Megasquirt users thread to discuss all things Squirty

[nuk1ear]

yeh i followed similar to what your process is. I have 1000cc injectors and running sequential.
Basically, with my current required fuel if i use 49 VE it is unhappy at about 13.5afr but then if i put 50 it will be very happy but suddenly at 12afr lol.

I might adjust my req fuel down a little more possibly, i think it can go down a little, might help with resolution. I havent adjusted the idle advance much yet, its all sitting at 19deg, but ill try what you said, set a map point for 600rpm and 800rpm and 1000rpm etc, for 600 which is lower than i want ill remove some advance and up fuel a bit right? then for at my wanted idle ill set values for good idle.

I havent tuned the AFR targeting much yet, but it was oscilating all over the place because i was trying to get about 13.5afr with super rich idle ve table.

what AFR do people find their vehicle idles nicely at?

[nuk1ear]

can anyone help?
I got idle working ok now, but i cant get starting to be easy. Its insanely hard. It backfires like a mofo and sometimes feels like its fighting the car starting (cranking suddenly becomes super slow and then it will start).
I started with suggested settings (MS2/Extra Tuning guide) and NO PRIMING PULSE at all. It backfired a lot and eventually started.

Now tried dropping the PW heaps, even down to 90% and it cranks for a few seconds then backfires. Could those settings from link above be a little too lean? Maybe its just getting too little fuel and multiple cranks are flooding it and then backfire????

Sometimes if it cranks for too long, ill hold the throttle down (flood clear mode) then it will start first crank!!! This makes me think its either way too lean PW% or its way too rich, but i have no idea which!

Points to note:
-currently no IAC as my XF one died so just trying to start without one, if its not too cold it can idle at about 600rpm until warm which sits at about 850. Maybe this is an issue and i need one set to 100% open to add more air for cranking.
-timing is spot on, i checked it while the car was running at warm temps, locked timing to 10deg and got it correct.
-3sgte, 1000cc delphi injectors and 1zz COP. when the car runs its ok now, but its so hard to start

[thechuckster]

What is your ReqFuel for such large injectors?

You do need cranking pulse-widths much larger than 100% as what's getting squirted is basically the reqFuel.

Use the figures suggested in the manual and make SMALL adjustments only. (you can ignore the stuff that's below 0 degrees C)

Also, what is the timing doing when cranking? I always set it up to stay at ~10BTC until the ECU think's the motor is running.
http://www.msextra.com/doc/ms2extra/...on.htm#moreign

I would also set up one of you idle control valves to open up when cold cranking. There's simply not enough air for a cold start if just relying on the throttle-plate being slightly cracked open.

...

hang-on. You are using an MS2 ECU? then you only have sequential spark not sequential injection. Can you post a pic of how this screen (Settings/Injector Control) is setup for you?
MS2-Extra Conversion Manual

[nuk1ear]

no no no no no. Im using MS3+MSx and peak and hold driver. Req fuel set to 3.0ms. I think the idle valve is the issue cause its not getting any air to start it and im trying to start with too low fuel. I think i need similar cranking PW thats suggested in the manual, but the idle valve open 100% at cranking.

Is it normal to backfire like a mofo when trying to start it and tuning cranking PW?? Cranking timing is sitting at 10deg BTC which i set and i think is pretty normal. I noticed at one point tho in my data log that cranking went a tad over 300 so i change cranking RPM to 350 limit.

Suggestion on a universal idle controller? Im thinking of going and getting a hyundia one from the wreckers atm. The XF one i had im pretty sure is stuffed, but its possible that it just wont work with the frequency settings in TS (i tried every single one)

[thechuckster]

Ah, MS3 it is.

What inj PW are you logging during cranking? and system voltage?

Given you have such huge injectors and such a low ReqFuel (in fact, that is a very, very low number), I'd hazard a guess that when you take away opening time (and the lower voltage during cranking) they might not be opening enough during cranking to get a half-decent fuel charge into the cylinders.

You really need the ISCV or similar if you're not holding the throttle open during cold cranking.

You shouldn't be getting any backfire thru the intake when tuning cold start - if you ignition timing and spark are correct. if anything, you'll get the odd pop out the exhaust from unburnt fuel catching alight in the zorst.

I have a few idle controllers to choose from: a hyundai (aka bosch) item (apparently 200hz is the suggested freq to drive them at), an old (and simple on/off) solenoid from a camira, and for my 3SGE a nissan idle control valve as it combines a simple solenoid and PWM valve in the one body.

Biggest hassle I had was the after-start enrichment and taper-down settings to let the engine get to a smooth idle from startup. It would fire OK but then stall or stumble unless I upped the revs as it came down to the idle.

[nuk1ear]

with the recommended setting for PW% i was getting about 6ms in the datalog during cranking. The log shows a few sync errors, but they only come up once every now and then during cranking phases. I never get a loss of sync in TS.

