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1990 mk3 turbo
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Discussion Starter · #1 ·
Greetings all! I have not been able to find the answer to my question I am about to ask so please don't beat me up too much about using "search"! I have been spending a ton of time on the forum.

I am the recent new owner of a 1990 Supra in fantastic condition! It has the original 45,XXX miles and is relatively unmolested with only the head gasket and bolts replaced along with a manual boost controller and gauge. The body is in my mind, a 9 out of 10. It is a five speed.

I have found the accordion intake hose is shot and falling apart at the turbo. Upon further investigation, the turbo impeller is in bad shape too. I have reached out to driftmotion about a new intake and intercooler, and at this point, am thinking turbo replacement as well. It has a few leaks here and there I am going to diagnose soon. Power steering and possibly oil. All that being said, here is my most pressing issue...

I have three warning lights coming up on the dash. Battery, brake and the rear light fault (I think) lights. I had the battery and alternator checked and the alternator failed the test so I replaced it. After getting everything buttoned back up, and turning it over, the lights were gone! However, after a short trip around the block, the lights came back on when stopped. When I rev the engine, the lights go off, then come back on at idle. Any ideas what this could be?

This has been a dream car of mine since I was 10. It has been wonderful talking about it with folks who really know what it is!

I really appreciate the insight and look forward to future conversations! I have included a few pics of the car and turbo...

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1990 mk3 turbo
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Discussion Starter · #2 ·
update to previous post. Again, at idle the three warning lights are on. When I rev the engine, they go off but only between around 1100-2000 rpm. Then they come back on when above or below those numbers...
 

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id be seriously worried about running let alone driving my car with the turbo in that condition. those pieces missing off the impeller must be somewhere, so that would be the first thing id replace.

and as for the rear break light warning light thats a pretty common problem with the stupid 30yo module failing. i remember a thread not long ago talking about how to delete it.

Overall that looks like a damn clean car. nice find!
 

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1990 mk3 turbo
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Discussion Starter · #4 ·
id be seriously worried about running let alone driving my car with the turbo in that condition. those pieces missing off the impeller must be somewhere, so that would be the first thing id replace.

and as for the rear break light warning light thats a pretty common problem with the stupid 30yo module failing. i remember a thread not long ago talking about how to delete it.

Overall that looks like a damn clean car. nice find!
Appreciate the reply. The car is in such good shape I simply could not let it get away from me!

I am happy to delete the module and will search for that post. Have you heard of it causing all three warning lights to go off?

As far as the damaged impeller and the missing pieces, the engine sounds great and there are no noticeable "sounds" of metal in the internals... Hopefully that is a good thing...

I will also add the previous owner had the car inspected, threw new tires on and parked it in the garage three years ago. It hasn't seen rain in at least that amount of time.
 

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MKIII Bodykit Connoisseur
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Welcome! sadly I am not sure what could be causing the those specific warning lights to go off at low rpms. But I agree that impeller is in rough shape. The rest of the car seems to be in really good condition!
 

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I Can Has EBT?
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test your alternator again with the car running. could also be a really bad battery too that is no longer charging, due to bad alternator prior.

One thing you can figure out, lookup how read error codes from your ecu. something like this. http://www.mkiiisupra.net/bbs/the-guide-s/37837-guide-reading-fault-codes.html
If you ecu does not throw codes, it could be the cluster. In my MKIV, I had to resolder bunch of dash boards because over the age, the connectors get loose. (did not add more solder, just heated the existing one)
 

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1990 mk3 turbo
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Discussion Starter · #7 ·
test your alternator again with the car running. could also be a really bad battery too that is no longer charging, due to bad alternator prior.

One thing you can figure out, lookup how read error codes from your ecu. something like this. http://www.mkiiisupra.net/bbs/the-guide-s/37837-guide-reading-fault-codes.html
If you ecu does not throw codes, it could be the cluster. In my MKIV, I had to resolder bunch of dash boards because over the age, the connectors get loose. (did not add more solder, just heated the existing one)
Thanks for the link. This will be extremely helpful. I am hoping to get around to giving it a shot tomorrow.

