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Db9 or ethernet/rf45 cables for engine harness?


turbogrill
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I am redoing my engine harness (again). Thinking of using either db9 serial cable or ethernet cable for sensors and logic ignition coils. They are shielded and each cable contain 8-9 wires.

 

Would run several cables from main fuse/ecu "box". For instance oil temp and oil pressure would be in one cable from left side of engine to the main box. Map and iat would be one cable from main box to right side and so on.

 

I would have a pcb at the main box where I can add pullups. High amp things such aa injectors would be the megasquirt harness that is made by them. 

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3 hours ago, atxe30 said:

@turbogill hey swing by the house tonight and i'll give you an idea of what is being done for my harness. mostly milspec grade wiring, connectors as @mhr650 indicates. 

So, I always wondered if you screen name meant Auto Trans E30 - now I'm wondering if it's "a Texas E30?" Which is it?

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11 hours ago, mhr650 said:

I wouldn't touch either with a 10 foot pole in a race car. Proper sealed automotive grade connector, for signal Deutsch mini is the way to go. 

 

I built my old harness using weatherpack and the megasquirt harness, but it's soo many wires. Also needed to chop up the megasquirt harness to add resistors and stuff.

 

Maybe I just need to do it better...

Edited by turbogrill
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Not sure how many you need, but I'd look into Deutsch connectors on Amazon (maybe ebay).  Or use weatherpack connectors if you have some left.  Either way, you probably should pick up a decent crimper.  I think you can get a decent crimper for ~20 on one of those sites or you can just buy the pigtails and splice like a hero. 

 

DO NOT NOT USE A PROPER CRIMPER.  You will live to regret it if you do (ask me how I know).

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Give @vtjballeng a call,  Motorsports Wiring is Ballenger Motorsports's bread and butter.

 

I couldn't stomach the $200+ real Deutsch crimp tool, so I got this kit, It has been excellent so far,

https://www.amazon.com/gp/product/B01B4DCDQK/ref=oh_aui_search_asin_title?ie=UTF8&psc=1

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Last harness I did utilized weather pack connectors and I was able to get everything from Del City.  https://www.delcity.net/

 

Weather Pack has a 22 pin bulkhead connector that helped allow  ECU placement in cockpit and have a simplified engine harness that allows for quicker engine removal.

 

Have seen many recommendations for Deutsch connectors, have not personally used.

 

 

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1 hour ago, tneker said:

Last harness I did utilized weather pack connectors and I was able to get everything from Del City.  https://www.delcity.net/

 

Weather Pack has a 22 pin bulkhead connector that helped allow  ECU placement in cockpit and have a simplified engine harness that allows for quicker engine removal.

 

Have seen many recommendations for Deutsch connectors, have not personally used.

 

 

 

2 hours ago, zack_280 said:

Not sure how many you need, but I'd look into Deutsch connectors on Amazon (maybe ebay).  Or use weatherpack connectors if you have some left.  Either way, you probably should pick up a decent crimper.  I think you can get a decent crimper for ~20 on one of those sites or you can just buy the pigtails and splice like a hero. 

 

DO NOT NOT USE A PROPER CRIMPER.  You will live to regret it if you do (ask me how I know).

 

14 hours ago, mhr650 said:

I wouldn't touch either with a 10 foot pole in a race car. Proper sealed automotive grade connector, for signal Deutsch mini is the way to go. 

 

Ok, seems like I should do it the standard way using weatherpack and automotive grade wires. That bulkhead connector looks nice, thanks for the tip.

 

1.

What did you do with the sensor ground cable. This goes to a million different things.

Option A. one wire per sensor from ECU/main box to each sensor. More wires but no splicing required.
 version2.thumb.png.79248bdec619086615bc9d1b51346d98.png

Option B. one wire from ECU that goes around the engine bay. Less wires but plenty of splicing.

version1.thumb.png.d2d448fd7b988770ead4be16fc4fcfc0.png

 

Leaning towards A. More wires but cleaner since there are no splices.

There are no electrical differences between the two, just what is easiest. (The extra resistance in the wire is negligible).

2. 

What did you do with pull up resistors that are needed for various things (ADC inputs, crank trigger. etc)?


Option A.

Solder resistors on a PCB/Veroboard at the ECU and have individual wires to each end point. More wires but cleaner.
rversion1.thumb.jpg.fb8185a4dcecce6db053c1f489f399d0.jpg

Option B

Pull VREF around the engine bay and splice and add resistors whenever is needed. Less wires but a lots of splices and in-harness resistors and kludgyness.

rversion2.thumb.jpg.7323f660eba0684f635d521ca560554a.jpg

 Again, leaning towards A. I like the idea with the harness just being wires and no "function". 

 

Also adding new funcitons or moving sensors is easier with option A. With the  OEM style (option B ) it's much harder.

That is one reason my current harness is a mess, added more and more stuff to it than I first thought.

Thanks!

Edited by turbogrill
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@turbogrill Below is a draft of what I am planning for a new harness for transition from OE ECU to megasquirt. Plan to have one sensor ground wire thru firewall, and splice in engine bay. If we end up needing any pull up resistors for temp sensors or similar, I would put those all in one spot in a 3D printed box adjacent to ECU in cockpit. 

diagram 20190122.JPG

Edited by tneker
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15 minutes ago, takjak2 said:

 

Alternator needs to run to the other side of kill switch. Current draft will keep the car running when kill switch is hit.

