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Registered:
May 2002
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Wiring loom problems (3TGTE)
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Fri, 07 February 2003 00:43
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well i've finished wiring up the loom for my 3TGTE, but having some trouble starting the engine. I'm definately getting a spark, but the spark plugs are dry and i've got power to both sides of the injector connections. It seems like the computer is not earthing the injectors. I'm going to try and wire in the cold start injector tommorrow to see if i can get some sort of life out of the engine (do i really need this?). The injector relay is getting power, also it seems like the connection from the relay to the computer that should be earthing the relay isn't. I have bought a normal relay from the shop for the injector relay, will the normal 4pin 12v relay work or is the injector relay special?
is there anything i could try, any suggestions?? i know its damn near impossible to kill these electrical gremlins over the net, so does anyone have any experience with injectors not firing or any EFI procedures/checks i could do?
cheers
robert
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Registered:
June 2002
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Re: Wiring loom problems (3TGTE)
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Fri, 07 February 2003 01:00
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It has been a while, but you may need to earth the pressure switches if they are not connected ie high boost connector PC also you should fit a pressure switch to come on around 2+psi for boost enrichment PE if you haven't got this connected it should be open cicuit. With PE earthed you should notice a higher idle? it been a while but I think the configuration is something like this.
Definately need PC earthed to fire the injectors I think you will find this will be your problem if you haven't done it.
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Location:
Brisbane
Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Fri, 07 February 2003 01:07
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I've had similar problems with my 18R-GEU recently. After much wailing and gnashing of teeth it turned out to be a bad ground. Make sure the ECU is grounded with a good, solid connection to the body, and make sure the injector circuit is grounded to the inlet manifold using heavy gauge wire (pins E01 and E02).
A good way to check the injector circuit is to unplug the ECU and bridge pins #10 and #20 to E01 and E02 on the ECU plug. Then use a multimeter to check the resistance between the injector plugs and the inlet manifold; it should be zero. Finally, briefly switch on the power to the injector circuit (only for a fraction of a second) and listen for a click from the injectors, which should be quite audible. If that works, your injector circuit if fine and the problem exists with the ECU itself.
Finally, have you checked the fuel pressure? I bought an oil pressure gauge and hooked it up to the fuel rail (where the cold start injector is supposed to go), and this was invaluable when diagnosing problems with the EFI system. As long as you have fuel pressure and spark, you know the problem is electrical. BTW, the cold start injector is not needed - mine has been disconnected ever since I broke it a few years ago.
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Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Sat, 08 February 2003 22:40
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i've got the fuel cut pressure wire earthed (the red wire), and the other two pressure switchs are connected.
All the grounds are good, and the fuel pump definately works (got a spray in the eye before) and it has been tested before, and the fuel rail is hooked up the correct way.
I am thinking that the injectors are not hooked up correctly. I wired injectors 1 and 3 together, and 2 and 4, and did not bridge these injectors, when on the wiring diagram i was to bridge the injector earth wires #10 and #20, and connect 1,3,4 injectors together, and leave injector 2 on the #20 wire. This would definately bugger all the resistances up for the injector circuit and explain why they won't fire, if i got it wrong(?). I got the wiring diagram from here-
http://users.senet.com.au/~mezz/wiring.htm
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I supported Toymods
Location:
Perth, Western Australia
Registered:
December 2002
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Re: Wiring loom problems (3TGTE)
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Sun, 09 February 2003 04:13
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Rob,
I have only ever wiried up "copycat" to the diagram, where number two injector (I think) is seperate to the other three. I've never had a problem with the injectors not firing this way. Another area you might like to try is the AFM. The fuel pump relay works through this - When there is air flowing through it (ie: open), power is directed to the fuel pump, and vice versa when closed.
Clint
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Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Sun, 09 February 2003 05:05
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Clint, i tried bridging the injector banks today but it still wouldn't start. I'll try and wire up number 2 injector separate. I haven't got the circuit open relay connected as i'm just using the fuel pump off ignition for now (want to eliminate the chance of the relay not working), so the wire from the AFM is not connected.
Also the Fr connection that is supposed to earth the injector relay has power when the ignition is on, and hence the relay isn't supplying the power (but the injectors are still getting power from the otherside/white wire). should the computer always be earthing it or does the injector relay only supply power when the negative injector side is earthed?
