Leeroy_25

Sorry guy's but I really need some more ideas.. After triple checking everything, verifying with microtech all my wiring and settings are correct and finally getting some measurements from another engine to accurately position and check my timing marks. The issue is not resolved!
I am really at a loss here as I have run out of resources and things to check.

Please HELP!

My timing marks and they are **** on, my CAS stab seems to be bang on too. Pointers just cutting the corner of the sensor. CAS is set about middle of the adjustment slot.
I am running microtech LTX-12 ECU with stock 20B coils direct fire from the ECU. Just to re-cap.
Input Trig +Pos
Spark Trig -Neg
Now when I run the car up and put on timing lock to check with a timing light the timing comes up about 15degree BTDC instead of 5 degrees ATDC. I double checked with the trailing timing mark and then marked all 3 leading positions and they all come up the same.
I cannot see any global adjustment in play on the ECU but it can only be something ECU driven causing the issue now as I have checked and verified everything else!?
If I try and adjust this out there is not really quite enough adjustment on the CAS slot to pull it back in and when I start moving it the rpms drop right off until it stalls at max adjustment. Idle is quite low anyway but as I understand usually idle maxes out roughly at the right timing? Or it is normally a good gauge. My idle drops off as soon as I start pulling the CAS back.

I originally checked it because I felt the engine was running a bit hot and it seems to want to run quite rich on idle to keep a stable idle.. 11.5 ish AFR. Can just about get a low 12 but not consistently. Hence it is quite fumey at idle. I believe these may well be symptoms of over advance but not sure.

Can you shed any light on what it could be or if it is normal to have to put a global adjustment in on a microtech to pull the timing back in? I have checked all the wiring on the CAS and coils numerous times and that is all correct. so I am stumped! Was certain it had to be timing marks wrong but they came up bang on.
Please help. What happens if I swap the input or spark trig settings? will it damage something. or would that setting show a far bigger timing error? Is there any other setting I might have missed that can override the timing lock function?

Thank you

Leeroy_25

If anyone else running microtech with stock 20B coils can post a picture of the adjustment on their CAS that would be great. I have just had a picture come through that implies the extreme adjustment to one side of the slot that mine seems to want might in fact be correct. Would like to see if that is common for microtech set-ups for some reason.

Thank you
Lee

Aaron Cake

iTrader: (1)

Extreme adjustment to one side of the slot means that either the CAS input polarity is wrong (in software or wired wrong) or the coil trigger polarity is wrong (again, software or wire).

Having seen this exact problem when LT8s wire wired to trigger CDI boxes without going through the stock ignitor, I'd wager the coil trigger is wrong.

CAS is easy enough to verify. Same settings as 2nd gen, same wiring I believe.

Leeroy_25

Thanks for the reply Aaron,
Both yourself and Microtech have verified my settings and I have checked and verified the wiring multiple times?
Off hand I have input Trig +Pos and Spark Trig-Neg. It is somewhere earlier in the thread I think.
Microtech sent me a picture of the CAS on there 20B Adjusted the exact same way and I have managed to dig up quite a few threads discussing the same thing which I am working through now to try and figure if this is right or not?!
I adjusted it back today and if anything it makes it want to run richer. I think I might be struggling with 1000cc primary and secondary injectors on that though? I can only get idle down to about 10.8-11.2AFR one click leaner and it stumbles and AFR's start shooting all over the places until it stalls? Smells way to rich for my liking and a bit smokey. That is another discussion though!

Would be grateful for timing thoughts though. Sounds like you don't think it is normal?!
Also when I set timing L1 to leading timing mark should there be a value of 5 in the static timing under screen 30 or should this be 0? what about input timing on screen29? or is this just for temporary global adjustment purposes?

Aaron Cake

iTrader: (1)

Honestly, I don't know. I don't see why the 20B would require extreme movement of the CAS on a Microtech. Any 13B I have seen with the CAS way off was because trigger polarity or coil polarity was wrong and the CAS was moved to compensate. But the error increases as RPM increases so it is not a fix for the issue.

