Found My Problem, Timing Related, Advice Please

[Richie-Van-GTi 71 2 Cars]

so for anyone familiar with megasquirt please tell me what adjustments to make to get my engine firing at the right time please as I just strobed it. With a snap on strobe I get +34 degrees when number 1 sparks in relation to TDC, obviously way off!!

I currently have trigger angle 78, trigger a=7, trigger return a=19, trigger B=37, trigger return b=49.

[Guest larson]

so for anyone familiar with megasquirt please tell me what adjustments to make to get my engine firing at the right time please as I just strobed it. With a snap on strobe I get +34 degrees when number 1 sparks in relation to TDC, obviously way off!!

I currently have trigger angle 78, trigger a=7, trigger return a=19, trigger B=37, trigger return b=49.

 

It looks fine to me.

This is just the same as

trigger angle =60, trigger a=10, trigger b=40.

 

trigger return a=19 and trigger return=49 means your cranking timing is 6 deg BTDC.

 

All of the above is true assuming that tooth No20 is under CPS when cylinder No1 is @TDC (or in other words cylinder 1 is 120deg BTDC when tooth number 0 (first gap) is under CPS).

 

However I have a feeling that something is wrong here with these 120deg, as it seems that Bosch counts differently then MS (falling edge of the second missing tooth

instead of middle of the first missing tooth). Then trigger angle would be in the region of 50-54 degrees then when trigger a=10.

Need to thing about it more.

 

Please post your thoughts.

 

Anyway +34 degrees are just too much.

No I wonder if my pistons are still in place if I drove my car with such an offset in timing..

 

Sorry for image sizes, those 60-2 wheels are just too large

 

trigger angle 60, a=10, b=40

 

trigger angle 78, a=7, b=37

Edited August 16, 2007 by larson

[Richie-Van-GTi 71 2 Cars]

tooth 14 is under senspr according to my calculations. To check it I found actual TDC using a DTI, marked the flywheel through the timing cover against the block then counted back how many teeth there were until the space, counting the marked tooth as 1 and the first missing tooth as the last.

So what should I adjust to bring that timing back into place? I was thinking add 6 to all the trigger points as that would equal 36 degrees retard wouldnt it? Then fine tune from there using the tables and crank advance.

[Richie-Van-GTi 71 2 Cars]

another thing, time based or trigger return, what difference does that make? People on the forum keep saying use time based but Im thinking if time based runs of the trigger and trigger return is 8 teeth behind that would make a huge difference.

[Richie-Van-GTi 71 2 Cars]

haha, had a quick play, set at trigger return, trigger angle 84, crank advance 0, triggers 9,21,39,51 and it now strobes bang on TDC.

[Guest larson]

haha, had a quick play, set at trigger return, trigger angle 84, crank advance 0, triggers 9,21,39,51 and it now strobes bang on TDC.

 

I just can not believe it

 

Thanks for your observations. Just can not understand where the hell these 120 degrees came from then.

There are several success stories with mi16 alloy blocks listed on MS sites, where 120 degrees BTDC (or teeth number 20) was said to be right.

Not even just for Mi16, for any Bosch 60-2 setup it was said to be right.

 

Could it be just the difference between mi16 and gti6? Guess no. Position of the wheel changed during assembly? Just trying to find an answer.

I know that my engine was not rebuild after running under ML4.1 management, so flywheel should be in the stock position.

 

So what else?

 

But wait. If you are sure it is teeth 14 is under CPS when @TDC then my ignition should be well retarded, by 36 degrees. How the hell it has started at all then?

Something else somewhere else... dark side of the moon.

Edited August 16, 2007 by larson

[Richie-Van-GTi 71 2 Cars]

Im now left doubting the whole scenario as it still wont start, it tries sometimes but then backfires, literally flames out the bodies , anyway after playing for hours and killing batteries like they are the spawn of all evil I halfway gave up, bought yet another set of brand new plugs, strobed again with trigger angle 78 and trigger points as above and sure enough number 1 still fires bang on tdc with everything set at zero. So I thought I would check number 2 fires on 180 degrees, and guess what, it doesnt. I cant even find the firing point for it yet the strobe flashes and spark plug sparks etc. This makes me think that it must be sparking further than the 180 degrees Im allowed on the light. So my other trigger point is out somewhere, which will explain tghe huge misfire, guessing its way too far out.

One thing I have noticed is the flywheel missing teeth just looks like one long flat tooth, I wonder if the ecu is reading this as a 60-1 and hence Im getting these issues?

[Guest larson]

haha, had a quick play, set at trigger return, trigger angle 84, crank advance 0, triggers 9,21,39,51 and it now strobes bang on TDC.

