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timing/idle speed tutorial?
Topic Started: Feb 21 2013, 01:16 PM (1,673 Views)
hotwire
Member
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Im sure there is a timing and idle/TPS set turtorial, but i am having trouble finding it. 3cyl 1994 with updated emissions. spicificly a check for the two idle stops, I think they were tampered with and would like to reset to factory so I can be sure I am adjusting the TPS right.
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rjsdotorg
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R E Member

I have the same motor.
The idle stop should be just enough to keep the butterfly from sticking/rubbing the bore.
Set the TPS as per other posts with a .14" feeler.
Check for vacuum leaks.
Jumper the connector at the firewall to stop the ECU from messing with base timing.
Set the timing to 5 BTDC.
If idle is not 800-900, THEN try adjusting the screw/stop for the ISC.

Others here have additional suggestions?
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Vkhelldog
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Sounds right. I don't know how to test the motor on those ics that's the only other thing, of course other than compression test etc to make sure the engines healthy. 1 dead cylinder makes them idle funny
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99metro
putt-putt

TPS should be set for 1.00 VDC at idle. Measure at the wires coming out of the TPS - I used small finishing nails stuck in there and a volt meter.
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hotwire
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Yeah I did the TPS to 1V but because you put the feeler between the idle stop and the throttle I would assume that it is critical to have the idle stop adjusted proper first. Can you be more specific about the firewall jumper plug? Haven't messed with that yet, or are you talking about the one on the fuse panel? Just had to replace cap and rotor so re timing is required. Also anyone have a good trick or cheap device to recommend for a temporary 3cyl tach.
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rjsdotorg
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Vkhelldog
Feb 21 2013, 02:45 PM
Sounds right. I don't know how to test the motor on those ics
http://geometroforum.com/topic/3279581/1/#new
is a start
I'll look in the FSM
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clarkdw


A 9volt battery and a couple of test leads to hook it up to pins 1 and 3 on the isc will test the actual function. Reverse the leads for advance and retract functions. The troubleshooting if you have a code is here. HTH

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t3ragtop
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Turbo3 and Twincam Tweaker

warning! don't connect any voltage to wires leading to the ecu or to any sensors that are plugged in. the illustrations have the schematic symbol for switch closures shown but they are really cmos electronics controlled fets. if you apply 9 volts to those ecu sink circuits without the ecu being properly energized, you will screw the pooch and the ecu will be shot in the ass.

the same goes for trying to measure resistances on those ecu circuits. multimeters use batteries to supply a current source through the lead probes to measure circuit resistance. cmos circuitry, properly powered, uses 3.3 volts. improperly power them with 9 volts and the magic smoke is released. :D

don't go charging in there with your harbor freight multimeter, sparky! :D
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hotwire
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It's ok I have a fluke, and I think clark was asking to run the motor with the plug dissconnected. that I have, and its good, also moves with TPS micro movment 'engine off'. Electrical is my trade so I will be careful, but thanks for the warning. Im off to get a tach.
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hotwire
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So, where is the jumper supposed to go for timing?
Ok, found it, sorry I just cant rely on the hood sticker, its from a diff vehical.
Edited by hotwire, Feb 21 2013, 09:05 PM.
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hotwire
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OK, Timing set, 6 degrees BTC, TPS set 1V @ .14" . Everything is running smooth.

The ISC seems to do a overly frequent amount of Idle speed changes, any ideas on that.
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Vkhelldog
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Could it be a vacuum leak? I'm not much help with that year
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rjsdotorg
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Once hot, it should be fairly still.
Spray around hoses etc with carb spray and see if speed changes.
Make sure your TB heater hoses are clear and hot. Check the 3 wires grounded to the back of the TB too.
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clarkdw


hotwire
Feb 21 2013, 09:57 PM
OK, Timing set, 6 degrees BTC, TPS set 1V @ .14" . Everything is running smooth.

The ISC seems to do a overly frequent amount of Idle speed changes, any ideas on that.
Drop your TPS voltage just slightly. There will be a sweet spot in the adjustment. It took me about a week of minute changes before mine was just right.
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hotwire
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OK by dropping the tps about .1 v it stopped surging, now It idles HIGH and no adjustment of the tps will correct it, anymore CCW rotation of TPS makes it go back to its surging ways, Also I thoroughly cleaned the EGR system, taking off the exhaust manifold and the whole bit. Next I would like to check for VAC leaks and the MAP sensor. What tells the ISC where to idle when all other prams are meet, idle switch, engine temp, volts are at 13.8?

Note: ISC DTC no longer sets with extensive driving, but the EGR still does, I wonder if air is getting into the intake somewhere past the throttle.
Edited by hotwire, Feb 22 2013, 10:16 AM.
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