Please help me get my car running again

Was hoping to pick everyones brain in a possible solution to get this b back up and running.

About a month ago, i started getting a no start issue when the engine got warm. After a few times of cranking she'll start and run fine. Checkt code and got a code 14 so i started doing a thorough check of the starting/ign system. Replaced both cam sensors, swapped igniters and new coil pack clips. Now car wont start even when cold and still throwing 14.

While going through wiring i noticed i wasnt getting any igt 5v from ecu on cyl 2&4 and all 12v igfs are there as well as the othe 5vs to the other cylinders. Is this normal? I thought i was getting a short between igt2 and igt4 so i checkt continuity between ecu n igniter clip and eveything was good, voltage wasnt hopping between wires.


Any other suggestions would be well appreciated.

Thanks and have a great weekend

 

Something else to check is the health of the alternator and the health of the ECU.

If the alternator‘s voltage regulator has ever caused an over-charging condition this could have affected the ECU.

Alternatively, if the ECU has not yet had its capacitors replaced then it is time to do this.

It may also be a good idea to track down the same ECU part number, make sure that it has also been capacitor serviced and keep it on standby to swap in to rule out any issue with your first ECU.

Also, pick up a new igniter from Driftmotion or Amazon and don’t use it until you can try it with a new ECU.

The same issue happened to me with my 2JZGTE a couple of years ago and I finally traced the issue to a malfunctioning ECU which had already been capacitor serviced. An over-charging alternator had damaged it a bit internally even though it would work fine... but it would burn out working used and brand new igniters within 2-3 week spans.

The issue was solved with a brand new reman alternator, another ECU in good condition and of course a fresh igniter.

Igniters should last 20 years or more so it is unusual for them to fail. Further, for reasons that get very complicated to get into the unfortunately only good way to test them as good or bad is by running them in a car.

 

Thanks for your response Kahn,

Its most likely an ecu issue. I decided to repin the igt signal wire with a working slot and it changed the location of the missing 5v. The ecu hasnt been serviced before and hopefully its whats needed. Would the crank sensor prevent igt 2 and 4 from giving a 5v? I cranked the motor with the multimeter on igt2 and voltage did fluctuate going from .02 to .08. Is it even worth replacing atm?

As far as tracking down an ecu, its almost impossible. Its a auto soarer ecu and non-vvti, pretty hard to find (by itself).

Any reputable ecu repair spots? Driftmotion stopped ='(

Im really interested in this alternator issue u talking about. Ill look it up

 

Take a look at my build thread. I had a nightmare issue tracing a bad 2JZ-GTE USDM ECU (still have it in a storage box) which seems to have been affected by a bad alternator that I used. That ECU had been capacitor serviced by Driftmotion previous to my use of it. I installed a brand new alternator and found another ECU which solved my issue. That said I keep yet another good ECU as a spare just in case, plus a full set of correct type capacitors to service any of my ECUs.

I do have a couple of places I can recommend apart from Driftmotion: Tanin Auto Electronix can capacitor service your Soarer 1JZ-GTE Auto ECU. They just won't be able to test it on one of their shop cars as they usually do for final QC. I think Relentless Motorsports in Texas also may be performing this service.

I'm not sure about the crank sensor question. I think the 1JZ is a batch-fire ignition system whereas my 2JZ-GTE uses a sequential-fire ignition but I don't think that makes any difference concerning IGF signals. I started with all new sensors so yes I'd recommend just replacing the crank sensor anyway at the same time you replace the alternator.

 

Thanks again for all your time and recommendations. I will give those guys a call tomorrow.

 

Spoke to Aaron at dm. He said just buy a standalone 1k. Spoke to Josh at Relentless and he said starting at 200. What would you suggest? Im only on stock twins and just want to get up n running. Have you had any luck with ecu services lasting?

 

ECU service to replace capacitors with the required OEM-spec types (sourced from Digi-Key, Mouser or another quality electronics supplier with their same high reputation) generally future proofs these ECUs for another 20+ years once completed. The variable depends on whether or not there is any extensive board trace damage due to electrolytic capacitor fluid leaking too much and other rarer factors. But the most common ECU issue by far is worn out capacitors that need replacing with the same exact type as stock (CL user Yamae who is a retired Toyota ECU engineer explained this extensively in a big thread many years ago).

I would recommend you try Relentless or Tanin Auto. I have more experience with Tanin but they do not specifically advertise 1JZ ECU repairs although they should be able to by special request.

Aaron of Driftmotion is a great fellow and I understand where he's coming from but in your case in that state of tune an aftermarket ECU would be overkill. Try getting your stock ECU repaired first and see if capacitor repair, some board cleaning and, if actually necessary, a few wire trace repairs can cure the issue.

