2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

TPS Question - I've searched and read so much I am now confused.

Old Feb 20, 2004 | 02:13 PM
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TPS Question - I've searched and read so much I am now confused.

OK, I've searched and read until I'm blue in the face. I have the FSM and the Haynes manuals and have read both in regards to TPS adjustment. My car is an S5 N/A. Idle hunts, surges when warming up, etc. Using the resistance method, the narrow range sensor adjusts and stays where I put it (it is set at 1KOhm now.) No problem. The Full range sensor is at about 1.35KOhms (clearly out of spec from the stated .6KOhms - .9KOhms) and turning the adjustment screw does not help.

I read in this thread:

https://www.rx7club.com/showthread.p...AND+Adjustment

where it is stated:

FULL - Probe the FULL DATA line. It should read close to 0.8v. (Safe range is probably 0.6 to 1.0.) If it is off, take a large pair of pliers, and gently bend the entire metal TPS "platform" left or right as necessary to bring the voltage to 0.8v. A little goes a long way, so be gentle. Once the voltage is close to 0.8v, you are done with the FULL range.

That's the only place I have seen this solution to the Full Range Sensor. Am I just late to the party on this or is this a/the common way to set/adjust the Full Range Sensor?

Also in that thread RETed states that the Full range sensor is primarily for the OMP. Does that mean that it has no/little effect on idle?

Any clarification or suggestions on Full Range adjustment would be appreciated.

Thanks
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Old Feb 20, 2004 | 02:34 PM
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Yes, full-range section is only used for OMP use - I don't know why anyone would recommend to **** with it.  It's the narrow-range section that affects driveability, and that's the wires would should be monitoring and adjusting to.


-Ted
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Old Feb 20, 2004 | 02:57 PM
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Thanks. I guess that poses another question then. Why is this thing idling like ***?

I have done the following:
replaced Throttle Body
replaced TPS (and adjusted)
replaced plugs
plug wires
cleaned and tested BAC
replaced vacuum hoses (and bought and installed new pressire sensor orifice)
tested compression
replaced and installed new ground wires

Should I look at resoldering the ECU? WTF? This thing is gonna make me insane. I thought I had this problem licked about 5 times only to have it come back and bite me.

Thanks in advance for any further insights/help.
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Old Feb 20, 2004 | 03:25 PM
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After the initial 15 second cold start up, the ECU limits RPM to 2K.
If your fast idle warm up cam is holding the throttle above 2K the ECU cuts fuel back to 2K, giving the zoom zoom.
A vac leak will also do it.

I assume it idles normal after warm up?
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Old Feb 20, 2004 | 04:05 PM
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The idle surges between 1200-1700 rpm's during warm up. If it's really cold outside it won't even do the normal cold start (guess I should start testing that huh?) The idle when warm can range from a solid 750 to 1100 to trying to stall out. I have checked and rechecked and even had someone else check for vacuum leaks and found nothing.
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Old Feb 21, 2004 | 09:58 AM
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From: Freaking Poland!!
Hey i have something similar to that!
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Old Feb 21, 2004 | 12:15 PM
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I have the same problem so but it only does it somtimes HELP US
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Old Feb 21, 2004 | 12:36 PM
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i'm in the same boat guys!
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Old Feb 21, 2004 | 01:45 PM
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You've cleaned the BAC, but have you tested it?
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Old Feb 21, 2004 | 03:07 PM
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my ****** idle is around 1650 (tach is a little high though) so lets say 1250, and during the first minute or so of driving, itll just die, unless i watch the tach and rev it a little. Once its warm, the idle will fluctuate between 1650 and 1850, like wah, wah, wah, wah. then itl go away then it comes back, etc. Ive cleaned the BAC, havent had a chance to test it though, i set the BAC screw all the way in. Im thinking about using some PVC pipe or something to replace my intercooler (teporariyly)so i can mess with the actuall throttle screws since the IC is in the way.
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Old Feb 22, 2004 | 10:16 AM
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Cleaned and tested BAC. After spending most of yesterday fooling/working on this problem I am convinced that there is something sticking. 90% of the time now, it will idle at about 1200 RPM's (after going through the warm up surging) but occassionally, I can blip the throttle and it will drop down and idle rock solid on 750. The other thing that makes me think something is sticking is that when it's idling at this 1200 range, I can adjust the idle down to 750 and occasionally when I blip the throttle or something to that effect the car will try to stall.

I'm gonna look at the fast idle warm up cam but does anyone have any thoughts on what could be sticking or give that effect?
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Old Feb 22, 2004 | 10:32 AM
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i spent an hour adjusting the idle and the TPS, it finally stopped doing that.
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Old Feb 22, 2004 | 10:42 AM
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I've spent more than that in both time and money. I've had 2 different "rotary experts" work on it only to have it start this crap back up again as soon as I drive it any length of time.
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Old Feb 22, 2004 | 11:12 AM
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Electronically unplug the BAC and see if your idle changes at all.

There is a procedure in the FSM for adjusting the idle, and TPS. Follow that (it may be posted on the board somewhere as well). Arbitrarily turning screws isn’t going to get you anywhere.
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Old Feb 22, 2004 | 01:33 PM
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"Electronically unplug the BAC and see if your idle changes at all."

Done per FSM. Idle drops and resistance is 10.9 Ohms



"There is a procedure in the FSM for adjusting the idle, and TPS. Follow that (it may be posted on the board somewhere as well)."

Done.

Idle:


TPS (1.0 KOhms):



"Arbitrarily turning screws isn’t going to get you anywhere."

No **** Sherlock. Has anyone suggested that?
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