I think i'll try ripping the loom out and re-wiring it again  , hopefully it will work when i copy the diagram exactly.
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I supported Toymods
Location:
Perth, Western Australia
Registered:
December 2002
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Re: Wiring loom problems (3TGTE)
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Sun, 09 February 2003 09:56
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Rob,
I've also always wired up the circuit open relay, feel it's safer that way regarding the fuel pump and it's control.
My understanding is that the injectors require a constant 12volt supply, and to fire they are earthed out dropping the voltage to 9volts which allows them to fire. Short of checking your efi relay wiring, I'd say you need to take you previous option and rewire according to the diagram!
Clint!
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Location:
Newcastle, NSW, Australia
Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Sun, 09 February 2003 21:27
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Have you checked for injector pulse? Have you had the injectors cleaned? Just because the pots aren't wet doesn't mean the ecu isn't firing the injectors. Injectors have a tendency to 'gum up' when left sitting for long periods and often result in the injector being stuck closed.
BTW, that diagram is WRONG. Do not bridge the injector banks.
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Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Mon, 10 February 2003 22:32
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i've tried rewiring it (messy for the moment, but correct to the diagram) and still no luck. The injectors are bridged for now, but checking resistance it seems that they are bridged just inside the ECU anyway.
i put power to each injector and heard my fuel pump change sound, so i'm quite sure each injector is working, even though i haven't had them cleaned.
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Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Tue, 11 February 2003 05:53
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Are there any 3TGTEU computers that have external ballast resisters for the injectors?
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Registered:
June 2002
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Re: Wiring loom problems (3TGTE)
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Wed, 12 February 2003 00:18
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No there is no need for them on 12 ohm injectors
roger
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Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Wed, 12 February 2003 00:37
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but they are 1.7ohm injectors!?!?!
well i've ripped the loom out and done some probing, seems the injector relay is definately working alright, at least when the ignition is on.
I'm getting about 12V to the injectors when ignition is on, when the starter motor is cranking the voltage on BOTH sides of the injectors steadily drops below 2V, so i'm not getting enough power to the injectors, and the negative side doesn't seem to be earthing them.
Does the power to the injector relay come from the ignition switch (eg starter, ignition, accesories, off) because that is where i have it connected, and am thinking this is not a steady power source when the starter motor is cranking.
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Registered:
June 2002
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Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Tue, 18 February 2003 08:04
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The EFI specialists reckon the knock computer is buggered becuase it isn't sending an ignition signal to the EFI computer, so i've sent that away to get checked out. Is this correct, the EFI computer gets its ignition signal from the knock computer???
The two injector wires are definately not supposed to be joined, as the diagram suggests. This could be the reason why the EFI computer isn't earthing my injector relay, hence it has been sent in to be repaired aswel.
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Location:
1st street on the right
Registered:
November 2002
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Re: Wiring loom problems (3TGTE)
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Tue, 18 February 2003 08:31
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Are you using the circuit opening relay? This runs more than just the fuels pump/s I thought? and is earthed to switch via the AFM. And yes power for relays should come from the battery, voltage drop will be significant enough. The injectors aren't earthing? Check engine earth's, I know it's obvious but I spent two days with a car that wouldn't start because the earth was loose "but it's connected". I only found it when I put my hand on it and it was a bit warm.
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Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Wed, 19 February 2003 13:42
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ok, now i've changed my mind, the two injector wires, #10 and #20 are definately supposed to be bridged. If these are not bridged and the injectors are fired in two separate banks, the injector resistance WILL be too high for the computer, and it could shit itself, like mine did, now it has gone to heaven  . the total parrallel resitance would be about 1ohm instead of 0.5ohm with the 4x2ohm injectors, therefore it would be twice the normal voltage to the computer  .
I've spoken to a few people, looked at a few more wiring diagrams, it seems that all the injector negatives are wired together, this can be done with a single wire connecting #10 and #20, which connects to each individual injector, but the wiring diagram displays the wiring as it was wired from the factory, with injectors 1, 3 and 4 wired together then connected to 2 later down the wire.
