Well, the DC resistance checks out on the switch. But I encountered something very unusual in regard to the Cold Start Injector Time Switch. It appears to have been replaced. (There's some history there...)

Funny thing...it looks similar to the Engine Coolant Temp Sensor beside it and has only a single contact blade and the two-pin connector managed to shove on it loosely somehow.

Back to the history. A reputable guy replaced the head gaskets on this engine. There was a problem and he re-did the work although since it was a non-paying job he kept the darn car for about 4 months. It was not running right when he brought it back and he apologized and recommended a second guy since he didn't have any more time to mess with it. Guy #2 is probably the best (if not only) guy on the island when it comes to 'computer' stuff. I know HE didn't replace that Time Switch so I'm thinking the first guy broke it or screwed it up somehow and didn't know what he was replacing.

This saga is getting interesting. I'll try and post some photos later so you folks can tell me if I'm barking up the wrong tree.

 

Pix of the unknown thing.

Sooooo...the question of the day is would this open? circuit goof with the ECM brain and/or actual cold injection and be causing my problems? Not sure what the thing installed actually is - probably some other sort of sensor . Anybody recognize it?

 

That looks like the sensor for the gauge on the dash. There are three temperature sensors, that one for the gauge one for the ecm to control fuel mixture and ignition advance and the cold start injector time switch. Does your gauge work? The cold start time switch and ecm temp sensor have two connectors the gauge sensor has one. It's raining like crazy here, when it lets up I'll go take some pics of mine for you.

 

How does it run with the suspect sensor disconnected? I think brianh may have correctly identified it, but it may even be a switch-type sensor that doesn't come with a Toyota truck.

The regular CSI Time switch has a "timer" that shuts off the CSI after (very) short period of time, so that you don't flood the engine with long cranking on a cold day. Since you don't have the timer, you may be flooding the engine whenever it takes more than a second to start.

If it runs well in your climate with the CSI Timer just disconnected, well, you know what to do.

 

Well, brianh. It does indeed appear to be the gauge sensor. This is in conflict with the little drawing but it is what it is. Disconnecting it kills the gauge and has no effect on operation. So I guess the Time Switch is the one beside it? I was hoping to check the resistance on the gizmo but now I'm a bit flummoxed on what is located where. There's one other larger sensor in the 'row' back there. It would be the farthest left in the drawing. What is it?

 

It's the one closer to the passenger side here's a pic from the epc 89462 is the start injector time switch 89422 is the ecm sensor and 89428A is not applicable.

 

I'm totally confused now - not that I wasn't to start with. Neither drawing agrees with what I'm seeing.
In order, pretty much in a straight line counting from driver side, what I have is:
1. hose
2. hose
3. large sensor (I think this must be it)
4. the sensor in question which is the gauge sensor
5. hose
6. another large sensor (2 plugs)
7. hose.

Thanks for all the help guys. My vacation ends today and the fish are calling so I don't think I'll have time to get back to it before leaving tomorrow. I'll be back home in July and attack it anew

 

There seems to be a lot of variability in the layout of the sensors and hoses. I don't know if it depends on the year, the equipment, or other. Mine is a '94 4x4 with automatic, and I have one one-wire sensor I can't account for.

 

Amazing, huh? In case I didn't say so before mine is a 95 4WD automatic. 3VZE. Doesn't resemble your '94 at all. You would think....uh, no...that's the wrong assumption!

So what is the default state of the temp and timer sensor? If either is bad or open is the valve OPEN or CLOSED on the Cold Start Injector? The symptoms point to mine being open even when the temp is 75 degrees (although I haven't taken it apart to actually see if there's a spray of fuel) and that would account for the initial flooding and non-start once the engine is even slightly warm. You can see my mind at work here...disconnect everything and hope the valve remains closed at startup but what does that tell the computer? I might be thinking too much here and can't work around it so easily.

 

The CSI is closed (no spray) until it gets power through the CSI Timer. The timer is closed (conducts current) at lower temperatures. The Timer is powered by the STA (key turned) signal (so the CSI is never open once you let go of the key), but as soon as it gets power a tiny heater warms up a bi-metallic strip to open the timer (no current) after a very short interval. Closing the CSI, even if you're still cranking.

