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Turns over but wont start till i...................

  
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Turns over but wont start till i...................

 
jmv7428 jmv7428
New User | Posts: 1 | Joined: 11/13
Posted: 11/26/13
08:25 PM

my 86 vette turns over like a pro but wont fire till i advance the timming, then it will start and run like crap till put the timming back. Any ideas?  

wayne712222 wayne712222
User | Posts: 125 | Joined: 10/13
Posted: 11/27/13
12:05 AM

find a scan tool... plug it in.. get into the live data stream...


compare it to this chart...

this chart is printable..
Scandatagm

take a look at the data stream of a corvette L98 going about 60MPH...

C4livedata Zpsad4aa4a5


please... pay close attention to the TPS voltage..

if the TPS voltage is NOT at 0.53 volts with the throttle closed.. you won't be able to start your car..

also look at the engine coolant temp sensor either with the scan tool.. or sometimes.. at the info center near the radio on center..  NOT the instrument cluster that temp gauge is from the sensor in the head.. not the 2 wire sensor in the intake manifold front..



please..  turn the crank and bring the timing marks to what ever the base timing is..  0 or 8.. i forget right now..  its on the sticker..

pull the cap and rotor..    turn the housing slightly to align the tips of the reluctor on the distributor shaft and the tips of the pick up coil..

thats where base timing is going to be at..  you can lock the distributor down...

turning the distributor to get it to start is covering other issues..

can you do me another favor..  with the scan tool hooked up looking at the TPS voltage. depress the throttle several times and release... it needs to come back to the exact 0.53 volts each time...

if it comes back to changing voltages... get out.

grab the left on the throttle body..  open it slightly..  see if the shaft wiggles in the housing bore.. if it does.. you will need to have the throttle body rebushed.. or a replacement throttle body installed that has NO play in the shaft to throttle bore..

what happens.. if your closed throttle voltage is very far above 0.53 volts.. it goes into the clear flood mode..  shuts off most of the fuel injection pulse width..


if you don't have an OBD1 scan tool.. look around the active posts.. i have a post up on scan tools for the C4 corvette...


let me know what you find...  i drop in thru here at least 5 times a day looking for new posts..  

wayne712222 wayne712222
User | Posts: 125 | Joined: 10/13
Posted: 11/27/13
04:33 PM

here is a link to the scan tools post i put up...

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


let us know what's happening..