Spec's in Sig.
1.9l twincam NA mota.
All stock saturn ( GM ) sensors/valve.
The v3 pcb is jumpered for IAC use according to the assembly guide.
First Question!
On the Relayboard, is this correct?
S1 = 1A ("A" = "+" positive)
S2 = 1B ("B" = "-" negative)
S3 = 2A ( " " " " )
S4 = 2B ( " " " " )
more less do the A and B signify Pos, Neg....?
ok moving on
My IAC valve...
O-ringed type
Infinate resistance between the Middle 2 pins...
The day I got my relayboard/wireharness/MS2blah blah blah....
I put everything(MS2/harness/RB/GMIAC"in a TB"/CLT/MAT) on my desk, connected everything... Hooked up my Lamda power supply... Bench tested my IAC... Always on And No Heat...
for the IAC valve I have the Saturn Wireing Scematix... (lookn now as i type, to copy correctly)
IAC A HI --------- Light blue wire / White trace
IAC A LOW ------- Light blue wire / Black trace
IAC B HI --------- Light green wire / White trace
IAC B LOW ------- Light green wire / Black trace
With that Blue would be coil 1 , green would be coil 2
I wired
A HI ---- S1
A LOW -- S2
B HI ---- S3
B LOW -- S4
Tired..
I have contacted a friend that is going to come over and turn the key for me.
I will be using a spare throttle body and SAME model IACV "but different unit", to phically watch IACV movement.
While doing so I will note Step Time and test to see how small I can to with out missing steps. When I have proper "Visual" function of the valve.
And
Set the Start Step more accuratly...
GM IAC PROBLEMS UPDATED
Forum rules
Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
Read the manual to see if your question is answered there before posting. If you have questions about MS1/Extra or MS2/Extra or other non-B&G code configuration or tuning, please post them at http://www.msextra.com The full forum rules are here: Forum Rules, be sure to read them all regularly.
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Lordprimate
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GM IAC PROBLEMS UPDATED
Last edited by Lordprimate on Sat Feb 11, 2006 10:23 pm, edited 9 times in total.
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Lordprimate
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Bernard Fife
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Lordprimate,
Where the documentation hasn't caught up with the code, the best explanation is always in the source code (the .c file).
I'm not sure I follow your problem, other than that the idle is inconsistent. Read this thread to start: http://www.msefi.com/viewtopic.php?t=14005
Then make sure that the number of starting steps (start value, which refers to the initial positioning of the stepper motor, and has nothing in particular to do with engine cranking) to fully retract the pintle is sufficient (but not so much that the stepper stalls against the stop for many steps, then the chip overheats and goes into PWM mode).
Then make sure the final value in the IAC step table is 5 to 10 more than the start value. Note that the start value represents retraction, and the IAC step table values are extensions.
Getting the start value right is important for consistent operation, it can't be too few at all or too many by very much - either of these will definitiely result in inconsistent operation.
Also, read the above link above IAC icing to see if this might apply to you.
The IAC is temperature controlled in normal circumstances, except for cranking and immediately after a start.
When MegaSquirt is powered up, the stepper is retracted by the 'start value' number of steps.
It is then extended to the 'Cranking Position (steps)' while cranking. When cranking stops and the engine is running:
- if the temperature is above the time based afterstart 'cold temperature', the pintle extends (or retracts) to the value in the IAC step table for the current coolant temperature. It does this over the 'time to run taper time (sec)'.
- if the temperature is below the time based afterstart 'cold temperature', the pintle extends (or retracts) to the 'cold position (steps)'. Then the pintle extends (or retracts) to the time based afterstart value over the 'cold taper time (sec)'. After that, it follows the timed based scheme to reach the coolant controlled number of steps from the IAC table.
Lance.
Where the documentation hasn't caught up with the code, the best explanation is always in the source code (the .c file).
I'm not sure I follow your problem, other than that the idle is inconsistent. Read this thread to start: http://www.msefi.com/viewtopic.php?t=14005
Then make sure that the number of starting steps (start value, which refers to the initial positioning of the stepper motor, and has nothing in particular to do with engine cranking) to fully retract the pintle is sufficient (but not so much that the stepper stalls against the stop for many steps, then the chip overheats and goes into PWM mode).
Then make sure the final value in the IAC step table is 5 to 10 more than the start value. Note that the start value represents retraction, and the IAC step table values are extensions.
Getting the start value right is important for consistent operation, it can't be too few at all or too many by very much - either of these will definitiely result in inconsistent operation.
Also, read the above link above IAC icing to see if this might apply to you.
The IAC is temperature controlled in normal circumstances, except for cranking and immediately after a start.
When MegaSquirt is powered up, the stepper is retracted by the 'start value' number of steps.
It is then extended to the 'Cranking Position (steps)' while cranking. When cranking stops and the engine is running:
- if the temperature is above the time based afterstart 'cold temperature', the pintle extends (or retracts) to the value in the IAC step table for the current coolant temperature. It does this over the 'time to run taper time (sec)'.
- if the temperature is below the time based afterstart 'cold temperature', the pintle extends (or retracts) to the 'cold position (steps)'. Then the pintle extends (or retracts) to the time based afterstart value over the 'cold taper time (sec)'. After that, it follows the timed based scheme to reach the coolant controlled number of steps from the IAC table.
Lance.
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Lordprimate
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Lordprimate
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eightvalver
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Lordprimate
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eightvalver
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Yes, try the reflash.
The same thing almost happened to me.
What fixed it was switching the polarity of the wires for the IAC motor for both sides.
but I am still hunting for that magic number for consistent operation. I think the newer embedded code releases should solve some of the inconsistent problems.
keep us posted.
The same thing almost happened to me.
What fixed it was switching the polarity of the wires for the IAC motor for both sides.
but I am still hunting for that magic number for consistent operation. I think the newer embedded code releases should solve some of the inconsistent problems.
keep us posted.
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Lordprimate
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- Location: Richmond, VA
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eightvalver
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- Joined: Tue May 17, 2005 10:43 am