1992 with TT ecu (aristo) mod, non turbo w/dizzy delete

Car was running fine before battery relocation

Thought relocating the battery to the trunk would be a piece of cake, but now its turning into a big headache. The engine starts but immediately shuts off. When I give it gas nothing happens. After trouble shooting the ground, fuses, relays, etc. I ended placing the batter back into the engine bay and it still will not start.

Checked wires from igniter to ecu/coils and all are fine (solder and heat shrink)

I checked for codes and I’m only getting code 14. Thinking it may be the igniter I swapped it out for another (DD62) and still won’t start.

The next thing I’ll try is the 12 volt fuel mod.

Any help would be greatly appreciated.

 

I'm not very familiar with the DD62 igniter modification with an Aristo 2JZGTE ECU but a CEL 14 is the ECU saying there is a bad or inconsistent IGF signal for so many consecutive firing cycles which causes shutdown during operation or a no-start condition.

I chased this horrid bad/no IGF CEL 14 for months with my more or less "stock" swap and for me it came down to a few possible culprits: failing ECU capacitors (serviced on two ECUs, possibly an over-charging alternator with a failing voltage regulator giving my electrical system very inconsistent voltage and likely affecting one of my ECUs (I replaced my first and then second one and had both former ECUs capacitor serviced), simply pre-existing electrical malfunction on one of my used 2JZGTE ECUs (who knows really?), and finally some poor pre-existing ignitor and coil wiring that I had no addressed initially when I first did my engine harness conversion.

At the end of the day the first instance of this was likely bad overcharging alternator related which probably damaged my fist ECU. In the second instance it was not really certain what caused it. I did have a turbo timer hooked up and have suspected that even my meticulous wiring harness for that or just something to do with how it works might have influenced my ignitor failures once on my second ECU.... but I have zero evidence to support that theory so far. Nonetheless I have left my turbo timer disconnected for the time being and have had no issues since I swapped to ECU #3. My cap serviced ECU #2 remains a backup as there still should be nothing wrong with it.

I went through several igniters chasing this issue. An obscene amount of new ones. I always been a brand new backup on hand now just in case and will buy yet another brand new backup just to have. Igniters should pretty much last the 20+ years so it's a weird thing to happen.

Back to your issue Joe, you've got to trace what could be causing that igniter to not report back to the ECU that it has fired every time it has been told to. There technically is an unofficial and very complicated way to test an igniter to determine if it is firing correctly but it's not really a reliable test and therefore I'm not going to get into it here as it really won't help in the long run. The bottom line is that IF your igniter has been burned out or is beginning to fail, there is no way to be 100% sure it is the reason your car won't start unless you swap it out with a known good used one or new one (and DON'T buy one from a Toyota dealer-- ridiculously expensive from any Toyota dealer).

Coil packs themselves are not that complicated internally and so I doubt many of them differ too much but igniters do have a little simple proprietary chip in them to make them do what they do in tandem with your ECU. It's part of the reason they are difficult to impossible to test without just swapping a suspect ignitor out for a good one as your "test".

Moving the battery shouldn't have caused any irregularity but if that was then one thing you changed before this no-start issue arose then you have to suspect it for now.

What gauge electrical wire did you use to run the current for that distance? If going back that far you want at least an 10ga wire and probably even 8ga is best.

For the +12V fuel ECU mod, to run a relay back there from the battery you want to use a 10ga wire. I listed a good pictorial guide on how to do it while using the control from your stock fuel ECU and for a Supra TT fuel ECU (both methods listed) here:

https://www.clublexus.com/forums/bui...l#post10256118

And the electrical connection explanation here:

https://www.clublexus.com/forums/bui...l#post10245454

Supra TT Fuel ECU (and possibly Aristo 2JZGTE as well?) diagram specific (if applicable):
https://www.clublexus.com/forums/bui...l#post10249619

You should be able to test if your stock fuel ecu is the issue by jumpering with a paperclip the "FP" and "+B" in your disgnostic port under the hood and then attempting to start. But.. if you are getting a CEL Code 14 (no/bad IGF Signal) then I do not think your fuel ECU is the issue. It's something electrical that is affecting the health of the igniter or preventing it from exchanging regular firing confirmation signals with the Aristo ECU.

The +12V fuel ECU mod has more to do with separating very high current draw (20A or so) away from the main ignition circuit so that fuel pump operation is managed on its own circuit with a relay that is controlled by the Fuel ECU. This is actually 100% what the stock wiring in an MKIV TT Supra is set up to do for exactly the same reason. It is theoretically possible that this is related (for that reason) but I've never heard of high flow fuel pump current draw affecting the igniter circuit. However if you have a turbo and therefore a high flow fuel pump it's definitely a good idea to do the +12V Mod + 30/40A relay to the Fuel ECU anyway.

