DIY_EFI Digest Wednesday, November 10 1999 Volume 04 : Number 634 In this issue: 3.4 L DOHC RE: electric supercharger on eBay Re: DIY_EFI Digest V4 #607 Motronic 4.1 newbie--still struggling Electromotive CPS Pinout See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Tue, 09 Nov 1999 14:20:39 -0700 From: "Daniel Furgason" Subject: 3.4 L DOHC This is a bit off topic, but does anyone have experience with the GM 3.4 L dohc V6? Just curious if it has any bad habits as my daughter is about to buy one. Thanks Dan Furgason ------------------------------ Date: Tue, 9 Nov 1999 14:16:32 -0800 From: "Randall Young" Subject: RE: electric supercharger on eBay > -----Original Message----- > > there was one on ebay for sale > the guy selling it said it made no noticable difference to > his Cavalier > it was very recently > there is probably still a liting for it http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=192495543 Auction doesn't end 'til Thursday. But, it doesn't seem to be the same unit. Randall ------------------------------ Date: Tue, 9 Nov 1999 19:42:32 -0800 From: rpettibo@xxx.com Subject: Re: DIY_EFI Digest V4 #607 Doug - I can not find my dyno sheet from the session with the the fuel injection so I will just give you rough numbers based on memory. I do have the dyno next to me for the same engine when I compared a Performer RPM Vs a Bowtie single plane (similar to a Victor Jr.). The dyno I ran on would only pull down to 3000 to 3500 RPM so all runs were begun at 3500 and ran through 6500. The minimum gains with the fuel injection were in the 30 to 35 lb/ft range even at 3500. There was no loss in power compared to the carb at any piont in the pull. I know the increase in power has carried down in the powerband because after the conversion the car no longer hooks up from a standing start. I run about 2300 stall with a built 700R4 and it will light it up, in smoke, to 6500 right now. It did not have those beans before. I shift at 6500 to 6850 and I think the drop is to about 4000 in second, I just have never paid attention to the tach after the shift. I will check it out this weekend and E-mail you directly. Part of the success I have had is spending the time (2-3 hours at a time) driving and tuning the fuel curves at various loads and rpm points. This has made a big difference. I probably have 40 to 50 hours in tuning time dialing things in. Your thoughts with the single plane Vs dual plane with carb are accurate based on the dyno runs I made with the same engine comparing a Performer RPM to a Bowtie single plane. When I first built this engine I ran the Performer and a carb. In essence they were both about the same on the bottom end (5 to 10 lb/ft diff. max at some RPM points) but I gained on the top end (above 5000) 10 to 20 HP. One thing which put the Bowtie at a disadvantage was the dual plane was port matched and the bowtie was not. When we were putting on the Bowtie I could see the ports were not matched very well. At that time, if I had not spent the money to port the dual plane, I would have gone with the Bowtie/carb combo. I know I would have gained back what I lost on the bottom and gained more top end if everything was ported. On another note I am just beginning to build a 440 small block and am anticipating going with the Speed Pro system. Anybody have any thoughts or experience with this system? To me it seems to be the most up to date and well thought out system out there especially with the wide band O2 capability. ------------------------------ Date: Tue, 09 Nov 1999 21:00:15 EST From: "Derek Kaznoski" Subject: Motronic 4.1 newbie--still struggling I checked the engine temp. sensor, its OK (thanks for the suggestion). I just want to confirm: the AFM flapper IS supposed to be slightly open at idle, right? Now for some more novice troubleshooting: I disconnected the idle air bypass hose from the intake ducting and left this end open to the air. I plugged the hole left in the intake ducting. As I expected, the car would start and "pseudo-idle" (with flapper reference advanced on the AFM potentiometer to increase resistance, as before). However, when I blocked the open end of the idle air bypass tubing, the car stalled. Thus the idle speed actuator must be working. (previously, I had just clamped the tubing to test this, but I must not have completely blocked the flow) I disassembled all of the upper intake ducting, and found no holes or potential leak spots between the AFM and ISA or throttle assembly. It seems to me that anything causing any leak into the plenum chamber would effectively decrease the vacuum in this chamber and decrease the amount of air flowing through the idle speed actuator (and thus, through the AFM). So,I also checked everything that connects to the plenum chamber (oil vapor hose, fuel vapor hose and solenoid, fuel pressure regulator tubing) and found no leaks. I can hear a distinct hissing sound coming from around the bottom of the plenum chamber where it intersects with the engine or just forward of this area. This hissing intensifies just after the throttle is blipped and before the engine responds. It continues with decreased intensity as the rpm's rise. To me, this sounds like an air leak, but I've never heard one. Could this sound be coming from something else, such as circulating coolant? When this idle problem first started (weeks ago), I checked the rubber sleeves and clamps that seal the joints between the plenum outflows and intake runners of the cylinders. I noticed that all of them were slightly loose and had worked their way toward the engine side. I could even see the joint past the edge of one of them. At that time, I loosened all of them, moved them back toward the plenum side, and retightened the clamps (really tight). I guess I could've damaged them in the process since they were very difficult to get to. I can't see any obvious damage, but I can't see the underside of them. What is the best way to localize the leak (specifics please!)-- I've read about using a propane torch, but I'm a bit leery of this. Also, what could be other potential sources for the leak if there is one? Thanks again in advance. - -Derek Kaznoski '90 Alfa Spider ______________________________________________________ Get Your Private, Free Email at http://www.hotmail.com ------------------------------ Date: 10 Nov 99 18:00:33 +1200 From: "Tom Parker" Subject: Electromotive CPS Pinout Hi, I've just bought an electromotive crank trigger wheel and sensor. The sensor has 3 wires: a red one, a black one and a braided shield. I'm assuming that the sensor is a normal hall effect device. This would mean there is a ground, a power supply and a sensor output. Now, I could guess that the red wire is the power, the braid is the ground and the black is the signal, but I don't want to blow it up. Does anyone have a pinout for this sensor or a schematic for a circuit to drive it? Does it need any current limiting resistor in the power supply? - -- Tom Parker - parkert@xxx.nz - http://www.geocities.com/MotorCity/Track/8381/ ------------------------------ End of DIY_EFI Digest V4 #634 ***************************** 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".