Oh dear, if you have 1000 CC primaries and are running gasoline then you're never going to have an engine running very well. Those primaries are way too big to control on a Microtech due to extreme lack of injector resolution because of the way they stage injectors. I'd really recommend going down to a smaller primary. 550CC or 680CC. The 1000CC are going to be way too twitchy as you have discovered.

So wait...

I reread your initial post.

You are running an LTX12 with stock coils?

I'm not sure you can do that.

The LTX is designed to run with the Microtech X6 IGBT ignition box and Microtech coils.

If so, that may explain the timing issues. The Microtech X6 probably fires going high while the stock Mazda coils fire going low (at least FC coils do, so I'd assume 20B as it's a very similar ignition system).

You're at the edge of my knowledge as I haven't ever messed with the X version of the ECU as it's such a convoluted system in my opinion.

My honest advice after seeing you struggle for so long is to ditch the Microtech. Sell it to someone else, and buy a Haltech. When you do, you will wonder why you ever wasted so much time with the Microtech. I'm not saying that the Microtech won't work or is the cause of your issues. Just that the Haltech is about a universe better.

Leeroy_25

Thanks Aaron,
I will stick with the Microtech for now.. Even if just to get me going adequately and maybe chop it in later. I am close after all.
The LTX-12 can run direct fire with the stock coils. Microtech confirmed this directly and said my settings were right. I have googled and searched a lot and a whole heap of people reported the same thing and then tuned and run just fine?!
mis-typed my injectors sizes.. I have 1600CC Bosch EV1 all round currently. I think I need the fuel of at least a 750CC primary keeping the same Secondaries which is what I am currently looking into I a wary of such a big jump in the sizes due to the staging transition issue people report. I was planning on some ID1000 which are reported as very good at low flow rates. They are high impedance though and the Bosch are low impedance so I am not sure if I can run the high impedance on the Microtech or indeed if I can mix high for primary and low for secondary. Do you know? If the ansqer is no, my other option is RC1000 injectors which are Bosch style and Low impedance. So a straight swap.. It is pretty close on the 1600's to be fair just a bit plumey so if I can get it a little better I would live with it for a weekend toy. Value and appreciate your input though.

Thank you
Lee

Aaron Cake

iTrader: (1)

With 720CC primaries and 1600CC secondaries, I do over 500HP on my 13B with duty cycles around 8mS at wide open throttle and full boost (16 PSI). How much power are you trying to make? 720CC primaries and 1600CC secondaries on a 20B are enough for over 800HP.

As for the transition, that is actually one of the areas where the Microtech does well. Because of the weird way they increase the primary PW when off stage, it ends up making a rather smooth transition. So staging 680/720CC primaries with 1600CC secondaries is no problem.

The Microtech resolution is so poor that it makes no difference whether the injectors are high or low impedance. You can mix and match as LONG as both primaries and both secondaries are the same impedance. The injector driver circuit will handle both.

Honestly don't spend money on fancy injectors with the Microtech. It doesn't have the resolution to control them. Just good old low impedance Denso / Bosch style injectors do the job and they are a dime a dozen.

As for your timing, I really don't know at this point. The only time I've ever seen timing drift during timing lock is when there was a polarity problem at either the coils or the CAS.

But since you've:
-replaced the CAS
-checked the wiring
-checked the coil wiring
-confirmed with Microtech
-posted your settings and had multiple people confirm correct

I just don't know.

Now if you lock the timing and can then move the CAS to line up the LEADING timing pointer, and it stays stable throughout the entire RPM range, then triggering is likely fine.

Leeroy_25

Thanks for the input.. I don't think the timing wonders if you vary the rpm with the lock on.. I am not sure I have ever checked that. May have given it a little rev but I know you are not supposed to with lock on!? It adjusts and seems quite stable with the CAS swung around!? Go figure.. Will see if it makes no power when I get it on a dyno!

For injectors I see you point about resolution. I will either get ID or RC injectors I think as I would rather get something I know is reliable as well than some real cheap rubbish. Will look into Bosch smaller options but don't want to get used this time around. by the time I get them tested and mess around and get adapters I might as well have just bought a new kit! Also in the event I do change ECU down the road I have the good stuff already!

