olie05 Posted July 11, 2006 Share Posted July 11, 2006 Heres the deal, I don't want to have wiring running all over my car, so I want to use the existing main relay and fuel pump relay with the MS. Trying to think of how to wire this thing, since megasquirt only grounds the fuel pump relay (seperately), and the stock main relay has a built in fuel pump relay. I'm thinking of just using all the wires that are in that location and using my own standard relays, but separating the FP and Main relay functions. Is anyone running the stock fuel pump/ main relay, if so how did you wire it to MS? Quote Link to comment Share on other sites More sharing options...
Mack Posted July 14, 2006 Share Posted July 14, 2006 I did what you want to do. Basically, I took a stock harness, lopped off the ECU plug and re-wired all of the stock wires onto the DB37 connector in the appropiate places. I dont have any wires that werent there from the factory. nevermind the fact that it took me about 4 hours with 2 wiring diagrams and a multi meter... but it looks stock as all hell And its been performing flawlessly. Quote Link to comment Share on other sites More sharing options...
olie05 Posted July 14, 2006 Author Share Posted July 14, 2006 Wow. Congratulations!!! I don't think I want to go quite as far as you did to retain the stock wiring to the relay. I notice megasquirt has a ground for the fuel pump. I also assume that it is important for this ground to be hooked up to the ground of the fuel pump relay, otherwise the ecu is not controling the fuel pump. This is a safety concern for me, and I don't like the idea of not hooking it up. that was the only thing i am really confused about. Can you elaborate your fuel pump wiring? thanks! Quote Link to comment Share on other sites More sharing options...
Mack Posted July 14, 2006 Share Posted July 14, 2006 on my car (1980) the fuel pump is kicked on by the igntion switch, not the EFI brain. so, basically I just wired my car using the stock EFI relay to power up megasquirt. I didnt have to muck with the FP relay. not sure how you'd do it on yours... I guess you could just run a hot wire to a relay for the FP, keep it hot all the time and run another wire to the ground for MS. Quote Link to comment Share on other sites More sharing options...
olie05 Posted July 14, 2006 Author Share Posted July 14, 2006 yeah, I'm thinking there is no way around the 77 relay. I can still use the ecu power off of it, but for safety's sake, I will end up wiring the pump externally. the thing is that the fuel pump wiring is like this: a power wire going from the relay to the ecu, and it splits off to the afm. The afm closes a circuit with that power wire and clicks on the fuel pump relay. I don't know if that made sense. Yes, I will definitely wire the fuel pump with my own relay. Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 19, 2006 Share Posted July 19, 2006 check with Bryan Blake, I believe, matter of fact I'm sure, he is using that funky dual relay in the 75 to 78 280Z to control his EFI power and Fuel Pump... Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted July 20, 2006 Share Posted July 20, 2006 ive tapped off the old harness on my '78 .. works fine Quote Link to comment Share on other sites More sharing options...
twoeightythreez Posted August 3, 2006 Share Posted August 3, 2006 I'm slowly beginning my MSII install in my '78. I'm gonna go turbo but I want to get the install done and running on the motor I have now. (L28E) I did find some interesting things in the J/Y today that I'm pretty stoked about...I'm open to suggestions/improvements on my ideas for this. 1) An electric fan from an 88 sentra coupe seems to line right up to the edges of the Z radiator (there was a '78 Z right next to the sentra) The bottom mounting is "slide in" so I can make up some angle iron brackets to the rad support, and for the top it bolts in (will have to figure that out) It seems to move a ton of air with both fans and the coolest thing is that the sentra rad has a temp switch for the fans. Talk about cheap way to get a self-contained electric fan! I'm gonna run the fans through a relay and the switch appears to be the same thread as the thermotime switch on the L28 stat housing. I'll find out for sure tomorrow. I know MSII can be used to control fans but this is cool, too. (Fans will run with the engine off this way if the coolant is hot enough) 2) The Stanza relay box I got I'll use to run the fans, and I also might use it to trigger the fuel pump relay I have. (or should I just replace all that crap on the r/h fenderwell with the stanza relay box?) 3)I got a GM IAC Valve and am trying to figure out how to incorporate it into my TB...will do a remote set-up if I have to but I want it to be clean. I'm wondering I I can drill out the stock idle screw on top of the TB to match the GM unit? (I'll adapt a mounting provision, probaby will hacksaw the seat and such from the GM throttle body) I want to keep my MSA 60mm if possible. 4)The '89 grand prix 3.1 that donated it's IAC also donated it's IAT press-into-rubber type sensor. The coolest thing about this is it fits right in the boot at the TB where the stock cold-air bypass hose goes. I just had to trim 1/4 inch from the nipple so the IAT sensor is in the airflow. 5)The Stanza TPS I'm going to mount to the stock TPS back plate after I smooth it out. This way I can use the stock adjustment screws with no problems. 6) The AFM, naturally is going away. I'm thinking for now I'll use an 8" piece of 3" exhaust pipe section to bridge the gap. 7)I got some 7MGTE injectors from the yard today. Is it worth it to change out connectors or should I get some with bosch type connectors? Thank you for your inputs (if you give any) Quote Link to comment Share on other sites More sharing options...
olie05 Posted August 3, 2006 Author Share Posted August 3, 2006 That has got to be one of the biggest hijacks I've ever seen. Quote Link to comment Share on other sites More sharing options...
twoeightythreez Posted August 4, 2006 Share Posted August 4, 2006 Welp the install is still going...I pulled all the cold idle crap off the intake, can actually see the intake now! Amazing. I pulled the TB and realized that there is no way to get the GM IAC in there. So I bought the DIY autotune remote IAC enclosure. Still have to modify the TB so it will work. Planning on drilling/tapping it for a 1/4 NPT pipe plug to block the opening aft of the throttle plate, then putting a nipple where the idle screw goes. Then it will double back into a nipple where the cold start injector used to be. I'll put a another nipple where the bypass hose used to mount to the TB and use it for the BOV. The enclosure itself at 2.25x2.25x1.75" should fit where the stock cold idle bypass went. This way it'll look a lot cleaner than the miles of hose with the stock setup. I have to run to the yard to try to find some plugs for the thermostat housing (where the coolant line for the EGR cold-shutoff solenoid nipple mounted) It should be the same size as the one in the front of the Z housing. I also need to find a nipple without the extra nipple for the heater hose connection. I also need to find some injectors that bolt right in to the nissan intake with no mods (I hope I can find that elusive 450SEL) The cooling fan idea fell through....will have to use MS to activate the fans, the sentra temp sensor has bigger thread diameter (but same pitch) by a hair then the thermotime switch. Doh! Still have to remove the stock fan and shroud, mount the sentra fans, and install the '83 CAS dizzy. Then the fun begins, hooking up the MSII. I have to get a camera so I can take some pics. Oh well thanks for all your support! Quote Link to comment Share on other sites More sharing options...
olie05 Posted August 4, 2006 Author Share Posted August 4, 2006 hijack Forum speak, is when a thread is taken from one direction of discussion to another completely off course topic or many different topics in a short period of time. Quote Link to comment Share on other sites More sharing options...
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