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Thread: Tuning without dyno. !!

  1. #41
    <BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> However we still haven't been able to get our engine past 7500 rpm.
    I think it might be because the ignition timing we are running is too far advanced but when I retard I get a lot of back fire in the exhaust.
    There is also have backfire in our intake manifold from time to time and our MAP sensor is malfunctioning currently. </div></BLOCKQUOTE>

    The timing can be verified very easily with a timing light on cylinder 1's coil. Find out what your actual timing is based on; say a 30 degree advance on the PE. Always have that offset (there will be an offset if you use the stock wheel) at the back of your mind. We ran last year with the ignition map flat at 50 degrees of timing and 30 degrees of 'real' timing, and had no issues. (The engine, however, would run out of 'usable' advance at about 11000 rpm, would backfire there and was a pain in the noise test). When I started this year, I used that as my starting point. Still works fine.

    Once you are confident of your ignition setup, go back to your fuel table, and change fuel values only, hopefully with a multiplier like 1.05. That should allow for finer control, and should yield positive results.

    Post back here if you have any news.
    Sanket Sirpotdar
    2010 Warrior Racing Captain

  2. #42
    Im still waiting for the new lambda sensor to arrive, so cant really do much worthwhile tuning till then.

    I was checking the spark plugs today and noticed oil on the thread of cyl #2 spark plug ( again ). When I took out other plugs, there was'nt any visible oil but they smelled of burnt oil.

    Is it normal to have some amount of oil on the spark plug ? Can it be a problem with piston rings or a oil leakage in the cylinder head ?

    Last week the ground electrode of spark plug in cyl #2 got distorted (see picture). You can see the oil on the threads. I am concerned as to how it happened and whether the oil on the plug and this is somehow related.



    If the piston ring is indeed the cause for the oil leak , could that also be a reason why the engine is not going above 7000 rpm. I can see a stream of gas coming out of the PCV when the engine is running , this again points to the conclusion that there is a problem with the piston ring(s).

    I wanted to know if Im on the right path with the diagnosis or after so much time of trying Im hoping for one cause for our many engine problems.
    Pradeep V. Pandurangi

    DUT Racing Team, TU Delft
    2013: Chassis engineer
    www.dutracing.nl

    Formula Manipal, Manipal University
    2010: Team Leader
    2009: Engine team
    http://www.formulamanipal.in

  3. #43
    Im still waiting for the lambda sensor to arrive.
    A new set of problems have started with the engine this week.

    1. Oil on spark plugs: While changing the spark plug I noticed a layer of oil on the thread of the spark plug. Plug in cyl #2 had much more oil than others.

    2. I've noticed is a stream of gas escaping form the blow-by (PCV). This is happening more during initial cranking.

    3. Very rough idle :When the engine starts it idles badly for sometime (like 30 secs ) as if only 2-3 cylinders are firing then suddenly its starts running well.

    4. Erratic starting : Since the last 2 days, the engine does not start in one go , after cranking many times (atleast 7-8 times) it starts. After which again it refuses to start (even when starter motor is taking it to 450 rpm).

    All these problems make me think that there might be a problem with the piston ring wear. The engine starting problem could be because of insufficient compression and the oil on the spark plugs could also be due to the same reason.

    Is my diagnosis correct ?
    What other symptoms do I have to look for, to be certain that this is the problem ?

    Thanks
    Pradeep V. Pandurangi

    DUT Racing Team, TU Delft
    2013: Chassis engineer
    www.dutracing.nl

    Formula Manipal, Manipal University
    2010: Team Leader
    2009: Engine team
    http://www.formulamanipal.in

  4. #44
    Pradeep,
    build yourself one of these. One of the best engine tools to have.

    http://www.vmaxoutlaw.com/tech/leakdown_tester.htm

    Pat
    The trick is ... There is no trick!

  5. #45
    Mr. Pat Clarke, thanks for the link.
    We have managed to find the compressor and pressure gauges in our college lab. The spark plugs have also been removed and tapped. Only thing remaining are some fittings which should be done by tomorrow. If everything goes to plan, we'll be able to complete the test tomorrow itself.

    Thanks again
    Pradeep V. Pandurangi

    DUT Racing Team, TU Delft
    2013: Chassis engineer
    www.dutracing.nl

    Formula Manipal, Manipal University
    2010: Team Leader
    2009: Engine team
    http://www.formulamanipal.in

  6. #46
    We did the test at 75psi pressure and there were no leaks.

    After that we tried starting the engine, it did start and ran for about 5 mins.But when we shut if off and tried starting again, it did not start.

    If cylinder leakage is not the problem, then what else could it be ?
    Pradeep V. Pandurangi

    DUT Racing Team, TU Delft
    2013: Chassis engineer
    www.dutracing.nl

    Formula Manipal, Manipal University
    2010: Team Leader
    2009: Engine team
    http://www.formulamanipal.in

  7. #47
    Senior Member
    Join Date
    Apr 2008
    Location
    Colorado Springs, CO
    Posts
    460
    Your tune maybe? Warmup enrichment, cranking values, etc. These engines are tricky to get to start when tuning from scratch. I've found that bumping up timing in the idle portion of the map can help. Make sure your plugs are fresh. This will throw you off more than anything, at least in my experience, when you're writing a new fuel map. If they are black and oily/greasy clean or replace them.

    EDIT
    I just looked at the ignition map you posted, you should be able to idle just fine with that timing once you sort out fueling. If you can't get it to start and idle nicely with fresh plugs, regardless of fueling, check your timing. We've been tuning and even though I thought I set up the trigger wheel properly, we still had a significant offset when I checked with a timing light.
    Mountain Lion Motorsports

  8. #48
    @ pandurang -

    we had a similar issue while starting ours on Megasquirt, i think you should play around with the enrichments and compensations a little, wait for the engine to cool down to normal room temp. and keep repeating if it does not start again when warm.
    Hiren G Patel

    FS Orion Combustion (Founder Member)
    -------Prototype '06
    -------Powertrain Lead '06 '07 '08 '09
    -------Composites guy '10
    -------Technical Director '10
    -------Technial Advisor/Mentor '12

  9. #49
    Make sure that you have some starting compensation for fuel even if the engine is hot. We have seen many cases where the lack of "Hot" starting compensation keeps the engine from restarting during driver change.

    Good Luck!
    Brian Lewis
    Performance Electronics, Ltd.
    www.pe-ltd.com
    http://www.facebook.com/Perf.Elec.Ltd
    Engine Management Systems

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