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Argh car won't start.... Help please


mclarenross
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Hi,

i know this is a long shot but id appreciate anyone thoughts.

So car has just been rebuilt and everything has been put back together.

Car cranks but won't fire, (we even tried some of that start up spray, but still nothing) coilpacks are generating a very small spark...

my mechanic mate, thinks it sounds like a bad earth somewhere. ?

quick question are the cam sensors are they the same( ie does it matter which order they are in?) and also should there be a spacer between the sensor and the head?

anyone ever had these systems before?? Please ask if you need any more details.?

Thanks in advance.

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I have today just got to the bottom of a problem with car with a long history of not starting bought recently for the missus. I had a decent spark, timed up right and could trigger each of the injectors at the ecu plug by grounding them, it also had fuel pressure but it just wouldn't start. There was lots of man made faults with this I guess due to it's long history of not starting, but in the end the real problem was down to an earth strap not being connected and lost under the inlet runners. We realised it was an earth problem when I saw 7.6 volts on the 5v leg of the MAP sensor and 2.6v on it's earth leg with reference to the negative terminal of the battery. David P was here with his car and we started making comparisons and realised the earth lead wasn't there and he found it tucked away under the runners.

 

Now although your car is not a NA and this was, it shows what a dodgy earth connection can cause. From searching through old threads, it appears that a couple of members had tried with this car and given up, and it was all just down to an earth strap that had been left off during earlier work.

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Guys,

thanks for the input, I'm hoping its the earth and I'll try different ones tomorrow, John the timing was all lined up with top dead centre, so hopefully that's not the issue and I struggle to do a diagnostic due to the wiring of a my 1jz to N/a wiring that I've got....

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Guest FullAttack

Fit many earths.. I go way overboard with earth straps when I do conversions.. Big fat cables like battery cable, from Head to chassis, and Block to Chassis on both sides of engine...

 

Can I suggest wiring a light bulb into the W pin of the ecu, there's one linked to it in one of the other plugs on the soarer loom, either the orange or white one.. Says on wilbo which pin in which plug..

Thatll tell you if the ecu is live..

 

To test the injectors are firing, unplug one and stick a test light(iv even used an interior bulb and rago bits of wire) across the terminals of the plug, turn engine over and see if it lights up, it should pulse on/off so it'll look like its flickering..

 

If the injectors are firing and there's fuel in the rail start looking else where..

 

Is it an auto ecu with manual trans by any chance? What you done with NSW & STA pins?

Edited by FullAttack (see edit history)
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Guest FullAttack

^ that's hag.. Just take a coil out and stick a spark plug in the end, earth the spark plug body and turn the key.. It'll spark or it won't..

Even rubbish coilpackes will usually work to fire it up, it's under load that they misbehave..

Edited by listy
Please don't swear. (see edit history)
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Hi guys

thanks, it's an auto ecu and auto trans.

My mechanic mate, put a tool in the bottom of the coilpack which shows if it's sparking and he's said there was a weak spark, but there was one, sound unlikely for them all to fail.

We've also just fitted 550 injectors with a resistor pack, I'll check the injectors are firing tomorrow.

Cheers

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Hi guys

thanks, it's an auto ecu and auto trans.

My mechanic mate, put a tool in the bottom of the coilpack which shows if it's sparking and he's said there was a weak spark, but there was one, sound unlikely for them all to fail.

We've also just fitted 550 injectors with a resistor pack, I'll check the injectors are firing tomorrow.

Cheers

 

First thing I think of here is is it (resistor pack) producing the correct resistance?

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Guest FullAttack

550cc won't really work with stock ecu.. Can get away with it with an air/fuel controller, but I'd go standalone ecu before piggybacking..

 

My recommendation at this point is to put stock injectors back in and see if it starts..

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Hi, yeah half a tank of fuel and fuel sounds to be going into the rail.

Any idea how to check the resistor pack is working? Was going to check that the injectors are getting a signal today,

And yeah I appreciate that I'm pushing the limit with 550 on stock, but I'm running a safc2 and lots of soarer owners run this set up.

Great feedback so far guys! Thanks

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550cc won't really work with stock ecu.. Can get away with it with an air/fuel controller, but I'd go standalone ecu before piggybacking..

 

My recommendation at this point is to put stock injectors back in and see if it starts..

 

I agree, but the resistor pack will need removing also. If not you could get a bang.

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And also what voltage should these bigger injectors be running at as we've got 12v running into the resistor pack and 12v coming out??

 

the car just wouldn't fire with the resistor pack in, we just decided to try the old configuration without the resistor, it fired up ( but a little rough...reving up and down) , so question... can I run the 550 without the pack ? Or will it blow out the injectors ?

Edited by mclarenross (see edit history)
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measure the coil impedance of your injectors and then come back and post, in the meantime I wouldn't run it. To do this unplug an injector and stick your meter across it with the meter set to low ohms. Also, what value resistors have you used?

