Microtech Area is for discussing Microtech systems

Timing query for 20B

Old 07-09-16, 05:51 PM
  #1  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
Timing query for 20B

I have read a few posts on here and think I have a rough idea what to do but would like some answers on what I have taken off my microtech today. First of all there is the t_rpm Map.This has a drop to 0 at 1000rpm which I am not sure is right? Should the values be consistent to create a curve dropping to 0 or 5 at 500rpm? Or does the value put in at 500rpm depend on the base timing value set?

Name:  t-rpm%20map_zpslytgr45u.png
Views: 475
Size:  37.2 KB

Next there is the T gap map.. If I understand correctly this is to alter the static 10deg separation between leading and trailing plugs. Does this map look fine and what are the benefits of changes? some rough pointers would be great. I have heard people talking about less separation but this seems to show more at lower rpm?

Name:  t-gap%20Map_zpspbb6qqg5.png
Views: 219
Size:  36.7 KB

Thanks in advance.. I am sure it is something I will be coming back a couple of times.

I need to sort out what on earth is going on with my timing light first as I checked today and it showed 40degs advance for the first mark and 60degs for the second! Something is not right?! That said I think my light only shows advance so I wonder if that is an issue? As I am looking for BTDC not ATDC like a normal piston engine.
Leeroy_25 is offline  
Old 07-10-16, 09:45 AM
  #2  
Engine, Not Motor
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Likes: 0
Received 23 Likes on 22 Posts
The t_RPM should show a linear progression as it is what sets the base timing curve. It is the "mechanical advance" in the stupid virtual distributor model Microtech uses. Bring that 1000RPM point up to be linear with the rest of the curve.

It looks like your t_gap map is the stock setting but I don't know for sure. Trailing gap is a WIDE subject of discussion. Best do a search in the EMS forums for "trailing split" or similar to turn up the discussions.

Basically, it should be either wide or negative split (not possible with Microtech) at idle, narrowing up close to atmospheric, then splitting again to around 15 once in boost.

As for your timing light issues...Sounds like you have a VR sensor connected backwards of the Microtech setup is wrong. Or your CAS is stabbed one tooth off.

You are looking for the leading timing pointer to line up with the mark on the pulley when the timing is locked on the Microtech.
Aaron Cake is offline  
Old 07-10-16, 05:37 PM
  #3  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
I will try and read some more on timing splits. Are you saying microtech cannot do negative split. Or cannot do any changes other than standard 10deg split at idle. When you say it should be wide or negative that reads as two opposite things or have I misunderstood? Please can you explain with some example numbers to be sure I am following right.
Does my t_rpm look fine other than that one point? Guess I will need to lower the 500rpm one bit?

For timing when you say VR sensor do you mean the signal lead on the timing gun? Arrow point towards the plug on L1? I had timing lock on so any microtech settings should not effect it. Cannot imagine it is a tooth out? Would it run okay like that? Sure my light only has degrees advance and I presume I would need to set the gun 5 deg ATDC to align the leading mark on the pulley? i.e Retarded? The odd thing is the timing marks come up at 40degs advance and then 20 degrees apart when of course they are only 10 degrees right?

Appreciate the help. I am new to tuning and want to start by getting my basic setup and idle sorted. Then progress to off idle low load. The rest has been base mapped already and I will hand it back to a pro for but want to have the understanding of how the settings work and what changes result in what.
I do have a rough idea don't get me wrong. I have used Power FC commander for fine tuning a bit but nothing like this! I am really kean to learn more though.

Last edited by Leeroy_25; 07-11-16 at 07:36 AM.
Leeroy_25 is offline  
Old 07-12-16, 11:26 AM
  #4  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
So I just found a good post on ignition timing and I think it may have partially answered my question. It says that to get the correct timing on a rotary you need to use a 2 stroke timing light? Something I never knew existed. That or you can divide the advance reading on the dial in half to get the correct advance amount. So if my light is correctly reading 40degs advance for the first mark that is in fact 20degs advance at idle. Think the second mark was 60degs which would mean that was 30degs. but now I am thinking the leading and trailing timing marks are 15degs apart not 10degs? is that right? Also I think the dial stops at 60 BTDC and it was not still quite aligned so could be working right from that point of view.
However. 20degs advance at idle I am assuming is not a good thing to have as it should be 5degs retarded?
So if my light does not have a ATDC option on the dial am I just setting the dial to zero and then lining up the first mark with the pointer to net 5degs ATDC leading timing?
I keep confusing myself. I will verify the marks and light are reading right before I move it as it seems to run just fine and has been dyno'd with low boost. Does seem to get a bit warmer than I would expect so that would be a symptom of over advance as I recall?

