KahnBB6

iTrader: (5)

Gerry, Rudy... thank you both for all your suggestions and support! When I last posted I had just hit a wall and wasn't able to think about or work on the car any further for a few days. Ever have that level of frustration? Well... it overwhelmed me and so I just had to wait for a bit.

Gerry-- I did buy one more USDM 6-speed OBD1 ECU for a reasonable price. I know you advised against it but I felt it would be a good insurance policy just in case.

Yesterday I swapped in the new-to-me ECU I'd just purchased and had no start.

I was very perplexed but then was compelled to just try each igniter I had all over again even though I had not had success with any of the previous ones.

The second spare one that I tried fired the car right up with no issues and drove with no issues! It turns out the newest igniter I'd just put into the car had an issue so I threw out that one out and threw out the other one I re-tested which also didn't work.

I will order a brand new OEM igniter from Japan now just to be safe but I also have one more spare which I think is also in good enough condition in addition to the one I threw into the car with success. Both of the good igniters I have likely do have at least *some* wear from being run in the car with improper grounding on the cylinder head... but for now the car is working again and with the last fixes I performed *shouldn't* cause this igniter burn issue any longer.

...

Next I will plug in my previous spare 6-speed ECUs to verify they are either in good working shape or not-- which I suspect they will be as you hypothesized Gerry. If any of them give a no-start I will open and inspect to see if any obvious damage is visible for potential repairs.

I also found a good local tuning shop I never knew existed in my area which seems to be professional and run well (and busy with customers which is always a good sign). I met with their on-site service manager who was a very helpful and knowledgeable woman undeterred by my questions. I get a good vibe from them and their Yelp reviews are all very positive so I think I will get a quote from them for replacing my leaking lower oil pan with the brand new one I have on standby.

For now though it feels really good to be behind the wheel of my SC again

KahnBB6

iTrader: (5)

I did end up buying another good one, lol. My friend you are always looking out for me to not spend unnecessarily But... I don't mind having just one more as an insurance policy.

Now that the car is running again with a "new" ECU I will test the others and report back as to their condition. I suspect you are going to be proven correct.

You mentioned my fuel filter.... even after my positive result that is a good question. I have the service record for it but will have to look it up. I think it was last changed out in Los Angeles a few years ago so even with a successful start and normal operation maybe it is time to get a new one put in anyway.

Another thing I would have tested next but having just gone through the wiring recently and with the plugs being so new with so few miles on them, and with brand new coil packs... was sure that part of the ignition system was probably okay.

It definitely wasn't poor compression. As you said, the engine is just too new (only about 6,500 miles on it in just over 4 years) and has never been abused, over-boosted or run lean. Oil always changed on time or early and the oil level always checked. When the failure occurred I knew it had to be something electrical.

Thanks Rudy! Your good diag vibes helped my peace of mind! I just needed to give myself a few days before I could approach the problem with a clear, calm and rested mind again.

Now your issue may be something else not really related to my car's symptoms. My issue has definitely been insufficient electrical ground related causing an overload on the igniter's circuit... due to my own error when building the engine. Which I had corrected now.

What I have found with igniters is that NORMALLY they rarely ever burn out. And that normally takes a couple decades or more of service. And when it happens it just dies. Nothing intermittent. Just total igniter death preceded only by some sudden engine hesitation bucks before it's totally kaput within a matter of seconds.

A malfunctioning ECU with bad capacitors could do what you describe but you had your ECU serviced already... so that logically shouldn't be the culprit of your issue.

I am happy to hear of your success in a flawless start again! Hmm... I would observe carefully to see if this may be a regular pattern. If when fully warm you experience this issue but it's always cured again once you start from full cold after the car sits for a long time then that would make me curious about what components can react in that way only when they're very hot under-hood.

I do not experience this myself, no. As much of my engine and build setup as possible was done with all new or fully reconditioned mechanical and electronic parts and all new sensors. But my Non-VVT-i system is also a little simpler than yours.

RudysSC

AWESOME NEWS Craig! I think a lot of us have hit that wall of frustration and it can really be discouraging. Glad to see you kept at it and got that bad boy working again!!

