DuoWing

Actually I managed to find the threads that FricFrac had linked to in the OP. The title of the thread is Rose's Ride. That's one problem I run into a lot on HybridZ is I'll find a thread with a link to another good thread, but the link goes nowhere, so I'm stuck trying to figure out what the thread was. Anyway from reading and searching it would seem my approach to a star ground is incorrect or at least closer to a loop ground. What I'm doing is going point to point, and branching from each point. So I'm adding a lot of grounding points which can apparently end up causing more noise/interference due to so many grounds. This is apparently why the star is so good because you're linking as much as possible to one singular ground point.

A good thread and I know I'm bringing it back, but I've started doing this on my Z. I like the idea of everything having a good path to ground. Now my only real question is on ground loops. I'm not really sure how to tell if I'm creating a loop or not. Basically I started the same way fric frac did. Then I run a leg to another bolt along the firewall and generally do 3 connectors per bolt. So I keep moving along running stars from each point. I will test each thing that I'm unsure of for continuity before connecting it in. I assume that I can keep doing this as long as I don't end up connecting something from one star into another star or someway running it back to the main ground a way other than it came?

I think the real problem comes from running such small gauge wire over such a large distance. If you're using the stock wiring you're running from the fusible link, to the relay, to the back of the car at the pump, which isn't even a straight shot. It goes through a grommet then back tracks a little to get over to the pump. Then your ground wire isn't even at the back of the car if I'm not mistaken, the ground for the pump then comes back in and runs back towards the front of the car and gets grounded in with the main harness. So you have a loooong way for that electricity to travel just to run this electric motor.

When I first did the Z31 ECU swap wiring was a thing that I really couldn't wrap my head around and it was a big ordeal to me, but it seemed simple compared to having to rip the whole harness out and build an MS harness from scratch and then tune it too! I would say the Z31 swap is a viable alternative if you have everything around or access to it for fairly cheap. I feel confident enough to say that I could do the Z31 ECU/MAF conversion in an afternoon. If anything for the original poster I'd almost say work on say swapping everything over to MS. Get that all running and you can probably pull a little bit more performance out of your existing N/A engine. Then work on going to a Turbo motor, or turboing the N/A motor. This way you'll have everything ready to go. The biggest problem I ran into with my Turbo swap was that I pulled the motor and rather than a straight swap, I put a rebuilt solid lifter P90 head, N/A cam, N42 EGR-less intake manifold, swapped fuel rail, new oil pump, chain, etc. So I dealt with having to re-drop the oil pump to get the timing right, finding all kinds of vacuum leaks that were just stupid things, along with swapping the harness over and then finding wiring issues with that. Too many issues with motor and wiring all at once, which more than a couple times had me convinced something was wrong with the motor and I was ready to scrap the whole thing, or at the very least pull the motor back out and have it completely rebuilt.

I originally ran a Walbro, and couldn't stand the noise. I ran a Bosch 044 afterwards and even still it was getting noisy. I see you have yours mounted horizontal which is good. I found a couple things though, the stock Z wiring in my opinion is not a good choice for an aftermarket pump. I was seeing as much as a 1v drop between the relay and the pump after running for a bit. I also found the stock relay that I pulled from my old 280ZXT with the harness was getting quite hot. When looking through threads pertaining to the Z31 ECU and swapping over on Z31Performance I found a post by JeffP where he was encountering pretty much the same issues. Finding that the old relays were really not good enough for newer high flow pumps, and the wiring was way too small. His solution was to run a bigger relay and much larger wire. I remounted my pump as low as I could so it would be sitting just below the tank outlet and the pump would get as much fuel via gravity vs. having to pull it. I ended up using a bigger relay, and 10 gauge wiring for my pump. The 10 gauge may be over kill and 12 gauge as SleeperZ mentioned is probably more than enough. After doing these things I was seeing at most only a .3v drop between the relay and pump + terminal. Now my pump runs nice and quiet. Before I was having the same issues as you. Louder than the exhaust. I was also about to add in a secondary low volume pump. I would only recommend this if you're mounting the pump elsewhere. Some people like to mount it up high, or in the engine bay, if you mount it there, then the low volume pump will be an advantage in helping the main pump get it's supply without overworking it. Otherwise work on improving your wiring and making sure the pump is positioned well and you should be fine.

