DIY_EFI Digest Wednesday, October 20 1999 Volume 04 : Number 591 In this issue: RE: Manual control of IAC motor IAC motor EFI for 71 vette EFI for 71 Vette Re: Manual control of IAC motor, DIY_EFI Digest V4 #590: Re: Manual control of IAC motor See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Tue, 19 Oct 1999 16:36:14 EDT From: A70Duster@xxx.com Subject: RE: Manual control of IAC motor In a message dated 10/19/99 1:29:36 PM Mountain Daylight Time, DIY_EFI-Digest-Owner@xxx.edu writes: << Can someone tell me which terminals of the IAC motor runs the pintle in and out? The wiring diagrams show two coils and the connector has 4 terminals. Does one coil send the position back to the ecm and the other is a 12 volt reversable dc motor? >> Sound like a job for STEPPER MOTOR CONTROLLER The circuit is more involved that just attaching power to it. A stepper motor controller will switch polarity on the stepper motor such rotation and speed is controlled. If your really interested, I could try to dig up some stepper motor controller info. The web should have some info on "Stepper motor controller" Good luck, Mike ------------------------------ Date: Tue, 19 Oct 1999 16:00:06 -0500 From: steve ravet Subject: IAC motor > Date: Tue, 19 Oct 1999 07:53:07 PDT > From: "Gary Moulton" > Subject: Manual control of IAC motor > > Can someone tell me which terminals of the IAC motor runs the pintle in and > out? The wiring diagrams show two coils and the connector has 4 terminals. > Does one coil send the position back to the ecm and the other is a 12 volt > reversable dc motor? > > Application is 1994 Mopar 4.0L EFI in a 1982 Jeep CJ-7, and what I want to > do is be able to manually adjust the idle lower than the 750-800 rpm when > off-roading. I have connectors and a harness and some electrical experience. > I plan to have a switch to disconnect the IAC from the system for manual > control and a spring loaded switch to "bump" the IAC position in or out. > There is a company offering such a controller for more money than I think it > should cost to build one myself. Thanks in advance > > Gary M > gmoabrim@xxx.net Gary, the IAC is a stepper motor. There's a very good explanation of steppers on the internet right here: http://www.cs.uiowa.edu/~jones/step/ A stepper motor has two coils in it, and the ends of both coils are brought out to the harness resulting in 4 wires. If you energize one coil the rotor will rotate to a position aligned with that coil. If you energize the second coil the rotor will rotate a little bit to be aligned between the two coils. If you turn off the first coil the rotor will rotate a little more to line up directly with the second coil. If you energise the first coil again with the opposite polarity of the first time the rotor will rotate a little more, and so on. Basically the ECM applies pulses in a particular sequence to the four wires to produce rotation, where each pulse results in some amount of rotation of the motor (a couple degrees or so). The motor can be made to spin either direction by changing the polarity of the pulses. That's a simplified explanation, if you want more details the link above has everything you could want and then some. - --steve - -- Steve Ravet steve.ravet@xxx.com Advanced Risc Machines, Inc. www.arm.com ------------------------------ Date: Tue, 19 Oct 1999 14:00:59 -0700 From: Doug Dayson Subject: EFI for 71 vette Hi Carl...thanks for the reply...I'd love to hear more about that Camaro of your's! I'm not familiar with the realibility records of the aftermarket systems...please enlighten me... I certainly agree with the "keep it all GM" concept...in that I do drive it long distances and it would be great to have the ability to service it at any GM dealer if needed while in the "boondocks"... Currently my engine only consumes somewhere around 625 cfm max...I believe that the BB TBI's flow 670 cfm so I too have thought about a BB TBI...Holley makes a SB TBI manifold good for 6000 rpm as well...I'll have to check it's height though? Questions... a) Are we assuming the the stock closed loop portions of the fuel and spark maps will be close enough...and that just the open loop WOT stuff would need adjustment...as well as the spark curve probably...I'm emissions exempt so I won't be needing canister purging or egr etc... b) Will the truck TBI ECM do Torque