C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

84 corvette throttle bodies from hell

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Old Jun 6, 2017 | 10:01 PM
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Default 84 corvette throttle bodies from hell

First off replaced fuel pump fuel filter all gaskets on intake and injectors. Replaced all spark plugs. New starter

Starter switch does not work on column so I have to jump with wire. Car starts both injectors spraying. As soon as it starts all the even cylinders spark plugs foul up and engine basically is only running on the even cylinders at full throttle. I have straight pipes and exhaust only comes out left side. Engine code says throttle position sensor but I get a solid 5 volts at wot and .5 at closed. Btw I have spark at all plugs. Please help what can it be.
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Old Jun 7, 2017 | 12:51 AM
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Originally Posted by Jdog91
As soon as it starts all the even cylinders spark plugs foul up and engine basically is only running on the even cylinders at full throttle. I have straight pipes and exhaust only comes out left side.
The "even" cylinders are on the right (pass.) side. Exhaust is from left side only? If both throttle bodies are spraying, why are you blaming the throttle bodies? There's something wrong with this evaluation.

Has this engine been apart recently? Has it ever run correctly?

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Old Jun 7, 2017 | 05:23 AM
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TPS should go from about 0.5 Volt to 4.5 Volts.

Firing order correct?



Last edited by JoBy; Jun 7, 2017 at 05:25 AM.
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Old Jun 7, 2017 | 07:50 AM
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Double checked if not triple checked.
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Old Jun 7, 2017 | 07:54 AM
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In reply to hot rod Roy yes this has been apart I cleaned the throttle bodies countless times car was sitting for 4 years but was running fine before. Could the security somehow be causing this?
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Old Jun 7, 2017 | 07:55 AM
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And by even I meant odd cylinders .
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Old Jun 7, 2017 | 10:01 PM
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somebody drop a rag down the intake manifold?
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Old Jun 7, 2017 | 10:04 PM
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what are the symptoms of a towel in the intake
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Old Jun 7, 2017 | 10:10 PM
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. Engine light on but doesn't show any codes even when I unplug a sensor nothing. Btw wipers don't work and horn doesn't work either. No power to radio either.
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Old Jun 8, 2017 | 02:50 AM
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Originally Posted by Jdog91
. Engine light on but doesn't show any codes even when I unplug a sensor nothing. Btw wipers don't work and horn doesn't work either. No power to radio either.
"Check Engine" light and not showing any codes indicate that ECM is running in "Linp Home" mode. Then it will definitly run like crap. Also not many sensoes are used.
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Old Jun 8, 2017 | 02:58 AM
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From fist post:

Engine code says throttle position sensor
Do you get cosed or not? How do you check codes? Paperclip?

Also ...
* Starter switch does not work on column
* wipers don't work
* horn doesn't work
* No power to radio

Could be random but seems a bit much.
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Old Jun 8, 2017 | 08:14 AM
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I have a code reader that I plug in and it flashes the check engine light. Not sure why it sometimes throws that code and sometimes doesn't. How do I get out of limp home mode?
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Old Jun 8, 2017 | 09:05 AM
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Some Cross-Fire information:

http://www.pcfred.com/Vettetip/ECM%20troublecodes.htm
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Old Jun 8, 2017 | 11:24 PM
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Update: some engine grounds might be shot. Hooked a ground wire directly to metal on wipers and now they work. Car was sitting on grass for some time.
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Old Jun 9, 2017 | 12:43 AM
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Originally Posted by JoBy
"Check Engine" light and not showing any codes indicate that ECM is running in "Linp Home" mode.
It is virtually impossible to get into "limp" mode. It only happens when the microcontroller stops executing program code and the "watchdog" kicks in.
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Old Jun 9, 2017 | 09:29 AM
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Originally Posted by Cliff Harris
It is virtually impossible to get into "limp" mode. It only happens when the microcontroller stops executing program code and the "watchdog" kicks in.
I agree, but if you have an active "check engine" light you should be able to read error codes unless it is in "limp" mode.

At least it should flash "12".
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