1990 Eunos Cosmo - Tinkering/Restoring/Upgrading
 

I picked up a 1990 Eunos Cosmo from Japanese Classics a number of months ago. It runs but has some kind of wiring/computer issue that i have yet to resolve. I figured i'd start a thread on here to get some input/help/feedback from anyone interested or knowing anything about these cars. Other than the fact that it has 3 triangles i've no experience with them.

It supposedly has a new D-code engine in it, a reman from mazda that was installed, in japan, prior to export to the US. It runs great, when it runs, but it likes to just shut off randomly. Sometimes imediatly, sometimes i can drive around for an hour before it happens.

It's not a fast car by any means but i want someting fun, different and interesting for crusing around and to show at cars and coffee type events.

First order of business is deciding if i should just look to repair the computer/wiring problems or completely replace the wiring, ECU, etc. I'd like to keep as much of the stock amenities functioning as possible. Power seats, windows, power tilt wheel, and mirrors, etc. Basically besides the car just shutting off randomly i also have no gauges. The instrument cluster seems totally dead. From what limited info i can find it seems the "TWS" is the weak point on these cars and may be the source of my issues. Id like to get it working and enjoy the car a bit before i tear it totally apart but it may be easier to just start from scratch with the electrical/electronics.

The transmission is another big question mark. I think id like to keep it automatic in the spirit of what the car is. It's never going to see a track so i dont really mind that it's a manual. But i'd like to get something a little more stout in there. I'm thinking maybe something from GMs aftermarket catalog?

I think either way the twins have to go. Besides how much of a nightmare the control system and vacuum mess is i'd like to get something from this millenia in there tech wise. So, i think a BW EFR 9180 with a custom V-band manifold will do nicely.

I hate you.

You got silly. Very cool car!

A 20B with a stout auto and the right converter would be a ton of fun. I’ve helped build several turbo LS cars and they always feel and go faster with a nice auto. I’m not sure if it’d fit in a Cosmo, but the 4L80E is damn near bullet-proof. A stock trans with a $120 Trans-go shift kit and a ~$1000 lockup converter, they can take anything you throw at them and are electronically controllable with a Megasquirt ECU. It’s pretty cool to be able to control shift points, kick downs, lockup, ect from the laptop. They are physically large though. The also don’t have a removable bell housing, but the share the same block bolt pattern as a TH350/TH400, so a plate-adapter should still work. TH350/TH400 adapters already exist, but you lose the 4th gear and any overdriving.

If you stay auto, I wouldn’t waste the money on the EFR. I have a 9180 on my 13B car and love it, but if you have the right stall converter, lag with a bigger journal bearing turbo is a non-issue. The 9180 already spools like a GT35R on a 13B and probably too small for a ported 20B. Something like a BW S475 would be better bang for the buck and come online as soon as you loaded up the converter.

Love that color! I've been inquiring with an importer who has one. Do you have interior pics?

Isn't the native auto trans in the Cosmo the same as Pathfinder/Z31 turbo?

My friend with Z31 turbo was saying that with a little inexpensive modding those things can hold a bunch of torque reliably.

I was looking into that trans as an option if I keep my RX-8 auto when I put the torque-y rotary from my TII in it.

so jealous! how much does this thing cost?

Just checked out the website, looks like it sold for $14,990 USD

I did not pay that....not that it really matters.

Id really like to import one when i get back to the USA. How do you like driving it?

Thanks for the input guys. It makes sense that the automatic probably squelches some of the benefits of an EWR turbo.

I'd really like to keep the drivability as good as stock, keep overdrive and keep the gear changes smooth, etc.

I'll be talking with Turblown about what turbo to use as they will likely build the manifold.

Ouuu, love that colour! Looking forward to this.

9180 EWG Vband inlet will definitely by the route to go!

Are you a member of Cosmo Owners Group on FB? Lots of Cosmo owners there.

Oh and I'm staying tuned for the single turbo set up!

I was not but I just sent the request to join. Thanks for the tip! I'm definetly looking for help. I'm pretty good with these things when i can read the FSM and wiring diagrams but without them it's a challenge.

Luckily that group has a good number of files saved in it, to include FSM's and wiring diagrams. Most are in Japanese, but sometimes you can get a rough translation if you have the Google Translate app on your phone. It can take a picture and scan Kanji.

As for your dash lights, unfortunately that's a common issue. I saw you mention the TWS. Do you know where it's at? If not, it's right above the driver's side kick panel directly above the fuse box. It looks like a big plug and when it comes loose it can cause all kinds of wierdness. It might not be the issue, but try unplugging it and plugging it back in and cross your fingers.

I've got a thread for my own too if you have the free time to take a look. I've owned mine for 2+ years now and have played around with a lot of it.

I also just purchased a Eunos Cosmo from Japanese classics. I love this this car. When i figure out how to post pictures i will put some in this post.

Fuel Tank
 

Based on it's behavior i'm figuring that the stalling is either electronic or fuel delivery. It seems the fuel tank in these cars suffers corrosion in a lot of cases. So, i pulled the tank and found the mess in the attached photo. Sludgy rusty bottom of the tank. Since i have it all apart I'm going to swap the fuel pump for a walbro 255 lph. That's just a temporary option until we can get a proper fuel system setup with an adjustible FPR etc. I just want to get it running properly first.

Based on what i found in the tank the fuel filter is going to need changing and eventually the injectors will need to be cleaned.

I dropped the tank off at a place that blasts it to bare metal, and coats it inside and out. I'll get the pump replaced, the filter replaced and hopefully fire up the car again in a couple of weeks.

I also bought a gauge cluster from japan. More pics on that later. Figured i try to swap it first and maybe repair the original.

That's scary, makes me want to take a peek at mine just for the hell of it.

BTW, here's a write up for the fuel filter replacement. There's also I few other helpful how to's on this site.

JC Cosmo

Update with no pics because i'm swamped at work
 

Latest update. I got the instrument cluster changed. Everything works now except the tach. I'd have to guess it's the signal that is not getting to the cluster and not the tach itself being everything else works and but the tach, which does not even bounce. We'll figure it out.

I pulled the hood struts. I'm hoping to have a company regas them. Looking around for someone who will tackle it.

I also pulled the wood trim out of the car, the lacquer on it is cracked everywhere and falling apart. I'm planning to vinyl over it to give it something of an updated look. There's really no way to rehab it and it's a terribly out of place looking trim on that car. Maybe it was suitable for 1990 but...

I need to find some new window regulators.

It' needs an undertray.

I got the fuel tank reinstalled with the new fuel pump, changed the fuel filter, etc. The car now runs quite well, until it gets all the way warmed up, then it's back to it's old tricks. It stalls bucks and generally wont run right. If i didn't know better id say it was vapor lock in the fuel lines above the motor. But, being its fuel injected, that's unlikely. I'm out of time for the year to work on it so....

I dropped the car off at turblown and we worked up a build plan. It's getting the new Adaptronic Modular ECU and a BW EFR 9180. More to come.

Let me know if you find someone to get your struts re-gased. I'll be keeping an eye out on the Adaptronics install!

Also on the list is a trans flush and some good quality ATF.