DIY_EFI Digest Wednesday, 26 June 1996 Volume 01 : Number 180 In this issue: Re: 280ZX ECU in '78 BMW Re: Looking for Cadillac Error Codes Re: OEM CONTROLLERS Intel 8051? [none] Re: See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- From: "Josh Karnes" Date: Tue, 25 Jun 1996 14:15:10 +0000 Subject: Re: 280ZX ECU in '78 BMW > * Why doesn't the closed loop system compensate for any mismatch in > the EFI system? > > There are two problems. [snippo] > 2. the other problem is that the closed loop is only operational > when the > car is cruising and hot. Makes sense :) > * MW is 180, Z car is 135-150 > > Using all the Z stuff in the BMW may cause you to run lean at max > power. This is because the air meter 'might' run out of range at > about 160hp. Now, the AFM in the BMW is considerably bigger. I'd say about twice as big. > This is important if you use the all the matched > components from one car. You can of course use larger injectors, or > a different air meter. The problem is which ones? Well, howabout the ones that came stock in the BMW? Here's my case: the 280ZX digital injection was just about like the earlier analog L-Jets that the Datsuns were using. The only big differences are the ECU, harness and O2 sensor. So, they basically replaced those parts and had a similar, better? running car. In theory, then, can I just do the same with my car? The ECUs are similar between my BMW and the Nissan unit found in the good old analog 280Z, right (I'm asking, because I don't know for sure)? > You can > calculate the injectors, but you will still need to trim the result. > > > * The existing system is open-loop and runs rich > > See first item above. Very few systems run closed loop when burning > valves etc is a concern. I don't know of any system that truly runs > closed loop when under max power. Some digital systems calculate the > mixture during cruise closed loop running, and then apply enrichment > for max power. Makes sense. > > I think your best bet is to back off the enrichment (change the tune > on you existing car), Alright, so how do I do this? I know, monkey around with the AFM, and it will run leaner up until the AFM is no longer a part of the equation, maybe 3000 rpm or so. But what about the rest of the range? Does someone know exactly which part does what on the Analog ECU? Like, which part do I change if I want the car to run richer over the entire band? Is there a schematic for this ECU bouncing around somewhere? Or for the 280ZX ECU? > run a custom system like the TechII, or get a > system from a car witht the same injectors and engine size. > Otherwise it is too difficult unless you have lots of equipment. Well, all I can say is that right now, the car runs so bad, and is so inefficient, that anything would be better. It gets MAYBE 9 mpg in the city. For a 3300 lb car with a 3.0L six, that's about half of what I would call minimum acceptable gas mileage. So, I need to do something. My options are to try to monkey with the L-Jet that is in there and see if I can improve things, trial and error, or to start over and replace the entire ECU and harness. Nobody says I have to run this thing in a closed loop if I put the Nissan ECU in there. My bet is that the ECU from the 280ZX is tuned to run the car maybe a hair rich based upon the input from the AFM, TPS and O2 sennsor. So, seems like if I tune the AFM and perhaps the fuel pressure with the Nissan computer then I should be in good shape, eh? Maybe just an adjustable pressure regulator is what I need. This must be better to make broad-band changes in the fuel curve than AFM mucking. Later- _____________________________________________________________________________ Josh Karnes joshk@xxx.com Renaissance Man http://www.tanisys.com/~joshk/home.htm Tanisys Technology http://www.tanisys.com Austin, Texas '78 BMW 530i | '72 Datsun 240Z | IZCC #308 _____________________________________________________________________________ *** opinions expressed herein are MINE, ALL MINE!! *** ------------------------------ From: arthurok@xxx.com (ARTHUR OKUN ) Date: Tue, 25 Jun 1996 20:59:36 -0700 Subject: Re: Looking for Cadillac Error Codes You wrote: > >A couple of weeks ago the "Check Engine" light in my father-in-law's 1990 >Cadillac Fleetwood 4.5 litre has come on. Accessing the error codes on its >built-in system displayed: > > E49 E98 EE 70 > >I cleared the codes and the light did not come on again for 2 weeks, this >time the codes are: > > E31 E34 E49 EE E49 70 > >None of the books I can find explain what these codes mean (I guess the >Caddy is different from other GMs). > >Can anyone translate these for me? > >Lloyd Ferguson >ferguson@xxx.ca > the E infront of the two digit error code just signifies"error code" inthe first group 49= ?? 98=p/n d/r engaged problem . 70= intermittent tps second group 31= shorted map sensor circuit . 34=map signal out of range 49= ?? 70= intermittent tps this is from a 1992 chilton . i assume the info is correct. i would check for bad connectors and connections and burnt wires. after you do that email us back. > ------------------------------ From: "Stuart Woolford" Date: Wed, 26 Jun 1996 16:43:20 +1100 Subject: Re: OEM CONTROLLERS Intel 8051? > Are there any OEM engine controllers using the Intel 8051 cpu or any of its > variants? > toyota TCCS, I believe... - ---------------------------------------------------------------------- Stuart Woolford, stuart@xxx.nz >>>>In VI Where Available<<<< - ---------------------------------------------------------------------- ------------------------------ From: walter.kaufmann@xxx.ch (Walter Kaufmann) Date: Wed, 26 Jun 1996 09:10:20 +0200 Subject: [none] Hi, sorry, I am new here on this list, so I have to ask...... What system would you recommend for air flow(or air mass flow) measurment? I know three systems: This one with the round plate in the air flow, the system with the air 'trap' and that one with the platinium wire(air mass). I am looking for a system for a very small car(mini) who has no room for big ones.... Does anyone know more about that? Does anyone has an idea? Thanks Walter P.S> Oh yes, the idea is to build my own fuel injection, two ported (Mini's has two siamesed inlet ports...) and electronic ignition. All controlled by a Motorola 68332. ------------------------------ From: dzorde@xxx.au Date: Wed, 26 Jun 96 16:02:20 Subject: Re: Wow, the car will have more processing power than engine power (only kidding). If there is no space why not consider a MAP based system ? Hi, sorry, I am new here on this list, so I have to ask...... What system would you recommend for air flow(or air mass flow) measurment? I know three systems: This one with the round plate in the air flow, the system with the air 'trap' and that one with the platinium wire(air mass). I am looking for a system for a very small car(mini) who has no room for big ones.... Does anyone know more about that? Does anyone has an idea? Thanks Walter P.S> Oh yes, the idea is to build my own fuel injection, two ported (Mini's has two siamesed inlet ports...) and electronic ignition. All controlled by a Motorola 68332. ------------------------------ End of DIY_EFI Digest V1 #180 ***************************** 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".