Hello all

I am currently in process of setting up Megasquirt II v3 board running the latest ms2 extra S/W rev 1.0.2 on a 2nd gen 13b with two opposing teeth cut on cas.

The problem:
When i crank i get a tach of roughly 300 rpm. Engine fires briefly reaching approx 400 to 500 rpm then tach signal disappears. Engine falls flat. I have a shielded cable running fom the cas to MS. Positive wire "red" is connected to pin 24 and ground "white" is connected to ms ground. I have tryed to adj trim pot (R52) for vr with no success.
Any suggestions?

Thanks

 

Try spinning the CAS manually to verify proper operation. You could drive the CAS via drill, or even by pulling on a string pre-wound around the shaft a dozen times or so. Either way, be sure to have the fuel system disabled so you don't flood the engine.

 

You might be triggering on the wrong edge of the input signal... Do you have VROUT connected to TSEL, or VROUTINV connected to TSEL?

 

Thanks for the reply.

VROUTINV is connected to TSEL.

 

Which edge of the signal is your ms2 configured to trigger from? Also, for now, make sure you have the noise filter turned off.

Ken

 

The rising edge.
Also, what should the wheel setup be ,12 teeth with one missing?

Thanks

 

12 teeth 1 missing is right..

With VROUTINV wired to TSEL, you should be using the falling edge.

Ken

 

Thanks for the help.
Setting the sig to falling edge fixed the problem.
In the process of setting up MSII discovered major problems with my recently rebuilt 13b so MS will be on hold for the time being.
I am sure I will have other issues in the not to distant future.
Thanks again for your help.

 

Ok, Back to good on my rebuild.
New set of problems,

Current setup:
1. Megasquirt II v3 board running the latest ms2 extra S/W rev 1.0.2 on a 2nd gen 13b with two opposing teeth cut on cas.
2. Trigger wheel set to 12 teeth one missing.
3. Trigger on falling edge with spark output going high with wasted spark.
4. Set to rotary mode ON, in "more ign settings".
5. set ign timing dead on at 5 degrees atdc "yellow mark". (Checked with timing light apon crank).
6. number of cyl is set to 4 with 2 injectors "2 squirts" per port injection.
7. setting trigger angle "trigger wheel setting" per ms2ex manule".
8. Have set for fixed advance on crank and idle. (so timing will not change after start or crank) "just so i can regulat my settings and my self"
9.Fuel map and ign maps are set to the default settings included with the canned ms2 exrta download from the following URL
http://msextra.com/ms2extra/files/re..._Installer.exe
10.Map sensor reads roughly 92 kpa apon crank. (I am located goe in Va and the map sences registers 101 at a static pressure.)
11. Coolent temp and air temp registers at approx 29 to 31 C correct for the temp today 85 f.
12. priming pulse is set to 0 at 31+/- c colent temp sense so not to flood rotors during testing.
13. PWM1 apon crank is 17msec.
14. crank speed is set at 300
15. engine cranks at roughly 250 to 290 RPM according to MS output.

Symptoms:

When cranking timming light flashes in sequence with timing mark 5 degrees atdc.

Engine trys to fire with no idle, I get a constant stumble. (NO Backfires). Almost like I have a huge vacume leak, possably running lean on crank?.

Possable' but I have tryed unplugging the fuel pump and running the engine on starting fluid with the same results.

I had considered the possablity of a masive vac leak so I taped up the intake and cranked the engine and produced approx 75 kpa. "almost sucked the tape into the intake plenum".

As far as I can tell with the limited info I have access to all registers look good via megatune apon crank.


I am running this on a custome built car (locost7) and there is nothing stock about this engine. All emisions related components have been remove (example: airpump, egr, MAF).

I am truly at my witts end.

I truly love the challenge but I am not sure where to go from here.

Any help would be greatly appriciated.

Thanks in advance.


Newmanmullen

 

Could you post up a datalog of your start attempts? That might shed some light on the situation. Your vacuum leak idea seems to fit the symptoms, but it should still fire if it's getting enough fuel. These engines will idle over a very wide ignition timing range, so I doubt it's related to that. Other things to check:

1.) Fuel pressure after priming, and while cranking.
2.) Verify injectors are actually firing.
3.) Emissions removal - check for leaks (EGR?)
4.) Pull plugs after start attempt - are they wet?
5.) Compression test?

 

Thanks for the response.
I had checked compression, checks at 75 psi at crank
Fuel is 40 psi
I had noticed fuel drip from exhoust. Indicate super rich.
After further thought I had decided to check and see if secondaries where firing apon crank.
Sure enough they were.
So i set up the staged injection to fix this problem and lowered my req fuel to 5.2.
According to rx7 service manule the displacement is 40 cu inches x 2 (80).
the injectors are 111 cc per 15 sec. I had multiplied this by 4 to get 444 cc per min.
I had set air ratio to 14. (how is this inputed 14 or 14:1?)

Plugged all this info into the fuel req calculator to get 5.2 ruel req.

Still same symptoms
I have attache a datalog.

Thanks again for your help.

 

Additional info

PW is around 5.XXX at crank.
Enginge fires briefly and runs for approx 5 sec.
Once above crank speed "400 rpm" PW decreases to around 3.xxx sec.
Engine falls flat.

Logic would tell me PW should increase with rpm.
Is this correct?

Any suggestions?

