rndmheroxx

iTrader: (1)

------------- RESOLVED!!!! -------------


Hey guys, new to the forum but i have played with and built many turbo cars so engine and electrical knowledge are pretty good. I would give you guys more background, but I am kind of in a rush to get this old girl running so I can finally make it home, stuck at a friends house for the last 24hrs. Okay so long story short, was doing a Toyota COP conversion, to get my car ready for an autox on Sunday (tomorrow).... Made up a wiring harness for them. Changed the dwell settings in my MSPNP v1, didnt try to crank the engine but had the ignition on when I smelt hot/burning plastic. Checked the coil packs and they were HOT! ****, okay checked my wiring, and Im an idiot, I wired the connectors on each plug backwards, aka power->gnd and gnd->power, and the signal->tach and tach->signal ANNNNDD I didnt put the 1kohm resistor in the diagnostic box, I dont know if thats necessary but I also added this in after to try and see if it did anything =/ .... Anyways, fixed the harness, turned ign on, they were nice and cool , all seemed good. Tried to crank the engine, nothing. However after a few tried, turned ign to on, and before trying to crank... POW! I had a cylinder fire, sounded like a gunshot out my exhaust! lol Okay so today I ran to the used auto parts place, picked up 4 new COPS, took a plug out, grounded it to the head and had a buddy crank the car... upon turning the ignition on, I get a yellowish spark from the plug which from what I understand is normal with megasquirt... and when cranking NO SPARK!??! I checked every fuse I can find in the car, all were good. Megasquirt is getting tach signal apparently. Am I missing something here!?!? I felt like it had to be a fuse somewhere, but then I was getting that spark upon turning ign on, so megasquirt apparently is still able to send signal, but its not during cranking.... Im stumped. Also, may be unrelated, but I am unable to get any TPS reading either. PLease help, I would really like to go home and shower! lol

rndmheroxx

iTrader: (1)

I should also add that we tried reinstalling the stock ignition system, however also no spark due to a suspected fried igniter from cranking/trying so many times >.< Tried to source another one today for diagnostics sake but was unsuccessful sorry!

psyber_0ptix

iTrader: (4)

all the connectors were all wired backwards?

did it fry any of the harness by the original ignitor?

edit: oops, had the edit window open too long

rndmheroxx

iTrader: (1)

Hah yeah, all the harness' look fine! Thanks for the input though!

Update: I checked my diy harness for continuity, power and ground and double checked all pinouts. Everything good there, also tried relocating the ground. No luck. Also Im wondering if maybe I should have more engine to chassis grounds.... It seems there is supposed to be one near the throttle body and alternator but Im having trouble finding it if it exists?

I should also note, I didnt think of this til just now, In the past I have notice, very rarely, that the tach needle might jump around about 500-1000rpms, seems very random, only coincidence I could even guess at would be it seems to happen only at night on my way home. Cooler weather? fully warmed up car? Beats me... seems pretty rare but does indicate a likely bad ground.... hm

rndmheroxx

iTrader: (1)

Another update ... pulled the cover of the megasquirt, d14 "Spark output A" is solid red as soon as you turn ignition on, and stays constant red while cranking.... i dont know what this means, or if its good or not! lol help a brotha out

rndmheroxx

iTrader: (1)

still messing with this. Here is a pic of my MS in case that helps anyone determine what i have or if something needs to be added/modded to be able to run these COPs

Ben

iTrader: (33)

Does TunerStudio show RPM when cranking?

rndmheroxx

iTrader: (1)

Yes it does! Does that mean the CAS is good? I have a line on one locally and was getting ready to go pick it up to test it

rndmheroxx

iTrader: (1)

bump for still not having a car :/ ... should i go pick up a CAS to try? Or is there a way to check if its functioning in Tunerstudio? I checked voltages at the plug, and also back probed the sensor and everything seems to be functioning fine in that respect, however that aparently isnt certain?

rndmheroxx

iTrader: (1)

Okay i really need the Megasquirt gurus to chime in here. I went out today and picked up a known good CAS and igniter.

First I swapped in good CAS, still using the COPs, no spark.

Next swapped in stock coils and known good igniter, no spark.

Finally, plugged in stock ECU, SPARK!!

So this isolates the problem to megasquirt... Im HOPING that perhaps transistor 2N3904BU could be blown? I have no scope to check, so im hoping that with this information you guys can help me out from here!!

Please help i need my DD back :/

Matt Cramer

Good guess on the transistors; they'd be the first things I'd suspect, too. The D14 and D16 LEDs should switch on when you turn the key on; if they don't, the transistors are probably dead.

rndmheroxx

iTrader: (1)

D16 and D14 are on when the ignition is on. It is my understanding that D14 should flash when cranking, it does not, at least not visibly.

rndmheroxx

iTrader: (1)

Could you at least point me to the transistors i need? Ill just replace all of them on the board and see what that does, i just need to make sure im getting the right ones.... not all of the ones are physically printed/labeled on them....

rndmheroxx

iTrader: (1)

Was checking some of the transistors, and found continuity between these 2 marked pins on transistor Q6.... the same continuity was NOT observed on Q7 and Q8 ... culprit???

Matt Cramer

If D16 is flashing while cranking and D14 is not, Q6 is dead. The transistors can be ordered from Digi-Key.

rndmheroxx

iTrader: (1)

ad16 is not flashing either. i didnt realize it should have been. I assumed it was for injector pulse width until i checked the settings in TS. Can you get me a link to the correct transistors? Theres a million different kinds of MMBT3904's

rndmheroxx

iTrader: (1)

Well this is what Im going to order I suppose, a few of these and a couple of those. I didnt bother to check exact quantities. Guess Ill let you know if these work! If you dont hear back from me, I blew up.....

1 8 MMBT3904FSCT-ND TRANSISTOR GP NPN AMP SOT-23 8
Immediate 0 0.15000 $1.20
2 2 TIP125TU-ND TRANS PNP DARL 60V -5A TO-220 2
Immediate 0 0.64000 $1.28
3 2 TIP42C-ND TRANS PNP GP 100V 6A TO-220 2
Immediate 0 0.67000 $1.34
4 4 PN2222ATFCT-ND TRANSISTOR GP NPN 40V TO-92 4
Immediate 0 0.22000 $0.88
5 1 IRLZ44ZSTRLPBFCT-ND MOSFET N-CH 55V 51A D2PAK 1
Immediate 0 2.30000 $2.30

mellowout

iTrader: (2)

Make sure you don't have the COPS wired in backwards. Also, what are your inverted spark settings? If I'm not mistaken if you get them wrong it may hold the coil open and it just sits there and fries itself.

rndmheroxx

iTrader: (1)

Im guessing you only skimmed over the thread.... Me wiring the COPs in backwards is the assumed cause of my problem, and was fixed before even creating this thread. Spark settings are, and always have been, set to "normal"/"no".

rndmheroxx

iTrader: (1)

SOLVED ... replaced transistors, runs like a champ