Nomad final assembly

[chevynut]

I thought I finished the interior wiring a couple days ago. However, I just realized I forgot to put the braided shielding on the coil wires like I wanted to do to prevent EMI issues so I'll probably have to backtrack a little. Damn.

Everything has power and ground and all the interior signals like the tach, FP relay, I/Os and WB02 wiring are done. The WB02 connector was difficult and contacts are small, and in retrospect I should have cut more of the sheath off of the cable to free up more of the wire length to work with. I also put the red protective covers on all the breakers so nothing can short out on the studs.

IMG_6753.jpeg


I've started on the engine compartment and have cut the wires down to rough length but I have to get the shielding on the coil wires before I can finish them. I split the sensor power into two leads, and the sensor ground into four leads. The injector harness connector is installed. I plan to use black braided wire loom so you can't see the wiring and I need to put it on the coil wires and other wire groups so I can put the connectors on the main engine harness. I'm working on the injector connector, then the distributor, coil, and on to the 4 EFI sensors and IAC.

[chevynut]

I like your description of your +battery and -ground wire rationale. It seems logical to me, and is how I wired mine up too (lots of grounding points all tied into to the chassis/block and a few common +battery connection points near where power is needed...rather than multiple long runs back to the battery itself).

I don't understand why Holley is so adamant that you have to connect power and ground leads to the battery. They claim the battery acts like a "filter". So you have a battery with two long 10 gauge leads to it from the ECU. I fail to see how that's better than a short 10 gauge wire, a short length of 8 gauge wire, a couple feet of 2 gauge wire, and a long 1 gauge wire to the battery. And as for ground, I have about 8" of 10 gauge wire, then the car body as a ground conductor. They even say not to connect it to the starter lug. I have seen no rational explanation as to why they think connecting directly to the battery is necessary. I think they're just trying to CYA for guys who don't know what they're doing.

[BamaNomad]

The battery can be viewed as a giant capacitor, which smooothes out spikes caused by such things as alternators, starters, etc..

If you have an oscilloscope, hook it up to the battery (and alternatively) to wherever you are planning to power your Holley device, and view power spikes at each location during alternator charging, engine running, starter engaging, etc...?? I suspect they are just saying hook it up as 'close' to the battery itself as possible and farther away (electronically) from the spike generators. The battery FILTERS out spikes on your DC circuits wherever they are hooked up but it may be better filtered when connected closer to the battery?

[chevynut]

[QUOTE=BamaNomad;68129]The battery can be viewed as a giant capacitor, which smooothes out spikes caused by such things as alternators, starters, etc..[/quote}

I agree, but why does it matter if you have 10 feet of #10 wire to the battery or shorter lengths of larger wire? It still goes back to the battery.

If you have an oscilloscope, hook it up to the battery (and alternatively) to wherever you are planning to power your Holley device, and view power spikes at each location during alternator charging, engine running, starter engaging, etc...?? I suspect they are just saying hook it up as 'close' to the battery itself as possible and farther away (electronically) from the spike generators. The battery FILTERS out spikes on your DC circuits wherever they are hooked up but it may be better filtered when connected closer to the battery?

I don't have an oscilloscope, but I understand electricity and electronics. What you need to do is minimize the total resistance to the battery which is what matters. I'll bet the resistance of my connections is lower than long #10 wires. With low resistance, a capacitor acts the same no matter where it is in the circuit. The voltage at the battery is going to drop virtually the same as it will at the starter when cranking.

Here's what Holley says "Holley HP and Dominator ECU’s use the same main power cable. These wires should be run directly to the battery. 10 gauge wire is used. The harness comes with a 40 Amp fuse pre-installed. Do not substitute smaller gauge wires."

The 40A fuse is also unnecessary, as I was told the ECU only uses around 10A. I used a 30A resettable breaker that you can see at the bottom of my last pic.

