Mitch91Z28

okay Ive had my service engine light on for a little while. The scanner i borrowed said code 43-spark control module failure. Also when I start my car no matter the temp or conditions the engine revs up to 2000-2500 and stays for 5-15 seconds and my tachometer bounces around sometimes but usually stays at 0 like the engine is off when its not. my engine idles at 900-1000 rpm in drive. Is This a bad spark module( is this also called an ignition control module?)? also at the checker they asked if i had an electronic distibutor. My car is a 1991 z28 vert w/305/auto
Any help is appreciated

Gramps

iTrader: (1)

replace the module, its the part of the distributor where all the wires plug into, its kinda pricey but worth it. you can get the parts # from your dealership, and either order it from them or go to your local parts store and get it there...

Mitch91Z28

Alright I replaced the ignition control module. The tach works fine now. The service engine light is still on code 43 I tried to clear the code with the Checker Auto scanner, the scanner said vehicle is not responding. and disconnecting the battery did not work. also it still idles a little high like 900-1100 in park but i did accidentely disturb the distributor while replacing the module so i will reset base timing tommorow. Is it possible that the problem is elsewhere? I know that my cruise control and heater/ac controls vacuum lines are not connected i cant find where they plug in to the intake. Any help is appreciated, This is my daily driver right now and i need it running right.

Gramps

iTrader: (1)

well if your running high on RPM and your vac lines arent hooked up then thats why...youve got a vacuum leak. i dont know about your heater/AC controls, but the cruise control comes off a small nipple at the back of the plenum on the passenger side (right beside the vac line for the fuel press regulator). that tube goes under the plenum and comes out the drivers side and goes to your cruise control vacuum and that ball thingy (i dunno what its called but its literally a plastic ball about 6" in diameter).

to clear your codes, near the battery there should be an orange wire with a connector, thats the power for your ECM. disconnect that instead of disconnecting your battery (so you dont lose your radio station settings). its bright orange and has a big connector so you cant miss it.

Mitch91Z28

okay i plugged my cruise vacuum line in i could not even find the line for my ac/heater controls, there isnt even a line behind the controls in the dash. while i was driving home from work today my tach started bouncin around a little. and i still have a service engine light. i still idle at like just under 1000 rpm and it still revs up to 2k rpm when i first start it and takes like 10-15 seconds to come down. also, every once in a while my car will get a boost of power like something was kickin in. hard to explain its like no change in throttle and it will kick and start pulling harder. I read some where these tpi engines have problems with their intake gaskets leaking oil and such. Could that cause my high idle and oil burning smoke on startup. I do see some oil sitting on the intake near the intake\head mating surfaces. Please help this is frustrating!
-Mitch

ajk511

looked it up on ll data. check your knock sensor. should read 5 volts. if not then replace your knock sensor. if you KS is fine then replace the mem-cal in you ECM. thats what the flow chart said. i've had code 43 on my 91 z for a while now too. not that big of a deal.