The black is that main wire I am trying to find out what its purpose is.The blue is to show a comparison of how dark the black wire is. It ties into both the CSi and the cold start switch. is it a ground?

 

OK so took just about all weekend Fri-Sun but I finally got it all back together. This thread was originally for the CSI and the cold start timing switch having trouble where my truck(lucy) would start fine cold then have issues like not fire but cranking when warm or after i ran errands with it. After already having an injector go out (about 3 months ago) I jumped the wires off another injector and it seemed to have worked. NOT! this time I dug into the harness as shown. To bacck up my case on the cold start I did have to re-crimp/solder the ground because it was pretty nasty. I also took the cold start switch out and cleaned up the inside threads as well as the switch itself. I think I did a decent job on the harness, could be more waterproof but oh well. after all this work I put the key in and she fired right up. let her get warm and tried again and again and again to see if it would not fire but it did every time. Took her to town and she ran great, actually better than before shes purring like a kitten and does not have a spud-er anymore. I would like to say thanks to all who chimed in and sent the pics that helped out a lot I owe y'all a beer on me.
found some high heat electrical tape at lowes
all tucked into bed with a protective cover

 

All fixed up!

Nice job!

 

Thanks!

 

Thanks for the update, Rick!
An lovely story on your build, your fiancee and your assignments. Thanks for your service. Land of the Free because of the Brave!

STJ pins of both are connected to each other with GREEN wire.
STA pins of both are connected t each other with BLACK wire.
Black wire goes to output of starter relay so CSI gets 12V ONLY while cranking.

 

Well I spoke to soon. Was running great for two days and then after the gym i got stranded again. No start when engine was still warm. Waited till it was cool then it fired up again. I got it home then check the resistance between the two pins on the cold start injector time switch and its sitting at around 50. for that link you posted it should be above 70 when warm. if I did that right. I also checked the pin to ground and that was sitting at 65. so I'm at a lost is it a bad cold start injector time switch?

 

Well... crud. I was all excited for you. At least now you know one more thing that the problem isnt.

That switch isn't cheap either. I skimmed through this, and I guess maybe I missed it, but... if it isn't starting warm... why are you chasing the CSI? I only ask that, because, as you know, I'm chasing a similar ghost. Albeit not as ambitiously as you. But, if the engine is still warm, the CSI is not in play anyway, as RAD4Runner already mentioned. So, why are you thinking it could be the timing switch? I could see thinking the CSI was firing when it shouldn't and flooding it, but it seems like you're going the other direction, and not getting fuel (same as me).

Have you tried Noid lights on the injectors? Or anything to confirm that they are pulsing when hot? (repeating info from my problem here).

 

Rick,
pls put us in front of that engine so we could help better. Always specify exactly what pin u are talking about.
STJ or STAon CSI
STJ or STA on CSI timer switch?
you measures with connectors disconnected or connected?
Unfortunately, Toyota does not have specs for STJ on timer switch to ground
when cold or hot. That is most critical. I'll try to measure mine tomorow AM.
​Possible that IF STJ is low even when warm, it turns on CSI and floods intake.
How about, next time u come back to car warm, disconnect the CSI? Then then see pattern.
Also, did you check if CSI leaks? FSM has test procedure
​​​​​​.

 

thanks for the fast reply. I will post a pick on both multi-meter reads tomorrow. unfortunately between my wife and myself we work on the opposite sides of town so tomorrow i will have to make sure it does not die when warming up or cold.
To explain what happened today. I had a 2hr drive to the VA and back today then reported into work and everything ran great no issues what so ever other than narly crosswinds. no issues starting hot or cold. then after work I went to the gym for maybe 30 minutes then come out (engine is still a little warm) turn the key and it fires right up but sounds like it was struggling to run I quickly a pressed on the gas to try and revive it then dies. After that I have to wait for it to cool 30-45 mins then pray to GOD it starts first go or i will be waiting another 30-45.
Again thanks for helping out I will spend more time under the hod tomorrow. Good thing is I know a guy in our off road group who works for Toyota and has offered to check it out.

 

 

I have same^^^ problem occasionally at warm start, but it does not die. Always starts well when cold, with expected wait for fuel pressure to get to proper level. Suspecting correlation between coolant temp sensor reading and actual temp of combustion chamber; i.e., coolant sensor says to ECU it's still warm when a actually combustion chamber has already cold down, OR sensor says it's cold but combustion chamber is actually hot. Would like to monitor THW, E2, etc. and see if those correlate to the rough warm idle.



Graphics on mine above are from 1988 PDF than I have BUT I EDITED TO SHOW 1986 (1986 has no connection between STJ and ECU, 1988 has) and I erased things around it that do not matter to make it easier for people to understand.

 

Made it to work. thanks for the FSM photos by the way. I will have to print them and keep it in my archive of toyota paperwork.
Once I got to work I shut it off and tried to start it again..Fired right up. So either this is a intermittent issue or this is a issue that comes up not when hot or cold but warm. Once home(if I make it that far) I will upload the different multi-meter readings on the cold start injector time switch on both hot,cold and if it struggles to start again.

 

Ok update. I was in Denver all weekend so I did not get a chance to work on my truck. But on Friday afternoon once I got home I shut it of and it would not fire because it was hot. I pulled the AFM connector then cranked it. It fired then I quickly reconnected the AFM connector. I tried this because of a video on here I saw. My next guess is the EFI relay? they are 18$ at my parts store so I will pick one up today after work.

 

As I told rancherman about that video. You need to unpin those signal wires from the AFM connector to track down why that works.

If it is VC/Vcc (5volt reference) its a power problem. And a clean new relay may fix it.

If it's VT(air temp, yeah VT might be the wrong abbreviation) the ECU is either ignoring all temp readings or using a different fixed/failsafe table that generally means more fuel.

If it's vta(that's not right, maybe it is VA, vane angle aka flap position) I have no idea why it would read that during cranking. A theory of what happens is on the ECU that doesn't have the CST(cold start timer) linked it uses the position to determine if the iacv is open or closed (an air fuel ratio calculation). Otherwise it leads back to that 5volt reference dropping to low, which throws all the sensor inputs off.

 

I have noticed my coolant temp sensor is not connected but there is two wires from the harness . A black one and one with a blue plastic female clip could that be the issue?

 

How can I check if the Coolant sensor for the ECU is functioning properly and giving the ECU the right signal(bottom circle). As in probe the ECU and see the difference both hot and cold? Hot water read out in a cup? already checked that.
This is the Sensor that is not hooked up to anything (top circle). But my gauge cluster in the dash is fried anyways so this should not have an effect on no hot start, although I will connect the blue wire for the 4WD and the Original(broken) wire for the gauge to it.

 

 

What advice I was given on the injector pulse was to buy the little "T" pins from a sewing store, and stick those through the wires at the connector.

If you can figure out what wires it is from those diagrams above, you should be able to trace them to where it enters the firewall.

 

[QUOTE=RASALIBRE;52389849]

 

To see if the injectors are getting pulse or to see if the cold/warm coolant sensor is working properly at the ECU?