I do have the Nakamichi system in this car, which I think just has the one amp. That's good to know the head units are robust.
Okay. That does change my hypothesis. Factory Nakamichi SC's have just the one amplifier, yes. No subwoofer sub-amplifier setup on those cars. They have a conventional center subwoofer (higher output and higher grade) driven traditionally by the more powerful factory Nakamichi amplifier unit. So the issue of your rear package tray speakers and center subwoofer is related to something else.
All those factory Nak speakers are good quality with very decent specs so unless they were noted to have issues before installing the new amplifier it's likely not related to them specifically. They are generally known to be long lasting. Of course these cars have seen a lot of years now so wear on them will vary.
I also don't think it's this... but when fitting an aftermarket head unit (I know you have not but for the sake of info) some of them do not have an Amplifier Power On signal wire. I had to install an aftermarket one of those when I put in a German made aftermarket VDO/Continental head unit since that head unit did not have an amp power on signal wire built in. I retained my factory Pioneer amplifier and Pioneer sub-amplifier (which I replaced once) at that time.
Since your head unit is still stock it probably isn't related. Unless there is some wiring peculiarity related to how the stock Nak head unit and stock Nak amp are wired in an unconventional way in the electrical diagrams.
Thanks that gives me more things to think about. I'm pretty sure the previous two POs of this car were chasing this issue and I'm not sure what they might have done. Also there are some signs the door panels were taken off so who knows what has been going on. I just need to really dive into it. Later this week I will have time to test it more thoroughly. Luckily this car is pretty good mechanically, nothing else needs attention.
Thanks that gives me more things to think about. I'm pretty sure the previous two POs of this car were chasing this issue and I'm not sure what they might have done. Also there are some signs the door panels were taken off so who knows what has been going on. I just need to really dive into it. Later this week I will have time to test it more thoroughly. Luckily this car is pretty good mechanically, nothing else needs attention.
My SC300 was basically 100% stock when I bought it (I'm the second owner) but even so the low beam headlight wiring and 29-94 style cornering lamp wiring had been messed with before me and needed repair. Luckily the rest of it was untouched but it's always possible with cars of this age for someone to have messed with things before us.
It is possible but highly unlikely that you may need to make sure wires going to the back are intact and in good shape. The quality of the OEM wires is very high. But as an example I had a sunroof leak in my SC a couple of years back which among other things managed to damage part of the wiring harness under the rear section of my rear seats.
A huge aggressive saga of multiple interior deep clean sessions, sunroof drain cleaning, rear seat cushion reupholstery and wire by wire rear seat body harness repair later that I'm finishing up now and it's fine. I am not certain off the top of my head but I think a couple of the wires in that harness which I repaired may be related to the rear speakers and sub audio.
Hopefully you have NO issue like that to tackle. I think you'd know it if so. It's a ridiculously rare thing to ever happen but it's a very easy thing to inspect before you dive deeper into other investigations.
....
My main hunch is still in something very minor but not immediately obvious related to how the factory Nakamichi head unit receives and sends signals to the factory Nakamichi amp and maybe the wiring from the amp to the rear speakers and sub which differs in some proprietary way from how most common amplifiers are wired.
My SC300 was basically 100% stock when I bought it (I'm the second owner) but even so the low beam headlight wiring and 29-94 style cornering lamp wiring had been messed with before me and needed repair. Luckily the rest of it was untouched but it's always possible with cars of this age for someone to have messed with things before us.
It is possible but highly unlikely that you may need to make sure wires going to the back are intact and in good shape. The quality of the OEM wires is very high. But as an example I had a sunroof leak in my SC a couple of years back which among other things managed to damage part of the wiring harness under the rear section of my rear seats.
A huge aggressive saga of multiple interior deep clean sessions, sunroof drain cleaning, rear seat cushion reupholstery and wire by wire rear seat body harness repair later that I'm finishing up now and it's fine. I am not certain off the top of my head but I think a couple of the wires in that harness which I repaired may be related to the rear speakers and sub audio.
Hopefully you have NO issue like that to tackle. I think you'd know it if so. It's a ridiculously rare thing to ever happen but it's a very easy thing to inspect before you dive deeper into other investigations.
....
My main hunch is still in something very minor but not immediately obvious related to how the factory Nakamichi head unit receives and sends signals to the factory Nakamichi amp and maybe the wiring from the amp to the rear speakers and sub which differs in some proprietary way from how most common amplifiers are wired.
Yeah, Lexus wiring is the best. Lexus quality is unmatched, especially in the 90s-00s. The only thing that can kill a Lexus is water soaking the wiring harness/computers.
The speakers all seem to be wired normal. One difference is that all the input channel grounds are tied together with the Lexus system, and not separated like most aftermarket stuff. Otherwise it just have + and - for each channel.
I had time to dive in deeper and all the speakers were completely blown out. The sub looks fine, though. I replaced the speakers with some Pioneer ones, 4" in the front an 6.5" in the rear. Connected it all back up and everything works! I'm getting some distortion at higher volumes. I adjusted the gains on the amp all the way down and tried to tune it in but I don't really know what I'm doing. I've never known much about car audio. I think it needs a cleaner 12v source than what it's getting also and there is a buzz in the speakers tied to engine revs.
