Another S30 Turbo Project

[AtlantaZ]

I'm continuing to work on the main engine wiring harness. It was nice to be able to remove the entire harness, inspect it for damage, cut out unused connections, and generally clean things up. I've gotten pretty good at soldering and heat shrinking! As a guy who used to only mess with the bolts and nuts, it's nice to get into the electrical side of a project. I wouldn't dare do most of this without a good wiring diagram; thankfully, the PDF version of the Factory Service Manual is available. I plan on marking up the drawing with my changes so that I can update the drawing and keep a current copy for future reference.

 

Here's a summary of the electrical modifications so far:

1. Fusible links: Converted to a 4-circuit AGU fuse block with 50 amp fuses. The input (feeder) circuit to the fuse block is a #4 AWG wire that runs from the battery (+) terminal to the starter solenoid (+) terminal, then to the input side of the fuse block. This setup will be much more reliable and easier to troubleshoot in the case of a major electrical problem. The stock wiring used a messy spliced/branching wire setup that fed voltage through the stock fusible links.

 

2. Junction box: To make it easier for me to wire up things like Megasquirt, headlights, new gauges, and the new alternator, I made a simple junction box with two terminal blocks: a "Hot" block that connects directly to battery (+), and a "Switched" block that connects to a voltage source when the ignition switch is in the "Start" or "Run" position. I will feed this block from the old ignition coil (+) feed - a black/white wire that comes from connector C4 (see the FSM wiring diagram).

 

3. Alternator: Upgraded to a 60-amp, internally regulated alternator from a 280zx (bought a reman from Advance Auto). This link was very helpful: http://www.atlanticz.ca/zclub/techtips/alternatorswap/index.html

Since I'm using Speedhut gauges, I won't be using the stock voltage charge light. There are three wires that I have to concern myself with at the alternator: the BAT feed to the fuse block (the main charging circuit), the S ("sense") circuit that will connect directly to the battery (+) terminal to provide voltage information for the internal voltage regulator, and the L circuit that "excites" the alternator field when the engine is first starting. I will wire the L circuit to my 12v switched block from #2 above.

 

4. Backup lights/starter control, aka "Pac Man": On the 1976 wiring, the oil pressure sensor, backup switch wires (to turn on the reverse lights), and the starter solenoid control wire all go through a big round connector that I call "Pac-Man." If you were to look at the lower left portion of the FSM wiring diagram, you would see that there is a male-to-female locator pin in the middle of the connector that looks like Pac-Man on the wiring diagram. These are the sorts of things you start to say and think after you've invested 100+ hours in a project... Anyway, on my 1976 California Z, the backup/oil pressure/starter control wires are all that's used on this clunky 8-pin connector - and I'm using a different oil pressure sensor anyway. So I decided to delete Pac-Man.

 

5. Headlights: The HID ballast boxes have an audible hum (albeit quiet), so I decided to mount them in th eengine bay. The most convenient spot was at the old charcoal canister mounting point. I am also mounting the headlight relays in the same place. Now I just need to clean up the wiring.

 

I am installing the wiring in three layers:

-"Stock" harness with headlight, A/C, wiper/washer motors, turn signals, and horns

-"Megasquirt" harness with MS hot/switched power, MS sensors, and EDIS/coil pack wiring

-"Instrument" harness with Speedhut gauges and pigtails

 

Somewhere in here I also have to figure out how to drive my tach. I'm hoping to use the blue wire with inline resistor from the stock wiring.

[AtlantaZ]

I forgot to mention that I got my same-side bar/plate intercooler and 2.5" piping from CXRacing's eBay store. I was a little disappointed that these guys refused to combine shipping on the intercooler and piping kit (to save me a few dollars), even though they DID combine shipping when they actually shipped the intercooler and piping together. Still, it's one of the cheapest new setups around, so I guess I can't complain. As long as the thing works...

