For now I limitied the max timing to 32 degrees until I get back to that. More than 32 degrees timing causes the spark to jump to the wrong post in the small cap distributor. I have one problem left with the setup that I haven't had time to work on. When the engine fires up check the timing at the crank matches the timing from your spark table. Set the cranking timing to about 10 degrees BTDC. I suggest cranking the engine with the injectors disconnected and a timing light hooked up. (I did not use fast idle)Ĭonnect pin R of the 8 pin HEI module to TACH input of relay board.Ĭonnect pin B of the 8 pin HEI module to X12 (S2 connection on relay board)Ĭonnect pin E of the 8 pin HEI module to X11 (S1 connection on relay board)Ĭonnect pin G of the 8 pin HEI module to groundĪssuming that your not trying anything fancy you will already have the coil wiring in place for the stock GM coil. Hook up injectors, IAT, CLT, TPS, O2, fuel pump etc. They both function the same)įit wire between XG1 and right side of D5(non band)įit wire between bottom of R10 and small hole above D9(this is a +5v source - you could also use the hole to the left of D4)įit 1.3K resistor in place of D8 (1k-2k ok)Īdd 1k resistor from (-) of D17 to the right (5v) side of R23Īdd 1k resistor from (-) of D19 to the right (5v) side of R27Ĭonnect the relay board in the normal manner.
The following mods need to be made to your MegaSquirt hardware to run 7 or 8 pin HEI modules (some TPI distributor use a 7 pin module, some use an 8 pin module. Go to the "spark" tab and the go to "spark settings"įor all the rest of the settings in MegaTune you are on your own to decide if you use traction control, water injection, staged injection, NOS, etc etc etc. Go to the "spark" tab and the go to "dwell settings" Go to the "code config" tab, then go to the "codebase outputs and function" tab Go through all of the tabs and all of the settings and make sure everything is either disabled or set correctly for your system. The stock TPS, FPR, injectors, TB, small cap ditributor, 8 pin HEI module, etc were all used.įamiliarize yourself with all the settings available in MSnS_Extra024s9 code.
The TPI manifold already had places to install them. The recommended GM air temp and coolant temp senors were used. MSnS_Extra will NOT support control of the TPI IAC valve. Or else end up with air bypassing the throttle plate, high idle you can't get rid of. Otherwise you have to figure out a way to close it or remove it and block off the air inlets to the plenum/throttle body. Mine happened to be in a closed postion, but you may find that yours is open somewhat, you can turn the motor to close it manually I think. NOTE about IAC: from what I understand the IAC valve will be in the position it was last in when the car was shut off. You can remove the cap over the throttle plate adjuster screw easily with a punch. The idle air controller on the bottom of the thorottle body was left disconnected and idle was adjusted with the throttle plate. TPI was from a 1987 305, 19# injectors, small cap distributor with 8 pin HEI module and external coil. (be careful to follow megatune setup procedures and copy msns_extra.ini file or you won't get all of the new feature tabs) MegaSquirt v2.2 hardware with relay board Files can be found by going to then following the link at the MSnS_Extra forum. Let me know if anything critical is missing. MegaSquirt Reference Description Digi-Key Part Number 10 C1, C3, C17, C18, C22, C25 to C29 Capacitor 0.1uf 399-1880-1-ND 3 C2, C4, C10 Capacitor 0. However, given that I can check my average mileage upon fueling, I can just look at a wide or narrowband O2 to determine when I'm running leanest and consequently getting the best mileage.Here are some various notes from the TPI install. Having knocked the idea, I wouldn't mind doing something similar. So, now you'd know you were getting better mileage at cruise than in passing. For example, your calculations may show you're getting 28mpg at 5th gear cruising and 12mpg when passing, but you could very easily be getting 22mpg at cruise and 6mpg when passing. Ultimately, as stated already, all this is doing for you really is giving you a delta to show where you're getting the best efficiency.
I agree that can work pretty good, but you really have to know what's going on with everything and constantly update it to account for any changes made in the system (ie the whole car). Like I say, it works pretty good, but you have to make a gauge for each gear you want to see so I only did 4th and 5th. The instant mpg gauge I added used rpm, tranny and diff ratio, tire size, inj pulse width and injector size to determine mpg.