I am out of ideas (other than hauling the rig to the local dealer) on how to fix this code 22 problem. What I have done/checked thus far:

Disconnected connectors on ECM and temperature sensor:

• Verified wire connection between connectors' pins on both wires (10 ohms end to end)
• Verified no short between wires ("overload" or infinite resistance)

Checked, replaced, and rechecked temperature sensor:

• Both the new (2.9 K-ohm) and the old sensor (3.0 K-ohm) is within specification for the temperature (68 F).

Verified resistance measurement of the sensor, installed, as measured at the disconnected ECM connector.

According to the repair manual schematic, there are no other loads on this circuit and therefore no other components that should affect operation.

With the ECM connector connected, the voltage specification on the sensor wire (THW-E2) was OUT OF SPECIFICATION (0.2 to 1.0 V).

• I replaced the ECM.
• The new (used) ECM has exactly the same behavior (same voltage at the pin, same diag code flashing on the dash: 22; yes, I reset the code each time).
• Reliably measured either 0 V, or 2.5 V on each of the two ECMs, depending on the phase of the moon (yea, I know...). In every case, the code keeps coming up 22.

I figure the probability that the two ECMs are both faulty with exactly the same problem is about zero. I can find no information on what might cause an ECM to run funny. I can't find a schematic diagram for the ECM to see how the voltage is sourced/measured on THW.

Other Important Information: the engine does not run correctly. We just rebuilt the entire 3VZE as a Father/Son project (we bought it broken: broken piston rod, main bearing cap, head gasket, and more). It will start (kind of) and chug along at about 300 RPM. It will not accelerate past that. I don't think that this is due to the temperature sensor, but thought I'd clear all the error codes before moving on. Thus far we have replaced, adjusted and verified: distributor, airflow meter, throttle position sensor, EGR temperature sensor, temperature sensor, and ECM. We have cleared all codes thus far (24, 31, 32, 41) excepting 22.

Most of the measurements/connections have been checked at least three times, mostly because it simply doesn't make sense and it seems that I must be missing something.

 

Your low idle sounds like a vacuum leak. Check and recheck all vac lines are plugged in correctly. I deleted my EGR and left a bolt out that was actually the cause of my leak. I have the notes in my build thread.

The code 22 is what the ecu depends on to monitor engine temp and regulate idle when cold or warm. Timing set correctly? Did you jump the diagnostic port for timing set?
Mudhippy is the absolute business when it come to the 3.slo, he'll probably chime in at some point. I've learned heaps from that chap about these engines.

 

You probably noticed, but the voltage between THW and ground is only relevant when the engine is warmed to operating temperature, so if you were measuring at different temps that could explain your different readings from what I get out of the FSM.

Also do you mean to say that you get 10 ohms of resistance, that is when you jumper the wires where they would plug into the ECU and measure ohms where the plug into the sensor? If so, that seems like an extremely high reading for a short run of wire.

On the bright(ish) side, the temp sensor is unlikely to cause anything but failure to go into closed loop operation, and not the symptoms you describe. Personally, I would focus on the bigger picture, getting it driveable at all before tinkering with things which only affect optimum operation. Checking fuel pressure, compression, spark and vacuum leaks, as RBX said. Good luck.

 

Thanks for the responses...

1. 10 ohms. Better said would be near zero. I was too lazy to set the range to ohms, so the meter auto-jumped between ranges. In short (no pun intended), there is no reason to believe there is a break in the line.

2. Timing. Well, it really isn't running well enough to time; I can't get it up to normal timing RPM and can't hold it constant. So, it sits on the marks (0 TDC, alignment marks to distributor). I don't doubt that the timing is off a couple of degrees, but that probably isn't causing problems this bad (more below). Loosening the bolt and rotating the distributor through the range makes no observable change in how "well" it runs.

3. Fuel pressure. The pressure is generally correct. Meaning it is up to full pressure (top of acceptable range) and sticks there when running, but I didn't check for a proper drop when engaging the vacuum line on the regulator.

4. Vacuum leaks. Sigh. The tricks I know for finding a vacuum leak are problematic in that -- for instance -- squirting carb cleaner around doesn't change how the engine operates when it isn't operating. I've visually checked and rechecked all the lines and there is nothing obvious missing. I have not checked the VSV's for correct function, thinking that those might keep it from "optimal operation," but probably wouldn't make things this bad.

5. Spark. Oh I wish I had one of those really cool diag machines for this one. There is spark, and plenty of it. Whether it comes at the right time or more importantly comes consistently for every cylinder I don't know. There is no corona around any of the wires or sparking (when it is completely dark in the garage, the engine compartment has less light than a black hole).