When/if you begin modifying the fuel, igniton and turbocharger(s) for far greater than BPU power then you can look into a standalone.

Try to get that ECU repaired first and then barring that consider other options.

I myself am limited to OEM ECUs with my SC's build type so a standalone is also not really in the cards in my case.

 

So you were able to complete the ref cert? Hence, limited to oe?

Caps were pulled off yesterday and on to buying some from digikey *fingers crossed*

 

The list of capacitors to order for 2JZGTE ECUs if it helps but there may be one of two different ones for a 1JZGTE ECU. There must be a page off Google telling the exact caps needed for your specific ECU but it sounds like you got them all identified from the old ones.

You’re using a temperature controlled ESD safe soldering station for this, right? I only mention this because it’s important to use that type of soldering gear when working on these boards to protect them. Apologies if you’re already very used to working on small electronics boards.

.....

By ref cert you mean the California BAR referee process? That hasn’t happened yet but my SC is totally built to all the stock emission legal Supra TT OE specs, yes. It’s ready for inspection.

I completed the build process in Florida some months ago but due to health complications with a close family member and then the Covid-19 pandemic affecting everything my plans to move back to CA and bring the SC have been delayed. The original plan was to have gone through the process well over a year ago. Still that remains the plan.

The engine has been limited to all-OE stock tune at stock boost with functioning OE cats and EGR but for me it’s fine for an all-around semi-daily driver. It’s not as fast as most home built SC turbo builds but it’s very quick and very fun. The one aftermarket part is a CARB legal K&N intake filter which I mostly added in order to not have to re-locate my factory cruise control unit.

And it turns out my used #2 turbo was bad so I’m soon going to replace both turbos with a new fully rebuilt stock set that I have waiting on standby.

Other than that I’ve been slowly planning ahead for a repaint of the car in stock black.

Once I have it back in California it will be ready to be ref inspected as if it were a stock vehicle. Other than the twin plate clutch but they won’t care about that.

 

Ended up getting these bad boys to replace the old 1s. Hope theyre great!




Im excited for u bro. Hope it all comes together soon enuf! Its been my dream to convert these f***s to ca bar approved autos but it takes patience that i dont have lol.

Thank you soooo much for your wisdom n guidance. I cant be too optimistic that the caps are the problem but fingers are crossed.

Stay safe bruv!

 

Btw, u see the engine bay pic??? Thats an injen intake ca carb legal from the sc3. They should be fine for u to rock that with the k&n n stock twins. I fab'd it for camo lol (even tho ic piping gives it away). Injen kits actually came with k&n filters and worked with my 1j. Its short cause it factors in the maf but i added a piece of pipe to keep it away from the heat/fan and added the aluminum shield that came with it. I put a bigger k&n cause the one that came with the kit was tiny. Looks kinda cool though. Carb sticker and everything lol

 

They look like the right types all right but definitely look up those exact brands and part numbers and order them brand new from Digikey or Mouser before soldering any caps back in. You want all brand new genuine brand name caps in the exact spec the ECU calls for.

And you're welcome! Hope I've helped a bit, lol!


I did not see that but it's very cool that the Injen intake also fits the old 1JZ-GTE engine's top inlet! Happy coincidence there! I like that metal looking box where the stock plastic airbox would normally be. It makes me think of the Soarer 1JZ parts that ARC used to produce. The bigger K&N must help even with the small CT12A's. Are you going to keep those and have them rebuilt and upgraded a bit for a kind of stealth look?

Yeah, the CARB Legal K&N kit (which costs way too much for what it is) is good for MKIV Supra Turbos from 1993-1995... in the legal sense. So they'll have no issue with it. I added an MVP Motorsports MKIV aluminum cone air filter isolation box with a little bit of modification to fit the SC and that keeps the underhood heat mostly isolated.

Thank you! The SC is doing pretty good now. A BAR approved automatic is a little easier than a manual BAR approved 2JZGTE but only by a bit. The main thing is you would need to track down many parts and be okay with stock or near stock power. For what it's worth it took me about eight years of steady parts acquisition as I could afford to do a little at a time just to get ready to begin my engine build. If you don't have a lot of money you need a LOT of patience... and time

There is *technically* another way you could get that 1JZ-GTE Auto legal in CA but it involves going through Sean Morris of TopRank Importers for engine emission modifications and then a very expensive lab certification process. All doable if you have the money to spend but it's still more expensive than what I did. Usually this is done for the high dollar original Skyline GT-R's and other RHD high value JDM and Euro gray market vehicles that come in 25 years old or older.