[BamaNomad]

[QUOTE=chevynut;68130]

The battery can be viewed as a giant capacitor, which smooothes out spikes caused by such things as alternators, starters, etc..[/quote}

I agree, but why does it matter if you have 10 feet of #10 wire to the battery or shorter lengths of larger wire? It still goes back to the battery.
...

I don't know either, Lazslo. I was hoping you'd run that experiment for us so we'd all know..

[Rick_L]

"I fail to see how that's better than a short 10 gauge wire, a short length of 8 gauge wire, a couple feet of 2 gauge wire, and a long 1 gauge wire to the battery."

The problem is not that this is dead wrong. It's not going to be a problem if all connections are good with good materials. It's that it's going to be a problem if something is not right in the many connections. Their recommendation is just trying to minimize the number of possible failure points, especially when done by someone who is not knowledgeable or diligent. Factory wiring has a lot of connections too. Virtually all aftermarket EFI mfr's use the direct to battery recommendation.

[chevynut]

It's not going to be a problem if all connections are good with good materials. It's that it's going to be a problem if something is not right in the many connections. Their recommendation is just trying to minimize the number of possible failure points, especially when done by someone who is not knowledgeable or diligent. Factory wiring has a lot of connections too. Virtually all aftermarket EFI mfr's use the direct to battery recommendation.

Like I said, I believe they're trying to CYA to avoid customer problems and I don't blame them. Not everyone understands electronics. The ECU undoubtedly has filtering inside of it to handle noise and spikes. I understand the risk with multiple connections but the ECU only draws maybe 15A so the load isn't high.

Funny thing is the C950 has almost the same current draw and it supplied power to the WBO2 and spark control module which are integrated into the TerminatorX ECU. The power wire to the ECU was only a 20 gauge wire. They still said to connect it directly to the battery, which I didn't do. The TerminatorX drives essentially the same things as the C950 did. The ECU doesn't even supply power to the injectors since they are grounded by the ECU. Same with the spark output to the CDI box. If it really drew 40-50A I'd be more concerned about it.

Let's take a quick look at this. Let's assume the battery voltage is 12V and you connect the ECU directly to the battery. In this configuration you won't see the voltage drop through the positive battery cable to the starter while cranking. But you will see the voltage drop at the battery when the starter motor draws 400A, which could be around 1.5 volts depending on battery condition and starter load.

If you connect the ECU to the starter lug, you will see a little more voltage drop on cranking. A #1 wire has about .146 ohm/1000 feet. With 400A starting current, you would see an additional .47V drop there assuming 8 feet of cable for a total drop of 1.97V.

Now let's assume you run a 10 gauge wire all the way to the battery. You will still see the 1.5 volt drop at the battery. A 10 gauge wire has about 1 ohm/1000 feet. That wire would give you a drop of .12V at an assumed 15A ECU draw. So the total drop while cranking is 1.62V.

With the car running the voltage drop with the single 10 gauge wire is obviously going to be more than the drop with the larger wires most of the way if the length is the same. That assumes of course that the connections are all good. This applies to any wiring you're doing on a car. And actually while running the alternator is supplying the current and the voltage is going to be around 13.5V with my alternator sensing at the breaker bus. Voltage drop from there to the ECU is very small.

On the ground side of the ECU I have a 10" or so of 10 gauge wire to the body, and the body is grounded to the chassis in at least two places, with the chassis grounded to the battery.

I'm not advising anyone to do what I did, I just want to point out the actual numbers if done a different way. I don't think an additional 1/2 volt drop while cranking is going to affect the operation of the ECU, and I think either way will work fine. You could make the argument that everything in the car should be run back directly to the battery, but that would be an ugly mess. And electrically everything actually is.