 

Quick comment on another wiring issue regarding my fuel pump setup:

I'm using a Walbro GSL392 fuel pump (the 255 liters per hour model that everyone seems to like). I'm also using Megasquirt II, v3.0, with the Megasquirt relay board.

 

The relay board has a fuel pump relay and 10amp fuse onboard, and a fuel pump wire, but the fuel pump wire itself is only a #18 AWG wire. According to my research, the Walbro fuel pump draws up to 20 amps of current, which is WAY too much for a tiny #18 wire. It seems that the relay board setup is okay for a smaller stock-ish fuel pump setup, but the wire and fuse are woefully undersized for a high flow model like the Walbro, let alone a Bosch 044 or dual pumps! In addition, I couldn't get a large enough wire to fit inside the tiny relay board screw terminal if I wanted to. So what's the solution? Another relay!

 

My plan is to use the Megasquirt relay board fuel pump wire as a trigger to run another relay. I'll use #12 AWG wire for the Walbro's power and ground circuits, with the ground wire terminating on a piece of clean chassis metal near to the pump. The power wire will be routed up to the passenger side kick panel, where it will connect to a 30 amp automotive relay. The "trigger" terminal of the relay will connect to the Megasquirt relay board fuel pump circuit. The "source" terminal of the relay will be routed to my 12V "hot" terminal block in my junction box, with a 25 amp fuse inline between the terminal block and the relay. I recommend sizing a fuse at 125% of the planned maximum load on the circuit, and I recommend sizing a relay at no less than 150% of the maximum load. So for a 20 amp fuel pump, I need a 25 amp fuse and a 30 amp relay. I used the following chart to properly size the power wire to the fuel pump: http://www.tessco.com/yts/industry/products/itm/automotive/get_wired.html

 

If you've looked at the Walbro flow/pressure/load chart, you might be thinking "Well I'm only going to flow ~45psi, so I only need about 7 amps." However, the motor's initial load will spike much higher than its normal operating load, as it has to overcome inertia to both rotate and to pass fuel. So plan on 20 amps!

 

Hope all this stuff helps! I'd love to save somebody a little research time.

Edited April 25, 2011 by AtlantaZ

[AtlantaZ]

I picked up some #12 wire and a 30-amp automotive relay so I can rewire my new fuel pump. I hope to do that tomorrow.

 

I got the modified "first layer" stock wiring harness laid in place in the engine bay. This harness is for the headlights, turn signals, backup light switch at transmission, side markers, horns, A/C, washer/wiper motors, starter, alternator, and the fuse block feeds to the interior wiring. Most of the wires are routed and connected, so I should have this finished tonight.

 

I plan on mounting Megasquirt and wiring the sensors tomorrow, then on to the Speedhut gauge wiring. Once that's all done, I'll put the dash back in and attempt to fire her up!

[VKLR]

This thread will help me this winter on my swap. Thanks.

[AtlantaZ]

Hopefully I'll have a fully functional car that you can check out in person. Tim (another HybridZ user) was gracious enough to let me comb over his setup, and I'd be happy to pass on the favor to another Z-car fan.

[AtlantaZ]

Wiring up Megasquirt relay board now. I'm about to mount my homemade junction box , land the wires on the terminals, and plug in sensors. Will have an update in a few hours!

[AtlantaZ]

WOW. That was a long, long, marathon car wiring session. About 20 straight hours of measuring, cutting soldering, bolting, heat shrinking, cable routing, and so on. My engine bay is a mess right now as I haven't cleaned up the wires, but that is way down low on my list of priorities right now. So here's what I did:

 

1. Finished connecting stock harness to lights, alternator, etc.

2. Mounted and wired Megasquirt and EDIS ignition module, plugged in necessary sensors.

3. Connected Speedhut sensors to their respective wires and routed into the engine bay.

4. Wired up my junction box with 12V "hot" connections to headlight and fuel pump relays, and 12V "switched" connections (tapped the old black/white wire from now-gone ignition coil) to alternator exciter wire, Megasquirt switched input, EDIS switched power to coil pack and ignition module, and... something else... I'm blanking. Man I need some sleep!

