7MGTE won't start after conversion - FIXED!!!

[Mr Ed]

was going to suggest your ignition barrel... could be a signal thing somewhere assuming u're using a 1G's ignition system and it's not compatible with the 7M.. not too sure but i could be wrong.. have heard of a few issues with key ignitions but not sure if this applies..

I was going to suggest this too as I had a similar problem, but he says the engines cranking so I guess thats not it.

[amichie]

I'm sure this is not news to you but worth amention anyway.

Injectors should always have 12v on ones side while cranking or running. The ECU shorts the otherside to ground to pulse the injector.

The ECU only uses the Ne signal or crank position sensor to pulse injectors while cranking.

[CrUZida]

Peewee - Injectors will not fire if a valid IGf signal is not present.
The ECU first fires the coils, waits to see if the coil fired (via IGf), and then fires the injectors. (You can immobilise an engine by disconnecting the IGf pin.) So you have to get your spark first, then chase fuel.

Reading the pdf's on Toyota ignition systems, it says that the ecu will wait for 8 to 11 failed attempts before cutting the fuel.
So I should see 2 or 3 injector pulses before it cuts fuel.

Do you know if a standard interior globe is fast enough to use as a test light? I turned off the lights at night and tried it, not even a glow.
Or should I use an LED with a resistor?

Do you have a scope? How did you check the CAS?

Just with a DMM. I don't even have an analogue one to try it with.
No scope either.

It could be that the output device for IGT is blown.. (Most of this is guesses, so I could be completely off).

I've tried different ecu and different ignitor, so faulty equipment is at the bottom of the list right now.

[thechuckster]

it does sound rather frustrating - i'm rebuilding an ECU to engine bay loom for the Msquirt to get around this very kind of flakey wiring.

an LED with a resistor will be the way to see if an injector is being earthed - globe not good enough.

[cambelt]

7MGT coils are not weak at all , sure if people drive them with wrong igniters they may fail but with the stock system im yet to see a 7MGT coil fail.
D

[CrUZida]

Ok, I have just verified that I do have fuel pulse. (vid LED and 400ohm resistor)

So that rules out CPS, injector drivers, ECU, and half of the wiring.

Back to triple check for spark and for bad wiring.

[CrUZida]

Ok, I have got the Check Engine Light working (helps when you wire it to the correct pin), and it threw code 51 (Switch Signal Condition).
So I earthed the NSW pin, and that code went away.

So, no codes basically.

Checked a whole lot of other wiring, everything came up fine.

Went to start it, few turn overs (injector pulse working) then battery flat!!

GREAT!

Will give it a quick turn over tomorrow morning (its on charge ATM), and get back into it tomorrow night.

[JustCallMeOrlando]

Haha, good luck

[CrUZida]

Ok, verified this morning that I have no spark.

The injector will fire twice before the ecu cuts the fuel.
So the problem lies in the ignitor circuitry.

I'll make sure no wires between the ignitor and the ecu are severed/crossed, and then... I don't know.

Anyone know if the NOISE FILTER (as per this pic) needs to be connected for it to work?

Coz I can't find it... (as in, its lost somewhere in my shed..)

[wilbo666]

Interesting that it is not throwing any codes....

If you crank it for over 15seconds (alyways felt like a long time to me!) without it starting it 'should' throw a code at least....

Cheers
Wilbo

[CrUZida]

It threw code 22 this morning, but thats just the water temp sensor.

I'll put the battery on charge again overnight and see if anything happens after a 15second crank.

[triptek]

So your getting no spark.

Had the same problem with my ma70 7mgte. Took my bro about 3 days of fucking around to find out it was the CPS. This went twice within 3 months.

Should get 140 to 180 ohms on the resistance check according to the supra haynes manual.

If it's stuffed my mate has one.

[CrUZida]

Yeah, tested that, all worked out fine.

I've got fuel pulse though, so the CPS works fine.

I'd say the problem lies in the ignitor wiring between ecu and ignitor.

[camrygt?]

an LED with a resistor will be the way to see if an injector is being earthed - globe not good enough.

very true especially with bigish injectors with short pulses

[CrUZida]

Ok, its not code 22, but code 11.

Does that make any sense to anyone?