Fotis Posted July 19, 2019 Report Share Posted July 19, 2019 Hi everyone, so i was tuning my own vehicle today, B18C with bolts on N/A. I did one run with 18deg at wot to start my base line on the dyno. Everything was okay, but once i added 2+ deg of IGN timing, Rpm cut occurred like is was a rev limit. Does this only when i go further away from 20 deg advance. Changed Spark Plugs still does the same thing should i check my distributor? Here are two logs . Please dont mind the fuel being too rich it was for test only to make sure there wasn't any knocking occurring. Thanks prob 2.llg prob.llg Quote Link to comment Share on other sites More sharing options...
Brad Burnett Posted July 20, 2019 Report Share Posted July 20, 2019 2 questions for you: 1 Did you sync the initial timing in the ecu to match the motor? 2 Did you set the rotor phase angle on the distributor? Quote Link to comment Share on other sites More sharing options...
Fotis Posted July 20, 2019 Author Report Share Posted July 20, 2019 Yes i synced the initial timing. But what you mean the rotor phase angle? Isnt that done from the ecu while you sync the timing to match? Quote Link to comment Share on other sites More sharing options...
Richard Hill Posted July 20, 2019 Report Share Posted July 20, 2019 Looking at your log files, I suspect something might be wrong with your triggers, just before the RPM limit cuts in, the engine speed ROC changes dramatically. Can you post a triggerscope of the event? HTH, Richard Quote Link to comment Share on other sites More sharing options...
Fotis Posted July 20, 2019 Author Report Share Posted July 20, 2019 Yes but later bc i took out the dizzy to change the igniter. The thing is if i retard the timing 2 degrees this will go away and it will operate like normal. Quote Link to comment Share on other sites More sharing options...
Fotis Posted July 20, 2019 Author Report Share Posted July 20, 2019 Anyone? Quote Link to comment Share on other sites More sharing options...
Fotis Posted July 21, 2019 Author Report Share Posted July 21, 2019 Dwell time 12.70ms isnt that too much? I am guesing the MSD Coil went bad and it does that? Quote Link to comment Share on other sites More sharing options...
cj Posted July 21, 2019 Report Share Posted July 21, 2019 can you grab a trigger scope at idle and about 5-6k? Those dwell spikes are a similar symptom as what Richard Hill was talking about with trigger or timing issues. Quote Link to comment Share on other sites More sharing options...
Fotis Posted July 21, 2019 Author Report Share Posted July 21, 2019 Yes i will post em tomorrow but timing is locked and correct i've checked it 3 times. Maybe my external msd coil went bad. If so i will do a COP. Quote Link to comment Share on other sites More sharing options...
Brad Burnett Posted July 22, 2019 Report Share Posted July 22, 2019 On a distributed ignition engine, it is possible to have the timing syncd with poor rotor phase angle. When that happens and you try to advance the motor too far, it is possible to have the spark try to jump to the next cylinder instead of the correct one. I always set the engine to 20ish degrees before tdc and rotate the distributor to have the center of the rotor button pointed directly at the number one pole. Then lock down distributor and sync the rest of the timing thru the computer. Quote Link to comment Share on other sites More sharing options...
Fotis Posted July 22, 2019 Author Report Share Posted July 22, 2019 Yes i did it as you said and still doing that also i forgot to mention that i have an external msd coil instead of the stock inside the distributor. Quote Link to comment Share on other sites More sharing options...
Richard Hill Posted July 22, 2019 Report Share Posted July 22, 2019 Post a triggerscope of the event and 1 at idle, there probably is something wrong with your triggers which is manifesting itself at high rpm. Also, a copy of you map would help. Quote Link to comment Share on other sites More sharing options...
Fotis Posted July 23, 2019 Author Report Share Posted July 23, 2019 Here you have it i checked the triggering at idle was okay this is somewhere 5-6K rpm. Update : Changed my dizzy and spark plug coils Still does the same thing. could be the ecu it self?.. for sure its not the trigger i have checked it Trigger Scope Log 2019-07-23 8;10;19 pm.llg Quote Link to comment Share on other sites More sharing options...
Fotis Posted July 23, 2019 Author Report Share Posted July 23, 2019 Anyone from the LINK Tech Team that can help me? Quote Link to comment Share on other sites More sharing options...
Simon Posted July 23, 2019 Report Share Posted July 23, 2019 You mention having an external MSD coil what igniter is being used to drive this coil? Can you also post a copy of you map/tune Quote Link to comment Share on other sites More sharing options...
Fotis Posted July 24, 2019 Author Report Share Posted July 24, 2019 Hi yes Simon i had the MSD external coil and changed the whole dizzy to a stock. So now i am running a stock ignition system from honda, and still does the same thing. The msd coil was used with a stock igniter from honda named "hitachi". Now setting the base timing etc what i did : Placed the dizzy at the center of the top bolt mount. Then locked ignition to 16 degrees and did my offeset untill i see 16 degrees at the crank. How should i set the rotor phase angle? I quite don't understand. Even with this dizzy still cant get over some degrees. I was thinking of doing a COP but i have to be sure that the problem comes from my ignition system. Here is a copy of my map and a new log : Thanks. spoon.llg Quote Link to comment Share on other sites More sharing options...
Simon Posted July 24, 2019 Report Share Posted July 24, 2019 Given it only happens with the extra advance I'm relatively sure it is a cross fire issue. Which is then giving noise on the triggers causing the dwell to miscalculate. Only other bench test would be to spin up the distributor in a lathe or distributor graph machine to check how It responds with no load on the ignition. Quote Link to comment Share on other sites More sharing options...
Fotis Posted July 25, 2019 Author Report Share Posted July 25, 2019 Alright i will do Cop conversion today and i hope it will get fixed Quote Link to comment Share on other sites More sharing options...
Gregconboy158 Posted July 25, 2019 Report Share Posted July 25, 2019 Remember to change the dwell table to accommodate the k20 cop. I can send my table later if needed when I get home from work. Fotis 1 Quote Link to comment Share on other sites More sharing options...
Fotis Posted July 25, 2019 Author Report Share Posted July 25, 2019 Yeap or just confirm if this are correct. 1.6-2ms @ 14V? Thanks man Quote Link to comment Share on other sites More sharing options...
Gregconboy158 Posted July 25, 2019 Report Share Posted July 25, 2019 This is mine Quote Link to comment Share on other sites More sharing options...
Fotis Posted July 25, 2019 Author Report Share Posted July 25, 2019 Thank you Greg. I will tell if the problem is solved Quote Link to comment Share on other sites More sharing options...
Simon Posted July 25, 2019 Report Share Posted July 25, 2019 Make sure to change over the spark edge too for the K20 coils. Fotis 1 Quote Link to comment Share on other sites More sharing options...
Gregconboy158 Posted July 25, 2019 Report Share Posted July 25, 2019 Yes completely forgot to say that too! Make sure you do as Simon has said! I forgot and fried some new coils lol Fotis 1 Quote Link to comment Share on other sites More sharing options...
Fotis Posted July 25, 2019 Author Report Share Posted July 25, 2019 Just to confirm, is this correct? By the way how do i check the timing light while having coils? i have the innova 3568 timing light Tomorrow is the day of truth hehe. Quote Link to comment Share on other sites More sharing options...
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