Kauai 93' Yota

Aloha All,

I recently added some R134a freon to my system and did everything correct. Gauge in the green and the A/C blowing cold. The problem im having is that when im driving and start pressing on the brake or come to a complete stop, the engine starts to surge...

But when the A/C is not on, the truck idle is perfect and no surging what so ever. The last couple days i have been driving, I just click the A/C button off when coming to a stop lol.

My question is, has anyone experience this??? and if so, how did you fix it?

As far as im concerned everything is original and was retro fitted to r134a. A/C hasnt ran in this truck for atleast a couple years until I just added freon.

Any tips, tricks, or advice will help! Also I know i will probably have to replace the full ac system, anyone knows where I can buy a full kit?

Mahalo!

aztoyman

I've seen problems with the adjustment of the Idle up valve on the intake. (idle set too high) Also surging caused by the IAC valve sticking. But stepping on the brake makes me suspect a vacuum leak at the booster or hose. Turning off the A/C making the problem go away kind of rules this out though. Look into these three things I mentioned. Good luck with it and please follow up with what you find.

Discombobulated

I have read many threads on this and still I have the same thing since I installed AC, booster isn’t leaking, no vacuum leaks. Same issue, brake pressed it surges with AC on but mine only does it when cold and warming up, once it gets warm all is good, which makes less sense I guess

I did have the surge all the time until I messed with the idle up adjustment, you may try that as suggested above as it’s the easiest thing to start with.

Kauai 93' Yota

Whats up guys,

So this morning I did a cold start and immediately blasted the ac on high. No surging what so ever. I had it going for about 5 minutes before i noticed the ac clutch starts turning off and on (completely normal). Whole time ac is blowing cold.

Once the rpms went to normal, I pressed on the brakes and here comes the surge lol.

I went ahead and located the black knob which is the ac idle up valve. I went to turn it counter clockwise and noticed it was kinda seized/stuck. So i just wiggle turned it a few times and it budged. From its original position I turned it a couple times counter clockwise... went in the truck and pressed on the brakes. It kept doing the surge.

Then I turned it back clockwise to the normal position and pressed the brakes again... still surged.

I gave it three full turns clockwise and boom.... pressed on the brakes and the surging disappeared.

Turned it one time counter clockwise after. Pressed on the brakes and the surge is not there. Closed the hood, went for a quick 2 mile drive, stopped a few times, pressed on the brakes, and the idle is now perfect and no surge.

Basically gave my idle up valve two full turns clockwise.

Thank you discombobulated and aztoyman for the tips🤙 Now i can enjoy some cold A/C in this hot weather here in Hawaii.

Discombobulated

Glad you got it sorted, I’ve learned to live with mine surging until warm. One day I may really dig into it…….one day