SoulShadow

I recently swapped the motor in my 92 pickup. The old motor had a blown cylinder, and we happened to have another 22re sitting around that we weren't using (how often do you say that?). The newer motor has about 30K on it, and is a custom LC Engineering job. Not a damn thing wrong with it. So here's my issue:

After the swap, on first crank the idle was surging (continuously revving and lowering), but we figured the computer would adjust it out. We were a little wary, since the motor is obviously not stock, about whether the computer would be able to handle the new setup without some major adjustment. The last truck this motor was in was a 22r with a carb, even though the motor itself is a 22re, so it's built for fuel injection setup anyway. As far as I can remember, the heads have about 2K worth of work done, the block may have a slight bore and I think there's a stage 2 cam in it. On the other truck, the little bit of cam work on this motor has a heavy cam noise. After initially cranking it and running it around the house and up and down this dirt road, the idle quit surging and the computer seemed to have everything eased off. The only thing it was doing was idling up to compensate for the cam. Fast forward two weeks...finally got tags on the truck and drove it to work yesterday. Since then, the idle has gone back to surging and we're not really sure why. We thought maybe it was a vacuum leak, but if it was, it should have continued to surge the whole time, right? We know we need to adjust the timing, but we're not sure exactly where to start looking for other issues. Any ideas?


OK--- Update.
I lied. Now when you press the brake pedal, the idle bogs down. Sounds like a vacuum leak, but why would it start all of a sudden after having it on the highway for the first time? Again, this didn't start until after driving it on the highway. It was idling fine driving it under 30 mph up and down the dirt road at the house. Now I have idle surging.

Flash319

The surging idle could be a few things. The reason it was doing it when you first started is because the coolent had not got to the cold idle valve under the throttle body. This causes the idle to be to high and the ECU keeps cutting the fuel off and on. Your TPS must be set up properly or your idle will never be right as well.

Your brake pedal idle issue may be your EGR valve stuck or a vacuum leak somewhere. Steps I take for good idle:
1. Make sure throttle plate is closed (if someone has been screwing with the screw on stop)
2. Setup TPS
3. Make sure temp sensor is working
3. Set timing (with pins jumped TE1-E1 timing should drop, if not your TPS is not adjusted right)
4. Make sure engine is warm and adjust idle (screw on top of throttle body) to under 1000rpm (I run around 1000 at idle but manual says 750. Anything under around 1100 and you are okay). If idle is to high at operating temperature the engine will surge at idle (fuel cut).

Before any of that make sure your intake track tubing is not leaking. Idle on these engines is somewhat erratic because it is controlled mechanically with engine coolant not computer.

SoulShadow

Well, after doing some reading yesterday, here's where I can fill in a little more information:

1: There is a whole bunch of crap floating around the coolant system, so I may have a blocked AAV, but can't check that now.
2: I also understand that a bad ground may cause it to do the same thing and The ground cable for the battery needs replacing fairly badly, which is most likely where the brake pedal results comes from. The battery is in questionable shape and the truck tried to strand me yesterday. While hitting the throttle in idle, the battery light was coming on, so the brake pedal issue is likely from load on a bad battery.
3: The butterfly has already been adjusted and is almost fully closed
4: TPS has no issue
5: Temp sensor is fine
6: The timing needs to be adjusted, but because of the stretch before highway driving was running fine. I'm not convinced on that one.

Thanks for the suggestions. Will update when I track it down.