Thanks again

 

If you are on the megasquirt pre-generated map, its more than likely too lean. I have found personally that you have to modify the maps that they use for standard displacement. Try using 2.6 liters as the displacement instead of 1.3. the rotary tends to use a tad bit more fuel than required for such displacement. Try adjusting your maps a little. To be honest, it seems a little high on pulswidth on crank than what I see. I could be wrong. My idle is as low as 3.2ms(around 14.1:1 afr) according to the ms. My required fuel is about 5.5 You'll want to shoot for 12.5-13:1 afr idle. Trust me it idles easier that way.
HOWEVER, I am running a MS1 V3 board. Hopefully this helps a little ^_^

dpf22

 

Have you checked plugs? If they are soaked you can crank all day long without starting.

Staged injection doesn't disable secondaries on crank, only on run. Take a look at "Advanced -> Fuel Table Selection -> Pulse Inj2 During Cranking" to ensure they aren't squirting when cranking.

You should specify 2 injectors (# of primaries) in the calculator, and the number will come out to around 10.

 

[QUOTE=renns;7072851]Have you checked plugs? If they are soaked you can crank all day long without starting.

Secondaries are not firing apon crank.
I have checked plugs and they are wet.
Seems to be dumping alot of fuel on crank.
I have set priming pulse to 0 at all temps. (so not to add to the flood situation while testing.
So what happens is I suspect excessive fule while cranking (flood condition) and disconnect the fuel pump to clear flood. As I am cranking to clear flood the engine stumbles to life for aproxx 5 sec run untill all fule has burnt out of chambers.
This tells me timing is not an issue. Seems to be getting excessive amounts of fuel on crank and run.

Questions:
Should this be setup as a 4 cyl or a 2 in engine constraints? (my current is 4)
As pulse width increases the fuel amount increases and vice versa. Is this correct?

Thanks

 

yea, you're correct on the pulsewidth thing.

I have it set up as a 4 cyl. My req_fuel ended up being 7.9 ms for 4 cyl, 2600cc, 550cc injectors, 4 injectors, alternating, (the last two should be 2 injectors, simultaneous as i now know, which changes req_fuel to 15.8), but for the previous setup, it started up great for a cranking pw of 7ms at 27*C. The changes from alternating to simult and the number of injectors shouldnt change this value, since its a specified pw.

 

4 injectors alternating and 2 injectors simultaneous will give the same req_fuel number.

 

right, i forgot that I had # of injections per cycle set to 2 for alternating, not 1.

 

Great news!!

Got it to idle at 1200 rpm at a fuel req of 12.0, I had started at 5.0 and increased at incraments of 1.0 untill engine came to life. (idles terrable)
But at the vary least it idles,,,,,
played around with fuel req, I had leand the fel req out to 9.0 with success, any leaner and the engine wont run.
So far so good...
I truly appriciate everyones help.

Few quick questions.
I am using the stock TPS that is potential up untill the secondaries open. (meaning the throw of the plunger extends out to the point of the secondary throttle plates opening) Also the tps reading flopps around at idle "between 1and3%.
Could this potentually give me my rough idle?

I am using the default fuel tables included with MS2extra V1.02 firmware. Where do I start on modifying this table? I soppose I can try "trial and error", but this seems a bit primitve to me.. (just my opinion).

I would like to know the true machanics of all the settings but I find the MS2extra manule is limited in some areas. Is there additional info out there that I can bone up on?
If so can you please point me in the right direction.

Also, is there a place to report Software bugs. I have a few that may be of value to the developers.

Thanks again

Newmanmullen

 

Great to hear you are making progress!

TPS will have no effect at idle unless it's jumping around enough to trigger accel enrichment. I don't have any experience trying to utilize the stock narrow-range TPS. You may want to simply disconnect it, and jumper the signal wire to ground on the MS side of the harness.

From a tuning standpoint, follow the instructions in the MegaManual for the MS2. The basic tuning steps should be very similar to the MS2extra.

The developers monitor the forums at msextra.com, so that'd likely be the best spot to post bugs.

 

Staged injection does disable secondaries on crank on ms2.

Ken

 

newmanmullen: what bugs? James and I are the ones who wrote ms2/extra, so I should be able to tell you if you're seeing actual bugs, or if not, how to fix the settings to remove the bad behavior.

Ken

 

One that comes to mind is when changing the cranking PW% at say 20c and try to burn value the setting would take fine. But when I had tryed to change any other values in addition to the 20c say at 35c the 20c value would remain changed but the 35c value would not take to ecu after burn. I had also tryed to generate a curve in wich I would enter the values and hit ok with no result.

Second one: After mucking with various settings (not including calibration) for a period of time my mat sensor reading would flake out. I would have to reload the default settings/reboot and then reload my saved settings/reboot to remedy the problem.

To be honest with you I dont know if these are bugs or not.
I have been having a hard time getting my engine to start, so last night I decided to wipe and reload the firmware. After reloading my settings the and playing with the fuel req the engine started. So with that said I may have had a bum firmware load from the vary beginning.

I have a few more in my notes at home.

I will try and reproduce these this evening and see if they still exist.

 

Quick question:
My tps accel inicator keeps flikering at idle.
I currently have my tps grounded. I have calbrated my tps at 0 (get current)

Any suggestions?
thanks in advance.

 

Setting your TPSdot threshold a bit higher will prevent false triggering. What do you mean by tps grounded? Is the signal wire grounded? If so, then that flicker may indicate you may have some grounding issues.