rich or juts has too much gas. It ran fine before it sat... like a gem, it only has like 60k original miles. I havent messed with the carb settings at all, just cleaned the pistons and floaterbowls... so I dont think anything could have changed there, I dont think the carbs are sinchronized though, I know ones idle screw is down a little farther, is there a way to do this? or did you mean for fuel/air consumption? thanks for the help. So, if theres no batteries, then the alternator isnt gonna charge? So its because of jumping it, or does it mean new alternator time? thanks!
Bryan Corey

Brian,

a black residue could be the mixture is too high as William says. If the carbs are not synchronized it may be a good idea to got through the whole tuning process and set them, as this would eliminate any problems with the mixture. I have also been told that unleaded fuel does not burn as well as the old leaded type & that it is not unusual to have some black residue in the exhaust because of this.

Good luck

Scott
Scott Ralph

should I use regular? I put in premium gas.
Bryan Corey

Bryan. Might I suggest that you restrict yourself to one question at a time? Set up some form of logical troubleshooting program and address each problem until it is successfully terminated. At the current time, you have several problems and your postings do not follow in any logical order. (Such as: "actually you were correct with the twin SU carbs. That really really seems like that would be it...the valve cover.) This is a direct quote, including omissions in punctuation and grammer. What, pray tell, does the valve cover have to do with the fact you have twin SU carbs?

Might I suggest that the first thing to do is to correct the ignition warning light problem. Get your new battery and install it. You do mention that you are jump starting the car, but do not mention if it currently has a good battery installed. Running the car with no battery or with a bad battery can cause alternator damage (depending on the type of battery failure). Have the alternator checked out and replace as necessary.

Have the carbs been cleaned and adjusted? Such wonderful statements as "Also, I dont (sic) know if its (sic) running rich or juts (sic) has too much gas" cause some problems for me because, by definition, "too much gas" is "running rich", simply a question of degree. So, the carbs need to be cleaned, inspected, adjusted and syncronised for operation. Your comment that the engine will only idle with a small amount of choke on would indicate that the mixture may be too rich. With only a small amount of choke on, the jets should not be retracted--only the fast idle cam should be comining into play, providing a higher idle speed until the engine is warmed up, at which time the choke is fully released and the slow idle or hot idle adjustment comes into use.

If you are getting oil to your oil filter, your oil pump is working. "I THINK the cams are getting lubed, but not sure, the filter gets oil to it fine." If you are using a B series engine, most of them only have a single cam. Rather hard to check to see if oil is flowing to the cam bearings. Running the engine for a while, then looking through the oil filler hole in the rocker arm cover should allow you to see if there has been oil moved up to the rocker arm area.

As to your white smoke and smell. Much would depend exactly where the smoke is coming from. Generally, this indicates that there is moisture getting into the oil system in some fashion, but might also indicate an excessively rich mixture and the smell and smoke are being caused by excess gasoline being vaporized. This problem may go away after the carbs are set up properly and, at the very least, one possible cause of the problem would have been eliminated.

For choice of gasoline, I use "premium" in my high compression engines and "unleaded plus" in my low compression engines. Using premium all the time will not damage anything except your cash flow, so you made a good decision to begin your work by using premium. Did you drop the gas tank and have it cleaned of old fuel residue? If not, you can disolve the old residue in new gasoline and carry it forwards to deposit out in your carbs and intake valves. This can cause the valves to function poorly, closing in a sluggish manner or not fully closing.

Break the problem down into its parts and attack them one at a time in a logical manner. Otherwise, it is very easy to become overwhelmed and not be able to find the root causes of the problems and correct them. Les
Les Bengtson

Im sorry about the confusion. I meant that I think the smoke may be coming from the valve cover where it seals to the head. I also was adressing the fact that we had manually put a little fuel into the block to get it started, and that Im not sure if its running rich or just burning off the excess fuel that is in there from the initial starting of the car. Also, William had stated he saw I had a weber carb, and I was just correcting him by saying I have twin SU carbs. The gas tank shouldnt have any resedue in it should it? It was 100% sealed the whole time it sat inside a nice garage. When I drained the old gas it looked 100% fine and exactly like the new gas that I put in.
Bryan Corey

You should NEVER run a car that has an alternator without the battery, as the battery acts as a capacitor to smooth out AC spikes that could damage the electronics.
George B.

