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Discussion Starter #1
hello mx6 people!

ive been peeking around this site for years, been avoiding it up until now.

figured if i have problems and serious questions, i should go to a mx6 specific site...

heres whats up, this is a copypasta from my original thread:

-------(first post)

After playing musical chairs with alternators, I finaly went back to the original with a bad volt reg...


Started, idled, died.


Found a blown main fuse (80), replaced, now fire.

Fuses under dash, all good

Main block fuses, fine

Spark, check

Fuel pump, check

Injectors, ?

Tried push start with a friend towing me, nope.

Could be a relay or a circut thingie somewhere somehow....


--------(second post)

took line off fuel filter and cranked, nice even flow of fuel came out...

so the pumps fine. but i already figured that.

took plugs out and cranked, all spark.

so its injectors, has to be.

both grounds on the injector harness, (egr side, and tb side,) are tight and clean.

--------(third post)

did some searching using the pmx626 thing (thanks ndm!)

so the EGI fuse on the under hood box is for the injector and fuel stuff huh?

hmm. mine isnt blown, but it isn't clean..

i swapped the EGI with the heater fuse since i don't even have a heater anymore.

different amp rating but whatever, still didn't start.

so i guess its not it? ill get a new one any way. shit ill get all new ones.

--------(fourth post)

replaced 30a EGI main block fuse.

replaced poor condition positive cable terminal.


--------(fifth post)


Replaced:

Alternator with good

Both yelow realys on the firewall

Black circuit thing with red dot

Still no start.


Injector plugs get 0.0 volts at crank.
 

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Discussion Starter #2
------(sixth post)

stopped by a really friendly mazda-nissan hole in the wall mechanic.

had a nice conversation, he actually CARES to solve this problem, just offering advice, no rushed "your not even paying just asking for help" type thing.


i got about 5-6 pages of wiring diagrams, showing relays and everything down to every detail.


when im back home i get to trace wires testing ohms and looking for crispy things..

there is a black relay, or at least a black cube with a green circuit board in side of it, sitting directly behind the ecu.


can anybody tell me what it is?


--------(seventh post)

$75 an hour if i took it in.

hmm no thanks.


1. why did the 80a fuse blow ( bad alternator maybe?) new alternator in now anyway

2. why are injectors not firing
a. main relay 1 replaced, relay 2 replaced, egi fuse replaced, main fuse replaced, fuel pump has power
b. black relay behind ecu still a mystery


relay # 1 and 2 both have current going to it, going out im not 100% certain yet.

if it wasn't going out it wouldn't make since, as i now have a total of 6 spares.

im beginning to think its the ecu, as thats where the injector drivers are im told.

------------

so there you are.

covered what happened, what ive replaced, and where i am now.

im well aware of the reputation this site gets, and i don't want to be chewed out my everyone and their brother.

if i worded, said, typed, or did anything wrong im sorry, and tell me how to fix it.

im looking forward to any help i can receive here, thanks so much in advance.
 

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your injectors may have been over driven. Take off the clips and see if you get an ohm reading using a multimeter. If you do, should be between 11.5-13.*

When those check OK, take off the clips to your ECU and measure the injectors for resistance.
 

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Discussion Starter #4
Will do zach, thanks


Also, I forgot to add that I've also swapped out all injectors with known good.
 

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Discussion Starter #5
key in, cluster lights on



-----



----

(side note)

what is this?

 

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Discussion Starter #6
i keep forgetting im not allowed to edit yet..

i should have joined 4 years ago....

that black relay is located behond the ecu fyi.


one of my diagrams i have says the injector wire out of the ecu is yellow, then yellow and black, is this correct?
 

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Discussion Starter #7

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Discussion Starter #8
2 weeks and counting. awesome...

getting power at both sides of plug when black probe is grounded...




should i be looking for anything here?




unplugged relays while on, both click when plugged back in, so they are good.

has to be ecu right?
 

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Discussion Starter #10
ask and you shall receive



----


#1, 14 to 13.9

#2, 13.9

#3. 14 to 13.9

#4, 14 to 13.9
 

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well they are good and they are getting power and injecting fuel. I wonder if your fuel pump is pumping too little fuel. Having fuel come out of your fuel line is one thing, having it come out at the correct flow is another.

did the fuel flow out of the hose or did it somewhat shoot out?
 

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Discussion Starter #12
It was a calm torrent. A strong flow.

Def not a trickle.
 

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Discussion Starter #13
I'm not confindent about the injecting fuel.

After multiple crankings and pulling plugs nothing smells like fuel.

Not even moist.


Ill tripple check that though. I even cranked with a plug out. No mist or anything fuel related.
 

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have someone crank and then stick a long screwdriver up to the injector to see if you hear them pulse. If they aren't working, then I would definitely swap out to another ECU.
 

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Here's a simple, perhaps even dumb, question.

Is your timing belt good? Are the cams turning when you crank it?
 

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Discussion Starter #16
Lol yea belt is fine.


Let's just assume the injectors arnt working.

I know for a fact.


Every relay is good. Maybe not EVERY but tbhats what I'm trying to narrow down.

Fuel pump is good, circute opening relay is good.


Both sides of injector harness plug get +12.


So what else controls the injector pulse, just the ecu right?
 

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Discussion Starter #18
Goin to a yard in less then an hour.

Pickin up:

Ecu

Ignition control module


Let's wait and pray gentlemen
 

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Discussion Starter #19 (Edited)
well after 154 views on this thread, and only one reply that actually helped....

i should have named the thread something different, i named crank but no start on the other place...

too many people fixated on the injectors, not what was CAUSING them to not fire.

picked up a 60$ ecu out of a 89 626 5speed.

whats missing in this picture?



THE CAR MAYBE?????

AHAHAHAHAHAHAHHAHAAHAHAHAHAHAHA

YESSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!


bad alt < main fuse < relay #1 and #2 < ECU

what a chain of events
 

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But you did diagnose it correctly. Always start with power supply when something isn't working correctly. ECU was the only thing that was left :)
 
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