 

You will need to explain a little.

 

Ok, you said it's teeth 14 under the sensor when cylinder number 1 is @ TDC (or cylinder 1 is 84 degrees before TDC when first missing teeth (0) is under the sensor, it's time when MS starts counting).

Your trigger angle is also set to 84 degrees.

Then trigger A should be set to 0 (first missing teeth).. not to 9. and I'm sure it's not a good idea to set missing teeth as a reference point.

 

 

If however everything is fine when you set these parameters then it points to the fact that teeth 23 is under the sensor when cyl1 is @TDC.

And trigger setting return A=21 (B=51) will give you 12 degrees of cranking advance.

 

So we really need to find which of these two is true

Edited August 16, 2007 by larson

[Guest larson]

Im now left doubting the whole scenario as it still wont start, it tries sometimes but then backfires, literally flames out the bodies , anyway after playing for hours and killing batteries like they are the spawn of all evil I halfway gave up, bought yet another set of brand new plugs, strobed again with trigger angle 78 and trigger points as above and sure enough number 1 still fires bang on tdc with everything set at zero. So I thought I would check number 2 fires on 180 degrees, and guess what, it doesnt. I cant even find the firing point for it yet the strobe flashes and spark plug sparks etc. This makes me think that it must be sparking further than the 180 degrees Im allowed on the light. So my other trigger point is out somewhere, which will explain tghe huge misfire, guessing its way too far out.

One thing I have noticed is the flywheel missing teeth just looks like one long flat tooth, I wonder if the ecu is reading this as a 60-1 and hence Im getting these issues?

 

Okay, so everything is not so bad then. Let's think a little

I hope someone will join us here to solve this issue.

[Richie-Van-GTi 71 2 Cars]

just used trigger logger on megatunix I get 58 spikes at 500, 1 at 1100 then one at 650, Im guessing this may be backwards as surely the teeth should be higher than the gaps?

[Guest larson]

just used trigger logger on megatunix I get 58 spikes at 500, 1 at 1100 then one at 650, Im guessing this may be backwards as surely the teeth should be higher than the gaps?

 

Have you tried to change over signal and ground wires on CPS?

[Richie-Van-GTi 71 2 Cars]

just tried it, if I reverse them the signal goes all over the place,random spikes in it, no 2 spikes are the same etc, swapped them back and they are nice and level right across apart from the 2 missing teeth which when I researched i correct

So its down to firing times I fail to see how my settings will not fire 180 degrees apart.

[Richie-Van-GTi 71 2 Cars]

damn them women, I had the gf count the teeth as I cranked by hand and she got 14, except she counted from the wrong marker, Ive marked the flywheel twice, once for where the sensor sits at TDC and once for where I marked the block and flywheel together through the timing cover, guess what, they are 7 teeth apart, double checked and its definatley 21 teth from gap to TDC under sensor Time to play again.

[Richie-Van-GTi 71 2 Cars]

well she was reluctant at first but finally she fired up an sounds pretty sweet, clearly over fueling still so I will have to work on that, but at least I should be able to now she starts and runs.

 

now settings are at 60 trigger angle then 11,20,41,50.

Gonna strobe it again and get some better timings done at idle then start playing with ve table

[Guest larson]

damn them women, I had the gf count the teeth as I cranked by hand and she got 14, except she counted from the wrong marker, Ive marked the flywheel twice, once for where the sensor sits at TDC and once for where I marked the block and flywheel together through the timing cover, guess what, they are 7 teeth apart, double checked and its definatley 21 teth from gap to TDC under sensor Time to play again.

 

 

It would never come to my head to let a woman to do this kind of a work.. Even if she is Dr. of mechanics.

No offence! I love women.

 

Ok, so which number is it then?

The first missing is number 0, the second missing is number 1, and then 21 more? The last one is under the sensor?

So it's tooth number 22 under the sensor when at TDC then. And it equals to 132 degrees. Still not sure

 

I'll wait for you to try it first

 

What settings you try now? Trigger angle=60, trigger A=12, B=42, A return=21 (for 6 degrees cranking) or =20 (for 12 degrees cranking), B return=51 (50)?

 

Remember you still need to specify Cranking Advance Angle even if you use Trigger Return mode. It's needed to calculate dwell.

Cranking Advance Angle should be set to the same value as trigger return angle, thus if you set A return=21 (as above), then set Cranking Advance Angle=6.

[Guest larson]

well she was reluctant at first but finally she fired up an sounds pretty sweet, clearly over fueling still so I will have to work on that, but at least I should be able to now she starts and runs.

 

now settings are at 60 trigger angle then 11,20,41,50.