I will update you with my findings.
 

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Discussion Starter · #9 ·
In my experience everytime the 3 lights come on its a bad alternator. Rebuilds are often DOA these days.
I really hope thats not the case. However, I did replace the new one this weekend twice.... The first time I did not tension the bolt enough and it sagged. I then over tightened the bolt and it broke off in the alternator... Thankfully I was able to grab the threads and replace with a spare bolt I had.

Needless to say, I can probably do it in less than five minutes at this point!

Nothing like learning from mistakes.
 

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Moderator, l337 M0d3r4t0r
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Hello Nate,

Yes when all lights are on it's usually the alt. You do not tighten the 10MM bolt to hold it in place. It's just a set. The 14MM bolt (which I doubt you broke) is what holds things in place.

I would change intercoolers, or some how reverse flow water out of the intercooler, as no doubt the parts of the compressor blades are stuck at the intercooler intake side (so flow water thought the out so it comes out the IN) washing out the turbo bits. DM can get you a rebuilt CT26 with a billet wheel, and you should be on your way. Since the car is 30+ years old, you should consider re-sealing the engine when you get some time and a full tune-up.

You can buy new accordion hoses, from the dealer, or buy the knock off stuff which is silicon 3 ply. It will last forever the Ebay stuff, but it looks nowhere near as OEM. Personally, I used a OEM accordion hose, but used all the other 3ply silicon hoses, for anything where the was coolant as the stock ones go bad in 10 years usually. (10 years comes quick believe it or not when you drive the car every other year lol)

You got yourself a nice find!

BTW that big vacuum hose that is looped is a problem. Because the closest line to you feeds the fuel pressure regulator under boost increasing the pressure with every pound of boost. I assume the previous owner did that because there was a boost leak on one of the vacuum hoses somewhere. You should find and fix that.
 

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Discussion Starter · #11 ·
Hello Nate,

Yes when all lights are on it's usually the alt. You do not tighten the 10MM bolt to hold it in place. It's just a set. The 14MM bolt (which I doubt you broke) is what holds things in place.

I would change intercoolers, or some how reverse flow water out of the intercooler, as no doubt the parts of the compressor blades are stuck at the intercooler intake side (so flow water thought the out so it comes out the IN) washing out the turbo bits. DM can get you a rebuilt CT26 with a billet wheel, and you should be on your way. Since the car is 30+ years old, you should consider re-sealing the engine when you get some time and a full tune-up.

You can buy new accordion hoses, from the dealer, or buy the knock off stuff which is silicon 3 ply. It will last forever the Ebay stuff, but it looks nowhere near as OEM. Personally, I used a OEM accordion hose, but used all the other 3ply silicon hoses, for anything where the was coolant as the stock ones go bad in 10 years usually. (10 years comes quick believe it or not when you drive the car every other year lol)

You got yourself a nice find!

BTW that big vacuum hose that is looped is a problem. Because the closest line to you feeds the fuel pressure regulator under boost increasing the pressure with every pound of boost. I assume the previous owner did that because there was a boost leak on one of the vacuum hoses somewhere. You should find and fix that.
Thanks for the reply. I spoke to Aaron at DM yesterday and will be sending my turbo in for a billet 57. I am also going to get a new intercooler, accordion hose and red HPS hoses. What are your thoughts on the HPS replacement for the accordion hose?

I removed that looped vacuum hose and routed correctly. The previous owner installed a manual boost controller. I wonder if he did that when that was installed...

I originally had plans to double the horsepower but have since come to my senses! I would much rather have a reliable, drivable, mk3 than a machine needing constant maintenance!
 
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1990 mk3 turbo
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Discussion Starter · #12 ·
test your alternator again with the car running. could also be a really bad battery too that is no longer charging, due to bad alternator prior.

