I'm now driving my TP (carby) sedan daily. Having adjusted the auto choke, it runs and starts well hot or cold and fuel economy seems good. It runs smoothly but has no real power.

It can cope with hills but I haven't encountered a long, steep hill at highway speeds yet. When I hit the accelerator on the flat, it picks up speed fairly well but does not surge forward anything like my EFI wagon. Yet when I bought the wagon, I was disappointed it was not noticeably more powerful than the previous carby TM sedan.

So, I am sure it is down on power. I've searched the forum and read the posts about seized secondaries and would put money on that being my problem. Either that or a vacuum line.

So my first question is: If a bottle of carby cleaner does not free up the secondaries, what do I do need to do to unstick them?

Also, one of the vacuum lines connected to the carby is blocked off. The previous owner cut it and blocked it with a screw but I don't think he or his mechanic had much of a clue.

I intend buying a few metres of vacuum hose and replacing all the vacuum lines because some are slightly perished. I will replace them one at a time rather than ripping them all off together.

Is there a complete diagram anywhere of the vacuum system? I'd like to identify the blocked off line and check that the others go where they are supposed to.

regards
Coldamus

seized secondaries... or leaking vacuum for the diaphragm

mine work 100% of the time since i did some re-routing of the vac and added a cable tie or two.

Thanks for the replies and to Magna Buff for the diagrams. I will have a go at it next weekend and report back.

Incidentally I just did my first proper fuel consumption check and it worked out at 14.3 litres per 100km - not as good as I thought, although it was all city driving (granny style).

seized secondaries... or leaking vacuum for the diaphragm

mine work 100% of the time since i did some re-routing of the vac and added a cable tie or two.

Yeah, who stepped you through that and got it working for you :cool:



A jet meters fuel. A throttle meters air. The jet relys on airflow to create a pressure difference past the venturi to induce flow through the jet.

If you have a blocked jet, your carb opens both throttles and only gets a limited amount of fuel.. it stalls and flat spots because its way too lean. This rules a blocked jet out.

If your secondary throttle doesn't open, no air flows, no fuel flows and you rely on primary throttle/fuel to power the car... its not enough for high rpm/power and the motor just doesn't produce power.

BCX7, why don't you take some photos of what I told you to do on your setup, and I will host it or you can make a sticky thread about it.

Thanks, I've printed off both diagrams so there's no need to keep them up. I think the second one may be for EFI but it still gives me something to go on. I've also found another diagram of the emission control system, as below. It's for a TM but should be similar.

Turbo_charade is spot on with his description of the symptoms. There's no flat spots, it just doesn't put out much power.

THE JETS ARE NOT BLOCKED

It is only possibly 1 thing. His secondary throttle is not opening because of a cracked diaphram in a dashpot or a vacuum hose error/leak.

This morning I spent a couple of hours on it. I changed the fuel filter since I had a spare one on hand. When I took the old filter off, I was surprised that no fuel ran out of it. I went to blow through it and it was partially blocked.

With a new fuel filter on, the car seemed slightly improved but still not up to scratch.

Next I poured some carby cleaner through the carby throat, ran that off and took it for another drive. Again there seemed a slight improvement. I can see that the auto choke butterfly is now opening about 80 degrees when hot whereas previously it only opened about 30 degrees.

I then tried to trace the vacuum hoses. I did not have much success there. The diagram in my previous post seems to be very simplified. In practice, there are connectors, tee pieces, double and triple adaptors everywhere. The only fault I could definitely identify was a split in the return hose from the distributor vacuum advance where it joined a connector near the carby. I'm not even sure it is going to the right place but I fixed the split by snipping the end off and re-connecting it.

While I had the air cleaner off, I adjusted the TPS and now have that adjusted spot on. (re my other problem with the auto being reluctant to change up)

The car is now more responsive and certainly much improved but I'm still not sure it is giving full power. I need to try it on the highway on some long steep hills. Might also do some 0-100 kph tests.

Maybe I am expecting too much. I read a review of a Trabbi the other day (East German car from the Communist era). They said you could measure its 0-100 kph time on a calendar. Mine is not that bad, just doesn't get up and go like my wagon does.

Thanks for the help everybody.