Gonna strobe it again and get some better timings done at idle then start playing with ve table

 

Oh well, it's 21st then. That's better, just as in default MS files for 120deg,60-2. Everything is clear now for me.

Let us know after you strobe it then.

[Richie-Van-GTi 71 2 Cars]

still not strobed it, trying to get it to idle now. Anything below about 1300rpm it stalls and even at 1300 rpm it needs to be stupidly rich, Not sure if the timing still needs a tweak.

starting is a bitch as well but it does catch eventually, guess I need to try various cranking pulse widths.

[Richie-Van-GTi 71 2 Cars]

just strobed them settings, was giving me 5 degrees advance so I have knocked them back to 12,21,42,51 so I have 1 degree retarded, much closer to zero so the spark table is a bit closer for working with. Cranking advance angle is indeed 6 at the moment and when it catches it springs into life, I think half the problem with starting right now is battery only showing 11 volts and me not getting pulse widths sorted for cranking. I think it may be flooding, or possibly the bodies are strangling the air low down hence it wont idle. Gonna look into the air bypass on them, see if it makes any notable difference. Jonand has sent me his map so I can look at the spark tables, hopefully I will get a better understanding from it

[snillet 1]

Your wheel seems very differently lined up then most that´s for shure.

 

Mine has the "standard" where the mid section of tooth number 20 is under the sensor at TDC.

[Richie-Van-GTi 71 2 Cars]

It may be down to the combination of the MI flywheel and XUD crank although Ive not heard of other simialr issues. One thing I do know is that for whatever reason the current set up works. I now need to sort after start enrichment, any pointers will be appreciated. Right not it fires pretty quickly but then dies straight after unless the throttle is held open.

[Hilgie 16 2 Cars]

Where is your no 1 cylinder? On Pugs thats on the flywheel side....

 

The XUD crank and Mi16 fly should not make a difference.

[Richie-Van-GTi 71 2 Cars]

No1 cylinder is TDC when sensor is under tooth 20, the timing is all correct now, its been strobed multiple times and it does indeed always meet what its supposed to

I still need to sort the after start enrichments and the idle speed but Ive been focusing on the bodywork at the moment, getting it into a driveable state so it can be road mapped

[snillet 1]

No1 cylinder is TDC when sensor is under tooth 20, the timing is all correct now, its been strobed multiple times and it does indeed always meet what its supposed to

I still need to sort the after start enrichments and the idle speed but Ive been focusing on the bodywork at the moment, getting it into a driveable state so it can be road mapped

 

The afterstart enrichments and all that can take a while to sort out, especially since you need to establish a good VE map first, THEN start working with the ASE, AE and all that since they´re on top of the map.

 

Good thing you´ve sorted it out finally.

When i started to use the XU9 engine i made a VERY basic map out of the centirfugal and vacuum advance points for the D6B ignition, worked quite well as a starter actually.

 

But since it only had 4 used RPM coulmn it wasn´t very sofisticated, but..... still the interpolation between the colums was very very close to what i ended up with later on anyhow, except for low vacuums around idle, meaning it did go a bit to low when stabbing the throttle from around 1200 rpm.

 

Think the numbers where these:

1200rpm - 8 deg

2000rpm - 24 deg

5000rpm - 30 deg

(that is between 70kpa and 100kpa, the distributor works that way).

And then the vacuum advance is at max at 20kpa which is 22 degrees, and as said above it ends at 70kpa.

 

Noted though that for example the 2000 and 5000rpm rows can´t be all advanced from these figures at the bottom (around 20-40kpa), you´ll end up with over 50 degrees advance *lol*, not good for most engines.

 

This is just from the top of my head......, don´t have the spec sheet in front of me.

But as i said before the ignitionmap i use now is very much alike these numbers except for the "idle throttle stab" area.

[Richie-Van-GTi 71 2 Cars]

not had much time to do anything further with this car due to new job and other commitments, as it stands now it starts up pretty easily but has to idle (if you can call it that) at 2500. I did spend a fair chunk of time experimenting with various wiring configurations for the crank sensor and now have a perfectly clear signal, fingers crossed that will allow me to bring that idle down further as I suspect from the rpm fluctuations previously that is where the problem originated. Im tuning with alpha N as the cams and bodies create a very erratic MAP reading low down. The current advance runs from 5 degrees cranking, 8 at idle up to 26 full steam. These hopefully will give me a decent starting point to tune the Ve around to get it somewhere towards driveable. Once its driveable in a way that wont cause a big bang or lean spots etc I have access to a set of rollers for free so will make some time from work to have this popped on the rollers for further playing.

Incidentally, the bodywork is almost completed