Item Posts    Sort Order

vaccum issue with crossfire and car is not running well

 
waterman406
I love my Chevy Chevette!
Posts: 1
Joined: 09/11
Posted: 09/03/11 09:10 AM

My crossfire corvette has a aftermarket cam and now the car is running absolutely terrible. I have been told the map sensor is not reading vaccum properly and thus the computer is not controlling the system properly. Is there a chip to overcome this problem or should I install a factory cam  

Post Reply
waynep7122
I mow my lawn and find Chevys
Posts: 1114
Joined: 08/09
Posted: 09/03/11 11:01 AM

first...   i would find or borrow a Obd1 scan tool that will plug into your corvette.. i did put up a post a few months ago on scan tools to work on C4 corvettes...

look in the active posts..
 
that is where to start..

verifying the vacuum hose between the intake manifold and the map sensor is intact.. not spongy.. not clogged..  not leaking..

how did you set the timing????    there is a connector to disconnect to set the base timing..   remember.. that car has full computer timing..  and with the timing connector connected..   if you try to set the timing.. it will be way retarded from where it should be at...

i am away on a repair job right now..  you can dead stick the timing..  by setting the marks on the crank to the proper base timing.. then pulling the distributer cap and rotor..    then turning the housing so the tips of the reluctor line up perfectly with the tips of the pick up coil...   i have been sticking distributers in for years presetting them this way.. i can usually get them close enough that i only have to check the timing.. i don't have to move the distributer at ALL...

please verify the ground wires from the fuel injection harness are properly attached to ring terminals and that those are properly attached either to the intake manifold or back of the heads.. as the computer is ONLY connected to ground via these ground wires..     if they are loose..  or any of the other ground wires between the battery negative and the engine block ,  the battery negative and the chassis.. and the engine to the chassis are intact and properly connected..    if they are not.. you will have different voltage between parts and you will have problems..


did you replace the coolant temp sensor and the pig tail with the newer style.. ??? i have posted this info many times in the various c4 forums on this site.. i will be glad to do it again..  

Post Reply
waynep7122
I mow my lawn and find Chevys
Posts: 1114
Joined: 08/09
Posted: 09/03/11 11:03 AM

here is the link to the scan tools..


http://forums.corvettefever.com/70/8585187/c4-corvettes/which-used-scan-tools-for-82-to-94-corvettes-with/index.html  

Post Reply
TO TOP