I was reading a few people complaining about the staging of injectors with big size differences which was my reluctance? i don't want to fix one problem to create another! I am only hoping to push 600bhp flywheel at this point. nothing mega.
Will do some more research on this before I commit to buying anything though. Surely closer in size has to be better? You really think 1000cc will be that bad?
Slight side note, someone mentioned on my other thread about using mixtrim to get a finer adjustment on idle fueling and adjusting the rest of the map to suit? Any mileage in that do you think?

Just absorbed the fact you run 720/1600cc combo! What version ECU if that matters? What is your staging% set at? is it like a straight forwards ratio calc? I gather 50% is setting for same size injectors? So is it ratio/2 +50% or something to work it out? And you have issues as the secondaries come online?

Thank you again

Aaron Cake

iTrader: (1)

You can rev the engine with the lock on. You can even drive the car. Just that timing will be frozen at the locked value so it won't run very well. Lock the timing and make sure the pointer (L1) doesn't waver from the locked value more than a degree or two through the rev range. If it stays put, then your timing polarity is probably correct. If polarity is correct, then you should be good to go to make your timing adjustments to the map to bring it into sane levels. Of course the Microtech uses a silly virtual distributor model for timing so you will find that your timing map will absolutely be a compromise between safety, drivability and what you are able to set.

Staging on the Microtech is actually very easy. With the RevStage % set correctly it is easy to get a smooth stage. Just keep in mind that more RevStage decreases the primary injector resolution because it is multiplied by the %. So I'd suggest sticking with 550CC or 680CC injectors to give you as much control as you can muster.

The problem with 1000CC is that realistically your minimum injector duration with the Microtech is about 1.8mS or so. That's the appropriate injector time for a stock port engine to idle on 460CC injectors! With 1000CC, you are injecting more than twice the required fuel. More capable ECUs can run modern large injectors down to much smaller PWs.

I'm running an LT8s. RevStage set at 99% I believe. Since Microtech hasn't updated their ECU firmware in 16 years on the LT series, I don't see how yours would be an issue with a similar setup.

Yes, 50/50 is for the same size primary/secondary.

Leeroy_25

Ohh.. I am nervous.. what do you fiddle with to get a smooth transition? I thought it was the rev stage value.. still cannot work out how that works.. it doesn't sound right.. i imagined it would be s the secondaries come on the primary fuel flow is reduced by the revstage %. for same size injectors you end up with 50% fuel from primaries and 50% secondaries. then ratio accordingly for different sized injectors? This is not how it reads and I don't know why they would make the setting compromise the primary injectors? surely if I go smaller than 720 cc like you I would need more than 100% staging? there must be a point where there is a trade off for just keeping a slightly gibber injector?
On that note I came across Deka Siemens ones yesterday that look like the
ID ones but come in long length and different plug options. Are also about half the price! heard of them? unless I get bad feedback I might go for these. Sizes are a bit limited.. I have been looking for some 725 after your comments. These come in 825cc I think it is. So I might try this and see how it goes for a relatively low outlay. It is nearly half the size of my current ones and they are high impedance which I gather is better. i am prepared for some idle compromise. I would prefer that than transition issues under load. As long as I can pull AFR's into the 12's I think it should be alright. People claim to be doing so with 1000cc primaries on microtech so we will see!

Leeroy_25

On a side note does the LTX-12 have battery voltage compensation in it? I have not seen it. I read the MT series has it?
Apparently useful for injector set-up and there is some other data you can get which might be useful to input somewhere to optimize the injectors? The guy from ID injectors has been giving me loads of info. Although I am now leaning towards the cheaper options!

Aaron Cake

iTrader: (1)

Easy question first: as far as I know, as I remember pestering Microtech years ago with this, battery voltage compensation is "automatic". It's done in the ECU without any user adjustment. Another area where Microtech is stupid.

The manual also doesn't describe the RevStage thing properly. Basically, when on the PRIMARIES ONLY the injector time is INCREASED by the RevStage percent. So say at 99% when you tell the injectors to open for 1.5mS the ECU is actually opening them for 3mS behind the scenes. Then at the stage point, the PRIMARY injector time is reduced to the ACTUAL value while the secondaries are brought online.

