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Post by mmanatrey on Jun 25, 2019 21:20:15 GMT
Hello,
It seems like my 1977 998 with an auto is finally having some issues with the transmission. Whenever I put it into Drive or reverse, the RPM's drop considerably and it idles almost too low, eventually dying. Ive had this issue before but not to this extent. Whenever I would be driving and stopped at a stoplight, I would either put it into neutral, or pull the choke to up the RPM's until I got moving again, but now even with the choke pulled it still will eventually die. I checked all the vacuum lines to no extent. I will say that the car is running rich right now if that changes anything. Don't know if I missed a vacuum line or something, but if anyone knows what to do please let me know!!
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Post by puddingmobile on Jun 27, 2019 2:39:28 GMT
When it starts to die does it feel like it's trying to drive through the brakes?
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Post by wimfournier on Jun 30, 2019 12:47:34 GMT
It is always the question where to start looking for 'the problem'.
In this case I struggle on the fact that you mention that the mixture is already (bit) rich and that pulling the choke doesn't make things better anymore.
This brings us to the possible conclusion that your engine is suffering from 'false air' in the induction tract.
So; take your spanners and see if the nuts on the manifolds are tight.
After years the gasket shrinks that much, that the airtightness gets lost.
Mind the nuts that secure the carburetor to the manifold too.
You will understand that when the engine is sucking in false air between the inlet valve and the carburetor, this air does not bring with it evaporated fuel. So since long time you have put the carb richer and richer to keep it turning over at idle. And in the end (now) the engine is running much too rich when driving and much too lean at idle.
When you find out all the nuts are just tight, then it is time to find out if the gasket is still leaking air. Therefore you take a spray bottle with brake cleaner an you spray it on the gasket from above and from under. with the engine idling. If the response is that the revolutions go up, it is clear you have found the leak. Spray a bit on the sides of the carb where the axle of the butterfly protrudes the sides of the carb body. These axles wear in the holes in the body of the carb. That can go so far, that there exists an serious airleak and that is in the inlet track 'behind' the point where the fuel is added to the inlet air.
Good luck.
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Post by jockduck on Jul 1, 2019 11:15:05 GMT
I am not saying that any of the last post is not true but there is an old saying that 90% of fuel faults are ignition, I would have to say that in my experience that is true, since putting in a electronic ignition system I have only had to adjust my SU once in 18 months whereas before I would be adjusting the carburettor every month. Once saw someone pull a Carburettor multiple times chasing an intermittent misfire turned out to be a loose ignition coil connection.
Jock
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Post by wimfournier on Jul 1, 2019 21:17:49 GMT
When you have a loose connection on the coil that give current interruptions at odd moments triggering a spark in one of the cilinders at a odd moment. When the piston is rising in the compression stroke it gives an adverse shock in the driveline. When the outlet valve is (still) open it gives a bark from the exhaust. None of these things do I reed in this message, so, look for false air first.
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