We just finished changing the head gaskets on our 1994 Buick Regal with a 3.8 series 1 engine. WE sent the heads to a machine shop and the guy said there was nothing wrong with them. He did replace the valve stem seals. We had the shop to clean the lower intake manifold while he was checking the cylinder heads.
We took the Mass air flow sensor off the throttle body and cleaned it while we had the throttle body off. The only other thing we did was new plugs and wires.

We have had the engine apart for 3 months.

We started the engine just briefly today. It did not want to start at first but the battery was low but would still turn the engine over. We tried to start the engine again after letting the battery charge for a while and the engine did start but was surging.

Is there a certain process one needs to follow for the PCM to set itself up or break in for the cylinder heads since the valves were taken out ?

Thanks
Anna

One more thing. There is a sensor just inside the breather tube where it connects to the throttle body. We do not have the breather on right now so that sensor is not connected.

Also the first time we tried to start the engine as mentioned above, it didn't want to start. It wasn't even trying to fire. Once it did start it did fine starting the 3 or 4 tines we tried during a 30 minute period. W haven't ran the engine enough to warm the engine yet, maybe less then a minute each time..
WE left it sitting for about an hour and when we tried to start the engine, it acted like it did the first time not wanting to start. After letting the engine turn over 5 to 6 seconds straight, the engine fired up and started back each time we started it after that. It is almost like it is not getting fuel at first.

WE still have to change the radiator and we have the thermostat out trying to flush out the stop leak the PO dumped in the coolant and didn't tell us about!

Thanks
Anna

If it'* the sensor in the rubber main inlet air hose, it should be the intake air temperature sensor. If it'* unplugged, the pcm should recognize it pretty quickly and set a code, and then ignore it. It'* mainly used for fine tuning and comparing data with other sensors. If it'* the mass air flow sensor, throttle position, or idle air controller, it'* not going to be happy.

You need to do the idle relearn.

I agree, we need to figure out what it is that'* unplugged.

Thanks for the help!
Yes it is sensor in the rubber main inlet air hose. I just checked RA and it is the IAT? IATS? sensor...

Nothing in the service manual called "Idle Relearn"... Is there any info on how to do it on the forum here?


So we got everything but the hood, coolant reservoir. and air breather, and thermostat put back on today but have some issues... Should I make a new thread or just stay in this one?

Haven't tried driving the car yet but did start the engine several times letting it warm up slowly to burn the oil and cleaners off of everything so it wouldn't catch on fire.
After it quit smoking so bad we let the engine run a good while longer. Below are the known issues right now.

When trying to start the engine:
When the engine is cold or has cooled down for over an hour, it will not start unless you let the engine turn over 5 or 6 seconds maybe a couple more.
Sometimes it acts somewhat like it backfires the first revolution while trying to start the engine and then it starts wright up.
Sometimes it acts like an older car with the timing set way to high making it hard for the starter to turn the engine over but then it starts right up.
Sometimes it starts just fine.

After the engine is running:
When pressing the throttle and the engine reaches 4000 RPMs, the engine starts surging back and forth from 3500 to 4000.

WE don't know much about how was doing before we took it apart but did seem to always start up and did not have the surging problem. It did have some smoke coming out the tail pipe if it sat idling for a while. Good news so far is that we haven't seen any smoke out the tail pipe since putting it back to gather yet!

Thanks
Anna

Ok just read that many of these cars have a rev limiter built into them.. Hope that is what that issue is..
this car also has that chip in the key.

The car will not rev past 4k rpm in park/neutral, that'* normal.

I would look at fuel pressure at this point to see what it is doing.

Idle relearn...Start vehicle (may stall a few times), Block the front wheels and apply the parking brake. Put in drive and let it go until the cooling fan cycles. You are done.

BTW....it'll learn eventually from just driving. It may stall at times during the learning process and can cause an accident if not ready for it.