About to lose my mind
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About to lose my mind
So there is a bit of a story to this before I get into the full technical details, but any help with this engine would be greatly appreciated...
Here we go. I bought a 1990 rx-7 convertible from a friend of mine about a year ago. 159,000 on the odometer with a rebuild 40,000 miles ago. The information he left me with was foggy at best but I will try to describe everything he told me. Now I knew about rotary's before he sold it to me but not much. The car started and ran fine nothing was majorly wrong with the car except a minor exhaust leak. He had changed out the exhaust manifold to an OBX Racing header exhaust. He also explained that he had a bridge port job done to the engine at the time of rebuild(all work done by Mazdatrix) and a few minor modifications such as a cone filter to bypass the stock intake and new wires(all that I remember off the top of my head).
Now unfortunately I had to let the car sit for about 6 months while I went out of town. When I got back the car had the normal symptoms of having stale fuel, so I cleared it out and changed the gas/oil/coolant. However a week later the idle seemed extremely erratic, surging from 750-250 and sometimes dying out when cold or dipping so low the starting lights come on as if it is going to die only to turn back on. Driving seemed fine, no major issues there. One day I notice the sound of the car is off and it sounds waaaaay too loud. I take a peak under the car to find the exhaust leak has turned into a full blown split in the header with a nice half inch gap between pipes. After inspection I find that the cat was plugged up which probably caused enough heat and back pressure to blow the headers. I've driven it a bit like this(I know I shouldn't have) but now new problems are showing up. Hesitation while accelerating through gears(usually only 1-2, once it gets over 4k RPMs it's fine), sometimes the car cuts out even at high RPMs as if it isn't igniting then turns back on when the clutch is depressed, and today I had the final problem... The car wouldn't rev between 1-3500 RPMs and even after that it was really shotty. When I was able to drive off, it was under 30 mph and sounding like it was missing still. After parking the car for a few minutes and running it again, the problems persisted for about 600 ft and then it magically disappeared and the car ran fine again.
I know I haven't treated this car with the love and respect it deserves but I'm in a place now where I have the ability to get things fixed and I am just looking for a bit of help as to what the problems may be and where I should start. Any assistance is greatly appreciated.
-Jon
TL;DR
Idle surging from 750-250 when warm
Idle dying when cold at times
Backfiring
Split exhaust headers
Hesitation while accelerating
Ignition disappears at high RPMs occasionally
Finally almost died on me with erratic ignition at 1-3500 RPMs and sputtering at 4k+, wouldn't go over 30 MPH, etc.
Here we go. I bought a 1990 rx-7 convertible from a friend of mine about a year ago. 159,000 on the odometer with a rebuild 40,000 miles ago. The information he left me with was foggy at best but I will try to describe everything he told me. Now I knew about rotary's before he sold it to me but not much. The car started and ran fine nothing was majorly wrong with the car except a minor exhaust leak. He had changed out the exhaust manifold to an OBX Racing header exhaust. He also explained that he had a bridge port job done to the engine at the time of rebuild(all work done by Mazdatrix) and a few minor modifications such as a cone filter to bypass the stock intake and new wires(all that I remember off the top of my head).
Now unfortunately I had to let the car sit for about 6 months while I went out of town. When I got back the car had the normal symptoms of having stale fuel, so I cleared it out and changed the gas/oil/coolant. However a week later the idle seemed extremely erratic, surging from 750-250 and sometimes dying out when cold or dipping so low the starting lights come on as if it is going to die only to turn back on. Driving seemed fine, no major issues there. One day I notice the sound of the car is off and it sounds waaaaay too loud. I take a peak under the car to find the exhaust leak has turned into a full blown split in the header with a nice half inch gap between pipes. After inspection I find that the cat was plugged up which probably caused enough heat and back pressure to blow the headers. I've driven it a bit like this(I know I shouldn't have) but now new problems are showing up. Hesitation while accelerating through gears(usually only 1-2, once it gets over 4k RPMs it's fine), sometimes the car cuts out even at high RPMs as if it isn't igniting then turns back on when the clutch is depressed, and today I had the final problem... The car wouldn't rev between 1-3500 RPMs and even after that it was really shotty. When I was able to drive off, it was under 30 mph and sounding like it was missing still. After parking the car for a few minutes and running it again, the problems persisted for about 600 ft and then it magically disappeared and the car ran fine again.
I know I haven't treated this car with the love and respect it deserves but I'm in a place now where I have the ability to get things fixed and I am just looking for a bit of help as to what the problems may be and where I should start. Any assistance is greatly appreciated.
-Jon
TL;DR
Idle surging from 750-250 when warm
Idle dying when cold at times
Backfiring
Split exhaust headers
Hesitation while accelerating
Ignition disappears at high RPMs occasionally
Finally almost died on me with erratic ignition at 1-3500 RPMs and sputtering at 4k+, wouldn't go over 30 MPH, etc.
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#10
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I have yet to pull codes on the car, I will certainly try that tonight. But other than pulling the codes is there any help that can be given regarding these problems? Haven't driven her in almost a week due to fear :s
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Okay so I finally pulled the codes and I have a bit of confusion but maybe someone can help clear that up here. The codes I kept getting were either a 10 and 3 or 13... Kinda difficult to tell if the pause was long enough. Codes being
03 - Crank Angle Sensor (G) - Fuel Injection and ignition cut
10 - Intake Air Thermosensor (AFM) - Intake air fixed at 68F
or
13 - Pressure Sensor (intake manifold pressure) - Fixed at 29.9 inHg
So with those 3 codes and my initial symptoms, is there any further assistance that can be given? How can I go about fixing these problems?
