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

1986 Service Engine Soon Light

Thread Tools
 
Search this Thread
 
Old 12-21-2006, 10:07 AM
  #21  
Muffin
Race Director
Support Corvetteforum!
 
Muffin's Avatar
 
Member Since: Jun 1999
Location: Merritt Ils Fl
Posts: 14,924
Likes: 0
Received 9 Likes on 7 Posts

Default

Originally Posted by RRT vette
To clear the codes...disconnect the neg side of the battery for ~30 seconds or pull the ECM fuse. This will erase anything learned in the ECM as far as fuel trims, ect. They will have to be relearned, but barely noticable to us.
If you disconnect the ECM connector near the brake booster codes will be cleared but the ECM not otherwise effected. If you can't/don't find the ECM connector remove the neg battery terminal. It really won't make that much difference.
Old 12-21-2006, 07:42 PM
  #22  
digits
Heel & Toe
Thread Starter
 
digits's Avatar
 
Member Since: May 2006
Location: Inland Empire California
Posts: 15
Likes: 0
Received 0 Likes on 0 Posts
Default

rick lambert, which switch is it are you refering to? I looked it up online and there is a temp switch, a relay(delay?) switch, and a position sensor. Thanks
Old 12-21-2006, 10:24 PM
  #23  
Aggravated4life
Race Director
 
Aggravated4life's Avatar
 
Member Since: Aug 2000
Posts: 14,130
Likes: 0
Received 7 Likes on 7 Posts
Cruise-In II Veteran

Default

On back of the passenger side engine,is a metal tube that has a foil looking wrap around it,it comes off the exhaust manifold and curves up over the valve cover and bolts to the back of the intake manifold.Thats the egr feed tube.

On that pipe,on top of it near the distibutor cap,theres a white switch with a black wire...thats the egr temp switch.They can crack and twist out some and throw the code.

The wire itself is screwed into the switch...the switch is screwed into the pipe...you should not be able to unscrew the wire from the switch if its not cracked..if the wire is loose inside the white part of the switch,thats a sure sign its bad too.
Old 07-29-2018, 11:00 AM
  #24  
Lydon Gree
4th Gear
 
Lydon Gree's Avatar
 
Member Since: Jul 2018
Posts: 4
Likes: 0
Received 0 Likes on 0 Posts
Default

i have same issue the service engine doon light came on for few minutes then i accelarate and went off , could be the ecu aranged the fault because it didint came on agine or there was high emmisions and it was cleared , thanks
Old 07-15-2020, 07:28 AM
  #25  
chevy john
Cruising
 
chevy john's Avatar
 
Member Since: Jul 2018
Posts: 11
Likes: 0
Received 0 Likes on 0 Posts
Default Hard start

I had the intake gasket replaced and I get the same problem. Hard start when first starting and the light comes on. I drive it for a while, shut it off, then restart and the light is off and starts good.
Any Answers?
Old 07-19-2020, 09:46 AM
  #26  
coupeguy2001
Le Mans Master
 
coupeguy2001's Avatar
 
Member Since: Sep 2006
Location: Phoenix AZ
Posts: 6,043
Received 144 Likes on 106 Posts
2021 C4 of the Year - Modified Finalist

Default Ses light

I have the same thing. 86 early.
changed the pump relay for hard start, Nothing changed.
put gauge on fuel rail, it was 40, going to zero when shut off. then changed fuel press diaphragm and now it does that.
took diaphragm back, got another new one, still hard start first start of the day.
pressure 42, pull vac hose, 48.
irregular idle.
dropped pressure to 38, and idles better, doesn’t take as long to start,
but i noticed there’s no pressure at gas cap when getting gas.
so i ordered a fuel tank pressure regulator.
all tjis stuff is rubber or plastic.
it doesn’t last forever



Quick Reply: 1986 Service Engine Soon Light



All times are GMT -4. The time now is 11:43 PM.