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Discussion Starter · #1 ·
Long time lurker looking for some input. I just purchased my first a80 supra and had it imported from Australia. The car is a 93 NA auto in stock configuration, with only changes made to the exhaust. I picked the car up on the east coast and it made the 800 mile drive to the midwest without a hiccup. AC blasting the whole way!

Let the car sit overnight, washed it, checked fuses to see it that was the issue with the non-operational drivers side window, then I went to start the car up and the MIL light is on with the check engine light. The car is running like garbage with the idle at about 1800-2000rpm and the transmission doesn’t allow the car to go past about 20mph. It appears to be in limp mode.

Looked around to see if water had maybe gotten to the distributer, checked random plugs and nothing seemed out of the ordinary. I decided to try jumping TE1 and E1 to read the codes, but the check engine light stay on solid. No blinking. I tried jumping the pins at both the diagnostics port in the engine bay and the plug in the drivers footwell.

I removed the negative battery terminal to clear the check engine light, no luck there. Every time I start the car it’s in limp mode and without the ability to read the diagnostics information I don’t know what the issue is. I have an OBD2 scanner, which doesn’t help. They make adapter cable that could work with an obd2 scanner (provided it is obd1 compatible). Has anyone used one of these before? Do they actually work?


I have searched and read through many diagnostic threads about jumping the pins to get the codes, but Im not having any luck. Hoping there is something simple that I’m overlooking. Thanks for your help!

251849


I know the wheels are horrendous, I’m changing them! 🙄
 

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Let the car sit overnight, washed it, checked fuses to see it that was the issue with the non-operational drivers side window, then I went to start the car up and the MIL light is on with the check engine light.
Welcom to NA Supra ownership! The statement above contains the answer. Specifically "washed it". You sprayed the engine bay right? On an NA Supra, water gets into the spark plug valley and causes all manor of chaos until every bit of water has dried up. Use an air compressor and small spray nozzle attachment to force water out of there. Let the engine idle with the hood open. Do everything you can to dry up that water. Also make sure the distributor is completely dry inside and outside.
 
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Discussion Starter · #3 ·
I did not spray the engine bay, it was just an exterior wash. I can look into whether or not water is hanging out in the spark plug valley. That is something I hadn’t checked. I left the hood up to dry out in the garage with the battery disconnected. I really didn’t think it was water related because I drove through some serious storms on my way home. Thanks for the warm welcome and your input. Gives me a few more things to look into!
 

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Discussion Starter · #5 ·
Update: Went through all ignition stuff and replaced valve cover gasket, distributer cap/rotor, spark plugs/wires, and an oil change to top it off. During the tear down I didn’t notice any water in the spark plug valley, but the wires were very brittle and the spark plugs were in serious need of replacement. There were a variety of old

Got everything together and adjusted timing and drove the car for about two days before the same issue came back.

Interestingly enough, I was able to get the car into the diagnostic mode by jumping TE1 and E1 after replacing all this stuff. This allowed me to make the timing adjustments.

I’m still stumped on why I can’t pull the codes once the car actually throws a code. I will continue to investigate and report back!
 

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Perhaps your ECU caps are starting to get a little leaky?

Another thing to replace if it looks old, is your fuel filter, as theyre often overlooked (not that I think its the cause of your problem)
 

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Discussion Starter · #7 ·
Fuel filter is a great idea considering I have no idea what this car has received from a maintenance standpoint. My last car was an imported jzs147 Aristo and I had the ECU service performed to replace the leaky capacitors.

I’ve got more free time this week so I’ll keep plugging away at things and see what happens.
 

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Another thing I would check is the map sensor, just to eliminate it from your list of potential culprits.

When you did your exhaust, did any 02 sensors get removed/deleted?
 

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Discussion Starter · #10 ·
So Im hoping that Ive found the issue after pulling the ECU 🤞

Two of the caps are leaking onto the board. Sending it out to get repaired today and I can hopefully report back in a couple of weeks.

252149


252148
Electronic component Electronic engineering Motherboard Computer hardware Electronics
 

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Discussion Starter · #15 ·
I figured I would share some photos of the repair. I went through a company called Relentless Motorsports and here are the results. Just waiting for it to be shipped back and then I’ll see if my problems are resolved.

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Auto part Technology Automotive wheel system Automotive tire Electronic device
Auto part Technology Automotive wheel system Automotive tire Electronic device
Computer hardware Passive circuit component Electronic engineering Motherboard Electronics
Electronics Electronic component Electronic engineering Technology Computer hardware
Electronic engineering Electronic component Electronics Computer hardware Technology
Electronics Green Computer hardware Technology Electronic device
 

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Discussion Starter · #17 ·
Update time!

I got my ECU back from Relentless Motorsports on 7/11 and decided to throw it back in almost immediately. I am happy to report that this was most definitely the issue of all the odd problems I was having. I’ve put ~150 miles on the car since the ecu repair and it has been running beautifully.

Now that Im confident in how its running I can start the tear down for the manual conversion.

Thanks for all the help!
 

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@Shakagash

Keep us posted here. I bought a USDM '93 NA about two years ago and went through a lotta shit like this. I may have some suggestions for you if it's still acting up.
Hey, @sworley
Mine is a 2jzGE and the throttle is at the end of the pedal travel. It only gives me, like a 10% percent of the throttle. If you could give me any suggestions, I'll thank you.
 

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Hey, @sworley
Mine is a 2jzGE and the throttle is at the end of the pedal travel. It only gives me, like a 10% percent of the throttle. If you could give me any suggestions, I'll thank you.
Hey there. Not really certain what to suggest for you. Is your throttle position sensor adjusted properly? Those are a little tedious to set but I'd try there first.
 

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Hey, @sworley
Mine is a 2jzGE and the throttle is at the end of the pedal travel. It only gives me, like a 10% percent of the throttle. If you could give me any suggestions, I'll thank you.
Are you getting any fault codes when you do the diagnostic test?

Can you give us a little bit of background to your problems, with as many details as possible? It will help us to help you more easily
 
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