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Master Auto Tech.
Master Auto Tech., master tech.
Category: Mazda
Satisfied Customers: 600
Experience:  A.S.E. Master technician. Over 20 years working on import & domestic. Owner/operator of an auto shop
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Red hot exhaust manifold and no gas pedal response. With

Customer Question

Red hot exhaust manifold and no gas pedal response. With resonator/cat convertor disconnected same issue plus flames coming out -noticed after two minutes while code reading within car. 2006 Mazda 3, 2L. First noticed that car will initially idle roughly for a few seconds and shut off. Sometimes on 2nd or 3rd try it will start with some sparatic fluctuating in rpms (approx. 1100 rpms with few hundred fluctuating at worst). No gas pedal response.
Action taken so far. Air filter not bad, Cleaned Throttle Body assy, improvement in starting and idling. No gas pedal response. Checked spark plugs (80k on them, getting seedy but want to solve gas pedal issue prior to replacing), cylinder on left was wet/oily but been find on next couple of checks.
Borrowed code reader and only paid attention to one of numerous codes. P0102 -MAF sensor air flow issue. Cleaned MAF sensor, no change.
Replaced Throttle Body assy with new one from Mazda. Noticed that within 2-3 minutes something was smoking, the exhaust manifold was red hot. Second guessed myself and disassembled looking for paper towel used with chamber while cleaning. Scoped but could find no blockage. Checked air flow at filter – lots of suction noticed. Appears to be firing on all cylinder.
Resonator was hotter than catalytic convertor after 10 minutes. Suspected resonator was plugged. Disassemble exhaust ahead of resonator(which is ahead of catalytic converter). Scoped and screen looked like new on resonator. Scoped fwd section to O2 Sensor. No issue seen. Reset computer, attempt to reprogram gas pedal to throttle body by key in for 60 sec, turn to on for 90 sec, then started (attempt for 5 min but had to shut down at 2-3 min due to exhaust manifold red hot and flames coming out of disassemble exhaust ahead of resonator).
Read codes during the 2-3 min. 11 codes picked up, some were repeats. Codes 2088 (Crankshaft Position), P0102 (MAF sensor), P2101 (Throttle Act Cntl), P2128 (Throttle Pedal), P0103 Exhaust Gas Response) noted. Restarted car after few minutes to check pedal but no response. Any suggestions?
Submitted: 9 months ago.
Category: Mazda
Expert:  Master Auto Tech. replied 9 months ago.

I'm sorry you are having problems with your vehicle. I will try to help.

I'm a full time mechanic and have been a mechanic for over 20 yrs and I work part-time here on JustAnswer to help you and others repair their own vehicles, and I get credited by your ratings.. So before leaving the site make sure and leave me a rating. You can still reply to me as many times as neeed, even after the rating.. I will need for you to be my hands and eyes since I'm not there.

So about the only reason for flames to shoot out and for the exhaust to get cherry red is because your injector or injectors are stuck open or leaking severely. First you need to check your fuel pressure. if it is good then you need to figure out which injector or injectors are leaking. you can one at a time pull the injector wires and see if it has any effect on the engine. The ones that have no effect or less then the others are the most likely culprit. After fixing this issue you can clear codes and programmable memory and see if you have throttle response.

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Customer: replied 9 months ago.
That should not cause the exhaust manifold to turn blood red within two minutes with and without the resonator/catalytic convertor connected. I will reconnect the exhaust and try your suggestion since i am out of idea. I will get back to you within the hour.
Expert:  Master Auto Tech. replied 9 months ago.

It will actually. The only reason for the exhaust manifold and rest of the exhaust to turn cherry red is because of unburned fuel entering the exhaust system. the usual cause is injectors stuck open. at times it can be extreme fuel pressure, but usually a stuck injector.

Expert:  Master Auto Tech. replied 9 months ago.

Do you still need help with this?
Please let me know.

Did my advice help? If so would you leaving a positive rating for me?
But if you still need help please let me know and I'll continue to help.


Expert:  Master Auto Tech. replied 8 months ago.
Do you still need help with this?
Please let me know.Did my advice help? If so would you leaving a positive rating for me?
But if you still need help please let me know and I'll continue to help.Thanks