Thank you for pointers.

Lee
Leeroy_25 is offline  
Old 07-24-16, 10:26 AM
  #5  
Engine, Not Motor
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Likes: 0
Received 23 Likes on 22 Posts
I've never used a 2 stroke timing light.

Don't try and use a timing light with a dial or any other fanciness. Just a regular old timing light that flashes with the spark fires.

The Microtech cannot do negative split, which isn't too big of a deal. It does have a very basic split curve based on RPM and with MAP corrections.

It is very limited in timing because it's essentially a virtual distributer instead of a 3D table.

An example: split at say 4000 RPM would typically be zero at atmospheric pressure. But 15 or so degrees at 4000 RPM under boost.

Your t_rpm will be fine to start with once you bring that 1000 RPM point back up to be in line with the rest of the curve.

The VR sensor is the actual crank angle sensor, which unless modified on your 20B, is a 2nd gen style CAS. Connect them backwards and the car will still run but the timing will be wildly off. It is VERY easy to stab the CAS 1 tooth out. I've done it, everyone has. When installing it you need to take the cover off and hold the rotor with your thumb to make sure it doesn't move.

Do not use the dial on your light. Lock the timing on the Microtech and make sure the dial is set to zero or disabled. Then adjust the CAS until the leading mark lines up.
Aaron Cake is offline  
Old 07-24-16, 03:36 PM
  #6  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
Thanks for the reply. I am going to double check timing with another light and see. Maybe I need to check he CAS sensor wiring if it still shows way off. All my marks and CAS position seem to line up spot on.
Cheers
Lee
Leeroy_25 is offline  
Old 07-28-16, 11:06 AM
  #7  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
It is even more curious now.. I double checked timing with another light and it shows same as mine leading is around 20degrees advance. If I try and adjust it back it runs out of movement on the CAS just as it comes around correct but also the engine does not seem at all happy idling there where as it does currently.
So I took out the CAS and checked alignment and dropped it in 3 times or more. Still the same. I could really do with a pic to verify where the CAS points once installed.
Mine keeps position pretty well so the points are at the corners of the CAS sensors. Someone told me they should be centre of the sensors which would probably bring the timing back correct on the light but no way I can get it there installing the CAS all correctly aligned. Plus the unhappy idle once adjusted makes me wonder? Please can someone help!
I also heard there was some 20b engines with a different firing order? Not sure if that I true and if it would account for my issue.

Other thing I noticed. If you rotate the engine by hand towards TDC or the leading timing mark should you hit a compression peak at TDC as you would with a piston engine or will compression and exhaust happen just before. Looks to me that compression is peaking around 20 degrees before which doesn't sound right to me. Aligns with the timing I am seeing too. But then all my pulleys and marks seem to tie up?! Confused as hell!

Cheers
Lee
Leeroy_25 is offline  
Old 08-01-16, 10:04 AM
  #8  
Engine, Not Motor
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Likes: 0
Received 23 Likes on 22 Posts
It really sounds like your ignition polarity is wrong on the CAS, or to the coil. Sounds like the exact symptom.
Aaron Cake is offline  
Old 08-01-16, 02:53 PM
  #9  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
Okay.. So does that actually mean the timing is off or it just appears that way when polarity is wrong?
Presume I can just check continuity from ecu to coil and ecu to CAS using the wiring diagram? Sound like a plan unless there is an easier option?
Not sure where the harness joins are for that as I did not do them.
Anything else I should consider checking? Is there a global correction I may have missed that could be in effect?
Thanks again
Lee

Last edited by Leeroy_25; 08-01-16 at 02:59 PM.
Leeroy_25 is offline  
Old 08-04-16, 05:19 PM
  #10  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
I thought you were on to something Aaron. However, this evening I verified that my coils and plugs are connected the right way around and wired correctly into the ECU. I also confirmed the CAS is wired correctly.
What next.. There is either some global correction at play I have missed or my timing marks are somehow out which I am discussing on another thread.
Thanks
Lee
Leeroy_25 is offline  
Old 08-06-16, 10:28 AM
  #11  
Engine, Not Motor
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Likes: 0
Received 23 Likes on 22 Posts
There is a setting, I think all the way in the options screen (screen 30?) that sets the ignition trigger whether it is on the positive or negative side of the pulse, and whether to trigger the coil on the positive or negative side. Perhaps that has been changed? It would cause the symptoms you describe.

