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-   -   Car wont start! Help! (https://www.miataturbo.net/engine-performance-56/car-wont-start-help-72089/)

Braineack Apr 12, 2013 11:22 AM


Originally Posted by 94LagunaR (Post 999624)
Getting no power to the injectors.


Originally Posted by Braineack (Post 999627)
is your fuel injector harness even plugged in?

the white/red 12v wires for the injectors are shared with the CAS and other components, like the ECU, powered directly from the MAIN relay. So if the CAS and ECU is working...

do you have 12v on the B+ in the diagnostics box?


Originally Posted by 94LagunaR (Post 1000367)
Braineack wanted me to check B+. To clarify im getting 11.7 at B+ and 0 at the injectors.

do you understand why?

you said you had no power at the injectors, but power at the CAS and diagnostics box. If that's really the case, then you need to power your injectors in order for them to fire.

94LagunaR Apr 12, 2013 12:27 PM


Originally Posted by Braineack (Post 1000374)
do you understand why?

you said you had no power at the injectors, but power at the CAS and diagnostics box. If that's really the case, then you need to power your injectors in order for them to fire.

Okay, so basically i need to follow the red/white wire to the ecu to check for breaks, and also to the CAS and and Mass Airflow sensor? Or since I am getting power to the CAS then there is not a break in the wire between the injectors and CAS/ MAF?

Braineack Apr 12, 2013 01:09 PM

Did you actually test for voltage at the injectors on the white/red wire?

tpwalsh Apr 12, 2013 01:14 PM


Originally Posted by 94LagunaR (Post 1000403)
Okay, so basically i need to follow the red/white wire to the ecu to check for breaks, and also to the CAS and and Mass Airflow sensor? Or since I am getting power to the CAS then there is not a break in the wire between the injectors and CAS/ MAF?

sorta. Brain's the better resource, but the ecu switches the ground side of the injectors, NOT the power side. The injectors have 12v on them all the time, and the ecu connects the other wire to ground when it wants the injectors to fire. Red/white sounds like a power wire, not a ground, but I don't have a wiring diagram in front of me.

Braineack Apr 12, 2013 01:28 PM

noggin, using it.

94LagunaR Apr 12, 2013 01:52 PM


Originally Posted by Braineack (Post 1000419)
Did you actually test for voltage at the injectors on the white/red wire?

Well I connected the multimeter one side to the white/red and the other to the other wire on the injector harness for each injector. I wasn't sure if this was the proper way to test them so i put one on the white/red and the other on bare frame. Either way I got 0v, but which way is correct?

Originally Posted by tpwalsh (Post 1000421)
sorta. Brain's the better resource, but the ecu switches the ground side of the injectors, NOT the power side. The injectors have 12v on them all the time, and the ecu connects the other wire to ground when it wants the injectors to fire. Red/white sounds like a power wire, not a ground, but I don't have a wiring diagram in front of me.

All injectors have the white/red wire and they all connect to the same pin on the ecu. Each one has another wire which connects to its own seperate pin on the ecu. Info via: http://www.madracki.com/miata/images/wiring/94sys.pdf

Braineack Apr 12, 2013 01:54 PM

no. put the black lead to the head or something, any engine ground, and with the key to ON, unplug an injector and test the red/white wire side of the connector with the red lead for voltage.

if you have voltage, then the issue is probably the signal back to the ECU.

94LagunaR Apr 12, 2013 02:09 PM


Originally Posted by Braineack (Post 1000433)
no. put the black lead to the head or something, any engine ground, and with the key to ON, unplug an injector and test the red/white wire side of the connector with the red lead for voltage.

if you have voltage, then the issue is probably the signal back to the ECU.

Okay I have voltage. 11.7v to each one

Braineack Apr 12, 2013 02:33 PM

okay.

so the injectors have power, you get spark, but we're pretty sure the injectors aren't firing?

and the pump at this point IS running?


(please bear in mind that doing this over the internet with little to go on is hard. Trying to narrow things down here.)

94LagunaR Apr 12, 2013 02:35 PM


Originally Posted by Braineack (Post 1000448)
okay.

so the injectors have power, you get spark, but we're pretty sure the injectors aren't firing?

and the pump at this point IS running?

Correct

Braineack Apr 12, 2013 02:38 PM

hmmmm....


what happens if you unplug the TPS and try to start it?


and we are positive the fuel lines are crossed or something?


next thing I'd try is making sure the 4 wires from the injectors make it all the way back to the ECU.

94LagunaR Apr 12, 2013 03:01 PM


Originally Posted by Braineack (Post 1000452)
hmmmm....


what happens if you unplug the TPS and try to start it?


and we are positive the fuel lines are crossed or something?


next thing I'd try is making sure the 4 wires from the injectors make it all the way back to the ECU.

With tps unplugged, same symptoms. Cranks but doesn't fire. Fuel feed line is going into the front of the rail, return like coming out of the fpr. If the fpr is bad what would be indicative? Are there any symptoms? I figure it would restrict the return flow. If, for example, the injectors themself are bad, but the regulator is good, would the flow out of the return line be the same rate as the flow into the rail?

Braineack Apr 12, 2013 03:06 PM

which hardline goes to the front of rail? closest to firewall or radiator?

94LagunaR Apr 12, 2013 03:15 PM


Originally Posted by Braineack (Post 1000460)
which hardline goes to the front of rail? closest to firewall or radiator?

Firewall

Braineack Apr 12, 2013 03:23 PM

have gas in tank? lol.

94LagunaR Apr 12, 2013 03:25 PM


Originally Posted by Braineack (Post 1000469)
have gas in tank? lol.

Lol yes. Can I just get a megasquirt and everything will be fixed?

94LagunaR Apr 12, 2013 03:34 PM

Is the ECU, coil pack, and several other ground wires bolted to the back of the intake manifold near egr? Are there any other grounds in the "rear of engine"? In the wiring diagram I linked, on page 8, it shows 3 different grounds to the "rear of engine" and on page 9 it shows 3 wires to a connector that go to 1 wire that grounds at the "right rear of engine". I can only find the 1 ground at the back of the intake manifold. Are there others?

fooger03 Apr 12, 2013 05:28 PM

1 ground at the bolt which supports the dipstick tube.

1 ground at the front of the engine to the mechanics right of the throttle body and slightly below.

94LagunaR Apr 12, 2013 06:00 PM

1 Attachment(s)
https://www.miataturbo.net/attachmen...ine=1365804052

Is this the cause of my problem?

thenuge26 Apr 12, 2013 06:06 PM

If it's not, I'd wager it's the cause of another problem you haven't discovered yet.


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