1jz won't start

[doommachine]

Another conversion - typical issues, it won't start. JZX81 in mx83, complete JZX loom.

The CEL stays on. If I earth out the TE1 pin the light stays on and won't flash.. there is voltage at the TE1 pin also.

It will start with TE2 mode sometimes - although today it won't. When it does, it starts every time and runs very badly. Idle pulses between around 1000 and 2000, goes up and down
at random. Opening the throttle makes it sort of backfire, the revs won't increase.

I've tested the compression, 175 170 175 180 175 170.
Getting spark. Pulled the plugs and made sure cyl 1 sparked at 5 below TDC.

12v at each injector connector.

CAS resistance is 1100 ohms
Cam sensors are both around 900.

What else is there?? Theres definitely fuel pressure as I had a fuel leak before.

I understand the TPS in these cars are extremely finicky, if it's out a little would that stop it from starting?

I've opened the ECU and it looks very clean, no capacitors bulging. There seems to be a transistor and a resistor
that have been unsoldered from the board, can't remember what the numbers are, but again, will take pics.


There are also numerous extra plugs that don't go anywhere. (Have to go to work soon, will try to take pictures tomorrow morning)

PASSENGER SIDE

Orange male and a blue female that will connect to each other (disconnected though - connecting makes no difference)

A white female connector (at least 20 pins)

A 2 pin plug, blue wires - seems to come off the air con loom. The heater/a/c fan doesn't blow either but obviously this isn't a concern atm

A 4 pin white connector, has a pink/purple wire in it.

DRIVERS SIDE

Big grey male
Big white male

- How else can I test the ECU?

- Any suggestion on non-start condition?

[George]

Manual or auto? Do you have jzx81 wiring diagram?

[doommachine]

Manual or auto? Do you have jzx81 wiring diagram?

Ah! I forgot something haha.. auto. And yes, I have the diagram, although of course just the EFI, transmission, abs and a/c diagrams floating about the web.

[George]

One particular troublemaker is neutral start switch. Check that you connected everything related properly. Especially check ECU sta/nsw pins (connectivity to switch in the auto).

[doommachine]

OK, it cranks over, and if I put it in reverse it won't, but I will check that circuit anyway.

[George]

so the switch is wired to starter relay, that's good, but at the same time ECU pins may not.
p/s also check power just for the case
so ground is E1,E01,E02, and E2 does NOT have continuity to car body
when engine is running, you should see +12V at IGSW,BATT,+B1,+B
when everything is off you should still observe +12V at BATT

when on P or N, you should have continuity between STA and NSW. Then connect everything back to ECU and check if you see 0V on both of the pins, when ignition is on and the above is verified.

p/s also try to read your error codes by first shorting TE1 or TE2 to E1 and turning ignition on only after that

[doommachine]

so the switch is wired to starter relay, that's good, but at the same time ECU pins may not.
p/s also check power just for the case
so ground is E1,E01,E02, and E2 does NOT have continuity to car body

Yes - to clarify - the first 3 earths DO have continuity to car body, and E2 doesn't? If I test E2 with the harness unplugged, there is no continuity with the body.
When the connector is plugged in to the ECU, there is continuity between E2 (from the o2 sensor) and the car body. I assume that E2 is internally earthed through the ECU?

when engine is running, you should see +12V at IGSW,BATT,+B1,+B
when everything is off you should still observe +12V at BATT

I'll check. B+ definitely has battery when the ignition is on, from the test connector.

when on P or N, you should have continuity between STA and NSW. Then connect everything back to ECU and check if you see 0V on both of the pins, when ignition is on and the above is verified.



p/s also try to read your error codes by first shorting TE1 or TE2 to E1 and turning ignition on only after that

I've tried everything to get the codes to flash. I've unplugged the battery for 10 minutes, then connected them.. the light simply never flashes.
Interestingly TE2 seems to work properly, if I have O/D on and TE2 earthed the O/D off light flashes.

[George]

E2 is earthed through the ECU. On later models (jzx100,110) even when ECU is connected there's no continuity from it to earth.

Since yours is a swap, parts of loom may appear disconnected from each other. The "additional" unconnected sockets may contain vital signals that normally go through body loom. That's why checking +B at the diag connector is not the same deal that inspecting the voltage right at ECU connector.

can't tell you enything regarding the TE1 pin. Try TC, though it should not work

p/s the diagram shows that boost sensor as well as speed sensor signals are sent to ECU through dash cluster, so it's questionable how will it work without one

[doommachine]

I see.. makes sense. I'll check it out tomorrow, update the thread with results.

[dumbass]

Check fuel pressure as that will cause backfire when u press throttle if it's low
Also if u can't get cel to work its usually a fkt ecu
So make sure u have wired the cel correctlyl
There's are piss easy to wire heheheh

[doommachine]

Check fuel pressure as that will cause backfire when u press throttle if it's low
Also if u can't get cel to work its usually a fkt ecu
So make sure u have wired the cel correctlyl
There's are piss easy to wire heheheh

If it wasn't for the CEL staying on I would assume it was the fuel pump. I had a horrible time with cross-threading the fuel line so I'm hesitant to unbolt it again to test the fuel pressure, but when I eliminate the wiring loom, that's next. I guess the fuel filter is also 20 years old and has 150,000 kays on it, probably, but the car ran before the swap was done - I guess the fuel pump makes perfect sense really, it's the only thing that ISN'T from the donor car.


The wiring loom hasn't been taken apart, the entire loom from the JZX81 was removed and put into the cressida.

[dumbass]

That's doing it the hard way
I hate removing complete dashes
Anyway just pull off return line check for fuel flow
Also spray something flammable down butterfly to see if it revs more
Otherwise bring it up here and I'll fix it heheheh

[doommachine]

That's doing it the hard way
I hate removing complete dashes
Anyway just pull off return line check for fuel flow
Also spray something flammable down butterfly to see if it revs more
Otherwise bring it up here and I'll fix it heheheh

OK looks like I am living up to your username...

I realised that since I don't have the throttle body to intercooler pipe I had effectively a massive boost leak. So, I shoved a bottle of brake fluid into the rubber inlet pipe, starts no problem.

BUT it still runs really shit, idle is rough, and I can't rev it at all, although when I had sat and babied it a bit, at random it came good and allowed me to rev it as if it was OK. Then I noticed a large amount of smoke coming out of the bonnet (looks like either a heater hose leak or something like that, it smells like coolant) so I stopped the car to check it out, and after stopping it it went back to being shit.

I'll adjust the TPS properly tomorrow, it could be that I guess?

No codes, plugging in the test lights still has the CEL solid. So.. if not a sensor, fuel pressure, probably?

[dumbass]

yes my username is a shit stir from issues i had afew years ago
find the cel light wire right at ecu
cut the wire and hook it to a test light and other end of testlight to battery pos
then get te1 wire and bridge it to a good earth
if test light still doesnt flash then u have ecu issues
they might not be enough to make engine run shit but if the ecu wont flash cells it means try another ecu
chech inside ecu and lean capcitors over and check for black marks
might be just starting to go
anyway try find another ecu just incase

[doommachine]

Ah.. I was afraid of that, I pulled the ABS codes yesterday, that worked (although the dreaded code 51 appeared.. the pump still runs, it probably just needs to be bled).

Alright I'll give that a go, with any luck it will flash. What causes the light to not flash? It comes on and stays on solid..