I think I'm going to replace the head unit with something aftermarket rather than mess around with the stock system. The CD changer does work fine though.
It's been running great on E85. On premium 91 gasoline I was getting 15 city and 21 highway MPG. On E85 I'm getting 12 city and 18 highway MPG.
Picked up a cheap head unit on marketplace for $20. Used some RCA cables to connect it to the amp. Works great, sounds awesome. I'm going to Australia and Japan in May I'm going to try and find a sweet JDM head unit on my trip to bring back for it and some other goodies if I can. I need to 3D print a cover for the gap under the radio. The Metra fit kit didn't fit at all.
I'll put a USB plug where the old volume **** is.
Also installed a cheapo wideband gauge to make sure it's running well on E85 and it is, AFRs are all where they should be. The gauge is a clone of the AEM wideband which I've used before. Will 3D print a mount for it where the ashtray is and probably add another gauge.
Love your progress man good to see another person sticking with a v8. I am curious what is your strategy with running the e85 while NA?
i know thw Radio was 20 bucks but DAMN yuck lol!!! hopefully you dont mind switching back.... Looking at the radio part you said you had distortion at high volume with the oem unit i see in the picture you have the Bass,treble,mid ***** in the middle position turn those all the way down along with the gain and bass on the amp then turn the volume up to slightly higher than where you like it then adjust gain slowly up on the amp until you get distortion then dial back slightly so its cleared again then on the unit adjust treble then mid just like the gain. you can play with LPF and freq after then dial in the bass as needed. if you need more help with that let me know i dont want to write a novel.
Love your progress man good to see another person sticking with a v8. I am curious what is your strategy with running the e85 while NA?
i know thw Radio was 20 bucks but DAMN yuck lol!!! hopefully you dont mind switching back.... Looking at the radio part you said you had distortion at high volume with the oem unit i see in the picture you have the Bass,treble,mid ***** in the middle position turn those all the way down along with the gain and bass on the amp then turn the volume up to slightly higher than where you like it then adjust gain slowly up on the amp until you get distortion then dial back slightly so its cleared again then on the unit adjust treble then mid just like the gain. you can play with LPF and freq after then dial in the bass as needed. if you need more help with that let me know i dont want to write a novel.
Running E85 basically just gives you high octane fuel at the same price as 85 octane gas. I've put flex fuel on all my cars since 2010ish. Never found a downside. MPG is worse but fuel is cheaper.
The radio is super ugly yes lol but it was just the cheapest I could find. Like I said I'm going to try and find a cool JDM one to bring back, I saw some on ebay that look awesome: https://www.ebay.com/sch/i.html?_nkw...sid=m570.l1313
It sounds awesome but my sub is broken. It looks fine but is broken underneath. Got a Pioneer replacement coming.
Quote:
Originally Posted by joewitafro
Are the fuel lines under the tank all OEM and still running E85? I imagine you changed out a fuel pump, but what about everything else?
I haven't done anything to it other than install the kit which just plugs in between the fuel injectors and install a flex fuel sensor in the return fuel line. I've never had a problem before with the lines or anything, but sometimes the fuel pumps go out quickly after switching so if that happens I'll replace it. Also I have a new fuel filter I'm going to install after a few thousand more miles since E85 will loosen junk in the fuel system during a short period after the switch.
I've been looking into redying the leather seats to match the beige of the rest of the interior and I think I'm going to give that a try. I could also get Lseats replacement seat covers for $350 that would match but I think I'll try to redye them for under $100 first.
Hopefully my speaker saga is over. I replaced the sub with a Pioneer TS-A2500LS4 (https://amzn.to/3PnZ23b). It didn't drop down into the hole all the way so I took apart the stock sub and cut out the speaker from the aluminum shroud. Then I used the aluminum shroud to mount the new sub. Fit perfectly under the stock cover and sounds amazing. Then I mounted the amp on the old amp bracket. Sad to have ditched the CD changer.
I've never had a car with such a kick *** stereo before. It really bumps. I spent some time dialing in the amp and getting it sounding good.
I also ordered new seals etc for my LSD so that's the next project on the list.
This damn car... Don't leave any snow on your trunklid before you open it. Never had a car that is able to dump so much snow into the trunk just by opening it. I've done this more than a couple times already
Noticed some wind noise and found the door seals had pulled inward. I used some 303 interior conditioner on them and cleaned the channels and they started getting more flexible. Pulled them back into place with a couple dabs of RTV and used a drop of super glue to hold it in place until it set up.
Now the doors are quiet but I notice some wind noise from the sunroof, I'll probably try the same thing there.
Just in time for the weather on the return journey.
Wife was away so I could park both cars in the garage. Put a coat of ceramic spray wax on it because I am parking it for 3 weeks outdoors.
Also here are some close ups of the A.P.E. flex fuel kit. It is my favorite flex fuel kit of several I've tried, it pulls power from the injectors so you just plug it in and hook up a ground.
