Yep - see this thread for more info and banter surrounding the procedure:
http://www.shoforum.com/showthread.php?t=10161
Yep, assuming that everything is kosher between the two units. There's always the small possibility that a damaged or fried driver, transistor or other electrical component on the mainboard could lead to the problems you've been experiencing.
The only easy way of verifying your actual engine speed (outside of a calibrated, third-party tachometer) would be to utilize some sort of real-time, J3-based data logging device like the TwEECer or SnEEC.
Once the indicated coolant temperature has reached a stabilized, preset temperature, then the EEC should enter closed loop (or attempt to cycle around a 14.64:1 AFR) at warm idle and begin learning/making adaptive corrections.
Unfortunately, the throttle butterfly screw adjustment will only help if your throttle butterfly is not completely closing within the bore against the stop (as noted by Paul above). It should also be noted that the throttle screw adjustment is not usually recommended for idle adjustment and should only be utilized when all other diagnostic avenues have been explored.
Negatory.
Yes, and although Ted usually makes his timing adjustments and power gains this way (by adding a specific amount of global advance to the overall timing mixture), one cannot achieve this same type of timing adjustment through the cam or crank position sensors alone.
Connect a timing light, pull the SPOUT connector (to ensure 10 degrees BTDC at idle) and go to town.
Although a bad motor mount and certainly a vacuum leak can cause the problems that you're seeing, I previously forgot to ask - have you checked and/or replaced your VSS recently? Despite the popular misconception, the VSS is used to control idle speed on
all V6 SHOs, both MTX and ATX. I would verify that you have proper connection at the VSS itself and then double-check your cruise control operation during one of your high idle episodes. I would also go back and verify that the J3 edge card connector (where your LPM plugs into the computer) is
completely free of any residual oxidation, gunk and other material, even if the LPM is not currently on the car.
If neither of these areas prove the be the culprit, then it's very likely that we are still dealing with a leak somewhere.
You can disagree with me all you want. That still will not change the fact that the famed "TPS modification" does nothing for
any EEC-IV- or EEC-V-equipped vehicle when the closed throttle TPS voltage is already within the expected, specified range.
I think you're getting two separate issues confused here. As I noted in my previous reply, the EEC expects to see the TPS voltage within a certain range (or around 0.45v-1.2v, depending on vehicle computer calibration) when it is in a closed throttle state. If your closed throttle TPS voltage falls outside of the expected range, then you could experience any number of driveability issues, such as a rough and/or excessively high idle, decreased performance and altered shifting patterns on automatic-based vehicles. In this case, the TPS voltage adjustment could prove beneficial.
However, once your TPS has been adjusted and the closed throttle voltage falls
within the expected voltage range, there are no further adjustments to be had. In other words, you could adjust your closed throttle TPS voltage all day long and, so long as it stayed within the expected voltage range given above, it would make absolutely
no difference.
The only BS here is in believing that this modfication actually produces any performance enhancement, which it does not. As I noted above, the only possible benefit one would receive from performing the original "Mustang" TPS modification would be a restoration in proper, factory-like idle quality. If you were experiencing poor idle quality or driveability before you performed the modification, it's likely because your closed throttle TPS voltage was out-of-range to begin with and needed to be adjusted. You will realize absolutely
zero performance benefit from adjusting the TPS once it's closed throttle voltage is within the expected voltage range.
While it is true that the factory engineers utilized many of the same core strategies across various vehicle computer programs, not all of these programs shared the same logic when using the same type of sensor, solenoid or actuator.
That said, though, and speaking from my intimate knowledge of the Ford EEC system, I can safely attest to the fact that the factory powertrain engineers have utilized the same relative TP strategy (posted above) since the advent of the GU strategy which governs the '89-'93 5.0L Mustang computer programs. This same strategy was also carried over into other '89-'95 EEC-IV calibrations (such as those used on the '89-'95 V6 SHO) and continues to live on today in the newer '96-up EEC-V calibrations.
If your Mustang truly ran "perfectly" after installing those modifications without any EEC reprogramming, then you are an exception to the rule. I also submit that if the TPS adjustment improved your driveability, your sensor was likely out-of-range to begin with.
