DIY_EFI Digest Thursday, September 9 1999 Volume 04 : Number 514 In this issue: re: O2 Sensor Voltage Sequential Injection injector overlap? Re:Corrado or Golf VR6 BIN Re: O2 meter Fuel pump See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Wed, 8 Sep 1999 14:20:46 -0700 From: "John Dammeyer" Subject: re: O2 Sensor Voltage Hi all, I think you have to consider the input impedance of the measuring device when checking out the O2 sensor. Unlike parts available from semiconductor manufacturers there doesn't seem to be a lot of information out there about O2 sensors. However, measuring the voltage the way you are is fine as long as the load the meter presents isn't too low. Normally a standard digital meter is adequate. As for an isolated ground... this isn't really needed unless the O2 sensor is also still connected to the Engine Control Unit. This is because you don't know what the electronics inside the ECU looks like. Both sides may be isolated above ground so connecting one side to ground will do strange things. But as far as measuring the ECU output relative to ground, I use a standard LM324 operation amplifier to isolate the low input impedance of the uC A/D converter from the O2 sensor and once side of the O2 sensor is connected to ground. What I have also determined empirically is that 0.5V is 14.7:1 ratio and that 0.7 is about 14.3:1 and 0.3 is about 14.9:1 or thereabouts. Note too that some A/D devices (like your digital meter display module), may require a stable signal in order to create a valid reading. This is why some systems use a Sample and Hold (S/H) circuit to freeze the value while the A/D performs the conversion. Cheers, John ------------------------------ Date: Wed, 8 Sep 1999 19:36:34 EDT From: PHXSYS@xxx.com Subject: Sequential Injection injector overlap? Hi I was wondering if anyone knows if the injector pulse widths overlap on sequential injection. The application is a Chrysler 3.3 v-6, 97 model year, but I am sure GM is similar. What I mean by overlap is, say injector 1 has fired, is it possible (or likely) for the next injector to fire while the previous injector is still on? Thanks Jon ------------------------------ Date: Wed, 8 Sep 1999 20:02:12 +0000 From: xxalexx@xxx.com Subject: Re:Corrado or Golf VR6 BIN If 16 pin obd2 connector, I can provide low cost tool. Alex http://www.obd-2.com >Wanted - Corrado or Golf VR6 BIN > Also, does anyone know how to get the fault codes from this ECU ? > > Alan Smith > ------------------------------ Date: Wed, 8 Sep 1999 20:02:12 +0000 From: xxalexx@xxx.com Subject: Re: O2 meter Check aquistion time on your digital meter. This probably a intergrator, with conversions time of 0.5 Hz. You could be getting a average and aliasing similiar to a DVM. Alex ------------------------------ Date: Thu, 09 Sep 1999 13:38:36 +1200 From: Steve Spiers Subject: Fuel pump Hi I am having probems with my 1600 with twin 40mm DCOE's I have bought this up before. It misses at high RPM I have checked everything and I am now just trying out theorys that people come up with. I checked the fuel supply into the carbs and it just dribbled out. What is an adiquate fuel flow rate and pressure that the pump should be supplying? Thanks Steve ------------------------------ End of DIY_EFI Digest V4 #514 ***************************** 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".