Aside, the difference between doing that mod with the stock SC Fuel ECU vs a Supra TT Fuel ECU is simple:

The SC Fuel ECU w/+12V Mod & Relay allows for full stock control and safety shutoff control but allows the fuel pump's voltage to be "12V" in the sense that it is whatever variance of current is going directly from the 10ga-8ga direct fused wire you have made for it right from the battery. In other words that could be something like +13.8V to +14V directly to the high flow fuel pump.

A Supra TT Fuel ECU w/+12V Mod & Relay does all of the same things as the SC Fuel ECU but as it was designed for the Denso TT fuel pump which has high current draw by design it additionally regulates the raw "+12V" (really more like a variable 13.5-14V) raw amount of power direct from the battery through its circuitry which moderates that into a consistent +12V for high load operation and +9V for "normal" or low stress load operation. Obviously depending on your fuel setup and state of tune the +9V mode may be more of a liability than a help to keep a good air/fuel ratio on a very beefed up non-stock turbo 2JZ engine. The TT Fuel ECU added to this setup has some advantages in *some* limited tune scenarios but not if you're pushing a 500whp+ monster engine.

But the basic safety shutoff control from just the SC's fuel ECU are worth it to keep and using the +12V Mod with Relay will not limit your voltage to the pump through it to the 9V/12V modes. All you'd retain is the basic ECU communication and safety shutoff functions controlling the high amperage rated relay.

 

Thank you for the detailed response.

Originally, all I did was run a 1 gauge wire to the trunk from the original positive cable. But, like I mentioned, I reinstalled the battery back to engine bay.
I placed a jumper between FB and +B and nothing. I guess the next thing I’m going to do is send out the ECU and get caps replaced.

 

Okay, sorry. I missed the part where you said you had reinstalled the battery back into the engine bay. I would also check your two ground connections on the intake manifold (the rear is easy, the front is kind of buried on the underside of the intake; I used a cheap Harbor Freight video boroscope to get in there to see how to inspect that one ground connection) and your main chassis ground connection on the driver's side.

The ECU may indeed require capacitor service. Aaron at Driftmotion still appears to be in hiatus mode for this service but a few months back I contacted Tanin Auto to service my 2JZGTE ECU and they were able to do this for me with the understanding that they could not test it on one of their shop cars the way they usually do. I said I was fine with that and they took care of me.

I don't know who else to recommend for this unless you were to do it yourself with an ESD-Safe and heat-adjustable and controlled soldering station (a Hakko FX888D is good), a desoldering gun (or a Velleman spring loaded vacuum desoldering pen) and using the exact right replacement capacitors from Digi-Key Electronics (one of only three trustworthy U.S. sellers of the required capacitors). I'd suggest going the Tanin route unless you're confident working on sensitive logic boards.

Also, check your alternator's health if it's not a new or recently new unit from a good brand (or Denso). If its voltage regulator starts failing in the higher voltage direction and starts overloading your car's circuits then this can indeed affect your ECU's internal chips and in some cases this can have the result of burning up an igniter's own internal chip(s). Very rare to happen but this did happen to me and did exactly that to an ECU and a couple of igniters before I saw a pattern and got to the bottom of it.

 

Again, thanks for the detailed response.
I’m going to purchase a denso alternator today, but not install until I get back the Aristo ECU.

 

This is a good plan. More than likely the issue will be in your ECU. If your cigarette lighter DC 12V port works you can also plug in a cheap combination USB charger w/ LED voltmeter and you should be able to tell right there if there are any abnormal irregularities with the charging system once the vehicle has been started.

 

Update

Swap in a different aristo ecu. Still won’t start but now the CEL is blinking rapidly, instead throwing code 14.
I’m thinking this ECU is shot as well.

 

Joe,

If the ECU gives you only a continuous rapid blinking CEL then that means it is saying it has no error codes. If that 2nd ECU has issues not immediately identifiable by a CEL code then it will be harder to determine what is wrong with it unless it also involves worn out capacitors or in rare cases a burned out chip on the board.

However the first thing to do is to go over your car's ignition system wiring again to be sure that every part of those circuits are in order.

I myself have had the experience of going to a 3rd 2JZGTE ECU before a particular issue went away but I still have no concrete evidence as to what affected my 2nd ECU before going to my 3rd and current one... other than perhaps that it had worn capacitors (which I did get changed out for new ones).

It's always good to have a spare ECU and it's not a bad idea to get an old ECU capacitor serviced if you notice it's acting abnormally.

Still, I think just for good measure you should go over the full ignition system wiring to be sure everything is in order. Believe it or not, sometimes in super rare cases even a connector can be the issue.