Well at least a couple of adapters have emerged. This should help people especially if you've never made brake lines before. Also another thought I had is that since 3/8-24 is smaller than 10x1 you may even be able to remove the aluminum line adapters from the MC and actually just tap them out to 10x1. Then everything should fit nearly perfect.

I've been interested in this trend as it looks pretty decent and doesn't require too much work, although I think for now I'm sticking to the old trend. Rustoleum.

Those fuse blocks do look nice, where did you find them?

Going with the getting off topic, I've never had these cars run exactly right when hot and then being allowed to set for a couple minutes. I believe it was Tony who a few years ago him and I had a back and forth over on Zcar.com where I hooked a pressure gauge to my fuel line and tested the whole heat soak theory. Within a couple minutes of leaving the hood closed after turning the car off after it had been nice and warm, on a warm day at least, the pressure gauge would go up quite a bit. Showing much higher pressure than what you should normall see. After allowing the car to sit for a while and start to cool down, the pressure would start to bleed off and actually rest a lot lower than what it was supposed to be at. You'd start the car up and now you're dealing with a few moments of sputtering do to the loss/bleed off of fuel in the lines and injectors, after a moment or two of throttle you'd end up supplying enough fuel to get everything straightened back out. On another note my current 76' Turbo Z never starts on it's first try from a completely cold start, or at least has a hard time. I'm assuming because of the aftermarket FPR that doesn't hold pressure when the car sits.

I'm trying to collect up and everything for my MS setup. The only thing I'm really trying to figure out is what's the best way for going about adding wiring and fusing for my setup. I've converted my fusible links over to Maxifuses, I also added two more. So I have 6 total maxifuse spots. They are run off a 6 gauge wire that then runs down to the starter terminal. 4 for the original 280Z fusible links, The 2 other power my EFI/ECCS setup. The one is a dedicated relay/line for just the fuel pump. So I have the last one I can relay for the main MS relay, and fuse block. I'm trying to find a good fuse block and I'm not really sure how many fuses I can run if I go with a 10 gauge wire. I was thinking of doing an 8 gauge wire, but even that is proving hard to find as well as I don't have any way to crimp anything to an 8 gauge. Just looking for some suggestions on what's a good way to go about doing this. Ideally I'd like to run 6 fuse spots so I can at least have two extra fuses should I need to add anything in the future.

Well I went and did a search for WPN079 on RockAuto and I get a Valeo water pump. So no idea what it's for, because it's not listed under Diesel Maxima. Never mind, looks like it's for a 280ZX and some other Nissan vehicles

What size wire are you running to your pump? I was having issues where after driving my Z at higher(freeway) speeds for a bit my fuel pump would get loud. I was also seeing a loss in fuel pressure until I shut the car off for a bit. The relay was also getting quite hot. I started measuring voltage and was seeing as much as a full 1v drop from the relay output to the + terminal on the pump. What finally fixed my problem was thanks to JeffP and some other help here. I now run a 70amp relay like they give you with those Electric fan kits and I also run 10 gauge wire straight from a maxifuse terminal connected to battery, to the relay, then a 10 gauge wire from the relay back to the pump. I run a 10 gauge wire from the pump - to a grounding point in the back of the car. I have yet to finish adding another ground wire from the back of the car running back up to the front for my star ground setup, but after this I then was only seeing a voltage drop of at most .3v, the pump was no longer getting loud and I wasn't experiencing the pressure drop. This is on my 76' I was originally using the stock wires which are far too small in my opinion. Also if you happen to be running an external pump like I am, make sure you're not making it work to pull the fuel to the pump. I mounted mine lower to make sure it was being gravity fed from the tank. Also external pumps seem to like being mounted horizontally better.