5. Ran a #12 power wire to the Walbro pump, and rigged up my fuel pump relay. That was a lot simpler than I thought it would be. Turns out relays are actually rather straightforward.

7. Semi-installed the dash (enough to hold it in place, but easy to remove if necessary).

8. Re-re-rerouted my intercooler plumbing. The air filter is now directly on top of the A/C compressor and fits quite nicely. I'll keep an eye on air temps and make sure that it doesn't get too warm, but for now I'm optimistic.

 

The interior is still a frightening mess of wires, but I made a great deal of progress. More to the point, I actually got to put the key in the ignition!!!

 

After checking for loose wires and obstructions, I hopped into the driver's seat and turned the key to the accessory position. Nothing happened and I started to worry, until I realized that I didn't have anything on that would've drawn accessory power. I checked my parking and brake lights, and both worked. So far so good.

 

Before turning over the engine, I made sure to flip the fuel pump kill switch to the "Off" position. Why? I wanted to give the engine a chance to circulate oil before igniting. So I turned it over for 5-7 seconds. The good news was that the starter worked and my laptop - connected to Megasquirt - showed an RPM reading. My sensors were working, electricity was in the system, and the engine was rotating. So far so good!

 

I then flipped on the fuel pump and heard Walbro say "vrrrmmmmmm!" Sounded a bit like an electric antenna extending. Jumped out and looked at the Aeromotive fuel pressure regulator, which showed ~30 psi. But also smelled a strong fuel smell and realized that the gauge port on my fuel rail was a bit loose. Whoops. Tightened that down and hopped back in the car, confident that Megasquirt was ready to bring my engine to life and that fuel was in the rail (and staying there now).

 

So I turned the key again and, despite about 20 seconds of attempting, failed to get the engine to light. I sent my wife to the exhaust pipe to smell for fuel, and she reported nothing. I hopped out and confirmed that there wasn't even a hint of a fuel smell! I knew my wires were good, so I checked the fuses on the Megasquirt relay board. Both 5 amp fuses were blown. I recall reading that 7.5 amp fuses were better for anything larger than a 4-cylinder, but I'm thinking that my 440cc injectors might need something even larger.

 

Anyone have inputs on fuse sizing for the Supra MKIII turbo injectors on a Megasquirt setup? 7.5 or 10 amps? Or even larger?

[FlatBlack]

Some of your initial settings are wrong, the size of your injectors should not be related to your fuses blowing out.

[AtlantaZ]

I'll replace my fuses tonight, check my settings, and post an update.

[AtlantaZ]

Still not running... Updates:

 

-Installed 7.5 amp injector fuses. They're not blowing now, so that's good news.

-Pulled a plug and saw that it was moist with fuel, but not soaking wet like I expected it to be.

-Laid all six plugs on the valve cover and saw sparks from all six

 

So I have fuel and spark, but I suspect that I'm not getting as much fuel as I should. The fuel pump is running and my FPR gauge shows about 30psi in the rail, so it's got to be in the Megasquirt cranking settings... right?

 

I'll post MegaTune settings later tonight. In the meantime, love to hear thoughts!

[AtlantaZ]

I have cygnusx1's tune, and all the numbers look fine - so I don't think it's my settings anymore. I still think I'm missing *fuel*. At cranking pulsewidths, I would expect to have a much richer fuel smell coming from the car. It may be an injector problem - either I'm not getting enough current at the injectors, or they're not opening correctly.

Edited April 30, 2011 by AtlantaZ

[AtlantaZ]

Checked my injectors, and they all read the correct resistance. But now I'm noticing a loud buzzing from my Megasquirt relay board when I switch the key to the "run" position.

[240zdan]

looks amazing so far!

[AtlantaZ]

Still not running. Update:

 

The buzzing was the Idle Air Control relay, which I had inadvertently activated when I turned on one of the Idle Control features in Megasquirt. I pulled the relay to stop the buzzing, and I'll poke around the settings later tonight and figure out what to turn off.