Here's an extreme: I had a totally weird problem initially with my injector system causing a misfire. Even after repairing some old wires and making sure they were all in the correct places, in the end it came down to a single injector connector on my engine's cylinder #5 that was actually causing +9V on the positive spade and something like +3V on the ECU Ground spade. The connector itself was not broken or physically compromised and the spades were not touching internally, yet *somehow* it was allowing electrical conductivity *through plastic* between the two terminals.

Of course this makes zero sense, right? Plastic does not conduct electrical current. That's what I thought at the time. Then, I got myself a new injector connector, put the same terminals into the new connector and like magic I got a solid +12V on one terminal and a sold 0.0V on the ECU Ground terminal. No more misfiring at all after that. I still cannot explain how it was possible that the one old physically intact injector connector was able to conduct electricity between two terminals through its plastic separations. Once I changed it out for a new one... there was no such issue and the problem was solved for good. That was an extremely weird and rare situation and there is no shop manual to tell you that such a strange thing should ever be expected or be possible.

I do not expect your issue is something nearly that weird but I bring it up to emphasize that when the usual suspects do not solve an electrical issue it is probably time to get out your multimeter and start methodically checking that one electrical sub-system as a whole and write down all your findings for each terminal for measured good/bad continuity, measured voltage and verified solid Ground.

Though if you didn't get your first ECU capacitor serviced yet to try out and your second one is having a similar no-start issue it is also entirely possible that both used ECUs, given their age, are in need of service. The only way to know for sure is to rule things out one step at a time and note any findings each time something is changed.

Aside, it is a good thing, I think, to have a spare ECU for your swapped car. But both of those ECUs may need new capacitors at this point in their age. Driftmotion isn't doing it now but Tanin Auto will change out the caps on a 2JZGTE ECU by special request.

I just advise not using any overnight mailing service since to get it to them and back to you since you're located in California (after a bad experience of mine with Fedex Overnight I do not trust or recommend overnight mailing services if you're located in CA).

Edit:

Since this problem started for you only after moving the battery to the trunk and then putting it back into the engine bay again, factor in checking anything that connects to it, fuses, accessories, etc. as well. Have to rule out any possible electrical anomalies.

But I'd definitely get one of those two 2JZGTE ECUs capacitor serviced and then try it again. The 2nd ECU yielding the constant CEL blink (ie: no error codes registered) is a good improvement but it's certainly possible that it's due to have its caps replaced since it's giving you a no-start condition.

Question: with that 2nd ECU installed can you even get the 2JZ's starter to crank the engine or does the starter not even respond?

 

The starter cranks, car starts, but immediately falls off. Even if I give it gas there is no response, but I do smell fuel.
I’m currently checking wire continuity and grounds.

Kahn, if the ECUs were not the issue, why would one throw code 14 and the other just blink?

Tomorrow my original Aristo 2jzGTE ecu will be here with service done.

 

You sure that ignitor is grounded properly? the ds62 has a pin for igniter ground.

The positive strap has a couple wire terminals in it, all of them need to be connected to the battery, its easy to miss one when the bolt is off like the metal tab for the alternator etc.. if I remember right.
If you are relocating to trunk the positive wire needs to connect to all of these, or you need to run new wires to alternator etc.. also

Make sure the ground wire from the battery terminal is still grounded to the drivers frame rail properly, sometimes these wire get corroded, split etc.. and can break the first time you really move them around.
If there is a weak connection here it might work intermittently until you load the system up enough.
A ground issue could very well cause a misfire which would throw a code 14 when it is bad enough and not throw it when it isn't bad enough.

Sounds like it started happening when you removed the battery, so recheck everything in that area. It is more likely related to touching that then something randomly failing.
Like Kahn said, engine off move key to on position, the CEL should come on for like 1-2 seconds and then go away. When you jumper the diagnostic port, it should blink steady = no codes.
If you do not see the cel come on for a couple seconds that is a sure sign of an ecu issue. if it blinks out a reasonable code then its less likely to be an ecu issue.
Still sounds like a ground issue to me but I am half a country away on the internet so just some suggestions on where to look.

I am also assuming you had a ground strap in the trunk when you relocated the battery. if not some fuses might have popped or relays have issues etc..

 

OMG. Fixed!

C2 from igniter to coils was disconnected. With relocating battery and Power steering reservoir, and not using heat shrink and solder, the wire coming from the igniter to coils must have disconnected with all the movement/tension.

Thank you Kahn and Ali SC3 for all the help. With all the trouble shooting and both of your detailed responses I learned a lot more about my SC. Greatly appreciated.

Time for DriftMotion turbo kit.

 

Good catch, when you get some time go back in there and make sure all the other connections are solid, you don't want them separating while you are driving.

 

Excellent, Joe! Glad to see you found the culprit! Sometimes it is something simple that you might least expect.