1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

exhaust overheating

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Old 10-19-09, 07:05 PM
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Lightbulb exhaust overheating

I am working on an 85 rx7 with a 12a engine. I have owned it for awhile now and got it started for the first time in about a year. I had it ideling while I checked stuff out under the hood and started to see smoke. By the time I figured out where it was coming from my exhaust system all the way fromt he manafold to the exhaust tip was beat red and small flames started coming off of it. i was told the timing or to lean of fuel mixture could do this. So I was hoping to know if I should start by checking the timing or fuel mixture or if it would be somthing else. Thanks for any help
Old 10-19-09, 07:22 PM
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Originally Posted by odden
I am working on an 85 rx7 with a 12a engine. I have owned it for awhile now and got it started for the first time in about a year. I had it ideling while I checked stuff out under the hood and started to see smoke. By the time I figured out where it was coming from my exhaust system all the way fromt he manafold to the exhaust tip was beat red and small flames started coming off of it. i was told the timing or to lean of fuel mixture could do this. So I was hoping to know if I should start by checking the timing or fuel mixture or if it would be somthing else. Thanks for any help
they all get verry hot but you should not see flame or smoke,by chance have you used any type of goop on the exhaust,oh and where do you live in WA, I live in spokane and love to meet other's with 7's here
Old 10-19-09, 07:24 PM
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Im from OR and I know they get hot but its was red like a bright shiny red apple
Old 10-19-09, 07:53 PM
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mabie your timing is way advanced
Old 10-19-09, 08:46 PM
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Check your timing, then your fuel system if the timing is okay. Often its these two issues, the FSM contains the information for timing and proper fuel delivery.

If it ends up being the carb delivering too much fuel you might be looking at having to rebuild it.
Old 10-19-09, 08:54 PM
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No it is not normal to have the exhaust glowing red. It is too lean either by a vacuum leak at the carb or intake or the timing is off.

Easy enough to first check the timing then check for vacuum leaks.
Old 10-20-09, 09:33 AM
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Yep, you probably either lost your leading spark, or the timing is very retarded. Most likely cause anyway. Good luck.


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Old 10-20-09, 04:52 PM
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Ok iv decided to check the timing I have looked and looked for the two notches I found one of them but cant find the other. I dont know much about cars but from what I think I know both notches should be right next to each other right? Any help would be cool
Old 10-20-09, 05:51 PM
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To see the seperate marks you have to be on t1 to see the trailing and l1 to see the leading mark leading is on the bottom and rotor one is closeset to the headlights
Old 10-20-09, 08:05 PM
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That"s why every member who chooses to work on their vehicle should down load a copy of their year FSM. Copy and paste the link in my signature and down load a copy. All of this basic trouble shooting and info is in the FSM.

Originally Posted by odden
Ok iv decided to check the timing I have looked and looked for the two notches I found one of them but cant find the other. I dont know much about cars but from what I think I know both notches should be right next to each other right? Any help would be cool
Old 10-21-09, 08:25 PM
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Originally Posted by Rx-7Doctor
That"s why every member who chooses to work on their vehicle should down load a copy of their year FSM. Copy and paste the link in my signature and down load a copy. All of this basic trouble shooting and info is in the FSM.
hey doc you know i have a hanes book but it really dosent cover my 85 gsl-se verry well any ideas of a book JUST on my year model of car,Since i have the fuel injection the books never seem to cover my car verry well
Old 10-22-09, 10:43 AM
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Check the appendix in the back for updates.
Old 10-22-09, 12:57 PM
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Originally Posted by chris rx7 gsl-se
hey doc you know i have a hanes book but it really dosent cover my 85 gsl-se verry well any ideas of a book JUST on my year model of car,Since i have the fuel injection the books never seem to cover my car verry well
Haynes books are OK for simple things, but the Factory Service Manual (FSM) is far better for anything critical.

I have both a Haynes and a Petersen for my first-gen, and both are full of my pen changes and corrections over the years. The FSM is far more accurate.

The timing marks on the e-shaft pulley should be about an inch away from each other. Locate them visually with the engine off first, and make sure they are not clogged with dirt or haven't been painted over or some such.

Also, make absolutely sure your ignition wires, both the plug wires and the wiring for the coils, has not gotten swapped around. If you have leading and trailing swapped anywhere in the system, it's just about impossible to get things timed right.

Finally, make sure your distributor cap and rotor are in reasonably good shape and on straight. A broken or damaged dizzy rotor will lead to misfires that pour raw fuel into the exhaust.
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