DIY_EFI Digest Friday, August 6 1999 Volume 04 : Number 452 In this issue: TBI to TPI Electronic transmission controller? Fw: Suburban VSS info RE: Ecu 6 See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Thu, 05 Aug 1999 12:21:51 PDT From: "David Sagers" Subject: TBI to TPI Shannen Thanks for responding, I really appreciate your help as it sounds like you really know your stuff on this subject. In fact, you are way over my head! Mind if I ask a few questions. As you suggested, I looked at the archives a searched for DRAC, found about 5 messages and the most useful is: Formula to find divide ratio when using General Motors DRAC speed sensor and changing gear ratios, tire sizes, and etc. Input Ratio=63360/RC*XR*P/128000 63360= #of inches in a mile RC= tire circumference in inches XR= axle ratio P= # of speed sensor output pulses per output shaft revolution. The 700R4 with VSS (not speedo cable) is 40 pulse/rev. 128,000 pulses per mile is DRAC output to RWAL module in fullsize pickup application. Rolling circumference is preferred method of obtaining tire circumference. Mark line on tire and corresponding line on floor. Roll vehicle back until tire makes complete revolution. Mark 2nd line on floor and measure distance between 2 lines. This is actual rolling tire circumference. (Circumference=(Pi)(Diameter) for estimating purposes.) Look up input ratio on chart to find proper jumper settings. Notes: DRAC is designed to use AC input signal. 73.8" rolling circumference and 3.73 axle ratio yeild 1.00 divide ratio. 747 ECM receives 1.11hz/mph signal Sounds like I need to try to reprogram the signal to the ECM? This might be more than I have enough experience to pull off. So I'm facing two routes. 1 - Don't try to reporgram the DRAC signal to the ECM. What happens if I if I just follow the instructions for the aftermarket harness? Basically the instructions for the VSS say there are two wires for the VSS. If you connect them correctly the speedo will work. If the speedo doesn't work then the wires are connected backwards. Will I lose the ABS function of the rear brakes? Will I lose the ABS for the front brakes? Any other features on the truck I'll lose? 2 - Dig into the DRAC and try to figure out the programming. In order to change this do I need to use a chip programmer? What I'm saying is that I read and re-read your message and can't quite figure out how to pull off the change. Any help in explaining would be very much appreciated!! >Ok, let's get that pained salesman straightened out. The >computer is looking for a 2k or 4k pulse per mile speed signal input. >The VSS in a 90 suburban outputs 40 pulses per driveshaft revolution. >Now without knowing your tire size, gear ratio, or driving habits I >can definitely say that this is not compatible. However... >Have you seen the term DRAC mentioned on the list? Maybe in the >archives? (hint, hint) Well, the DRAC's job is to take that 40 >pulse/rev ac signal and turn it into 2k and 4k (and 128k) pulse/mile >square >wave output. >Are things looking better? > >Now you'll need to locate one. Well, if you remove your >glovebox and reach into the dash toward the driver's side, you should >find a small white box about 3" X 2 1/2" taped or velcroed in. This >is the beast you need. >So what to do next? > >You'll need some wiring diagrams to connect it to the ecm. The >schematic for the 747 and the 727 are in "incoming", and there may be >a 730 pinout there also. Now that I've gotten around to it, you'll >also find a file called dracnfo.zip which has unconfirmed drac >pinouts, some pictures, and some instructions for using the DRAC with >non-original configurations. For anyone who may have a version of >this that's about 2 Meg, this one's a "lite" version, with some small >corrections in the conversion instructions. >Shannen _______________________________________________________________ Get Free Email and Do More On The Web. Visit http://www.msn.com ------------------------------ Date: Thu, 5 Aug 1999 16:03:52 -0700 (MST) From: d houlton x0710 Subject: Electronic transmission controller? Anybody ever worked on a controller for the GM electronic trannies? Specifically the 4L60-E? What about a commercial one? Is there one available that's stand-alone and adjustable? Were the OEM controllers stand-alone or part of the EFI computer? Is there an aftermarket efi controller (Haltech, TEC, Wolf, etc?) that can also control this tranny? thanks - --Dan houlster@xxx.com ------------------------------ Date: Thu, 05 Aug 1999 21:50:20 -0400 From: Shannen Durphey Subject: Fw: Suburban VSS info A gentleman just brought this info to my attention: > JTR "Jagsthatrun.com" markets a > device to read his Suburban DRAC output in 4KPPM and converts it so a 730 or > 727 ECM can read it. I've used one for a year in a customer's TPI S-10 with > no problems. Its about $45. Shannen ------------------------------ Date: Thu, 5 Aug 1999 19:08:52 -0700 From: "Al Lipper" Subject: RE: Ecu 6 The software is all in the file, but you will need access to an EPROM/Device programmer to program the flash memory. I put the board together with a standard soldering iron, but used a very fine tip (and a somewhat steady hand) for the CPU socket. Most parts came from a local electronics store, some from Allied, Hamilton-Avnet and Digi-Key (I think the RAM was from Mosel-Vitelic directly, however I'm sure you can find other distributors). I don't have anything sophistocated here. I used ice cube trays to sort the parts and just used sockets for all of the ICs. That's about it. Good luck. Al > From: RSRACE@xxx.com] > Sent: Thursday, August 05, 1999 11:32 AM > To: efi@xxx.org > Subject: Re: Ecu 6 > > > I'm not an electronics whiz but if the schematics are good and I > have a parts > list and who to get them from I guess I should be able to do it. Is the > software in your download to load the program into the unit? Is > there any > special soldering tools needed to do the job or can I do it with standard > soldering iron. I'm trying to learn more about the electronics and > programming because I would like to build several controllers for > my car to > valves for boost control, water injection, and a secondary valve > controller. > If you think I can do it with standard equipment I'll get it. > > Thanks Again > Tom > ------------------------------ End of DIY_EFI Digest V4 #452 ***************************** 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".