One thing you can figure out, lookup how read error codes from your ecu. something like this. http://www.mkiiisupra.net/bbs/the-guide-s/37837-guide-reading-fault-codes.html
If you ecu does not throw codes, it could be the cluster. In my MKIV, I had to resolder bunch of dash boards because over the age, the connectors get loose. (did not add more solder, just heated the existing one)
Greetings! I was able to check the error codes and came up with none. So I take that as a good thing! I am going to get the battery and alternator checked again. Alternator is brand new and battery was new in 2/20 but was dead this evening. Thankfully, it has a three year warranty.
 

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Moderator, l337 M0d3r4t0r
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Thanks for the reply. I spoke to Aaron at DM yesterday and will be sending my turbo in for a billet 57. I am also going to get a new intercooler, accordion hose and red HPS hoses. What are your thoughts on the HPS replacement for the accordion hose?

I removed that looped vacuum hose and routed it correctly. The previous owner installed a manual boost controller. I wonder if he did that when that was installed...

I originally had plans to double the horsepower but have since come to my senses! I would much rather have a reliable, drivable, mk3 than a machine needing constant maintenance!
Honestly, I would get the whole silicon Ebay kit, the HPS is just another brand that rebrands the other Chinese stuff on ebay. That way you can replace the coolant hoses. The accordion hose just doesn't fit the same in silicon. It fits, but just not the same. I got mine for like 60 or so from the dealer new. I'm sure Elmhurst Toyota in the sponsors can hook you up for something around that. That's why I didn't use mine.

As for power, it's 230 stock I'm making 430 wheels on an upgraded ct26 by Albert Meads. Not far off what I made 15 years ago with a 63MM turbo which was 445.

Honestly, before you even up the boost, I'd replace the following seals. (I did this on my 70k 91 when I got it about 3 years ago) Cam seals, valve covers, valve stems seals, CPS gasket. Replaced all the coolant hoses, (the 90 under the power steering and at the back by the exhaust are a bitch when they blow and they will blow).

The kit on ebay also replaces the intercooler hoses, which usually break if you go to 15-20 psi of boost, at least they always did on me back in the day. The 3 ply silicon works better anyways.
 

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Discussion Starter · #14 ·
Honestly, I would get the whole silicon Ebay kit, the HPS is just another brand that rebrands the other Chinese stuff on ebay. That way you can replace the coolant hoses. The accordion hose just doesn't fit the same in silicon. It fits, but just not the same. I got mine for like 60 or so from the dealer new. I'm sure Elmhurst Toyota in the sponsors can hook you up for something around that. That's why I didn't use mine.

As for power, it's 230 stock I'm making 430 wheels on an upgraded ct26 by Albert Meads. Not far off what I made 15 years ago with a 63MM turbo which was 445.

Honestly, before you even up the boost, I'd replace the following seals. (I did this on my 70k 91 when I got it about 3 years ago) Cam seals, valve covers, valve stems seals, CPS gasket. Replaced all the coolant hoses, (the 90 under the power steering and at the back by the exhaust are a bitch when they blow and they will blow).

The kit on ebay also replaces the intercooler hoses, which usually break if you go to 15-20 psi of boost, at least they always did on me back in the day. The 3 ply silicon works better anyways.
Thanks Eric. Are you referring to an eBay kit like this?
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If so, I think I will look for it in black. I do not want too much red to have to keep clean!

I have seen a stock, replacement accordion hose available if that is a better fit too.

As far as the seals you mentioned go, where do you suggest I source those from? Is eBay "good enough" for parts like that?
 

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In my experience everytime the 3 lights come on its a bad alternator. Rebuilds are often DOA these days.
FWIW I just put in a Denso reman from RockAuto and it looks to be working out ok so far. Figured Denso was a safe bet.