An interesting thing about the CHTS is make sure you haven't dropped it. Once you drop these things, at least in my experience they're done for and just buy a new one. I've dropped the CHTS, and O2 sensors before and then had nothing but issues with them functioning incorrectly. Another thing I've encountered, brand new CHTS, yet it's still bad and reading wrong.

Yeah I know that the CHTS would stay, I was just curious because a lot of people said they were just going to use, and I noticed some discussions about the temp differences between the two. So I was just curious if one had an advantage over the other. I'm percectly happy with using the stock CHTS. One less thing I have to add in, or figure out where to add in.

If you're not afraid of some tuning/wiring, etc I'd say go aftermarket. I'm one who has Nistune and really like it, but for the price and time in it especially if you're going to put some money into converting to the Z31 stuff, might as well take that money and go MS.

I skimmed through the topic, but I was just looking through my 76' wiring diagrams the other day and it goes very similar to 280ZX/Z31 wiring. Fusible link runs down to an EFI relay under the dash above ECU. Once that relay recieves the trigger signal to turn on a line comes from your EFI relay that then feeds the fuel pump and the Air regulator. I believe it's a GL(green and lavendar) wire. My fuel pump in my Z is almost completely disconnected from the EFI/ECCS harness. I have a 10 gauge wire coming directly from a maxifuse block in the engine bay, into a 70amp relay, then from the relay, through a 10 gauge wire straight back to the pump. The pump then is grounded at the taillight harness in the back. I just ran the original ECU wires to the relay to trigger it, but my harness is also a weird marriage of 280ZXT harness/with Z31 ECU components, mated to a 76' body harness.

Due to this thread, and Tony's comparisons. It was enough to push me over the edge and go MegaSquirt. I've had a really decently running L28ET. The Z31 ECCS/MAF was definitely a nice upgrade over stock, but I'm still stuck by some of the limitations of it, not to mention I'm using what is quickly becoming a butchered up 30 year old harness. I've changed a bunch of things, and continue to keep finding issues amongst the old harness, while adding more grounds, etc. I keep working on my wiring harness diagram, changing it to reflect what I have done. I'm at the point where I pretty much could have built a MegaSquirt harness and been done with it.

Thanks for the info guys. I had seen people talk about using it, but it seemed to be most people were using it just because it was already there. Does make sense then to have it seeing the higher temps quicker than what the coolant will see.

I'm planning to convert to MegaSquirt soon and I've been reading as much as I can. I think I'm pretty much ready to order. The only thing I'm interested in is what people are using or if there's a difference. I see a lot of people using the CHTS for the CLT sensor in MS and I managed to find the thread with the values for the actual datsun coolant sensor to put into MS. My only real question is if one is better to use vs. the other? I know the CHTS would reach operating temps much quicker than the Coolant sensor, I don't know if this would make a difference, or if it's better to go with the coolant sensor? Also I'd assume that the coolant sensor should theoretically see lower overall temps than what the CHTS would probably report. Just something I was curious on.

My main reason for not removing the rear suspension crossmember is that I like it as a jacking point for the car. If you go to just the R/T mount, where do you guys jack the car up then? These old cars and images of rusty ones punching and crushing things always has me afraid when it comes to jacking these things up.

In my experience in most cases of putting new pads and rotors, even on stock cars with a floating caliper. When brand new you almost always get some drag. As you'll start driving you'll hear it, then do your short break-in drive and usually by the end of that the pads, rotor, has already begun to wear and match to one another and you're good to go. I did have an issue when I put my 240SX rear calipers on my Z where the one side was really tight. I then realized that the pads were not all exactly the same and one of them had a little tab on the back. So I didn't put them together correctly and the little tab was pushing against the caliper, rather than letting it sit properly and was causing more drag. Switched them all around and was good to go.

You know jhm I read your post a couple times, and then after you just posted I went back and re-read it. For some reason it didn't click until now. I swear you must have edited that in just a bit ago So much for my comprehensive reading...

