3SGTE hard to start, runs fine

[nuk1ear]

I tried cranking to see loss of sync BUT NOT A SINGLE COUNT.

Then i got it running (same deal, cranking sometimes starts right away, but then dies immediately. Then i hold throttle for flood clear and it will start right up properly!). Then when running it suddenly tried to stall (1 loss sync count) but i kept it alive with throttle, but after that point no matter what i do with the throttle it wont stay alive. The idle valve duty DID NOT CHANGE DURING THIS TIME.

So my first issue it. WHY WONT IT START with normal cranking? I have to be doing something wrong, the hardware appears fine, no mechanical issues. Timing is good. Its definitely my tune somewhere. Im not sure what to change next tho.

I attached 2 logs,
1 me trying to crank (shows 3 sync errors but they dont seem to be the cause of the problem. They happen when i start pumping the throttle to keep it alive but it just dies anyway). During this crank you can see it starts almost immediately, but then doesnt want to stay alive at all. So i use throttle to attempt to keep it alive.
2 when its running and its fine and then suddenly decides to try and stall. I keep it alive for a little with throttle then i let go of the throttle and it just dies.

[pit_celica]

Something is strange. Sometimes, the lost sync reason stays at 11 for a while but the lost sync count do not increment. Lost sync reason stand for "too few teeth before second trigger". I would try to get a composite logger when you're cranking and having lost sync reason #11 to see the signals. When you're doing this, press throttle to 100% to be sure the engine will always stay cranking during the test.

Another thing, if you can, lower the VE in the idle region, you're at 10 AFR while idling. I know this isn't your main problem for now, but this may save you some spark plugs and there will be less contaminated oil from fuel going past the piston seals.

Sam

[nuk1ear]

yeh thats a good point man, it got the the point where the plugs were coated in so much carbon that it only ran on 3 cylinders (these plugs are brand new too. bkr7e gapped to 028"). I cleaned them before these logs and when running it runs perfectly fine, no misses and idle is solid during warm up as you can see.

Ill lower the fuel a bit for trying. But still not sure what to do about this. Im a little lost i guess, i mean i had a piece of junk microtech on this before and it started easily every single time. I cant imagine that these warmup settings and cranking settings can be so sensitive. Or maybe im just a tad ignorant. Surely the after-start enrichment must be WAY off to make the car start and then die instantly. And i cant explain why it wont start easily. makes no sense to me.

[pit_celica]

While reviewing your log, I can see that, when idling, when you press the throttle, the EAE is going super high (200+%). This causes a massive PW increase to about 8ms. With the injector you are using, 8 ms is huge specially at low RPM like off-idle accel. I suggest you to remove the EAE by setting all EAE curves to 100% (all 6 of them). Then, if it's still too rich, lower the VE value in the off-idle accel region of your VE map.

Again, a composite logger will be a must to diagnose the problem about the lost sync reason #11.

Sam

[nuk1ear]

ok. I switched off all EAE stuff and gave it another shot. Starting was the same, cranked for a few seconds and it didnt catch. So then flood clear and she starts up immediately (i guess the cylinders fill up and when i flood clear its enough to run the car for a few cycles. its really strange right?). anyway, it runs on warm up idle control until about 55deg and just dies randomly again. this is the 2nd log

then i tried cranking and getting it running again, but the same thing. crank, then flood clear and it tries to run BUT it wont run while around this temp. I dont know whats wrong with my tune to make it not want to stay alive above 50/55deg?

Then i actually change it to wasted COP and it tries to catch MUCH FASTER, almost immediately. Seems much better that way, so ill leave it as wasted COP for now until i figure this stuff out. But same thing, with wasted cop it will catch quickly and try to start but it will die immediately for some reason while warm. This is log 1.

Also, i attached my composite log while cranking (throttle 100%) for you. Looks fine to me. I also checked it while it was running and it looks fine again (to my untrained eye, but theres no stranges parts, and you can see the sync errors in the log at the start but no more after that).

Ill attach my tune too

[nuk1ear]

tune attached. Any and all comments welcome. Remember this is my first attempt at tuning a car. I know its not easy and i dont expect it to be.

[nuk1ear]

well, i possibly have fixed it (hope i didnt speak too soon) and hopefully this is helpful to others.

