My engine is suffering from bad idle. It idles smooth in about 1000 (I don't have tachometer but approximately) rpm, but when I try to lower my rpm, engine starts to shake, smoke more than before and run bad idle. I think my idle is too rich. Is there any kind of adjustment for idle mixture? I think I could get my engine idle smoother if I could lean idle mixture.
Is there any possibility to lean it in q-jet? What are those two adjusting screws in front of carburetor?
My ignition timing is ~7-degrees BTDC without vacuum advance in idle.
You mean the 2 small screws near the base of the carb? Those are the air/ mix screws. You have to have the car close to it's base idle speed to set those. They have an influence on idle, but should not make idle erratic. Go back to the exhaust and check out the exhaust pulse. Smoke, is it black, blue, or white? Exhaust pulse at it's best should be a steady flow. If, at low idle, you are getting small explosions (pomm, pomm, pomm) You have a possible cross fire in the ignition. Black exhaust and erratic timing to the exhaust note, the carb is dumping fuel and the excess is most likely firing in the exhaust manifolds upon hitting the exhaust from the adjacent cylinders. This can also be the case of an exhaust valve not fully seating and the excess burning off. You should do a compression test to determine the condition of your cylinders sealing.
Blue smoke is an indication of oil use. You see this on start-up, and then it fades? If this is the case, the valve oil seals or valve stem wear are possible suspects. More constant, something is wrong with the rings or pistons. :nono:
There is a cloud of smoke in startup and if i look into exhaust when the car is idling, I can see smoke coming all the time. Smoke can only be seen when i look into exhaust, it can't be seen if i just look at the back of the car.
My car also burns lots of oil 1 litre/1000miles.....
The oil burning could possibly be fouling the plugs. You should take a look at a couple of them. It could be the carb too, but it's hard to say without hearing it. I guess you could play with those idle mixture screws. They are generally 3 - 31/2 turns out. Don't turn them in too tight when seating them to count turns. They can be damaged if they are turned in too tightly; just lightly seated.
That is a considerable amount of oil use for one of these engines. I would do a compression test to see if the problem could be narrowed down to one general area. Does the smoke come from one pipe more than the other, or equally from both pipes?
Make sure you check the spark plugs of all cilinders to identify the one cilinder that is causing the irratic rpm. Then continue to pinpoint the cause: spark plug, wire, oil, valves...
I have those new wires now. They didn't help my problem.
My caddy idles worse than before. Lots of blue smoke coming out from the exhaust when idling, when Im accelerating, my car will "shoot in exhaust" a loud bang and black smoke comes out.
Could it be that my intake manifold gasket is leaking from lifter valley both oil and air? I think that would explain the blue smoke coming out from engine bad running.
It is possible for the intake gaskets to have fatigued, but that is usually caused by expansion/contraction and/or corrosion from the engine coolant going to acid and eating through the gaskets. The black smoke and the manner of operation you describe suggests a timing/carburation problem. It could be your timing chain needs replacement, you distributor advance mechanism has become inoperative, the timing and the carb settings need adjustment. :bigroll:
By the way, did you check if your spark plugs are connected the right way from the distributor? If you switched a connection it means two or even four cilinders will not 'burn' and dump a rich mixture in your exhaust... That could also cause irratic idle and bangs.
...still can happen to the best of engineers. :halo:
By the way, did you check if your spark plugs are connected the right way from the distributor? If you switched a connection it means two or even four cilinders will not 'burn' and dump a rich mixture in your exhaust... That could also cause irratic idle and bangs.
^^I was just wondering, because oil wouldn't cause the banging in the exhaust... :suspect:
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