bjh900rr

I wanted to know if anyone could explain when/how the cold start injector system operates.

From my understanding from reading a wiring diagram, it seems as though a cold start injector can only work while the key is in the "start" position, providing that the cold start timer switch gives a ground to the cold start injector. (Being dependent upon coolant temperature)

The Black wire (A/T), or Black-White wire (M/T) going to the connector for the timer switch only gets battery power when the key is in the "start" position, and does not have battery power when in the "run" position.

Is this correct? or is there more?

It leads me to believe that the cold start injector can only work while "cranking" the engine over.

I ask only because I am working on a intermittent hard start/ extended crank symptom.
I am aware of the TSB out on the cold start timer switch.

Any explanation would be appreciated.

bipolarandproud

This is how they explain it in the manual .
Idk If this helps you any.

"During cold engine starting, the cold start injector is used to supply additional fuel to the intake manifold to aid in initial start-up. The opening and closing of the injector is determined by the Start Injector Time Switch. When the engine coolant temperature falls below a certain point, the switch is tripped and then opens the cold start injector. As the engine coolant warms up, the switch will eventually close the injector."

abecedarian

so...
the cold start injector provides additional fuel during starting... if the cold start time switch decides the coolant is too cold...
at which point, the cold start injector will continue injecting fuel until the cold start time switch warms up enough to turn the cold start injector off, or for a period of time regardless of coolant temp, after which the O2 sensor, in conjunction with the TPS, AFM and coolant temp sensor should be able to take over mixture control.

4runnerx3

Check these, and check the timing.

bjh900rr

I am still not understanding how the cold start timer switch (and cold start injector) is getting battery power after the engine is running or key is in the "on" position, because it appears the cold start timer switch (and injector) are only getting battery power when key is in the "cranking" position.

Where does the power to the cold start switch and injector come from once the engine is running? or does it?
While testing for battery voltage at the c/s timer switch, I only got voltage while cranking the engine over. (key in "start" position)

I will try to post a wiring diagram to clarify my question.

abecedarian

please do post the diagram you have.
At the very least I'd like to clarify my drawings with your drawing.

desert-rat660

the cold start injector is only powered while the engine is being cranked

BrownsfaninMN

...is it possible to run wires to the cab and install a $2 push button switch from Radio Shack, basically to bypass the timer, push the button when you're starting in the cold?

khoopes

I have a 22RTE that sometimes takes extended cranking. I have not been able to troubleshoot yet.

ozziesironmanoffroad

thats a good idea if you find out let me know!

shantec

I recently ran into a cold start problem when I installed a push button starter and a hot shot relay when the factory starter relay died in my 5spd 4Runner (click, click!). Because I just put the key in the "ON" position and push the button to start it, the ignition in the start position no longer powers the CSI system via the black wire from the relay that used in the factory setup to give the signal to the starter. Just a FYI if you bypass your factory starter, I used a male spade lug coming off the relay signal wire to connect the factory black wire's female spade lug. IMO this was easier than rigging up another switch to power the CSI system because I don't use the key ignition's start position to crank the starter anymore.

abecedarian

guess I didn't look at the diagram for the 86 correctly.

galloway

so if i put a push button in my truck would this make the cold start injector stop working. i did the button because my wire going from the key to the starter stoped working

galloway

my bad i didnt see the post

badboy4x42003

I just used some speaker wire to run mine off of temporally till i can figure the system out I know there are several factors determining the operation of the cold start injector,
the cold start timer
the air flow sensor
the F.I. temp sensor
what takes precedence over the other, and when they are activated, is beyond me i have been searching the site for some time and have not found a thread yet that definitively lays out a plan for diagnosing each particular item in this circuit and addressing the value of each component. If I find anything I will post it here. The factory service manual seems to be layered with the different components in different sections cold start issues seems to be a common problem with Toyota it would be good to have a thread to direct problems to, if anybody knows where one already exists it would be good of u to point it out please !

Mudrooster

I had an intermittent hard starting problem, sometimes she fire right up, sometimes crank for 30-40 seconds. I tested my cold start injector, cold start injector thermo switch, and thermo sensor(one right next to cold start injector timer). They all tested within spec with my ohm meter. Then I was messing around further, and noticed I was able to spin the connection point of my cold start injector thermo switch- I called 22reperformance and they thought that was the culprit- and would explain why it was an intermittent problem. I have the new thermo switch ordered, and plan to install it, hasn’t arrived yet though. In the mean time I rotated the one that’s in there now all the way clockwise, and the truck fired right up. Is anyone familiar with the internals of that part? I hope I didn’t buy a $180 part for nothing. Maybe all I had to do was screw in the connection? Guy at 22reperformance seemed to think it was the culprit. I’m going to see if this keeps working, possibly return but most likely just install the new thermo time switch and hopefully my troubles go away.