Converter Lock-Up...that would be nice to put back in the car...currently defeated with the carb etc...I assume that it will? c) There seems to be a fuel delievery problem however...Holley sells a 2 barrel TBI rig and rates it for only 275HP with two 80 lb./hr injectors...will these things pass enough fuel for me...don't want to go lean at the big end... What's the SS454's output and at what rpm does it occur? I figure to be making 425HP @xxx.will need to support that! d) Would be very interested in info regarding the calibration process and procedures...tech writings etc...I have access to a EPROM burner etc... Thanks again...looking forward to hearing from you... Doug P.S...is digest the only way to recieve the list at this time? > Date: Sat, 16 Oct 1999 19:39:08 -0700 > From: "Carl Summers" > Subject: EFI for 71 vette > > Hi Doug, > There are some really nice units out there but I still haven't seen > anything I like(under $5000.00) better than a GM computer for a daily > driver,,,it offers you closed loop for better gas mileage, spark knock > control and even checks for octane upon start up to just name a few.....the > downside is without software to make the job easier you have to do a bunch > of work in hex once you locate the tables..(the breakdown of the 7730 is > completely available) Use any manifold you want, get the correct size > injectors(we can help with that) Use a Gm distibutor and sensors,,,,you can > buy an eprom burner and erasure cheap on ebay( http://www.ebay.com ) do a > search under eprom....I will go into further detail on how to do this job if > you are interested...I am currently doing a 68 camaro with a 396 multi > port(my own, basically a tunnel ram and a custom plenum) and am even having > the GM 7730 control the fuel enrichment and spark table for the > nitrous(still working on that but close) This car should run 11's without > nitrous and 10's with(traction a factor)......ttyl > - -Carl Summers > p.s. you can do this very reasonable and have an awesome RELIABLE > system.....check the aftermarkets failure rate....then think again about > using a proven GM system...... > > > > In a message dated 10/16/99 12:22:12 PM Pacific Daylight Time, > > DIY_EFI-Digest-Owner@xxx.edu writes: > > ------------------------------ Date: Tue, 19 Oct 1999 14:05:53 -0700 From: Doug Dayson Subject: EFI for 71 Vette Hi Greg... Thanks for the reply...I'll check out your ideas below...keep the list up to date on the EGOR... Thanks again...Doug > Hi Doug-- > > Hopefully Tom Sharpe will chime in here, he has done a bunch of Chebbies. > So has Carl Summers. > > My $.02-- > > Of the systems you have named, FP is far and away the class of the group. > Another one in the same price/performance class is the Autronics unit > (www.turbofast.com)--which uses the 68332 processor. > > One possible dealer for the FP unit is Jack Cotton, who can be > found on the > gnttype (Buick) list (www.gnttype.org). I think he sells them pretty > reasonably. > > The wide band O2 option is WELL worth having--mebbe Gar will > chime in here, > there may be a diy WBO2 unit available through this list fairly > soon. Do a > word search on EGOR in the archives for some INTERESTING reading on this > subject! > > As for the manifold--you might check out Force EFI besides the ones you > mentioned. > > Regards, Greg > << Date: Sat, 16 Oct 1999 12:50:47 -0600 > From: bearbvd@xxx.net (Greg Hermann) > Subject: Re: DIY_EFI Digest V4 #583 > > >Date: Fri, 15 Oct 1999 14:44:16 -0700 > >From: Doug Dayson > >Subject: Intro and SB Chev Recommendations... > > > >Hello all...my name is Doug Dayson...I live in the San > Francisco Bay Area in > >CA...I'm a musician/audio engineer/producer and software engineer by > trade... > > > >I'm currently researching converting my modified 71 Corvette Coupe to > >EFI...mostly because I run around with a club of people with > newer Vettes > >that are > >injected and when we get into higher altitudes I can't compete > w/o rejetting > >(which is a hassle) so... > > > >> ------------------------------ Date: Tue, 19 Oct 1999 16:02:10 -0600 From: "Al Jurenas" Subject: Re: Manual control of IAC motor, DIY_EFI Digest V4 #590: | Gary, If it's like my 90 GM, the IAC is a stepper motor. The pintle is on a worm gear, and rotation moves it in and out. The coils take turns to rotate the pintle by 90 deg. At any