Second what ZaZZn said about those small 90 degree coolant hoses. I just replaced the front one by the P/S reservoir couple weeks ago and hiding underneath it in the back was a rubber bubble ready to pop at any moment. I replaced the rear one when I bought the car back in 2003/4 but I had the head off at the time for a head gasket so it was an easy call. Chickened out of replacing it recently since I couldn't find a good way to pull the rear hose clamp off but I do check it periodically to make sure it's holding up ok.

When you're putting the hoses from those kits in you may have to cut them a bit. I have a SamcoSport kit and I had to adjust a few hoses by cutting them down a bit. In particular the one between the 3000 pipe and throttle body. I put in the accordion hose from the kit as well and had to cut the outside end by the AFM to fit an Apexi intake (still had to back out the screw on the Apexi kit braket to allow for more enough adjustment to fit). I'm probably going to get a new OEM one though as it did fit a lot better. Samco one isn't too bad though, I think they're British.

Clean car, enjoy it!
 

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Discussion Starter · #17 ·
I'd buy toyota seals
FWIW I just put in a Denso reman from RockAuto and it looks to be working out ok so far. Figured Denso was a safe bet.

Second what ZaZZn said about those small 90 degree coolant hoses. I just replaced the front one by the P/S reservoir couple weeks ago and hiding underneath it in the back was a rubber bubble ready to pop at any moment. I replaced the rear one when I bought the car back in 2003/4 but I had the head off at the time for a head gasket so it was an easy call. Chickened out of replacing it recently since I couldn't find a good way to pull the rear hose clamp off but I do check it periodically to make sure it's holding up ok.

When you're putting the hoses from those kits in you may have to cut them a bit. I have a SamcoSport kit and I had to adjust a few hoses by cutting them down a bit. In particular the one between the 3000 pipe and throttle body. I put in the accordion hose from the kit as well and had to cut the outside end by the AFM to fit an Apexi intake (still had to back out the screw on the Apexi kit braket to allow for more enough adjustment to fit). I'm probably going to get a new OEM one though as it did fit a lot better. Samco one isn't too bad though, I think they're British.

Clean car, enjoy it!
Thanks for the input. I am looking for hose kits now but am trying to avoid outrageous shipping costs! Do you think it is wise to replace ALL of the hoses or just the main radiator and power steering? Like I said before, finding a full kit in black is proving to be difficult without a huge shipping cost tagged on...
 

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I also had a weirdness in the gauge cluster warning lights happen when the brushes in the alternator got wore down to a nub. Replacing the brushes fixed it. Another thing to check is the taillight warning module that is above the rear driver's side tail light. You can open it up and check for corrosion on the circuit board. I used a toothbrush to remove corrosion that that was causing problems In the gauge cluster warning lights. They turn up on eBay from time to time. Another thing is when remounting it, put the module inside of plastic a baggie so water can't easily infiltrate again.
 

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Discussion Starter · #19 ·
I also had a weirdness in the gauge cluster warning lights happen when the brushes in the alternator got wore down to a nub. Replacing the brushes fixed it. Another thing to check is the taillight warning module that is above the rear driver's side tail light. You can open it up and check for corrosion on the circuit board. I used a toothbrush to remove corrosion that that was causing problems In the gauge cluster warning lights. They turn up on eBay from time to time. Another thing is when remounting it, put the module inside of plastic a baggie so water can't easily infiltrate again.
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Thanks for the advice. Were you getting the on and off warning lights when rpm's fell between 1100 and 2000 as well?

At one point yesterday, they blinked on and off when engaging the clutch alone.
 

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Thanks for the input. I am looking for hose kits now but am trying to avoid outrageous shipping costs! Do you think it is wise to replace ALL of the hoses or just the main radiator and power steering? Like I said before, finding a full kit in black is proving to be difficult without a huge shipping cost tagged on...
I would recommend getting a good enough kit with as many hoses as you can. I bought the one I have off of eBay over 10 years ago and just kept it around. When you're in the engine replace what you can as the opportunities come up. Prioritize the water hoses though as they'll cause the most trouble if they break on the road. Good excuse to do a coolant flush :)
 
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