How can i tell if im running too lean or too rich for cranking PW%? I agree, i really need to get an idle valve to provide enough air.

[knightrous]

The log shows a few sync errors, but they only come up once every now and then during cranking phases. I never get a loss of sync in TS.

As per wisdom shared on the MSExtra forums, fix any and all sync issues first before starting on the other stuff. Otherwise you could chase your tail for a bit.

[nuk1ear]

fair enough, but i have no idea what could be causing the sync errors. When it runs there no issues at all. I checked the VR sensors, looks like there some surface rust on them. Can that be an issue? If it is, how should i remove that surface rust? I have the trigger wires all shielded all the way from the ECU to the connector. Grounded the shield at the ECU.

Is it possible that the surface rust is hindering the VR signal?

[knightrous]

Which wheel is giving you the sync error, the crank wheel (NE) or the cam wheel (G)?

[thechuckster]

Rust won't be an issue unless it's substantial. Check that the shielding is grounded at one end only. Do you know which sensor is returning the sync error?

As for working out if lean or rich during cranking, I just turned the ignition off as soon as the engine caught and smelt the exhuast. You won't get enough gas flow for the wideband to do any good (and it'll probably be ignoring any data as the system voltage will be wildly fluctuating courtesy of the starter motor).

I would suggest you also re-enable the priming pulse.

[nuk1ear]

How can i tell which tooth is giving the error in megalogviewer? Can i select cam/crank signal error specifically from a drop down? The errors im stating are just under sync error.

Regarding the shielding, its 100% grounded at the ECU as is suggested by the ms3 wiring part of the manual, i built the entire harness myself.

I just read that someone with an MX5 was using 8ms and another even 10ms cranking dwell (with 1zz coils), before they used 3.5ms and it was very hard to start, similar to my situation (but this was at near 0 temperatures). Is it possible that 3.5ms isnt enough for cranking with 1zz coils? I thought 8ms is outrageous and will put them into protective mode?

Regarding priming pulse, ill switch it back on, but how much is a good value for 1000cc injectors? 3ms or something to start with? Gotta get my hands on a Idle vavle ey

Also, wanted to note that during cranking the TPS% goes up to about 4/5%, can this be an issue too? is it normal and does the MS ignore the TPS value as long as its below floor clear? Also had to up my cranking rpm to 350 cause i noticed that in the log it cranks very very close to 300 and at a couple of points went above 300, thought it might be safer?

[thechuckster]

If you had an MS2 ECU, you'd use Megatunix and it's tooth logger shows you the individual trigger signals. Not sure with TS.

From memory, the MS2 defaults for cranking dwell are 6m/s, any higher and you'd start destroying coils and igniters.

Default priming pulse is 2 m/s, however as your Req Fuel is only 3 m/s, you could try a smaller amount (1.5? 1.2?).

TPS isn't part of cranking, however, it does sound like the motor is trying to pull the TPS open as you crank - or the sensor earths are not that flash.

A higher cranking RPM limit won't hurt. I used to extend the number of trigger events before attempting to start the motor - theory being that more oil was being circulated before the motor burst into life. Not sure if actually did any good but I didn't have oil pressure problems.

Have you posted any queries on the msextra forums about the cranking PWs? Is likely that others have dealt with huge injectors on 4 and 6cyl motors.

[nuk1ear]

yeh i posted on msextra. few replies. someone thinks my timing might be off cause i mentioned that at some points it seems like the starter is fighting the engine starting. Seems plausable so as i said ill check it tonight during cranking.

Regarding grounds. I ran seperate wires from each ground on the ecu, and each sensor ground (that isnt suppose to be grounded to the ecu) to a large terminal which i bolted to the lower part of the inlet manifold with a 12mm bolt. Possible that thats not a good earthing postion too? I can extend it to the block directly, maybe better. And run a 2nd 8ga wire from that ground to the body also (MR2s are notorious for bad engine grounding). Bad earths can cause many different issues, does this also seem possible?

[knightrous]

Also, wanted to note that during cranking the TPS% goes up to about 4/5%, can this be an issue too? is it normal and does the MS ignore the TPS value as long as its below floor clear? Also had to up my cranking rpm to 350 cause i noticed that in the log it cranks very very close to 300 and at a couple of points went above 300, thought it might be safer?

Sounds like a ground or voltage problem. If your getting a 4-5% variance when cranking, it means the voltage is to the TPS is not stable.

EDIT: If your sensor ground is funky, it could be affecting all your sensors, TPS and crank/cam included.

[nuk1ear]

TPS is grounded at the ECU, not seperately. So a fluctuation in TPS% that big is pretty bad? Does anyone else get TPS fluctuation while cranking? obviously the motor isnt opening up the throttle, that would be silly, its a voltage flucuation. Ill try a different ground point and ill run an extra 8ga cable from that ground point to the body as well.

Then check ignition timing while cranking, see if its solid at 10deg.