Well I've disconnected every bulb, even pulled my dash cover off so I could remove the Speedo and Tach and finally the light went out, but there doesn't appear to be any short. Although I'm glad I did this as the back of the Tach is a bit rusty for where the turn signal bulbs ground so I can clean those up a bit. Anyway driving me nuts thinking about it and I started thinking about what would have changed with removing the glove box. I've come to a pretty concrete thought. The glove box light. No problems until I removed the glove box. My glove box never had a light in it, so I never really knew what that switch was for. Then it occurred to me that the whole body of it is metal. After removing the glove box it would have just been hanging there. So all I would have to do is turn the switch for the lights on and it just needs to swing into the metal support for the dash and ground out. This would also probably explain why it kept blowing fuses until I started messing around to test fit my boost gauge and magically the lights were working again. Then after pulling it back out and coming back the next day the lights immediately blew the fuse. I did just to confirm my paranoia use my multimeter in continuity mode and put one end into the wire that feeds the glove box light and then just touched on various parts of the body and was finding continuity. So after I finish playing around with the dash I think I'll put everything back and see if I randomly blow a fuse again. I'm really hoping that this is the issue.

Thanks for the tip Domzs. The only question I have on that is with the way it's setup. There's a wire going directly from the battery with a fuse inline. That wire then runs to the relay. The relay is tripped by the combo switch and then that wire from the battery passes through and becomes the new green/white wire for the parking/interior lights. Will the light ever actually go out as long as there is a bulb or two still plugged into their sockets? So far I got as far as having the bulb hooked up like you said and I took out all the sidemarker bulbs and one by one put them in noticing no change in the light at the fuse spot. Also I took the brake light bulbs out and noticed no difference. I'll keep going around unplugging. After following the wiring schematics I can see that there are several places where I can just disconnect large portions of the harness. So I can try doing that and then narrow it down. I'm thinking it's probably going to end up being under the dash in one of the gauge lights. Everything that doesn't work is entirely on the Green/White wire that feeds these lights. Even the double filament bulbs like the front turn signals and the rear brake lights still work on the single filament portion that is controlled by a secondary power. The green/white side controlling the other filament is the side that doesn't light. I also took my combo switch back apart and tried to see if I could tighten the box and everything up better. So I need to resolder the connections again, but hopefully the switch won't have the excess play that was allowing the connection for running lights to be finicky. With the switch on the second position or headlights, the headlights work fine and even the slight bit of rotating play that the switch had wasn't disconnecting the headlights or the running lights. I've also purchased another switch via ebay to test as well. Maybe I should start accumulating these as well until I can make the perfect combo switch. Thankfully since my Z has essentially no interior it should make getting at everything fairly easy. Also since I figure I'm probably going to be pulling the speedo out I can finally try and make sure my speedometer cable is connected properly and see if I do need to replace the cog in the tranny side. Update: I unplugged the connector on the passenger side that leads to the entire rear tail/parking lights to eliminate at least that portion for the time being, I've removed the front turn signal bulbs and side markers, no clock connector, disconnected hazard switch, and anything else with a green/white wire running to it. All I have left is the cigarette lighter, volt/fuel gauge, oil/water gauge, tach, and speedo to pull out. The bulb still lights up. I also took my switch back apart and made sure everything was tighter, re-soldered the wires and now it doesn't seem to have the finicky middle setting. The little wiggle on the parking lights step doesn't cause the connection to break. So one thing down. Also I know this car must have had problems in the past with the interior lighting as the connector coming from the combo stalk is burnt/slightly melted right around the pin for the Green/White wire.

Well I found the writeup on Z car about taking the light switch stalk apart, flipping the board and resoldering it. I did that and I'm noticing that the switch itself seems to be finicky. I don't know if that's enough to cause the relay to trip off/on can cause the fuse to blow? I would think the relay would be seeing a really random open/close for the main power wire and I suppose could short? Anyway when on the headlight position it seems to be fine, but when switching back from headlight to interior sometimes the parking/running lights will stay off. Sometimes when flipping the knob to just parking lights they won't come on until I play with it a little.