I may need to take your route one of these days and find a decent shop with a little old-school 2JZ experience that would be willing to help me with mine when I'm at my wits end. I'm always a "fix it myself" kind of guy, but sometimes a little outside help can be priceless.

KahnBB6

iTrader: (5)

Thanks Rudy! And yes I think we all need to know the good shops in our area who are both experienced and trustworthy in our particular cars and the MKIV's. It certainly helps when a shop sees these kinds of vehicles fairly regularly not just for tuning expertise but also for regular maintenance. And such shops which are trustworthy are VERY rare and may not be in everyone's immediate area.

It is best for us to know our cars well and try to do as much of the work that isn't basic things like brakes and oil changes ourselves but in certain circumstances having such local expertise, if available and trusted, can be a huge help

RudysSC

You're absolutely right Kahn. I know my way around a car fairly well these days but sometimes you have to know when to bow down and ask an expert for their help. Glad all is well on that little bad boy of yours. Cruising weather is almost back baby!!

KahnBB6

iTrader: (5)

I hope the spring weather will be cooler for you than it will be for me, haha!

Yes, there are some times where having a good trustworthy shop to help with their expertise can be a huge boon and stress reliever for an owner.

I used the SC a little tonight but did notice the telltale sudden hesitation again... which I attribute to the Igniter I installed being previously damaged/burned a bit but not quite so much that it can't start the car, idle flawlessly and drive very moderately with it.

Initially I was confused and wondered if it was my twin-disc clutch shift fork movement having an issue but I quickly ruled that out and knew it had to be the particular not-new Igniter that I threw into the engine bay a couple of nights ago which I had success with.

Once I noticed it I immediately backed off and just drove slowly with as little boost/load as possible and in a big change from previous such experiences I never once had the car die on me and never even had a momentary CEL (signaling a Code 14 "Bad IGF" condition). This only happened when I tried getting into some more than the usual gentle low end boost (sequential mode). I went as high as 4,000 RPM but didn't ever get into boosting with the second turbo this time.

In previous times that hesitation was almost immediately followed by total failure of an Igniter.... but this time as long as I just drove the car nice and easy like a grandma I got home with zero issues and had no issue letting the car idle for a few minutes to cool down before shutting it off.

My suspicion is that this subtle behavioral change despite this Igniter still having an issue may indeed be the result of having finally corrected my grounding issue the right way, thus allowing the power to flow correctly for the first time with no ground bottleneck.

....

A brand new OEM Toyota Igniter unit is already on order direct from Japan so I think once that part is in hand and can be installed that should be the true end of this. That other recent "new" igniter turned out to be a DOA inoperable part after all, much to my chagrin.

In the meantime I'm going to throw in the one other possibly good igniter that I have and see if there is any difference with it.

I have a minor surgery coming up so I'll probably take it easy with this and finish up the rest of the post-success vehicle diagnosis after I've healed up sufficiently.

RudysSC

Best of luck on the upcoming surgery Craig! I'm definitely curious as to what you find. Keep us posted and we'll help however we can!

Bimmerbill

Hey Craig,
Just wishing you LUCK with your up coming surgery. I just had another minor one this past Friday. But we will be thinking of you.
Bill

Barbary

^^^
Good Luck on yourself and Best Wishes
Joe

Bimmerbill

Hey Joe,
Thanks for the thought. Got my cover finally and have not tried it yet. Waiting on a real pretty day to clean the SC and then I will try the fit..
Joe, take care of your self also. How about a few more pictures on your next trip out.
Bill

KahnBB6

iTrader: (5)

Thanks guys!! I know it'll go fine for me. The surgeon is very, very good and up to date on the latest techniques. Both he and I are on the same page across the board. I know I am in good hands : )

KahnBB6

iTrader: (5)

Quick update: I've been healing very well from my recent surgery. Boy, did I look bad for a while, lol! I could have been a comic strip cartoon character until the swelling went down! But I'm doing MUCH better now. I feel very, very grateful to haven been able to get the help and expertise that I needed to set things right. One has to be thankful for the most important things in life like health, family, true friends, etc

.....

Anyway... I do believe I have uncovered another piece of this weird puzzle with my SC as of tonight:

1) My new OEM Toyota Igniter came in from Japan a couple of days ago. I set it aside at first.

