Frequency Valve, (or fuel timing valve)

dailyATX82sc · 10-14-2009, 11:29 AM

so i think mine is toast!.......I think the valve was for some reason "stuck on" even with out the key in it was buzzing from the eng bay right by the throttle body. Now it does not make ANY noise, key in or out or on.

2 questions:

1: can i test it, and how?
2: what would cause it to be stuck with power. I have replaced the relay under the pass seat ( that got wet along with the ecu, see other thread)

last sat i have the A/F all nice and adjusted and timing set just right...then i hit a puddle and get some stuff wet, now no run........

ARGGGGG

john walker's workshop · 10-14-2009, 11:33 AM

maybe the relay was sticking. a wet control unit is not good. pull the cover and see if it's all corroded up. the control unit works the FV, but you probably knew that.

Peter Zimmermann · 10-14-2009, 12:06 PM

Yep, wet is bad. I remember a beautiful, low mileage, well-maintained '81 SC that my shop took care of. It was parked under their condo in an underground basement area, which flooded. The water barely reached the lower door edges, but the floor and electronics inside the car got soaked. The car was towed to our shop, the owner filed an insurance claim, the insurance adjuster came to the shop, saw the damage and totaled the car on the spot.

We were dumbfounded, and asked why. He said it was company policy to total any vehicle that suffered water damage to "sensitive" electronics - it was not worth future/hidden costs to try to fix the car. I tried to buy the car, but it was towed away and we never saw it again.

One piece at a time; as John said, make sure the inside of the ECU is clean & dry. Then try to isolate the power to the relay and the Freq valve, and don't forget to check grounds. Remember to lift the sensor plate/arm slightly, with ignition on, to make the valve buzz if all is well.

john walker's workshop · 10-14-2009, 02:21 PM

the relay gets power from the dome light fuse. if the lights work, don't bother looking there.

dailyATX82sc · 10-20-2009, 06:02 AM

im still stuck with what to do next on this deal, i have a new valve on order but dont want to replace it if i dont need to.

how do i test my old one??

also how do i open up the ecu/brain...it looks crimped??

psalt · 10-20-2009, 06:15 AM

Does your engine run ?

The test port for the lambda system is under the plastic cover on the left of the engine compartment. All you need is an analog dwell meter and a few minutes reading the posts on this list.

don gilbert · don gilbert's Garage

your freq. valvle is prob. ok. Can you feel the relay clicking when you turn the ign. on? Check voltage to the relay, one is 12v constant, one is 12v switched. The ecms on these cars are pretty tough. Look and you will find the screws that let the circut board slide out, toothbrush it clean and let it dry out. Clean the grounds good (with sand paper) under the seat while your there.

don gilbert · don gilbert's Garage

one more thing, your freq. valve is your source of enrichment when you go past the 35 degree throttle switch, you are in a very lean situation at full throttle with it not working.