[chevynut]

I got my shielding yesterday and got it installed on the coil wires. If you get that stuff don't get it too big as it expands a lot. I grounded it to the console floor and ran it all the way to the coil then covered it with black expandable braid in the engine compartment so you don't see it. I tied up all the interior wires again and today I got the coil connected, injector connector, distributor connector, and MAP, MAT, CTS connectors installed. All I have left is the TPS and IAC and I can cover the harness with braid and call it done. Then I can install the new injectors and fuel rail, prime the engine oil again, install and sync the distributor, and install the upper intake manifold. Then I should be back to where I was a six weeks ago.

[chevynut]

I got all the engine wiring done yesterday so it's ready to start once I get the engine back together. I've put together a base config file for the TerminatorX using my engine parameters.

IMG_6768.jpeg

[chevynut]

We have power!!!

So I'm almost done . I installed the new Holley injectors and fuel rail and hooked up the fuel lines. The new injectors were a bit of a pain in the ass. I watched a guy on Youtube change them on a Chevy 454 truck by putting them all in the fuel rail, then installing them in the manifold....it can't be done that way with the Ramjet 502 manifold. I ended up putting the injectors in the manifold, then installing the fuel rail instead....the way I did it before. That was still a pain, but it worked.

I still want to flush the fuel rail again and probably change the fuel filter. Then I need to check the actual fuel pressure to put that value in the base map.

I installed the distributor and connected it to the harness, turned on power, and the ECU woke up and all the TerminatorX LEDs seem to be correct. The distributor LEDs came on so I synced it per the Holley instructions and tightened it down. The MSD cap is slightly smalller than the GM one so installing the plug wires was not easy. After messing around with different wire routing I found something that worked.

I still have the fuses for the fuel pump and CDI box removed but will need to install the fuel pump fuse to flush the fuel rail. That's the next step and when I get that done I still have to install the upper intake manifold but I want to make sure everything else is correct before I do that.

IMG_6789.jpeg

[WagonCrazy]

That engine is so clean looking.

[chevynut]

Well another delay. I found out that the "dongle" used to connect the laptop to the ECU isn't just a USB cable as I thought. It is an active cable that has a CANbus to USB converter in it. I have a ton of USB cables so I thought I could use one of them. I don't understand why Holley doesn't put a USB connector on the ECU and put the converter inside of it like they do with the HP EFI. It might add a couple of bucks to the cost.

I wanted to load a base map I've been working on so I can flush the fuel rail out but I realized I can just bypass the fuel pump relay to do that, and also check the fuel pressure. So that's my next task while I wait for the dongle. I might even install the upper intake and plug in all the sensors so I can check them out when I can use the ECU. The sensors all worked before, so any problem would be in my wiring.

Larry is coming over tomorrow to "discuss" my interior. He hasn't done a damn thing since before I left for Christmas.

[chevynut]

This damn car is fighting me all the way.

Last night I flushed the fuel rail and put the pressure gauge on it. When I went to pressurize the system, the AN hose end fitting on the pressure side was leaking. So I took it off and didn't see anything wrong with it. It's way back behind the intake, between the engine and firewall so access isn't easy as you can see in the pic below. The pressure line is the lower one. I put it back on and tightened it again, but it still dripped under pressure. I took it off again, had to pull the distributor to get good access, and I removed the aluminum AN adapter from the fuel rail. I saw nothing wrong with it but I took Scotchbrite to it anyhow to smooth the sealing surface. I reinstalled the adapter and put the line on, tightening it really good. I finally got the leak stopped. Then I had to reinstall the distributor and sync it again.

I have the upper intake sitting in place with a couple of bolts, and I connected all the sensors. If they all check out okay when I get the ECU fired up next week, I'll install the intake with new gaskets and hope it doesn't have to come off again.

IMG_5085.jpeg

[BamaNomad]

you can't curse or fuss at your car if you want it to cooperate, Lazslo.. caress it when you walk by it.. play sweet 'easy listening music in your shop.. etc... Tell it how much you love it every chance you get...

[otis]

Looking at your nomad pictures, It looks great, only question is how long before drivable.