 

But what's going on here? I have spark, the fuel rail shows about 55psi of fuel, and all my settings look okay. Megasquirt is definitely powering on, and I'm reading solid coolant/inlet air/manifold pressure readings. I did notice that the manifold pressure stays steady even when the engine is trying to crank - should it be dropping towards vacuum?

 

I'm pretty sure that my timing is solid too. I installed the timing chain when the crank damper was pointed at 0 degrees, and I hung the bright link in the timing chain on the marked tooth on the camshaft sprocket.

 

I'd love to verify that my injectors are firing correctly. Is there perhaps a test mode in Megasquirt? Or maybe I need to set some priming/cranking pulse setting? I may have to repost this in the Megasquirt forum.

[AtlantaZ]

Posted my plea for help on the Megasquirt forum: http://forums.hybridz.org/index.php/topic/99834-turbo-project-no-start-help/page__p__936094__fromsearch__1#entry936094

 

I do have a log file, and I just noticed that the battery is only pushing 9V. That could be a problem! To see my log file, visit the Megasquirt link above.

[Hollywoodman]

Wow! This looks a lot like my setup. Just got it re-tuned and came out to 292rwhp and 304rwtq

 

Good job and keep going!

[AtlantaZ]

Still waiting on my fuel rail. MAN I can't wait to fire this thing up! As far as I can tell, once I get the timing synched up, everything should be running 100%. Theoretically...

[AtlantaZ]

And waiting, and waiting, and waiting... rail should be here tomorrow. Hope to have good news!

 

Meanwhile, someone please buy my old parts! http://forums.hybridz.org/index.php/topic/98849-l28-and-begi-fpr-for-sale/page__p__927230__fromsearch__1#entry927230

[FlatBlack]

Posted my plea for help on the Megasquirt forum: http://forums.hybridz.org/index.php/topic/99834-turbo-project-no-start-help/page__p__936094__fromsearch__1#entry936094

 

I do have a log file, and I just noticed that the battery is only pushing 9V. That could be a problem! To see my log file, visit the Megasquirt link above.

 

I have an Orbital deep cycle in my car - I lost my alternator some time ago, but didn't realise it. MS wasn't outputting any spark on the 8V the Orbital was putting out when it was half dead, but a jump gave enough juice to start the car. A charged battery might be the answer. [i replaced the alternator and the car runs like a champ again].

Edited May 29, 2011 by FlatBlack

[AtlantaZ]

Got my new fuel rail! It leaked at first, but after tweaking the brackets a bit I got it to seal up. It's not running 100% yet, but we're getting close. I charged the battery, and the alternator works, so my running voltage is now 12-13V. Unfortunately I've hit another glitch... See below:

 

Here are a couple of little-known facts about 280Zs, and cars in general:

 

#1 - Car engines can get pretty hot. So hot, in fact, that the intake and exhaust manifolds can get hot enough to melt rubber hose!

#2 - When running a coolant line to a turbocharger, it is NOT a good idea to use rubber lines - use braided steel instead. See #1.

#3 - An L28ET's coolant also gets pretty hot. And when rubber tubes full of hot coolant lie against a blazing hot exhaust manifold, they tend to melt!

#4 - If you fail to install an engine cooling fan, whether mechanical or electric, the coolant gets really, REALLY hot.

#5 - If you combine extremely hot coolant with rubber hoses and scorching hot engine metal, the effect is pretty spectacular. Have you ever seen an old coal-burning steam train? Remember those huge clouds of steam billowing from the stacks? Well, if you let your coolant get above 230F and your hoses touch hot metal, you get the same effect. Very cool!

#6 - Boiling coolant smells terrible. See #1-5.

 

I can get it to idle at 1000RPM, and when I give it full throttle, it stutters briefly, revs up to 2000RPM, then sputters back down to 1000RPM (even if I keep the throttle wide open). I can send a MSQ and log file to any interested parties. Thanks for the encouragement, guys!