Wasted spark made it easier for the cranking to catch (almost immediately) but i still had the issue of that completely RANDOM sync error which makes the car stall. And the impossible starting after running the car up to any relatively warm temperature.

then i read this: http://www.diyautotune.com/tech_article ... _index.htm

That should seriously be in the manual somewhere now. That is important information. I switched the crank signal to falling edge, left the 2nd trigger as raising. And bang, started up within 1 second during cranking. Then after it was very warm and i was adjusting the #1 tooth angle (you must do this after changing between raising/falling etc) by mistake i input 720deg and it stalled. I changed it back to the correct value, burned, reset, then cranked.
it started immediately.

I will check this more tomorrow and let everyone know, hope this may be helpful to others.

[benckj]

I'm still following all of this trying to make heads and tails of the info. Will be in same boat as you when you started so hopefully I can manage my install better after I learn about your problems.

[nuk1ear]

hmmm ok starting good, warm up is good to idle. idle is fine.

Problem is that i tried starting it a few times. 1 time it started and wouldnt idle or anything, ran like crap and died eventually. This was a random occurance, not sure what happened. Either way im pretty happy, its starting and running really well now!

Not sure if its strange, but my low load VE and idle VE is mid 30s. My req fuel is 3.4 and im running through the jbperf peak and hold injector driver to 1000cc delphi low z injectors.

[benckj]

Not sure if this is fit and proper to do in this forum but I ran across another reference to MS2 and 3sgte installations. Seems they have great difficulties with the ignition systems and are hard to overcome without converting to crank wheel. Can you have a quick look at the link and comment on the problems? It may even help you with some of your issues.

http://www.alltrac.net/phpBB2/viewtopic.php?f=9&t=31249

jim

[nuk1ear]

The MS2 and MS1 i think have different circuitry for getting the VR signals. The MS3 seems to pick them up without an issue. I also read through that thread before, didnt find too much useful stuff tho, its mostly old info for MS1/2.

Dont worry man, u have a couple of good maps you can take of me and pitcelica!

[benckj]

Thats' good to know. Have a drag race this weekend and will see how things go before I decide if I should take the plunge this year or not. Local shop just bought a dyno and they have a good Tech working there who is keen to set-up performance cars. I would still install and get up and running before I start tunning.

[jsmcortina]

The MS2 and MS1 i think have different circuitry for getting the VR signals.

Well no.
They both use the same mainboard (i.e. V3.0 or V3.57).
The cam VR input will likely be through the MS3X circuit on the MS3 though.

James

[nuk1ear]

The MS2 and MS1 i think have different circuitry for getting the VR signals.

Well no.
They both use the same mainboard (i.e. V3.0 or V3.57).
The cam VR input will likely be through the MS3X circuit on the MS3 though.

James

Thanks for clearing that up, obviously im not familiar at all with the MS1/2. ANd yeh, my cam input is through the MSx circuit

[Kennyx]

i have the same issue like you ... if the engine start nicely .. everything run perfect and responsive, but if starting goes rough... the idle will be very unstable and throttle response are sluggish..usually an engine restart will solve all the issue .. if the engine restart is run good ... else it will fall to same issue again.

[Kennyx]

the rough start will usually showing leaner idle afr and unstable rpm( sometimes stuck at 15.0 afr, no matter how much u put at the prime , crank and ase .. all setting seems useless ) ... but it goes more richer than what is suppose to be when driving ... and very rough throttle response..
if the engine manage to start without issue ... it will have very stable afr in both idle and driving and perform according to my tuning.. this is really beyond what i can imagine ...

If the first crank/cam angle detection goes wrong ( when you first turn your key to start it).. will it affect the rest of the engine operation ?

KennyX

[nuk1ear]

hey man, yeh i know what you mean. Its a bit confusing for me too. Im still having trouble tuning start up and trying to get idle control working correctly.

[Kennyx]

After re-flashing the megasquirt ... it usually can run trouble-free for few day ... hmmm
I dont have idle issue when it run fine ... but hell a lot trouble when it start acting weird after few day or weeks

I put the whole ms3 within the dashboard .. sometimes when park at hot place .. the casing can heating up to around 60C ... will these temperature do harm to the circuit board ?



KennyX

[billr]

60C shouldn't harm anything, but might open up a solder-joint that isn't good; making for an intermittent problem. Careful visual inspection with a magnifier and bright lighting might reveal something.

[Kennyx]

Good Idea !!
I'll do all the soldering inspection by tomorrow... this is things that i never realise so far...

KennyX