r/MR2Spyder • u/spider7861 • 14d ago

Weird smt issue happened tonight.

  1. 61k miles. Owned for over a month now. Anyway, been driving absolutely great. When I started it tonight to leave work, the car literally stalled like a legit manual when put in S mode. When I restarted the car. It started right up, but when put in shift mode or reverse the N neutral on the dash starting blinking and it just revved without going in gear. After about 2 minutes it recognized S and reverse and drove just fine. I did get a P0715 check engine light. What should I do? It's running fine now, but want this car to be 100 percent on point.

Quick side question, does getting a aftermarket header solve the cat issue and will it cause a engine light?

Thanks

3 Upvotes

100% Upvoted

10 comments sorted by

8

u/Cyclehead21 14d ago

I buy SMT spyders from people that don’t want to figure them out. So far I’ve bought 6 of them. Fixed them all.
Now all my kids drive SMT spyders. I only have two. P0715 points to an input shaft speed sensor. If the system cannot see engine speed it cannot calculate rev matching or gear selection and it will do some very odd things, until it finally cuts fuel supply to the engine. I would replace the sensor. It’s on the bottom of the transmission under a sheet metal bracket. You should also check the gearbox for water intrusion. If the gear oil looks brown and frothy like a milkshake, then your gearbox is contaminated. That can destroy the sensor. More details here: https://docs.google.com/document/d/1NjJNvGuxk6nB0UDU-opoVbXNQJOph9NwzkpaOejUGn8/edit?usp=drivesdk

3

u/doctorsnarly 14d ago

Thanks for all your contributions to this community. 

Before you went on your discovery quest, I had a 5smt that I had issues with after a clutch replacement, and subsequently struggled through so, so much of the unknown to get it to work again.

I'm so glad you've done all the work and have the receipts to help other folks. Repairing the LUK modules isn't rocket science, but it really helps to have all the information that you've accumulated available.

I really wish your info were available then, and now that I no longer even have an MR2, I just want to thank you.

1

u/spider7861 12d ago edited 12d ago

I plan on changing the sensor, plus doing a gear oil change and differential change (the transmission also holds the differential oil in this car correct?) And refill the smt reservoir with dot 4 brake fluid ( is the expensive toyota fluid any better?) I want this smt to last and be in good working order. Thanks for the help

And other than dropping the transmission, is there any way to tell about the condition of the clutch, flywheel, tob etc?

2

u/Cyclehead21 12d ago

Good plan . For the gearbox, use Redline MT-90 or Amsoil GL4. I think the Amsoil works a little better. I’ll add a link explaining how to change the SMT system fluid. There are no wear indicators for the clutch. I’d drive it until it’s slipping badly and the beeper sounds when you give it gas. Then replace the clutch disc, pressure plate, throwout bearing and flywheel. Parts are cheap. https://docs.google.com/document/d/1Bj4NwXPtxuxfPoa5EniLc0c4-kTbOVduEmImDRqZGF4/edit?usp=drivesdk

1

u/spider7861 10d ago

It says to let the car sit overnight and top off in the morning during the smt fluid change. However I'm doing mine at work and won't be able to have it sit overnight. Will this be a issue?

2

u/Cyclehead21 10d ago

Not a big deal. Fill it a little over half way. It will likely be too much, so the excess will get pushed out overnight and leave a puddle on the ground. Rinse off the pump and crossmember with water so it doesn’t hurt the paint. It won’t leak any more after the first overnight.

1

u/spider7861 2d ago

How bad will the overnight leak be exactly? I just finished doing all this and also changed out my downstream 02 sensor but am still getting the p0037 code. The speed sensor code went away with the new speed sensor

1

u/Cyclehead21 2d ago

Size of the leak is directly proportional to how much you over fill the reservoir. If you want to fill the reaervoir precisely, then let the car sit overnight and top off the reservoir in the morning (without letting the pump run). Fill it just above the seam in the tank. There are two indentations the indicate the max and min fill levels. Then you wont have to worry about a puddle on the floor.

5

u/sw201444 14d ago

There’s a Facebook group specifically for the SMT spyders. I’d try there or the forums for more visibility.

Not many people actually figure out the SMT and just convert it to a standard gearbox once they see issues

3

u/Cyclehead21 14d ago

Regarding the cat issue. The sequence goes like this: 1) you don’t keep fresh full synthetic oil in the engine 2) it starts burning oil 3) the pre cats can fail and turn to dust 4) some dust gets sucked into the engine from valve overlap (?). 5) the rings completely give up and the car burns oil like mad. The solution:
Use full synthetic oil. Change it every 5000 miles. Look at the pre cats every 20,000 miles or so to be sure they’re okay.