check engine light still on

Asked by Feb 04, 2016 at 11:56 AM about the 1986 Chevrolet C/K 10 Scottsdale LB RWD

Question type: Maintenance & Repair

So i purchased this 1986 c10 scottsdale fixer
upper, did a carb rebuilt, valve cover gaskts, fuel
pump, battery new, thermstat new, hoses, radiator,
condenser, tranny radiator and so all parts brand
new seems like it runs great iddles funny n yet
smooth at times. But my check engine light still
on? Ive been researching and ive heard solenoid
control module ive heard n read it could be oil
pressure switch will make it go off or even my
CHOKE THERMOSTAT. And how do you check for
codes? I plugged a paper clip from A to B when
truck was off then turn on and nothing, did it with
truck ignition lights on panel on and nothing and
then i did it with truck turned over iddling at norm
at still no blinks? HELLLLLPPPPP  please
someone, its a california truck so it has to pass
smog and so it will not with the check engine light
on? Only 57,540 original miles on it. Bought from
first owner.

5 Answers


I would check the EGR valve and system, can cause these symptoms. And it sounds like there is no power at the ALDL connector to get the CEL to flash a code for you. Power a lot of times come from the cigarette lighter circuit. I would start there.

Ok ill double check thanks. The aldl has only 7 wires connected out of like 16 but no other wires are hanging or cut off. The old Gent. That owned the truck never messed with any wires when ever it needed service he took in. Fyi


Thats all the wires there are on that, not all the locations have a wire running to it.

Before the whole tune up on wire harness, my lights were working but after doing wire per wire no my dumb lights wont turn on with the switch. Only when i brake or when i signal theys will but like i said not with switch..... so frustrating


I should mention they didn't standardized OBD1 until I think around 90'. 1996 then standardized to the OBDII ECU to what is in all cars and trucks today. What I am saying I am not up on the old computers.

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