6. O2 sensor. Since this thread is taking a turn towards the more severe problems, I should add that the O2 sensor is connected, but not physically attached to the exhaust line. I'm trying to get it running before hooking up the exhaust to the headers.... At least is sounds cool :-)

7. Compression. Newly honed cylinders, new pistons, new rings, rebuilt head. Didn't check. Feels as expected when manually turning crank through 720 degrees when I...

8. Checked and rechecked timing belt alignments. Tis good.

In terms of "how bad" is bad:

a. It won't idle at the idle setting. It requires some displacement of the throttle (say 10-20%).

b. Too much throttle (say 50-60%) will kill it.

c. Running it long enough to warm even a little makes it impossible to restart (it will begin to run, but cuts out as soon as the engine light comes on within 2 to 5 seconds).

d. Squirting anything into the vacuum system will kill it.

 

Well, you've covered most bases. Hard to hear an idle up without vacuum on the regulator if it isn't running well either. You did check those PITA valve clearances also during the rebuild? For vacuum testing, short of dropping a grand on a smoke machine, you can try the youtube videos showing how to build your own, or this thread has a nifty trick which I've never tried but should work. http://www.bimmerfest.com/forums/sho....php?p=5165240

Definitely interested to hear the solution when you figure it out.

 

i'd hook up the O2, just to eliminate that.
You could be 180 out of TDC, I've done this. I thought i was just a few degrees off of TDC but i was 180.

Most of my complex problems turn out to be simple mistakes.

good luck

 

Well, it is difficult to imagine that I missed this one. The crack was hiding underneath the o-ring. This goofed up the alignment marks, which put the distributor off by I don't know how many teeth on the gear.

The engine is now running and sounds great.

Thanks again for all the recommendations.

(continued, below)

 

Kudos to jbtvt for the recommendation on vacuum testing!

The idea is simple. This is how I executed it:

1. Hooked up garden hose to my whole-house vacuum cleaner (which put the noise as far from the garage as physically possible).
   
2. Hooked other end of hose to the PCV hose on the driver side (blue arrow in pic).
   
3. Put duct-tape on the connections and on the hole into the valve cover (white arrow).
   
4. Put a plastic bag around the air filter (red arrow) and put it back and locked it down for an airtight seal.
   
5. Jammed a screw driver into the throttle mechanism to hold it open (probably unnecessary, but why not, it's easy).
   
6. Used a piece of silicon hose stuck into my ear to fish around and listen for leaks (worked better than my stethoscope).

Found a leak on the hose that tucked under the air plenum (naturally, I would have to remove the plenum to fix the one leak).

After replacing the hose, I then sought out a lesser leak that was difficult to find due to sound bouncing off various intake pipes. The dipstick was not fully seated.



That was it. Neither fix made a bit of difference on how the engine worked at the time, but might just make it feel better about life now that it does.

This was so incredibly simple. I will never squirt toxic chemicals around the engine compartment again!

The only part that didn't work fabulously was trying to start the engine after the exercise with the plastic bag still over the air filter. Duh.

Again, thanks jbtvt!!!

 

Great, glad to hear it. And congratulations!

 

O.k...but what about the code 22? That's what's still got me

I've got nothing to explain that one. Other than to add that there's a lot of good info explaining and describing ways of testing the ECT sensor, the ECT-THW circuit, and/or the ECM for faults found here: http://www.autoshop101.com/forms/h32.pdf

 

The code 22 issue is solved.

It was a bad pin (female side) on the ECM connector. Read on...

Using the method prescribed in the Toyota shop manual, I probed the back (wire side) of the connector while plugged into the ECM. The problem is, when thus probing, it forced the pin to make contact, resulting in no defect found.

Naturally, swapping ECMs, and sensors made no difference.

I discovered this by tearing apart the connector on the temperature sensor and measuring the voltage from THW to E2 while connected to the sensor. It was 0.0 V. Measuring THW to E2 on the back of the ECM connector registered 5.0 V. Measuring the resistance between the pins was 0.1 ohms for THW to THW and 0.2 ohms for E2 to E2.

Fortunately, I have sufficient background in things electrical to know that said combination was impossible.

Thanks for all the input. Just knowing that I wasn't missing something really simple was helpful. This was one for the books.

>>>>> P.S. While doing the build, I discovered an incredibly simple way to remove the Cam pulleys which should work on any rig. Where should I post that? <<<<<

 

Maybe a new thread with a catchy headline so future searchers can find it easily, or tech writeups? Depends how in depth you want to make it, I suppose...

 

Per reommendation by jbtvt, posted to: https://www.yotatech.com/forums/f166...y-have-261532/

 

Aha, good thinking! I for one have not seen that done before. Will have to keep in mind if the impact ever fails to do the trick

 

That's shear freakin' genius right there!

I only wish I would have thought of it myself.

Kudos to you man!