And I'll definitely stay safe, thank you! The mask is life here. You too!

Get those new capacitors from Digi-Key or Mouser and take your time getting that ECU set back right if you'll do it yourself. All of the 1985-1997(ish) pre-VVT-i Toyota/Lexus ECU's tend to have these capacitor issues eventually but in some cases it can take almost 30 years. Depends on many factors. But most of the time replacing them cures the issue.

It gets a little more complicated if you notice electrolytic capacitor fluid having leaked onto your logic boards. There are a couple of ways to deal with that which should in most cases cure it depending on the severity. Are you familiar with restoration of old electronics boards and old personal computer circuit boards? It's the same process but you have to be very careful how you do it. Hopefully that will not be an issue for you.

 

Nah, i still have another spare set laying around. Prolly last me 4ever. Hopefully lol.

i remember u saying u had a 4.sum diff and a spare 3.7 right? I just recently swapped to a 3.7 lsd n i really miss my 4.08. I know if i switch back to the 4.08 ill miss the 3.7. I think the 3.7 needs a bigger turbo.

prolly stay stock until that amazing BAR sticker makes it in the engine bay


I graduated from Youtube University. I got this lol. Wish me luck. Ill update

 

This is understandable. The 4.083 is better suited to the 2.5L 1JZ, its parallel twin turbos and its over-square high revving bore and stroke. Since the Soarer 1JZ's were marketed as upscale personal high performance coupes this meant they were geared for better performance off the line and for city cruising.

The Torsen LSD is a must have but the 3.769 ratio does do a lot better with the 3.0L and either a bigger single turbo or the stock 2JZ sequential twins. With my SC's stock 2JZGTE I felt that an SC400's 3.92 (which I ran for a short time after my swap was up and running) was a little too aggressive... but it was also like a kind of "hyper" ratio with my setup. Its downside was that the highway cruising RPMs in 5th gear (R154) were a bit too high for my taste. When I first started up my swap I had a 4.272 ratio with LSD and it was fun... but just too much gear with the 3.0L and stock sequential twins. Getting the 3.76 gearing back into my LSD pumpkin finally felt like a good all around ratio for my setup.

However I primarily chose the 3.76 because when doing the math it makes the R154 setup roughly equal the stock RPMs that a smog tech would see with a Supra Turbo running a stock V160 6-speed Getrag trans and stock 3.133:1 gearing in 1st, 2nd and 3rd.

I think if you plan to stay with your 1JZ-GTE you'd do well to have a diff pumpkin built (preferably the Supra finned casing) with the 4.08 ratio and the Torsen LSD. The Torsen is good and reliable up to around 500whp at which point you really would want a more predictable clutch type aftermarket LSD. 3.92 might also be a good ratio for a 1JZ. I think 3.76 may depend on the selection of single turbo and how responsive it is. I almost feel like a 1JZ-GTE VVT-i with its better low down torque than the earlier 1JZ would be better suited to a 3.76. Either that or a responsive modern single turbo and a quick spool valve. But if you keep the stock twin CT12A's and just rebuild/upgrade them for BPU power I think the 4.08 will still give you the most response. Your highway fuel economy will be better with a 2.5L anyway.


Haha. It's tempting but nah, I'll just let it be once I get to that point. It took a lot to get this far and I'm happy with this SC being a specifically built "stock" classic.


Wishing you luck! Just take your time and I do strongly recommend using an ESD-Safe temperature controlled soldering station such as a Hakko FX-888D and a grounding wrist strap. For the board tracing repair there are a number of guides on youtube. I especially like some of the circuit board restoration techniques The 8-Bit Guy has demonstrated on his channel. Principles are universal. Again, you just have to be very very careful and keep in mind that timing with any chemicals is everything when working with small electronics. Study different techniques. It's an increasingly rare ECU so take your time.

 

Wait, so they need the gearing to be the same too? Rpms at certain speed? I heard that you can choose different BAR spots and some might be more lenient than others.

I think the 3.9 might be the best. 3.7 is a beast on the freeway and not too bad down low, just needs a lil more spunk. I just added a boost controller so, once this is up n running, i shud be spooling faster. Hope it helps. The 4.08 was horrible on the freeway; Id be at 3k rpm going 65. Ive been trying to figure out my speed still. If i remember right the w58 with 3.76 was a difference of about -10% compared to my old setup. Its weird when your tach says 65 and you feel like youre zooming. I need to get a yellowbox or find a cheaper way to adjust my tach. Im running a trd diff =p





I get the caps on Saturday. I am optimistic about the repair but at the same time........lol.
Thanks again for your help! Have a great Halloween weekend 🎃