 

 

So this is a new kill switch we were thinking of transitioning to so perhaps I picked the wrong style or interpreted its function incorrectly.  Based on the wiring diagram they provided my assumption is that when you throw the switch you kill battery power by breaking the connection on the big lugs and you kill the motor (ignition) by breaking connection on two of the smaller spade terminals.  Engine dies, and alternator no longer turns, no more voltage potential available from the alternator.  It also has two additional spades that create a circuit when killed that allows you to use a resistor to ground to handle any alternator voltage spike.  Does that pass the sniff test?

kill switch wiring.JPG

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As far as connectors go, Deutsch plastic connectors are a solid, inexpensive option that work very well. We recommend them for most budget applications.

I'll take the rest from a prior response I gave on the subject (TLDR; never use weatherpack for any new work):
 

Quote

We carry wiring supplies here that are automotive specific:
https://www.bmotorsports.com/shop/

There are a lot of competitors with similar catalogs. We also carry a lot of the stock connectors to sensors, etc.

Nobody should be using Weatherpack these days. They were a 70s era design long ago obsoleted in the Delphi/Packard catalog. Since then they've had several additional design iterations which have also been obsoleted or nearly so. It's the engine equivalent of taking your modern overhead cam engine putting flat heads on it. Full Deutsch kits are available such as this: https://www.bmotorsports.com/shop/product_info.php/products_id/4119 . Though we don't have them on the site we have packages for DT & other options as well.

The biggest issues I see are:

On a related note, here is a failure from our ChampCar. Headlight failure analysis. Failure expected in ballast internals. Found it was in ignitor instead. Destructive analysis of ignitor showed failed crimps in aftermarket system.


Pulled copper to failure but only a couple of strands held between 3 terminals (3rd one destroyed but had no captive copper). Proper failure mode for a correct crimp is that all copper remains captive in all terminals. Relevant to you @Huggy, since y'all should have the same ignitor. Sebring ultimately caused the failure but inspection showed larger internal problems.


How many other failures do you see using our validation charts? http://news.bmotorsports.com/faq/terminal-crimp-validation-charts/

44979701_10158063529623782_8260188129957249024_n.jpg?_nc_cat=108&_nc_ht=scontent.fric1-1.fna&oh=8b25e41a27cb471b55a7839716992c3d&oe=5C881106

 

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1 hour ago, tneker said:

 

 

So this is a new kill switch we were thinking of transitioning to so perhaps I picked the wrong style or interpreted its function incorrectly.  Based on the wiring diagram they provided my assumption is that when you throw the switch you kill battery power by breaking the connection on the big lugs and you kill the motor (ignition) by breaking connection on two of the smaller spade terminals.  Engine dies, and alternator no longer turns, no more voltage potential available from the alternator.  It also has two additional spades that create a circuit when killed that allows you to use a resistor to ground to handle any alternator voltage spike.  Does that pass the sniff test?

kill switch wiring.JPG

 

You are correct on how the 6 post switch functions.

It's also a correct method of killing ALL power past the kill switch.

Edited by mcoppola
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2 hours ago, Team Infiniti said:

Wondering how the ultimate momentum machine is going to work without its 5 speed, we may be on course to find out...

 

Anyone have heads up magazine type of track data from back in the day?

 

Sorry for the derail

 

So how is your e30 project coming along? curious as to where you are going to spend your massive 50 pt reserve :)

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4 minutes ago, atxe30 said:

 

So how is your e30 project coming along? curious as to where you are going to spend your massive 50 pt reserve :)

 50 points? Ha ha,  The worry about spare points is far away...

 

 Last session ended with the discovery, can’t put the exhaust manifold on once it’s installed, can’t install it with the manifold on.

 

May have to relocate or delete the brake booster 

 

 

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1 minute ago, Team Infiniti said:

 50 points? Ha ha,  The worry about spare points is far away...

 

 Last session ended with the discovery, can’t put the exhaust manifold on once it’s installed, can’t install it with the manifold on.

 

May have to relocate or delete the brake booster 

 

 

Free swap headers

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8 hours ago, Team Infiniti said:

 50 points? Ha ha,  The worry about spare points is far away...

 

 Last session ended with the discovery, can’t put the exhaust manifold on once it’s installed, can’t install it with the manifold on.

 

May have to relocate or delete the brake booster 

 

 

geez, of course. forgot you were doing a swap, what motor are you stuffing in there again?

Edited by atxe30
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1 hour ago, atxe30 said:

geez, of course. forgot you were doing a swap, what motor are you stuffing in there again?

Infiniti V6 & matching auto trans.

Thread relevance:

The car will be stripped of all European wire , engine/trans (prob entire body) harness will be harvested from Infiniti, stock ecu/tcu will be used.

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2 minutes ago, Team Infiniti said:

Infiniti V6 & matching auto trans.

Thread relevance:

The car will be stripped of all European wire , engine/trans (prob entire body) harness will be harvested from Infiniti, stock ecu/tcu will be used.

 

lol.... Heresy!!!!

 

The Bimmer gods will not be pleased.....

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