1. turbofiat124

    turbofiat124 Premium Member Forum Donor

    I know this has been discussed in another thread but...

    Does the engine speed on your Trabant "ramp up"? Like the engine get's wound up and it takes awhile for the idle speed to drop?

    What I mean is if you rev the engine up or come to a stop light does the engine take several seconds (like seven or more seconds) before the idle speed falls and stabilizes? I don't know if that makes any sense. And an inconsistent idle speed. Is this a characteristic of the Trabant 2 stroke engine or is something else going on?

    It may just be that the engine is just loaded up with fuel and is just taking a while to "burn off" but I wonder if it's related to the ignition timing.

    Reason I ask is I wonder if the centrifugal advance on mine is sticking or delaying. Like the springs are worn or the mechanism needs lubricating or something.

    I converted mine to electronic ignition but still has the advance mechanism. Some electronic ignitions systems do away with this advance mechanism and use a pipe or something in it's place. I think Andrew in New Zealand electronic kit uses this.

    Up to around 1000 rpms, the timing is at TDC. The advance mechanism starts to engage around 1000 rpms and is fully engaged around 1400 rpms. Based on my observations using a timing light and my tune up tachometer.

    After I got my Trabant I had an issue where the idle circuit must have been clogged and in order to get the engine to idle, I had to raise the engine speed to over 1000 rpms so it would idle. This caused a really inconsistent idle speed because of the advance mechanism engaging and some stalling at red lights. After I gave the carburetor a good cleaning it idled much better and stopped stalling.

    I going to test a theory I have. The EBZA system uses a fixed timing. So does the EBZA system idle any better than the system using the points?

    The idea is to lock the advance weights in place and set the static timing to 4 BTDC. EBZA is suppose to be 3 BTDC. I don't know why the difference but 1 degree shouldn't matter. Especially since the fuel we have today is much better than what was sold in the DDR back in those days. If pre-ignition/pinking is of any concern.

    The reason for this is whenever you advance the static timing, the engine speed increases with it. So if the timing tends to wander, it's going to mess with the idle speed.

    I found on Fiat engines, which calls for a static timing of 10 BTDC, the engine idles much smoother at 17 BTDC. Before 1979 when the EPA mandated electronic ignition on all cars sold in the United States (American cars were already using electronic ignition as far back as 1973) the EPA called for the static timing on Fiats to be set at TDC. The result was the engines idled rough, bucked under acceleration and lacked power, etc. The "fix" was to advance the timing to 10 BTDC.

    So I'm thinking advancing the static timing on my Trabant would idle better as well.

    From my understanding the reason for TDC at idle with point systems (on Trabants) was to make the engines start easier.
  2. Steve

    Steve Loyal Comrade

    My first car, the 1983 601 limo which I converted from 6v to 12v had the same idle problem you descibe. I kept the points /condensers and standard carb, and when I came to stop at traffic lights etc., I got an increase in revs for a while and then I used to let in the clutch a little with it in 1st gear to slow down the revs which seemed to work. If I had the headlights switched on, this didn't seem to happen as the load on the alternator was greater.

    In my present car, the 1990 kombi, which has factory EBZA ignition, the idling is much better, although I detect a little slower revs when I switch on the headlights.
  3. turbofiat124

    turbofiat124 Premium Member Forum Donor

    I noticed the same problem after installing that 60 amp 6 volt alternator. I was able to fix this drop in idle speed using LED H4 headlight and auxiliary bulbs. Of course there is a work around involved when using 12 volt bulbs with a 6 volt electrical system.

    All four of these bulbs pulls about 4 amps total compared to 28 amps. I talked about this is another thread. They work OK on low/dipped but on high beams/main beams don't seem to cast as far as the halogens but I think if I aim the auxiliary lights up a bit, it may compensate. Since I have them wired into my high beams anyway.

    One idea was to simply wire them into a relay or the headlight switch so the headlights would come on with the car running and just bump the idle speed up but I found the headlights actually drags the engine power down a bit.

    One a side note:

    Right now I am trying to sort out the doggy wiring on my Citroen 2CV. I spent about four hours yesterday replacing the connectors in the engine compartment starting at the bulkhead and working my way toward the front of the car and I am still not done! The car also appears to have been involved in a electrical fire. The wiring harness goes above the driver's heat exchanger and someone had spliced in a foot long section of about 20 wires. Most of the wiring is green and uses these color corroborated sleeves that slips over the connectors. Trying to preserve these sleeves, I meticulously pulled each one off the original connector and crimped new universal ones on, one at a time to make sure I didn't get any wires crossed up. And had to wipe the black paint off with lacquer/cellulose thinner to see what color they were.

    Then to make matters worse there are these junctions where 4 wires are crimped together with a copper clamp and then taped up. The goal was to solder these junctions and use heat shrink tubing.

    I managed to solder some of these junctions together but others I could not because of the size of the wiring, I couldn't get my soldering iron hot enough. So I had to use those butt connectors and copper tubing in some places. Not something I really wanted to do.

    Hopefully I didn't get any wires crossed up. Otherwise I guess when I turn my headlights on, the horn might blow.
    Steve likes this.
  4. 'bant

    'bant Loyal Comrade

    I had a similar problem which I traced to a lack of lubrication in the throttle cable. I haven't experienced the problem since despite using the car in a hard winter with a fair bit of idling before driving off (to help another problem). Which, given the quantity of blue smoke produced in the first couple of hundred metres or so suggests that the engine has excess fuel in it. There are no odd effects if I rev the engine after it has idled for five minutes or so either.
  5. turbofiat124

    turbofiat124 Premium Member Forum Donor

    After I locked the advance mechanism so I can run a fixed 33 degree advance, my car seems to idle smoother and more consistent. My theory is because the advance engages at such a low RPM, this can cause the timing to advance causing the engine to speed up. Also based on my experience, engines don't idle very well at TDC. So this should create a more efficient burn at idle. Less likely to foul plugs from excessive idling.

    Check out my video on my wasted spark electronic ignition system I'm building for my Trabant. If it works on a 2CV it should work on a Trabant. So far I've just tested it in my garage.

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