Diego toyota

Good day to one and all ! There is a question I would like to ask, hoping someone
out there can guide us in the right path. Thanks. My son bought his 1st 92 yota, 22re and
is excited, as I once was when I bought my own. The only difference is, 4x4, cold
AC and power steering, which is great. The problem we are having now is, when
the engine is warm, and your foot is on the brake, the engine surges. If and when the AC is
on, the surging stops. Basically, if we had no AC, we would be surging all Day. Can someone
help? Thanks.

Neemox

Can't be too much help yet, other to say that this sounds like an issue that people have all the time. Have you noticed that your idle is also higher than it should be? (Idle should be approx. 800 or so, depending on your truck).

I have the same problem right now and am chasing it down. There are lots of topics on here about "idle surge" with and without brake. Try a search for that, but what you are going to find is a laundry list of things it might be :

Improper TPS,
Vacuum leak
Bad/dirty IAC (this one seems to usually be the answer)
Miss adjusted AC idle up (I don't think this is your problem, even though your AC is related, I think the AC is just masking the underlying problem)
Bad timing
Bad EGR
Dirty/ leaking throttle body.

That's usually the list, but like i say search on here.

Subscribed to see what the resolution is! Good luck

ev13wt

Adjust your idle.
What is happening is that the fuel cut is kicking in.


Old throttle cables can bind / Stick and then the valve won't close to spec giving you a very slight high idle, enough for the fuel cut to kick in. Somtimes blipping the throttle a bit lets the cable release all the way - so you have the surge intermittently.

Diego toyota

Thanks. I have tested the brake booster. I have taken an cleaned both throttle body and IAC. Will
continue searching, thanks again. Yes, I do notice the idle is higher than normal when the AC is
turned off.

Neemox

So, last night I figured out my problem. This is not necessarily your problem, but it was mine.

My throttle stop screw was not adjusted properly, so my TPS was not adjusted properly, so my idle was not adjusted properly, so my timing couldn't be set properly...

The rule is, "Don't touch the throttle stop screw!", Unless of course, it's set wrong. My butterfly valve was open just a bit leading to the high idle. Yours may be throttle stop screw, or dashpot screw (M/T), or a leak in the throttle body, or a bad mass air flow, or anything else that is letting air into the throttle body while it is supposed to be at idle.

I'd check all those things. The surging is just because the computer can't find idle, which it won't be able to do if there is excess air coming in making your idle high (or any of a bunch of other reasons)

Co_94_PU

iTrader: (-1)

Always start with verifying the base idle speed with the test jumper in place. If you can run the idle adjustment all the way in and not get below spec, proceed with inspecting the throttle body's throttle plate. Check the plate always returns to the same position regardless of how fast you close the throttle. If it's not reliable check the throttle plates not loose in the housing, then try disconnecting the throttle cable, and finally remove the dashpot (if the filter failed it causes issues)... Finally check the tps adjustment (it should be throwing a code if idle contacts are not closed), then look for vacuum leaks behind the plate and then clean and test the idle/aux air valve.

If your idle screw works as expected maybe skip right to the AC idle up RPM adjustment.

...
The VAFM will not have any effect on idle speed but your ignition timing will.

Diego toyota

Good day to one and all.I took the throttle body down and cleaned it. One of the egr vacuum hose was off,
Connected that and it was on It is a Toyota. Thanks to all the input and information.