90 k5 question

[Justin Fleming]

Well I just drove back a new to me 1990 k5, the good old chevy never failed....

Any how two things that came up on the trip

TPS code, a guy suggested it may be out of adjustment. What are te proper voltage readings closed and wide open and if it is three wire what wires am I measuring

The other issue is the idiot brake light is flashing on the dash. Everythign seems good, fluid is full, brake work well..... What is controlling the idiot light and how do I troubl shoot that.

thanks in advance

CK5 Forum Rocks!!

 

[4X4HIGH]

The TPS voltage should be around .54 volts at rest and around 4.7 volts at WOT. Not sure which wires to backprobe.

The brake light is set when the proportioning valve triggers it or when the E-brake is on. Make sure the E-brake switch when it is off is adjusted correctly and if not then adjust the switch accordingly.

 

[rampage]

For the brake light, it might be the ABS sensor malfunctioning. Disconnect it and see if the problem goes away.
http://coloradok5.com/forums/showthread.php?t=302063&highlight=abs+flashing

 

[Justin Fleming]

how about setting the timing on the 1990? What should the spec be and is there anything special you need to disconnect and or plug.

thanks

 

[scooter122983]

There is a brown wire with a plug on it on the left side of the master cylinder you want to disconnect that wire before you start the truck. Then, fire it up(may take a bit of cranking cause this disconnects the spark advance) then set the timing at 0. Shut it down re-connect the brown wire and you're done.

 

[Justin Fleming]

There is a brown wire with a plug on it on the left side of the master cylinder you want to disconnect that wire before you start the truck. Then, fire it up(may take a bit of cranking cause this disconnects the spark advance) then set the timing at 0. Shut it down re-connect the brown wire and you're done.

Is there any advantage of cheating this timing setting to the positive at all like the old carb K5.

 

[scooter122983]

If you want to cheat up the timing you would be better off getting a prom burned for a new spark curve.

 

[dyeager535]

What TPS code are you getting? High or low? I thought TPS was auto-adjusting for TBI?