suprahilux;1284544 said:
Yeah...
The 86-88 have an idle speed adjustment screw on the throttle body. It allows air to bypass the throttle valve and it IS designed to be adjusted. The 89+ do not have this(from what I've seen). Most toyotas from this era have this idle air bypass screw, even my 92 22re pickup, for some reason they didn't put it on the 89+ supras. They probably tried to make the idle more stable in varying conditions.
If you had any clue what you are talking about here, you would know the 7M tech specs say the idle bypass screw is set fully seated from the factory...the ISCV supplies the air to control idle. On the R22E (I have one) the screw is used to control idle...the EFI on that motor is way different than the TCCS on the 7M. The idle bypass screw was removed from the later 7M TBs because people (like you) kept messing with it, causing all sorts of problems.
suprahilux;1284438 said:
I told him to listen to me. Long story short, After several more times, I refuse to help him b/c he won't listen to me! HA!
Might want to think about this...seems you might want to practice what you preach. What do you think is happening here with JJ's responses? Sad for the OP...JJ is probably the most knowledgeable guy here about the TCCS. Now you've pissed him off and the OP has to filter the misinformation being spouted by you.
suprahilux;1284759 said:
Since you are the named official expert here, why don't you explain how it really works rather than just saying what is wrong. I can't speak for others, but I am here to learn. I'd rather know how it really works than just belittle others without the fancy 'titles' that were labeled to certain members (with all due respect). Give us something other than NO.
This is for the OP since you seem to have a hard time listening. Idle on a 7M is controlled by a step motor ISCV via the TCCS. The major input signals to the TCCS is engine speed (Ne), throttle position (IDL), vehicle speed (SPD) and coolant temp (THW). Additional inputs are used for specific situations...neutral start switch (NSW), ignition switch (STA), air conditioning (A/C), and electrical load (ELS). The ISVC controls idle speed, fast idle speed (warm-up), air conditioning idle-up speed, and electrical load idle-up speed.
The OPs problem is caused by either:
1) A problem with one of the major inputs. The absence of ECU codes for these makes it unlikely. However, the presence of AFM codes could be a problem...testing the AFM is not a bad idea. I hope you did not decide to clean the AFM sensor...it is very sensitive. Cleaning it with carb/MAF cleaner usually destroys it.
2) A mechanical problem with the ISCV or the air path is blocked. The ISCV should step full open on shut engine shutdown...you can hear it click when it does. If the ISCV failed closed (or almost closed), there will be insufficient air to maintain idle. The ISCV could also have deposits at the valve stem/seat that can cause this behavior. Or, the check valve under the ISCV could be clogged/stuck closed.
Removing the ISCV to clean it and testing for proper operation is what I would do. Make sure the check valve is clean/operational. There should be a clear air path from the accordion hose to the ISCV...it requires metered air after the AFM to properly control idle. Replace the ISCV gasket on reinstall.
I'll restate what JJ said...if you are not 100% sure of what you are talking about, do not post in the tech section. Suprahilux - It's time for you to STFU.
