skip myles

i have a 85 vett low milage changed tps set at .54 car runs great for a few trips then starts to idle high have to reset tps i was told that a bad ground to ecm would cause this also had to run ground to heater fan for it to work what do yall think

gerardvg

Hi

I would start by checking the throttle body returns and does not bind, the exhaust gas recirculation valve check it doesnt stick open.

Check for any vacuum leaks at the tpi inlet manifold, vacuum hose to brake booster and vacuum lines.

Set the base idle, see below.

Note auto trans needs to be in park, manual trans in neutral.


See the link below, it has a good easy to follow base idle setup procedure.
Note. There have been revisions to the base idle speed, a service bulliton now recommends 500rpm base idle setup. Perhaps try the 500 rpm base idle setting.


https://www.corvetteforum.com/forums...dle-speed.html

Good luck

skip myles

sorry couldnt get back but i have set tps and idle, timing several times checked and rechecked have used vacum gauge and everything checks ok but i have lost ground to blower motor and thought it maybe the same ground as the ecm causing bad signal thanks

I would start by checking the throttle body returns and does not bind, the exhaust gas recirculation valve check it doesnt stick open.

Check for any vacuum leaks at the tpi inlet manifold, vacuum hose to brake booster and vacuum lines.

Set the base idle, see below.

Note auto trans needs to be in park, manual trans in neutral.


See the link below, it has a good easy to follow base idle setup procedure.
Note. There have been revisions to the base idle speed, a service bulliton now recommends 500rpm base idle setup. Perhaps try the 500 rpm base idle setting.


https://www.corvetteforum.com/forums...dle-speed.html

Good luck [/QUOTE]

Cliff Harris

The blower motor and all the engine sensors use G104 as their ground. Depending on the year, it is either on the side of the block above the oil filter or on one of the bell housing bolts.