2) With the last good but slightly damaged Igniter that had started the car and driven for me but with some of the occasional sudden bucking while driving along I re-tested each of my four identical ECUs, two of which have been serviced with new capacitors. Only the one which had been installed when I was stranded (not capacitor serviced) refused to start the car. All three other identical ECUs both cap serviced and not WOULD start my SC and all idled and revved perfectly. No driving test with them yet.

3) The following day I installed my brand new OEM Igniter unit with my fourth non-cap serviced ECU which was verified to be 100% okay. NO START. Hmmmm....

4) Tonight I left that brand new Igniter installed and re-tested all four identical ECUs. None of them would start the car other than initially before immediately dying. Hmmmm....

5) While I was about to give up I scratched my head and thought to myself to re-try the TT Fuel ECU bypass once again. I had done this a couple of weeks earlier with no change in behavior but back then I still had not yet fully corrected the cylinder head ground wire issue that had been burning Igniters.

So now.... I took a thick paperclip bent into the needed shape and inserted it into the Diagnostic port's "FP" and "+B" terminals so as to bypass the TT Fuel ECU and go straight to +12V/Battery power to the fuel pump relay and thereby the TT Denso fuel pump itself.

On the first try the SC started right up!!!




....

So... I now see that I have had two issues all along:

1) I certainly did have an issue with prematurely burning up TT Igniters due to missing a crucial ground wire at the rear engine hook bolt at the back fo the cylinder head which needed to ground at the firewall bracket just below the windshield wipers.

2) The TT Fuel Pump ECU that I installed, used just as all my engine ECUs have been, developed issues sometime along the way when I embarked on this engine swap in 2018. This as most SC, GS and Supra MKIV owners will know is a classic problem which is usually solved with a +12V Mod w/Relay ECU bypass mod.

I never suspected this because that TT Fuel ECU was in fine working condition just a few years back. I believe that this issue may have been one that began either gradually over that time period or perhaps which only manifested very recently.... concurrent to my last Igniter burnout episode before I finally fixed the ground wire location.

....

I happen to have a spare TT Fuel ECU but now that I know what needs to be addressed I will investigate both my spare one and the malfunctioning one in the car and determine if they are possible to fix with new capacitors. If not then I will implement my original +12V Mod w/Relay.... but while including either a new or used good Fuel ECU wired only to act as the safety fuel cutoff trigger... but while bypassing the internal fuel pump voltage 9V/12V regulation functions.

The TT Denso pump can be heard as being a bit louder both from the back seat area and when the trunk is open but as we all know running that pump at a normal +12-13.8V is only going to shorten its service life by a couple of years at most (from 20 or so to 18 years so it is said on SupraForums).

...

This could also explain a bit of the weird inconsistency I have sometimes experienced under full boost. The pump might not have been consistently flowing at the full 12V mode under full load for brief moments. Hard to say.

But at least now I have a culprit that I can address and fix

....

In other news I am considering at this point getting another much newer car for primary use. It is long overdue and would open up some other possibilities for the future of my SC. Too early to say on that front but for a plethora of reasons I have had in mind to put my SC into secondary use true classic car status for a while now. Time will tell!

gerrb

iTrader: (34)

Glad you are feeling better health wise Craig !

Just do the 12v mod and do away with the Fuel Pump ECU permanently. In that way , you permanently rule out that fueling problem.

KahnBB6

iTrader: (5)

Thanks Gerry!! I'm feeling 100% better now!

Reluctantly I think this is what I'll do. I had it set up that way initially but switched to the TT Fuel ECU shortly after. However I will retain an SC300 Fuel ECU wired only to act as an ECU controlled trigger for the 12V fuel pump relay. Should some emergency situation ever happen then it'll keep things safe.

Barbary

I'm sure we are all relived and happy you are doing 100% better. I'm sure you were in all our thoughts, but sorry for your ordeal. Yes, health is wealth

On this 2nd part, maybe you are right. My thought has come to be, just mine, may be 100% wrong. The more things you change, the more you add, modify, the probability something goes wrong goes up. So there is that probability and does one want to drive around w that probability in the back their mind?
Simply put....the more things you add, the more things can go wrong. but it's hard to give up the ghost
Like I said thats just me

I for one would be curious what your much newer car turns out to be