time, one coil is in an 'enabled' position and can rotate the pintle in either direction, the other coil is in a neutral position (will not cause the pintle to rotate). So you apply a voltage to Coil A, the pintle will turn 1/4 rev in some direction. If it doesn't turn, then the other coil is enabled (needs to be activated first). The opposite polarity (on coil A) would have turned it in the opposite direction. Apply a voltage to the second coil (coil B), and it will rotate in the same direction another 1/4 turn, or back the way you came. Switch polarity if necessary. You can build a stepper switch with one DPDT latching-latching switch and one SPDT momentary-center-momentary switch. This will let you move the pintle in or out, one step at a time, by toggling the SPDT to alternate sides.. Hope this helps, and I hope my info is correct. Al | ------------------------------ | | Date: Tue, 19 Oct 1999 07:53:07 PDT | From: "Gary Moulton" | Subject: Manual control of IAC motor | | Can someone tell me which terminals of the IAC motor runs the pintle in and | out? The wiring diagrams show two coils and the connector has 4 terminals. | Does one coil send the position back to the ecm and the other is a 12 volt | reversable dc motor? | | Application is 1994 Mopar 4.0L EFI in a 1982 Jeep CJ-7, and what I want to | do is be able to manually adjust the idle lower than the 750-800 rpm when | off-roading. I have connectors and a harness and some electrical experience. | I plan to have a switch to disconnect the IAC from the system for manual | control and a spring loaded switch to "bump" the IAC position in or out. | There is a company offering such a controller for more money than I think it | should cost to build one myself. Thanks in advance | | Gary M | gmoabrim@xxx.net | ------------------------------ Date: Tue, 19 Oct 1999 15:04:43 -0700 From: "John Dammeyer" Subject: Re: Manual control of IAC motor Gary, Odds are this is a stepper motor and the motor is moved forward and back by energizing the coils in sequence. Check out L293D series device as a possible chip for driving the motor. John Date: Tue, 19 Oct 1999 07:53:07 PDT >From: "Gary Moulton" >Subject: Manual control of IAC motor > >Can someone tell me which terminals of the IAC motor runs the pintle in and >out? The wiring diagrams show two coils and the connector has 4 terminals. >Does one coil send the position back to the ecm and the other is a 12 volt >reversable dc motor? > >Application is 1994 Mopar 4.0L EFI in a 1982 Jeep CJ-7, and what I want to >do is be able to manually adjust the idle lower than the 750-800 rpm when >off-roading. I have connectors and a harness and some electrical experience. >I plan to have a switch to disconnect the IAC from the system for manual >control and a spring loaded switch to "bump" the IAC position in or out. >There is a company offering such a controller for more money than I think it >should cost to build one myself. Thanks in advance > >Gary M >gmoabrim@xxx.net > >______________________________________________________ >Get Your Private, Free Email at http://www.hotmail.com > >------------------------------ > >Date: Tue, 19 Oct 1999 14:44:57 EDT >From: EFISYSTEMS@xxx.com >Subject: Re: DIY_EFI Digest V4 #589 > >an eprom is an eprom is an eprom,,,,,doesn't matter what it's used in...not >GM specific....hth's >- -Carl Summers >p.s. a 7730 is used in 90-92 camaro/firebirds and others > >In a message dated 10/19/99 2:29:35 AM Pacific Daylight Time, >DIY_EFI-Digest-Owner@xxx.edu writes: > ><< > How exactly do you use the prom equipment talked about on E-bay to calibrate > OEM computers? > > > - -----Original Message----- > From: DIY_EFI-Digest-Owner@xxx.edu > [m >> > >------------------------------ > >End of DIY_EFI Digest V4 #590 >***************************** > >To subscribe to DIY_EFI-Digest, send the command: > > subscribe diy_efi-digest > >in the body of a message to "Majordomo@xxx. > >A non-digest (direct mail) version of this list is also available; to >subscribe to that instead, replace "diy_efi-digest" in the command > above with "diy_efi". > > ------------------------------ End of DIY_EFI Digest V4 #591 ***************************** To subscribe to DIY_EFI-Digest, send the command: subscribe diy_efi-digest in the body of a message to "Majordomo@xxx. 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