Hence the wiring diagram is infact correct. Everyone wiring a 3TGTE computer should follow this exact
CLUBAGREENIE: yep just wired in the circuit open, and no i'm sure it only controls the fuel pump.
i'm thinking of having multiple earthing positions for the computer just to be sure. everyone whos wired a computer has said they had earthing problems.
I should be getting a new computer tommorrow, will try again with that.
EDIT: Thanks to everyone for their help, i've managed to wire the loom without seeking an auto electrians help.
[Updated on: Wed, 19 February 2003 13:55]
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Registered:
June 2002
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Re: Wiring loom problems (3TGTE)
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Wed, 19 February 2003 22:05
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Inferno,
If you have fried your computer, are you getting it fixed? if not I maybe able to fix it for you depending on what is blown. let me know.
I have wired in the past two injectors off #10, two off #20 with a bridging wire between #10 and #20, yes the diagram is confusing, I think it is still missleading although it may give the right load in the end. The knock computer is not neccessary to provide the ignition signal, this come either straight from coil -ve of the ignitor.
The knock computer does not provide the ignition pulse the coil or the ignitor(same signal) will
Roger
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Registered:
June 2002
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Re: Wiring loom problems (3TGTE)
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Wed, 19 February 2003 22:12
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Also I will mention it again the standard 3tgteu injectors are 12 ohm ie high impedence the injectors not 2 ohm. All ljet tronic is designed for a high impedence load hence why alot of system use ballast resistors. If you are measuring 2 ohms then your injectors are stuffed if they are standard, but more likely they are not the original. Check what you have, they could be 2tgeu or 18rg injectors which are I think 2 ohm 200cc but if your lucky they may be larger ones the original are 12 ohm and around 295cc. If they are 2 ohm you must use ballast resistors.
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Location:
Terrigal
Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Wed, 19 February 2003 22:49
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Knock computer definately isn't required for the engine to run. I never put mine in. Ign comes straight from the dizzy/coils to ecu.
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Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Thu, 20 February 2003 00:18
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no i'm sure 3tgte injectors are 2ohm, 2TGEU are 2.7ohm(both L-jet tronic). i have two sets of 3TGTE, both measure 2ohm, they have part numbers 195500-0668 and 195500-0662. I have also been told 3tgte injectors are low impedance by a few people. I may need a ballast resister for it though. The 2TGEU injector ballast resister looks to be 2ohm, anyone know the impedance of the 3tgte ballast resister?
I sent the computer away to be checked, they said they haven't got the parts to fix it (i'll ask what broke on the board), if your able to fix it i'm sure we could make some sort of deal.
Good to know about the knock computer, not sure what i'm using it if i don't have the turbo bolted on yet!
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Registered:
June 2002
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Re: Wiring loom problems (3TGTE)
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Thu, 20 February 2003 02:39
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My injectors are 12 ohm, and I have measured other 3tgteu injectors at 12 ohms besides mine. I am 90 % positive of this but have no hard evidence interms of a 3tgteu injector specs. Can some one confirm for me that standard 3tgteu injectors are 12 ohm. All Ljet system I have seen have ballast resistors if using a 2ohm injector if yours are 2 ohm I suggest you put the ballast resistor on other wise the same damage will occur.
Roger
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Location:
Terrigal
Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Thu, 20 February 2003 03:19
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I can confirm that they are definately 12 - 13 ohms.
They do not use a ballast resistor.
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Registered:
June 2002
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Re: Wiring loom problems (3TGTE)
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Thu, 20 February 2003 03:31
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Thanks turboRA28, With that confirmation I would be checking the flow rate of the injector you have, you will be able to use them but you must have the ballast resistor or bye bye ECU => high current. You may need to get the injectors flowed and muck around with the air flow meter to get it tunned right.
Chances are you have blown the injector drivers in the old one, these may not be avaliable any more but there should be an alternative driver.
Roger
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Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Thu, 20 February 2003 04:13
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ok, i spoke to the guys at fueltronic who checked the ECU, they told me the 3TGTE has 4x5.6ohm resisters in series with the injectors, or alternatively one 1.5ohm resister for all the injectors. using my electronic skills that equates to about 2ohm totaly including all the 2ohm injectors, when if i had the 12ohm injectors the total resistance would be 3ohms. If i had no resisters and used the low impedance injectors it would be about 0.5ohm total, hence why the ECU shit itself. I will try four of these resisters and see how it goes.