Another possibility...Was your front hub and pulley ever mixed up with one from another engine? Or re-marked?
Aaron Cake is offline  
Old 08-06-16, 03:14 PM
  #12  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
Hi Aaron, I have never mixed up mg hub or pulley, but it is possible it happened in the past I guess. I will see if I can find this setting. Any idea what it might be called? I read there is TIMtrm in the manual last night for global timing adjustment. Not had Tim to plug in and check that though. I swear timing cannot be too far off as it runs pretty nice. I would guess a touch advanced if anything. If I ever get to the bottom of this we will see. I will check TDC with the oil in the chamber method next week as well and see where it all ends up!
Leeroy_25 is offline  
Old 08-07-16, 09:50 AM
  #13  
Engine, Not Motor
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Likes: 0
Received 23 Likes on 22 Posts
I honestly can't remember what that setting is called and don't have the manual handy. But it is in the manual where most settings are described.

If you are SURE the CAS isn't stabbed one tooth off, and you are SURE the ignition is triggering/firing on the correct polarity, and that your timing light works, then you can verify TDC. If the 20B is like the 13B (I don't know) then TDC is when the keyway of the eccentric faces the port side of the engine.
Aaron Cake is offline  
Old 08-07-16, 03:06 PM
  #14  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
As I am now not confident in anything not being 100% sure what was done before I owned the engine my best bet is to validate tdc with oil in the chamber method and go from there. I will hook my manual out and see if I can't find that setting. The more I think about it this setting or global correction seems the most likely answer.

Cheers
Lee
Leeroy_25 is offline  
Old 08-08-16, 07:23 AM
  #15  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
I Have found the settings in the manual I think. There are 2 that sounds like they could effect it but I am not sure on which should be changed or checked?
input Trig - Sets ECU to Trigger on either positive or negative edge of input signal. Default Positive.
or
Spark Trig - Sets ECU to fire spark on either positive or negative edge of output signal. Default Positive.

It sounds like they should be preset correctly from factory though and not messed with? So if they are correct (i.e set positive) do I leave them alone or if I check my TDC and everything and still have a problem change one or both of these? I guess there is nothing to say pins have not been swapped around in one of the plugs at some point. Verifying TDC has to be the first thing for peace of mind now either way!
Leeroy_25 is offline  
Old 08-09-16, 04:42 PM
  #16  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
So I checked out my ECU settings today. First looked at the global timing trim setting which is set at 0.
I then looked at the Input Trig setting. This was set to positive as it should be.
Next I checked the Spark Trig setting and ha haaa.. This was set to Negative.

<a href="http://s157.photobucket.com/user/Leeroy_25/media/spark%20trig_zpssuedqv3m.jpg.html" target="_blank"><img src="http://i157.photobucket.com/albums/t59/Leeroy_25/spark%20trig_zpssuedqv3m.jpg" border="0" alt=" photo spark trig_zpssuedqv3m.jpg"/></a>

The manual says this should be set to positive normally. However when I went to change it there was not an option for Positive. the other option shows SER4? See below.

<a href="http://s157.photobucket.com/user/Leeroy_25/media/spark%20trig2_zpswjihlnda.jpg.html" target="_blank"><img src="http://i157.photobucket.com/albums/t59/Leeroy_25/spark%20trig2_zpswjihlnda.jpg" border="0" alt=" photo spark trig2_zpswjihlnda.jpg"/></a>

What does this mean? Do I want this or is something else a miss?

Cheers
Lee
Leeroy_25 is offline  
Old 08-13-16, 09:58 AM
  #17  
Engine, Not Motor
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Likes: 0
Received 23 Likes on 22 Posts
Is this ECU configured by Microtech to run a 20B?