Bryan

I would agree with Les’s posting. I have one question; when you say you put fuel in manually how did you do this and how much? The best way to prime the fuel system is to use the electronic fuel pump. However this will not work unless you have batteries fitted. As I know doubt you appreciate. So purchase the correct battery (ies) you may need two depend on the year and set up. As stated previously you must not run the car without a battery or you'll damage the alternator.
The fuel tank is not a sealed system there must be a way for air to enter to replace the fuel as it is used under normal usage or the tank would implode. So things can get into the tank. If the fuel has not been use for some time it could separate into its constituent components that does not help when restarting a car either.
Keep posting we will get your car running!
HTH
Cecil Kimber

Ok, its not that I dont appreciate the alternator, I had no idea that it was a problem to jump the car without a battery, I had never heard that over my couple years of working on cars. I have stopped doing that now. Anyways, I allready put new fuel in, and also it wouldnt get enough fuel to start with just choke so I poured a very small amount of gas directly into the carbs (per recomendation from the local MG shop). It was the ONLY thing that worked to get it started, there was simply not enough fuel getting in after JUST choking it after sitting for 8 years. The car runs, Im just trying to figure out the smoke and why it dies. It ran 100% fine before we stopped driving it, sat for 8 years, had all the flueds changed, new HT wire, new plugs, all this, new battery, and a few new fuel lines. It starts now. I dont see how the carbs could get out of sync when the car just sat in a garage, even the local shop told me that if it ran fine before we quit running it, and all I did was clean the carbs without messing with the jet settings underneath the carbs that it should run fine now too once the little quarks are worked out.
Bryan Corey

Hi Bryan
Without being with you and the car it is a bit hard for me to say exactly where to start looking for the cause of the problem. I would hazard a guess that the carbs are caked up with residue. Petrol (gas) does not have an indefinite storage life and 8 years it would have more than likely separated as I previously described. If the fuel completely dries then it can leave a sticky residue behind this will gum up the carbs for sure. Dismantle the carbs and see if they are gummed up. If so they will have to be cleaned with carb cleaner. Whilst writing I would also suggest you look at the following pages. They describe how to restart a long dormant engine, it talks about an ‘A’ but the sequences are the same.
http://users.ntsource.com/~barneymg/mgtech/engine/de101a.htm

http://users.ntsource.com/~barneymg/mgtech/engine/de102.htm

Cecil Kimber

Ok guys, heres to help clarify, I was just out working on her. The carbs were cleaned by me, there WAS a sticky gummy gas stuff, but it was cleaned out a few weeks ago. I have narrowed the not idling problem down. It idles fine, a little high, but fine, UNTIL I put the clutch in. After that it just dies, why? It has a hard time starting with the clutch in too (in neutral of course). Also, the new Interstate MT-26 is in, the car will start on like second crank, it starts like a charm, but the ignition light is still on. Where can I check (i.e. what wires coming off the alternator) with a multimeter to see if the alternator is putting out current, and its a wiring problem to the light, or if it does in fact need an alternator. All belts work, so I know the alternator is spinning fine. The white smoke seems to be coming from between the valve cover and inlet manifold (maybe out of the manifold, just that general area). Any help is greatly appreciated again. Also, will my battery drain if the car is shut off without any ligths or anything on if the alternator is bad? as long as something isn't left turned on it shouldnt drain, correct?
Bryan Corey

Have you refilled the SU dampers after you stripped and cleaned your carbs? Do you have an alternator or generator fitted? If you have an alternator, its internal regulator or rectifier may be shot. As far as the white smoke goes, if you can determine if the smoke is eminating from the manifold seal the first action would be to put in a new manifold gasket. This may also solve your idle problems if it is leaking. The white smoke may be moisture in your oil, if you haven't changed it of course. Have lots of fun working on your B if it gets frustrating take it to a mechanic.....
Chips

yeah, the oil is changed, I have not refilled the damper oil. Do I juts turn the carb piston housings upsidedown and let it drain, then re-fill or what?
Bryan Corey

Ok, to help you guys out even more, I just filled the carb dashpots with oil (I didnt even think of them as being empty or a problem). Now there is nearly no flutter and im not really spitting anything out the exhaust. I guess that not having ANY oil in there to damper the carb pistons caused a massive flutter, which would easily contribute to too much fuel going in and a higher idle. The idle sits JUST over 1k now and is smoother, throttle response is a lot smoother, and as far as I can tell, I no longer have white smoke in the engine bay or black residue out the exhaust. Now to tackle the Alternator problem. Is there a way to test it? thanks!
Bryan Corey

Congratulations on the idle fix.

As to the alternator, you should have 12 - 13 volts at the batteries when the car is stopped. When it's running, you should have 14 - 15 volts. To test amperage, you have to shunt the meter into the line. Most multimeters aren't up to that task. Really the best test is to remove it and take it to a large auto parts store (e.g. Kragen, Napa, Autozone). They can test it for you in a minute.

I don't remember what year of car you have, but if it's a Lucas alternator, I think about 38 amps is the best you can hope for.

Matt Kulka

Actually, you should have about 12.0 to 12.5 volts at the battery. New batteries, fully charged, may show slightly more. Hook a volt meter to the battery clamps and take a reading. This is your base line. Then, start the engine and run it to about 1,500 rpm. You should see 13.5 to 14.5 volts. If you see higher, the internal voltage regulator is not functioning correctly. If you see anything other than 13.5 to 14.5 volts, the alternator is bad and needs to be replaced. If the ignition warning light is only glowing slightly and you are showing 13.5 to 14.5 volts, remove the alternator and have it checked for output amps. For the most part, the alternators seem to be physically interchangable. The one used on the late model cars will fit on the early model cars and gives, from memory, 43 amps of output rather than the earlier 34 or 38 amps, depending on model. Les
Les Bengtson

Thank you people... Ill check today, and most likely take it out and take it in.
Bryan Corey

Sorry to throw a spanner in the works…but I thought you did not have any batteries connected to your car, hence all the comments about not running the engine/alternator without some connected. If you don’t then how can you check the voltage?
BTW glad to see that you have cured the idle and smoke problems.
Cecil Kimber

I got a battery yesterday, an Interstate MT-26. I thought I stated that uptop further, sorry.
Bryan Corey

Ok, I just got it DRIVING, drives perfect, wow, I love it!!!! took it around the block a few times... anyways, The alternator light went off the first time, and didnt come back on until I came bumping back into my gravel driveway... the second time around the block it wouldnt go off, but the car starts FINE every time, and runs fine, all electronics work, etc etc... I think its maybe a short or bad connection... im going to start cleaning all the contacts to the alternator, but if you have any suggestions let me know, thanks.
Bryan Corey

Ok, I cleaned all the contacts on the alternator/wires and took it for a spin, no light, but then took it for a spin later and its back on, I have been driving it ALL day, turning it off and on and off and on when I stop at friends houses and stuff, wouldnt you figure the battery would be drained by now? especially with my brake lights on ALL the time (read my other post about that...)? It cranks perfect each time, no hesitation on startup, no signs of draining the battery, driving ALL DAY. I really dont think its a alternator prob, but more a short or some sort of wiring prob.
Bryan Corey

Bryan,

you could be right about the wiring problem. I had my alternator light come on & it turned out the alternator plug was loose. I made sure it was in properly & all was well.

Good luck & after finally getting it going i'm glad you enjoy it.

Scott
Scott Ralph

The smoke might have been caused when you added oil. If you get any oil on the exhaust manifold, it will take a few minutes to burn off and will produce a white smoke. As for the carbs, twin SU's, if the inner bowl moves up and down freely and doesn't catch you should be ok. You can check this easily with the air cleaners off. I am not sure how you cleaned the carbs, but I would guess there will be some residue in the bowls if it sat for several years. You may want to open them up and clean them as the residue can work it's way loose and gum up the fuel supply. If you have the early SU's with the bowls out side the carb you can probibally do this with the carbs on the car, allthough there is a float on the top of the bowl that must be removed carefully as it is set at a precise hieght. If you have the latter HIF carbs(no outer bowls), the carbs have to come off and be taken apart form the bottom, again with out disturbing the float settings. I would change the fuel filter after a few tanks of gas too, incase some residue has come out of the tanks and gotten caught by it.
The alternator light is on a seperate wire from the alternator. The large wire coming out is for charge and one of the smaller wires goes to the red light on the dash. If you are getting 13+ volts with the car on, you are probibally ok. I would check and clean all the wires and the connector and make sure they are all connected. You can snug them in the clip after the connector is in the alternator in my car. If that still does not fix the problem, you can reach behind the dash and remove the bulb form the warning light. I would make sure you have a good alternator first though, as if you are driving in the day, a battery can last a while. Try to run it a night with the headlights on, as the battery will drane quickly if the alternator is not up to par. The headlights should glow brighter if you rev the car from idle and the system is working well, if not the lights will start to dim after several minutes of the car running. Also if you do remove the bulb, if the alternator dies at a later point you will have no warning at all, so you may want to leave it in and deal with the intermitten glow.
Hope this helps. I see you have it running, just trying to make sure it doesn't quit on you up the road, as a bad alternator, or fuel reside will do.
J Arthurs

Bryan. The cost of a multi-meter, which will check both the voltage at the battery and the input voltage to the battery from the alternator, is about $25. Less for the simple, analog type. The multi-meter can also be used to check coil resistance and the continuity of suspect wires. To not invest in this simple piece of equipment, which will immediately tell you if the alternator is charging would seem foolish. I used to be able to run my GT for several hundred miles on a freshly charged battery with a bad alternator. But, only did that to get it home so the alternator could be checked out and, when found bad, replaced. That does not seem to be your case here. Les
Les Bengtson

Bryan,
Your correct you did say you fitted a new battery, I blame these poor old eyes!!
Anyway I had a thought about your white smoke…see you posting “Brake lights on all the time” and my reference to your servo. It could be this that is the cause of your white smoke.
Cecil Kimber

This thread was discussed between 19/06/2002 and 21/06/2002

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