In general it is one aspect about the Microtech that works very well. It's an odd way of doing it, and it reduces the resolution of the primaries off stage, but it works well. Confusing as hell. While it does work, other ECUs use a much more user friendly method like a staging table (Megasquirt).

You absolutely DON'T want any sort of "idle compromise" to get a smooth transition at load! Never! It is EASY to deal with a bit extra fuel under load as the engine tolerates it. But certainly NOT at idle.

Leeroy_25

Thanks for input and explanation! That staging does seem completely backwards! Surely it would make more sense as I thought. The staging reduces the ms opening by the ratio in size of the injectors when the secondaries come on? Maybe I have missed a point why that cannot work or be achieved?!
so It does mean the question over smaller primaries must be no benefit at some point if you end up having to put in 100% staging or higher if that is possible to get good transition?
Oh had you heard of Deka injectors? I am 99% made up I am going to go with these as cheap as chips.. Unless someone can give me a reason a not to!

Aaron Cake

iTrader: (1)

I really don't know why Microtech does the staging like that either. It does work, reasonably well, but seems completely back-arswords and isn't even explained correctly in the manual. One of the mysteries of the Microtech. As near as I can tell, the Microtech has been developed basically by necessity. Features are added years after the market screams for them, but then tacked on to existing code. Once the feature is there, it is never re-examined, re-coded nor improved. Because it just works.

The idea being that by increasing the PRIMARY by that percentage, Microtech can avoid trying to drive large secondary injectors at small PWs which their ECU isn't capable of. So they reduce the primary at the stage point back to normal values and then bring in the secondaries at exactly the value the table says.

Smaller primaries absolutely have a benefit! Would you rather be forced to reduce the resolution of a SMALL injector or a LARGE injector? If your minimum injector time on a 550CC injector is realistically 1.5mS, on a 1000CC injector that 1.5mS minimum is twice the amount of fuel.

Deka seems to be made by Siemens. That's about all I know. Probably used in a lot of OEMs.

Leeroy_25

Thanks Aarron, point taken! Regarding the Deka, yes they are Siemens and that was my exact thought about OEM use. Ergo they should be reliable. I think have to be worth a punt. If I need bigger or smaller or want to reduce secondaries too at some point nice and cheap to replace!
Shame the sizes are a bit limited is the only thing. I will have to go with 875cc I think as the next some down is 660 or around that. Which I think is maybe close on fueling and I would be worrying about staging issues to with such a large jump.
So is there a formula to work out staging percent by the way? Presume there is something to get you in the ball park? To rpm and hg valued just stay as set from factory?

rx3sum

https://www.rx7club.com/microtech-11...-works-182032/

Leeroy_25

Thanks for the link.. I found this before. I need to have a thorough read! I a ordering my 80lbs Deka injectors tomorrow. Will let you all know how it goes.

Aaron Cake

iTrader: (1)

800CC primary and 1600CC secondary use 99%.

I'd suggest setting the stage point to 3500 RPM and 0" of vacuum. The default setting of 2" of vacuum is stupid because the Microtech doesn't have any vacuum bins at that point and interpolation is terrible.

Leeroy_25

Thank you very much for the tips.. I have seen a few people saying about a 3500rpm point.
Is there not a calc to work out the Rev Stg%? Like (primary cc/secondary cc)/2 + 0.5 x 100?
Seems like there should be?

Aaron Cake

iTrader: (1)

There may be a formula, but I don't know it. Basically as you suggest, I just linearly increase the % as the injector size goes up. At roughly twice the primary size, 99% is as big as it gets. You'll still be able to get a smooth transition even if the injectors are larger, it will just make a noticeable dip in your matrix table.

Other more advanced ECUs like the Megasquirt have an injector stage table that allows the user to select how much the secondaries start contributing over a 3D table. Works very well.

Leeroy_25

Thanks Aarron, I will let you know how I get on. Started fitting new injectors today but ran out of time. Think length might be a bit off but will check it out tomorrow and maybe fire up if I have time!