No wonder i wasn't getting the injectors to open. I think there were two kinds of injectors and setups for the 3TGTE.
Roger: any chance of repairing the old ECU?
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Registered:
June 2002
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Re: Wiring loom problems (3TGTE)
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Thu, 20 February 2003 04:51
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I would be using 10 Ohm , around 50 watt resistors, which will give you the 3 ohm load you need rember the greater load the less current be safe and go at least 10ohm. Don't wrap the resistors up in the loom as they will dissapate a lot of heat.
I am yet to see a wiring diagram for a 3tgteu that has ballast resistors, I don't think fuel tronics is correct in saying 3tgteu's have ballast resistors. I would say that the injectors you have are not standard.
Roger
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Location:
Terrigal
Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Thu, 20 February 2003 05:41
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I've wired up a few 3tgte engines and none have had balast resistors!
If you are going to run the 2 ohm injectors you might be able to find a ballast resistor pack at the wreckers. When I wired up a 4age it was missing the ballast resistor and found one in a nissan that was easy to modify.
Cheers
Joel
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Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Thu, 20 February 2003 08:09
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my injectors are clicking!!! hehe! YEAH! Finally.
yep found a resistor pack, off a Nissan CA, with 4x 6.3ohm resistors in series with my 2ohm 3TGTE injectors, and the injectors are firing with the new computer. I'm going to test the old computer next, just to make sure its dead, then i'll put the new computer back in and adjust timing to get the engine to kick over. I am hoping these injectors are 3tgte, maybe the celica 3TGTE uses high impedance injectors and the corona 3TGTE uses low impedance injectors with a ballast resistor, because i know the engines out of each model car have quite a few differences.
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Registered:
June 2002
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Location:
Terrigal
Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Thu, 20 February 2003 22:06
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Good to hear! Just be careful those injectors flow the same as factory 3tgte injectors, as i'd be pretty confident they are not 3tgte injectors. Don't want to come on boost and engine lean out.
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Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Thu, 20 February 2003 23:11
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i'm very sure they are 3TGTE injectors... i've measured the impedance of 3 different sets, all around 2ohms, and i've had a couple of people tell me they are low impedance.
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Registered:
June 2002
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I supported Toymods
Location:
Perth, Western Australia
Registered:
December 2002
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Re: Wiring loom problems (3TGTE)
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Fri, 21 February 2003 04:46
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Rob,
Give me the part numbers of those injectors you got from me if they are the ones you are using - I'll check them against the other sets I have in the shed and make sure I supplied the correct ones!
Clint!
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Registered:
May 2002
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Re: Wiring loom problems (3TGTE)
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Fri, 21 February 2003 14:02
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well its a good feeling realising i've been pissing in the wind for the past couple of weeks, especially when i could never workout why i was getting wet!!
The injectors i had in there were dead!! i replaced them with the ones i got with the engine (cheers clint) and now they are clicking away, i can get the engine to stumble, haven't got it to start without the starter motor. It seems like one of them is blocked, but the rest are definately wetting the spark plugs. I think i may need the air bypass valve or at least cold start injector hooked up to get it to kick-over, unless its just a timing issue.
part numbers are -
195500-0668- dead ones i was sold last year for $90 .
195500-0662- ones i got off you (clint).
If you could check the resistance of the other injectors that would help clarify the impedance of 3TGTE injectors.
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Location:
Aucks NZ
Registered:
June 2002
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Re: Wiring loom problems (3TGTE)
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Wed, 04 May 2005 09:22
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digging up very old post here... just curious of some details..
roger.. those 3tgte injectors your certain are high impedance, can you remember if they were the same ones as inferno measured as 2ohm? ie # 0662 & 0668
i have also measured up some std 3tgte injectors with same part numbers as inferno.
oil cooled had 195500-0662 injectors, measured around 1.7ohm
water cooled had 195500-0668 injectors also measured around 1.7ohm
i can confirm both sets work perfectly.
have also chucked them in a factory std te71 2tgeu (that has 2.2ohm injectors and ballast resistor) and they run hella rich but still work fine up top end.
also have noticed a trend on 3tgte ecu's ive seen so far, (but may not be a 100% correct assumption), that oil cooled versions have a big 31 sticker on ecu and water cooled have 32 sticker.
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