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Hi Shane,

so we have 6ohms coming out of the resistors and 2.7 out of the injectors and it won't start.

Also the loom goes 6 wires at the individual injectors spliced into three and then into one, should I be wiring the 6 individual wires off the resistor pack into the 6 injector wires or is it alright to wire it into the three (doubling up).

last question should we be wiring into the black and orange wires on the injectors ( loom side and live feed) or to the other coloured wires on the injectors??

hope this makes sense

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measure the coil impedance of your injectors and then come back and post, in the meantime I wouldn't run it. To do this unplug an injector and stick your meter across it with the meter set to low ohms. Also, what value resistors have you used?

 

Hi Shane,

so we have 6ohms coming out of the resistors and 2.7 out of the injectors and it won't start.

Also the loom goes 6 wires at the individual injectors spliced into three and then into one, should I be wiring the 6 individual wires off the resistor pack into the 6 injector wires or is it alright to wire it into the three (doubling up).

last question should we be wiring into the black and orange wires on the injectors ( loom side and live feed) or to the other coloured wires on the injectors??

hope this makes sense

 

OK great, I just wanted to be very sure you did in fact have low impedance injectors. This being the case, you don't want to be running without the resistor pack, you will cook your ECU for sure in no time with that amount of current going through the injector drivers. We need to get to the bottom of the resistor thing now.

 

The black and orange wires are all connected to each other at source and as you say are your live feed to the injectors. You now need to introduce a resistor in series (in line) to each injector, so the 12v feed gets to the injector via the resistor. I haven't seen your resistor pack so can't say for sure, but the last one I saw had one end of each resistor all connected together and then the other end of the resistors connected to six away legs, is yours the same? So in effect, you should have a a resistor pack with 7 wires coming from it, a common and 6 away wires?

 

Sorry for the delay in getting back to you since last night, but will be at my PC for most of the afternoon now.

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Ok presuming you have already cut the black and orange wires, connect one black one from the resistor pack to each of the black and orange wires in your loom that go back to the injectors and insulate them individually and then the black and orange that come from the ECU end of the loom join together and connect to the white wire coming out of the resistor pack. Also, I presume you have ensured that the 6 x black and orange wires from the loom you identified and cut are 100% the ones that go to the injectors? I seem to recall there are other black and orange ones in there too.

 

So is that pretty much how you had it? once you have confirmed this we will move onto a quick and easy check back at the ecu end.

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OK STOP RIGHT THERE!!!

 

What ECU and harness are you using?

 

I have just been looking at how the 1JZ injection side of the ecu works and its not the same as the 2JZ.

 

On a 2j each injector gets grounded to trigger on it's own pin on the ecu, on a 1j, they are triggered in pairs, so the wiring will be different. This could be your issue.

 

Loads of info here: http://www.supraforums.com/forum/showthread.php?170792-mk4-550cc-injectors-and-resistor-pack&highlight=resistor&pp=25

 

And 1J ecu pin out here: http://wilbo666.pbworks.com/w/page/47216384/1JZ-GTE%20JZZ30%20Soarer

 

I have some work to do for the next little while but will look back in on this in a short while.

Edited by Shane (see edit history)
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I'm running standard ecu and harness. Thanks for finding that post, (post #30 seems to sum it up!)) i've been searching everywhere on the 2jz resistor pack rather than the 7mgte, but I take it that it's the same principle...

I'm clueless when it comes to electrics, but because there in pairs does that mean that the 6ohms coming out of the resistor is halved to supply the injectors with the low impedance of 2.7ohms?

Thanks 

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I'm running standard ecu and harness. Thanks for finding that post, (post #30 seems to sum it up!)) i've been searching everywhere on the 2jz resistor pack rather than the 7mgte, but I take it that it's the same principle...

I'm clueless when it comes to electrics, but because there in pairs does that mean that the 6ohms coming out of the resistor is halved to supply the injectors with the low impedance of 2.7ohms?

Thanks^

 

Standard ECU and harness as in 1J?

 

OK, the injector's impedance is always 2.7, and you need to add a resistor in line with either the feed to the ECU or the 12v feed to each injector to get it close to the original hi impedance injector's impedance. It's an unusual (to me anyhow) way of firing the injectors on the 1J, injectors being fired in pairs is not something I have come across before. Without seeing it and working it out for myself, this is going to be a bit difficult. So, the black and orange on yours still feed the 12v feed to the injectors do they? If so then how I described connecting it above should still work assuming you have not chopped or changed any of the wiring between the ecu side of the injector and the ecu plug.

 

What concerns me a little here is that the Black/Orange that we presume are the constant 12v feed to the injectors aren't. I would feel a lot happier if you could confirm that with your meter.

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