03 - Crank Angle Sensor (G) - Fuel Injection and ignition cut
10 - Intake Air Thermosensor (AFM) - Intake air fixed at 68F
or
13 - Pressure Sensor (intake manifold pressure) - Fixed at 29.9 inHg
So with those 3 codes and my initial symptoms, is there any further assistance that can be given? How can I go about fixing these problems?
#15
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Okay so I finally pulled the codes and I have a bit of confusion but maybe someone can help clear that up here. The codes I kept getting were either a 10 and 3 or 13... Kinda difficult to tell if the pause was long enough. Codes being
03 - Crank Angle Sensor (G) - Fuel Injection and ignition cut
10 - Intake Air Thermosensor (AFM) - Intake air fixed at 68F
or
13 - Pressure Sensor (intake manifold pressure) - Fixed at 29.9 inHg
So with those 3 codes and my initial symptoms, is there any further assistance that can be given? How can I go about fixing these problems?
03 - Crank Angle Sensor (G) - Fuel Injection and ignition cut
10 - Intake Air Thermosensor (AFM) - Intake air fixed at 68F
or
13 - Pressure Sensor (intake manifold pressure) - Fixed at 29.9 inHg
So with those 3 codes and my initial symptoms, is there any further assistance that can be given? How can I go about fixing these problems?
#16
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Disconnect the plug at the CAS. Then take a multimeter set to ohms and place one meter lead on the White wire and then place the other meter lead to the Red wire from the Cas pigtail harness (Yes, the one that is short and comes from the CAS itself) and take the ohm reading. It should fall between 110 to 210 ohms. While you're there also take an ohm reading from the Blue wire and the Red wire. Should fall within the same range.
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Went ahead and took the readings, red/white is 170, blue/green is 170. Now I also noticed that the attaching connect is backwards... Not sure if this will make sense but the little clip part is matched up correctly but the plug from the CAS and harness look like this
GB RW
WR BG
So they are "reversed" connected... Wires don't match up. But like I said the clips match up perfectly... Any help here? Also, thanks for the help.
GB RW
WR BG
So they are "reversed" connected... Wires don't match up. But like I said the clips match up perfectly... Any help here? Also, thanks for the help.
#18
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Went ahead and took the readings, red/white is 170, blue/green is 170. Now I also noticed that the attaching connect is backwards... Not sure if this will make sense but the little clip part is matched up correctly but the plug from the CAS and harness look like this
GB RW
WR BG
So they are "reversed" connected... Wires don't match up. But like I said the clips match up perfectly... Any help here? Also, thanks for the help.
GB RW
WR BG
So they are "reversed" connected... Wires don't match up. But like I said the clips match up perfectly... Any help here? Also, thanks for the help.
#19
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wow gotta say that was one of the hardest things I've done in awhile. Had to find the ecu in the car, then find a wiring diagram, and well that was alot harder than expected. Anyways! readings at the ecu were good aswell. Sitting at a solid 167. I disconnected, cleaned, and reconnected the plugs on both ends. What's next?
#20
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wow gotta say that was one of the hardest things I've done in awhile. Had to find the ecu in the car, then find a wiring diagram, and well that was alot harder than expected. Anyways! readings at the ecu were good aswell. Sitting at a solid 167. I disconnected, cleaned, and reconnected the plugs on both ends. What's next?
#21
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Yeah I did that. Grounded the connector to the negative terminal on the battery, went inside, turned key to ignition, and watched the codes. It was 1 long light(maybe 1 second) followed by a short pause (maybe 2 seconds?) then 3 quick flashes(half send a piece) followed by a long pause(maybe 5 seconds) then it restarted. Like I said, it was either a 10 and 3 or 13. Kinda difficult to decipher.
#22
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Yeah I did that. Grounded the connector to the negative terminal on the battery, went inside, turned key to ignition, and watched the codes. It was 1 long light(maybe 1 second) followed by a short pause (maybe 2 seconds?) then 3 quick flashes(half send a piece) followed by a long pause(maybe 5 seconds) then it restarted. Like I said, it was either a 10 and 3 or 13. Kinda difficult to decipher.
#23
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Other codes involve the Intake Air Thermosensor(AFM) and the Pressure Sensor(intake manifold pressure). I've check the connectors and vacuum lines on the MAP haven't yet checked the Intake Air Thermosensor however.
I'll see what I can do about maybe getting a video posted of what the car sounds like and looks like so I can get a bit more diagnostic help, but as far as all the other problems go is there anything else I can do to check?
Btw, I really appreciate you helping me out as much as you have.
I'll see what I can do about maybe getting a video posted of what the car sounds like and looks like so I can get a bit more diagnostic help, but as far as all the other problems go is there anything else I can do to check?
Btw, I really appreciate you helping me out as much as you have.
#24
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Other codes involve the Intake Air Thermosensor(AFM) and the Pressure Sensor(intake manifold pressure). I've check the connectors and vacuum lines on the MAP haven't yet checked the Intake Air Thermosensor however.
I'll see what I can do about maybe getting a video posted of what the car sounds like and looks like so I can get a bit more diagnostic help, but as far as all the other problems go is there anything else I can do to check?
Btw, I really appreciate you helping me out as much as you have.
I'll see what I can do about maybe getting a video posted of what the car sounds like and looks like so I can get a bit more diagnostic help, but as far as all the other problems go is there anything else I can do to check?
Btw, I really appreciate you helping me out as much as you have.
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Alright I went ahead and did what ya said and it seems as though the code was definitely a 13, which turns out to be the Pressure Sensor(Intake Manifold Pressure) which I believe is the MAP sensor? What can I do about fixing this particular part or is it a simple replace?