Things can go "bad" open or closed. Your CSI could be stuck open all the time (unlikely, as your smoke disappears). Your timer could be stuck open (also unlikely, as you would just get no CSI). Or your timer could be stuck closed, so that instead of opening after a second or so of cranking, it just keeps the CSI running until you let go of the key.

Like I said; this is easy to check. Disconnect the electrical connector from the CSI (eliminating the CSI's injection). If your problem clears up, you know where to look.

PS. Yours looks different? What should you do? (hint: you need a camera, ....)

 

Thanks for the explanation, I see the logic. I had no difference with the CSI disconnected electrically. More to think about. Thanks.

One last question. (I've got a plane to catch to head back to work this am, ugh) Judging by your photo, scope, it would appear that item #6 on my list above is the CSI Timer. Would you agree? And regarding yours, fwiw, my temp gauge is the one with the white connector. Can't get a decent photo of my complete setup because its quite crowded back there.

Thanks again.

 

Hi folks, I'm finally back and have some time to work on this beast. I might need to start a new thread though since the problem doesn't appear to be the Cold Start Injection system. Heck, that would have been too easy, huh?

I pulled the injector and stuck it in a cup to catch any gas. Sealed off the hole where it went. No gas (its 85 out and there shouldn't be) and it has the same symptom starting. It starts but runs very rough, takes about 3/4 accelerator to keep it going, blows a lot of black smoke, then over the course of a minute or so it gradually smooths out and runs quite well.
But...once it reaches this "runs well" point it will not start again if you turn it off.

So I need some direction here of where to go next.

Thanks, guys.

 

YAY, I found it !!! The Engine Coolant Sensor. Couldn't get my probes inside to measure resistance but the two prongs were sort of bent out of shape and the inner plastic part of the connector came to pieces in my hand.
I stuck a 270 ohm resistor (which is about right for this temperature) across whats left of the plug. Started right up and ran good. Got it up to temperature and no problem restarting.
The sensor looks new as did the temp gauge sensor. I think the previous mechanic was on the right trail but must have jammed on the connector and goofed it up and never caught his error.
I'm so happy to hear the rig running again. It has been a dead duck for about two years!

 

Good job, those kind of problems are a pain

 

Thanks. I'm pretty proud of myself right now. Or maybe better stated I'm pretty proud of my luck
Now that it is fit to drive we'll see what other problems crop up!

 

Hi,

Was wondering if you could help me with a cold start issue on a '88 3VZE 4Runner.

I seem to have cold start issues when the temp drops below 80F. I live in Houston TX and it fires up all summer long. At 70F ambiant temp it won't start, but at 80F it will...lol! I don't get it! Ive checked and replaced the cold start valve/checked the switch resistance (looks good). Seems to be getting fuel. It will sputter ever so lightly like it's just about to fire up but never does. A little smoke from the tail pipe and heavy with fuel smell. Seems to be getting fuel.

Should I be looking into spark?

Lots of moisture here too, and that could also be a factor with lower temps.

I don't know... do you have any ideas?

Thanks,
Mike

 

I don't really have a good answer, Mike. I learned a lot in fixing mine but have no other experience.
It seems to me that the Cold Start Injection system itself wouldn't be so critical within 10 degrees but a defective sensor (like mine) or electrical wiring issue apparently can drive the computer nuts to where it sends incorrect signals. In my case it would only start when COLD so I don't know if my experience applies.
Mine appeared to be flooding out which I started out blaming the CSI injection system but when I pulled the injector it was not adding fuel. It turns out the damaged sensor was causing the problem on the electrical (computer) side and that was goofing up the starting parameters.

Good luck with it!

 

I have toggle switch installed in my cold start injector and I'm not sure what its doing exactly!

The switch is wired into the console. When the engine is running, it will kill the engine entirely. (It is not an on/off switch, you have to hold it 'on') It will start with the switch in the on position.

Does anybody know what is going on with this mod? Why it would kill the engine?

I have cold start problems (which this thread has been very helpful) and I'm wondering if the PO installed this just to bypass the cold start injector rather than replace it.

 

Sounds like the PO bypassed the switch and your toggle switch makes the cold start injector fire. The engine is probably dying because too much fuel is in the system. The switch is expensive so I'm not surprised it was bypassed.

 

Interesting. Things you wish the PO had known when you bought the truck (dude had only owned it for a few months before selling it off). The cold start has been a real worry, seems like the easiest solution is the one someone else had already done!