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Discussion Starter · #1 · (Edited)
I have a 94 NA Supra 5 speed and it's been running like crap lately. I am not the most mechanically inclined, so I turn to the forums for help. I'm gonna try my best to explain what has been happening to my car lately.

About a week ago, my car was running fine. Until every time I would go to higher RPM's, the car would bog out. This problem would come and go, but not anymore. The car is locked on bog mode and the car feels like it dropped 80+ hp. Not to mention that it shakes a lot during idle and take off.
As the car idles, it sounds as if its misfiring. I did have a coolant leaking problem, but not anymore because I changed out the heater hose. A lot of people have been saying stuff like blown/bad head gasket, dead cylinder(s), bad spark plug(s), etc. Right now, the car sounds like a beaten up STi and reeks of fluid. The motor was smoking up on me once I turned off the car, but that only happened once. As of now, the car feels 10x slower and bogs. It sounds no where near how it used to sound when I first got the car. So any help/suggestions/advice is appreciated.
Oh, I must mention that the car is not overheating.
Thanks!

P.S. Here's a recent video of how my Supra currently sounds with this problem. You can hear it misfiring during idle.

http://s50.photobucket.com/albums/f328/lambo89/?action=view&current=f8ab2dc2.mp4

and a rolling video

http://s50.photobucket.com/albums/f328/lambo89/?action=view&current=d42ae908.mp4
 

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Here is a check list, before I make as guess:

1. When was the last time you had plug/distributor/distributor wires replaced?
2. Is your check engine light is on when the key is at the "on" position?
3. Anything like black clouds from the tail pipe?
 

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Discussion Starter · #3 ·
1. Well, I've had the car for 7 months now, so ever since I got it, those haven't been replaced. And I'm not sure what the previous owner did, because I got the car from a used car dealership, instead of a private owner.
2. The check engine light does not come on when I have the key in the "on" position, nor does it come on when the engine is turned on.
3. From what I've seen, it hasn't been throwing any smoke.
 

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cel light prolly needs to be resolder or dealer prolly took out the lights on u. Do a ecm diagnostic code check. (Mkiv.com tech article) sound more likev a bad injector. Or just need a quick tuneup(plugs, wires, cap and rotor) gl
 

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Discussion Starter · #5 ·
cel light prolly needs to be resolder or dealer prolly took out the lights on u. Do a ecm diagnostic code check. (Mkiv.com tech article) sound more likev a bad injector. Or just need a quick tuneup(plugs, wires, cap and rotor) gl
Sure, will do. Where can I usually get an ECM Diagnostic Code Check?
 

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1. Well, I've had the car for 7 months now, so ever since I got it, those haven't been replaced. And I'm not sure what the previous owner did, because I got the car from a used car dealership, instead of a private owner.
2. The check engine light does not come on when I have the key in the "on" position, nor does it come on when the engine is turned on.
3. From what I've seen, it hasn't been throwing any smoke.
1. The cheapest route is to get the plugs, distributor wire, distributor rotor, and distributor cap replaced. Then check if the engine is timed at -10 degrees at idle (you need an engine timing gun).
2. A healthy ECU should have the engine light on when the key position is on "on" (when the engine is not running). What your car symptoms are and what you just wrote on #2, points to a bad ECU. I suggest you borrow a NA ECU to find out (auto or manual will work with a 5-Speed, BUT you need to know if your is "California" Spec).
3. If the car is running crappy, you probably will see small puffs of faint black smoke.
 

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Discussion Starter · #9 ·
1. The cheapest route is to get the plugs, distributor wire, distributor rotor, and distributor cap replaced. Then check if the engine is timed at -10 degrees at idle (you need an engine timing gun).
2. A healthy ECU should have the engine light on when the key position is on "on" (when the engine is not running). What your car symptoms are and what you just wrote on #2, points to a bad ECU. I suggest you borrow a NA ECU to find out (auto or manual will work with a 5-Speed, BUT you need to know if your is "California" Spec).
3. If the car is running crappy, you probably will see small puffs of faint black smoke.
Pointing back to #2, I was sitting in my car not too long ago, and as I had the key in the on position without the engine being turned on, the check engine light was on. It would always turn on when i had only the electricity on, but it was just recently that it didnt show up anymore, but its back..im not sure how.
 

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Discussion Starter · #10 ·
1. The cheapest route is to get the plugs, distributor wire, distributor rotor, and distributor cap replaced. Then check if the engine is timed at -10 degrees at idle (you need an engine timing gun).
2. A healthy ECU should have the engine light on when the key position is on "on" (when the engine is not running). What your car symptoms are and what you just wrote on #2, points to a bad ECU. I suggest you borrow a NA ECU to find out (auto or manual will work with a 5-Speed, BUT you need to know if your is "California" Spec).
3. If the car is running crappy, you probably will see small puffs of faint black smoke.
Pointing back to #2, I was sitting in my car not too long ago, and as I had the key in the on position without the engine being turned on, the check engine light was on. It would always turn on when i had only the electricity on, but it was just recently that it didnt show up anymore, but its back..im not sure how.
 

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Discussion Starter · #11 ·
I would do a full tune up and a fuel filter change. And Even some fuel system cleaner in the tank won't hurt.
Yeah I was thinking a full tune up should do me justice as well. And it wasn't too long ago since I put fuel injector cleaner in my tank.
 

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Does your car run fine now with the check engine light on (when car engine is off and engine light is on)?
 

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Discussion Starter · #15 ·
Does your car run fine now with the check engine light on (when car engine is off and engine light is on)?
Unfortunately, no. The car is still running crappy and reeks of fluid. I can't really narrow it down to what the smell is, but it smells like something is burning. As for higher RPM's, my car bogs louder but doesn't go any faster.
 

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I have a feeling the ECU is dying, but only way to find out is swap out the unit which takes about 5 minutes. Unfortunately, my car is at FSR having an AEM unit installed. I will have a spare stock ecu unit to test,until my car is done.

If the burning smell is coming from the engine bay, I would check if the valve cover isn't leading oil. There is a coolant hose in back of the head that can also leak coolant.
 

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Discussion Starter · #17 ·
I have a feeling the ECU is dying, but only way to find out is swap out the unit which takes about 5 minutes. Unfortunately, my car is at FSR having an AEM unit installed. I will have a spare stock ecu unit to test,until my car is done.

If the burning smell is coming from the engine bay, I would check if the valve cover isn't leading oil. There is a coolant hose in back of the head that can also leak coolant.
That might be it. I was hoping to take it to FSR since I live about 10 minutes away from them, but they are hella busy.
The smell isn't actually come from the engine, its coming out of the exhaust. Here's a video I just took so you can here the misfire during idle.

http://s50.photobucket.com/albums/f328/lambo89/?action=view&current=f8ab2dc2.mp4
 

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Most likely the car is running extremely rich, which a dead ecu will do. If you have an engine bay shot, I can tell if it's California Spec. If your car turns out to be California Spec, I would call up Ian @FSR to have them plug up my stock Ecu to your car, it's really only a 5 minute swap. However, this is Ian's call if he has time.
 

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Discussion Starter · #19 ·
Most likely the car is running extremely rich, which a dead ecu will do. If you have an engine bay shot, I can tell if it's California Spec. If your car turns out to be California Spec, I would call up Ian @FSR to have them plug up my stock Ecu to your car, it's really only a 5 minute swap. However, this is Ian's call if he has time.
Sure thing. Here's an engine bay shot of how it looks right now.
 

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Your car is not California Spec, so you will need to find a NA ECU that isn't California Spec. The California Spec ECU's are rarer, so it's easier to find a non-California Spec ECU.
 
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