DIY_EFI Digest Sunday, December 12 1999 Volume 04 : Number 691 In this issue: [none] ECU pulse width calculations...? Re: how does tbi work engine swaps See the end of the digest for information on subscribing to the DIY_EFI or DIY_EFI-Digest mailing lists. ---------------------------------------------------------------------- Date: Sat, 11 Dec 1999 15:15:56 -0600 From: "Steve Schneider" Subject: [none] This is a multi-part message in MIME format. - ------=_NextPart_000_0004_01BF43EA.9F3AC3A0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Edelbrock MPFI for 350 TBI Part # 3501 The Edelbrock EFI works with the original wiring harness. You splice into the four wires leading to the TBI assembly. The Edelbrock MPFI wiring harness then plugs into eight injectors positioned on each side of the intake below the fuel rails. I have not installed the Edelbrock in my Z71 as of yet. The only snag that I can for see from my research is the in-tank fuel pump swap which must be done to achieve the 45 psi required for the MPFI. Other than that, I would suggest checking your EGR valve. I know I will probably need to replace mine since the Edelbrock system is more fussy and could cause poor idle and a rich mixture. Depending on the vehicle, there are also some sensor and throttle cable bracket issues you may face since Edelbrock did not make a bracket for all of GM's different brackets. srs - ------=_NextPart_000_0004_01BF43EA.9F3AC3A0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Edelbrock MPFI for=20 350 TBI

Part # = 3501

The = Edelbrock EFI=20 works with the original wiring harness. You splice into the four = wires=20 leading to the TBI assembly. The Edelbrock MPFI wiring harness = then plugs=20 into eight injectors positioned on each side of the intake below the = fuel=20 rails.

I have = not installed=20 the Edelbrock in my Z71 as of yet. The only snag that I can for = see from=20 my research is the in-tank fuel pump swap which must be done to achieve = the 45=20 psi required for the MPFI. Other than that, I would suggest = checking your=20 EGR valve. I know I will probably need to replace mine since the = Edelbrock=20 system is more fussy and could cause poor idle and a rich mixture. = Depending on the vehicle, there are also some sensor and throttle cable = bracket=20 issues you may face since Edelbrock did not make a bracket for all of = GM's=20 different brackets.

srs

- ------=_NextPart_000_0004_01BF43EA.9F3AC3A0-- ------------------------------ Date: Sat, 11 Dec 1999 13:38:23 -0800 From: "Andrew Brownsword" Subject: ECU pulse width calculations...? I finally got to try my modified program in the car's ECU today.. and (unfortunately) did NOT get the expected results. The car is a '93 Ford Probe GT (Mazda 2.5L DOHC V6 engine). I had modified the program by locating all of the places that the injector firing routines are called from, tracing backwards to locate the last place that the calculations are scaled by a ROM value before being passed to the firing routine, and then scaling back the injector values by the ratio of the flow rates of the old and new injectors. Doing this, as I understand it, should have reduced the pulse widths controlling the injectors and therefore decreased the amount of fuel being injected. We cut the numbers by fully half and measured the effect using a (high end) A/F meter. We expected to see the engine lean out significantly at idle... instead it leaned out slightly. From 11.5 up to 13.2 or so. It would momentarily jump up to around 14.5 and then slowly drop back down to 13.1 or so. Does anyone have theories, advice, hints, etc? Thanks, Andrew ------------------------------ Date: Sat, 11 Dec 1999 10:09:37 -0300 From: "Diego Martin Monteverde" Subject: Re: how does tbi work Hello Bill, I visited your page. From what FIAT does the efi parts came from? Thanks, Martin >Date: Sat, 11 Dec 1999 13:55:21 -0400 >From: Bill Shaw >Subject: Re: how does tbi work > >Hi Larry, > >I'm in the process of converting my '78 to EFI, you might want to >take a look at my page at http://www.connix.com/~bshaw/fiatefi.html >to see how I've gone about it. What you're proposing is possible, >but it'd be much easier to do using Fiat parts. > >There's also some real good general efi info at >http://hometown.aol.com/dvandrews/ems.htm, and much info >in the list DIY_EFI archives. > >Hope that helps, > >Bill ------------------------------ Date: Sun, 12 Dec 1999 02:10:05 -0500 From: Michael Baxter Subject: engine swaps john writes: >> ok, so help me out with the math here... << pre '81 258 = 535 lbs. '81 up 258 = 445 lbs. (apparently...I can't verify that number exactly) 360 = 540 lbs 401 = 550ish lbs. (thicker webbing in the block and bigger crank journals) Now the question of the day: Do those weights include the standard accessories like the alternator, fan, fan clutch, carburetor, air cleaner, air pump, etc or is that just a bare long-block? Jeep doesn't specify. Michael Baxter, MBaxter@xxx.net http://ourworld.compuserve.com/homepages/MBaxter From Reno, NV USA on 11-Dec-1999 ------------------------------ End of DIY_EFI Digest V4 #691 ***************************** 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".