Negative trigger is the setup on stock FC/FD coils. The LTX series uses Microtech coils which trigger differently as "IGBT" which is a stupid way of describing that the ECU is directly controlling the base of an IGBT coil driver and thus has to bring the coil high to charge, then go low to fire. What coils are you using? Can you provide some more information on the setup? Pictures, etc?
Aaron Cake is offline  
Old 08-13-16, 05:27 PM
  #18  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
I will post a picture tomorrow. I assume they are stock 20b coils. I do not have the option for IGBT in the setup. Just negative or SER4. I have no idea how or who configured the ECU. I bought the complete running setup in an unfinished FC project car which I swapped it all out of.
I checked out my TDC tonight and as best as I can tell the marks are pretty good so the CAS is in correctly. So it only leaves this setting you mentioned I think. Can I harm the motor swapping it? Just tk see if the timing then comes in correct?
Leeroy_25 is offline  
Old 08-14-16, 06:02 AM
  #19  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
Leeroy_25 is offline  
Old 08-15-16, 12:20 PM
  #20  
Rotary Enthusiast
iTrader: (1)
 
Join Date: Dec 2006
Location: east
Posts: 927
Received 5 Likes on 4 Posts
as you know a car can idle and rev, but doesn't mean it's running correctly.

I think the seller may have purchased the ecu used, and it's configured for a different CAS? did you check with microtech? they are pretty good at answering specific questions such as this.
stickmantijuana is offline  
Old 08-15-16, 03:10 PM
  #21  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
The car has been on a dyno and made 420bhp with only 8psi boost at about 5000rpm. It seems to run pretty well! Maybe a little.hot but that could be poor cooling system. And smoked a lot on overrun but I think that is fuel map too rich under vacuum. Maybe it is wrong.. I certainly hope not at this point but it would be just my luck. Messaged Microtech yesterday and hoping to get a reply.

Cheers
Lee
Leeroy_25 is offline  
Old 08-20-16, 10:10 AM
  #22  
Engine, Not Motor
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Likes: 0
Received 23 Likes on 22 Posts
Ah, those are Mazda coils. Which explains the negative trigger. You said LTX-12, so I assumed you were using Microtech coils.

Dumb question but the spark plug wires are on the correct plugs, right? We've all been there.

At this point I'm out of ideas. Your ignition capture settings look correct. Your trigger settings look correct.

Is there ANYTHING connected between the ECU and the coils?

And are you sure, 100%, the CAS is stabbed correctly? The way I usually stab them is to take the top cover off and hold the wheels in place with my thumb during insertion (giggity).
Aaron Cake is offline  
Old 08-20-16, 02:49 PM
  #23  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
Dam it! I thought that had sussed it! So the negative spark trig is definitely right with the positive input trig?
Pretty sure plugs are on right way! Leading, trailing and numbers wise! And the wires from ECU to coils and CAS to coils appear to stack up with a continuity test. Nothing else connected either? Maybe I need to try the trailing lead and see what that shows.
Did exactly as you suggested when stabbing the CAS. Pointer on the CAS remain pointing at the corners of the sensors once installed with pulley at tdc. Not centre as I have been told before. To be fair mine does not seem to have any inclination to want to go anywhere else but there during install.
I am at a total loss? And do not want to run it in anger without getting this sorted!

Thanks for all the help so far.

Cheers
Lee
Leeroy_25 is offline  
Old 08-27-16, 10:21 AM
  #24  
Engine, Not Motor
iTrader: (1)
 
Aaron Cake's Avatar
 
Join Date: Feb 2001
Location: London, Ontario, Canada
Posts: 29,671
Likes: 0
Received 23 Likes on 22 Posts
I'm out of ideas without actually being able to see it.
Aaron Cake is offline  
Old 08-27-16, 02:57 PM
  #25  
Rotary Enthusiast
Thread Starter
 
Join Date: Aug 2008
Location: Portsmouth UK
Posts: 1,101
Received 13 Likes on 13 Posts
Fair enough.. I am stumped. Doing other bits at the mo but will get back on this shortly and try and suss it!
Thanks for the help so far Aaron.
Leeroy_25 is offline  

Thread Tools
Search this Thread
Quick Reply: Timing query for 20B


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: