Going under the knife
- Max Welton
- Posts: 3023
- Joined: Mon Jun 03, 2002 12:01 am
Re: Going under the knife
Near as I can tell, I reversed the ground(85) and trigger (86) wires. The pins numbers are just legible on the bottom of the relays.
So viewing the plugs from the underside ...
I think got 30 and 57 right. The white(?) wires are the 86s and I want them all together so I can hook them to the +15 ignition switch.
Could reversing the 85 and 86 wires result in a weak connection between 30 and 87? Or are those parallel connectors the prime suspect?
I need to gang up the trigger wires and tie them to the +15 running to the ignition switch. Is there a cleaner way?
Also, could someone recommend fuse ratings for the various devices?
Max
So viewing the plugs from the underside ...
I think got 30 and 57 right. The white(?) wires are the 86s and I want them all together so I can hook them to the +15 ignition switch.
Could reversing the 85 and 86 wires result in a weak connection between 30 and 87? Or are those parallel connectors the prime suspect?
I need to gang up the trigger wires and tie them to the +15 running to the ignition switch. Is there a cleaner way?
Also, could someone recommend fuse ratings for the various devices?
Max
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- Max Welton
- Posts: 3023
- Joined: Mon Jun 03, 2002 12:01 am
Re: Going under the knife
Today I rewired this mess so that the trigger and grounds are now correct. It made no difference.
So I did some more digging. The relay itself is fine. The fault appears to be in the way I'm feeding +12 to the 30 pin.
https://youtu.be/2qAFCwdsVv0
Tomorrow I'll see if NAPA has some fresh relay pigtails and try this again.
Max
So I did some more digging. The relay itself is fine. The fault appears to be in the way I'm feeding +12 to the 30 pin.
https://youtu.be/2qAFCwdsVv0
Tomorrow I'll see if NAPA has some fresh relay pigtails and try this again.
Max
- vwfye
- Posts: 1008
- Joined: Sun May 21, 2000 12:01 am
Re: Going under the knife
Max, I was told, with my EFI that is going in later, that I had to run the harness away from the car harness. Maybe the same for you?
- Max Welton
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- Joined: Mon Jun 03, 2002 12:01 am
Re: Going under the knife
Not sure what you're saying.
The only connection this has with the car harness is the relay trigger, which is the ignition switch wire that would normally power the coil. And the battery. That's it.
Max
The only connection this has with the car harness is the relay trigger, which is the ignition switch wire that would normally power the coil. And the battery. That's it.
Max
- vwfye
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Re: Going under the knife
Is the harness away from the car harness or along side it in places?
- Max Welton
- Posts: 3023
- Joined: Mon Jun 03, 2002 12:01 am
Re: Going under the knife
It's nowhere near the stock harness. Nothing runs next to the stock harness.
All the MS stuff is behind the rear seat, below the package tray and above the load deck. We fabbed a vertical panel near the front of the luggage area to form a nice space for all the megasquirt stuff. Sensor and control wiring drops down through the load deck via a bit of conduit, then rearward to the engine area. When you open the trunk you would hardly known it was there. That space was never much good for rectangular things anyways.
Max
All the MS stuff is behind the rear seat, below the package tray and above the load deck. We fabbed a vertical panel near the front of the luggage area to form a nice space for all the megasquirt stuff. Sensor and control wiring drops down through the load deck via a bit of conduit, then rearward to the engine area. When you open the trunk you would hardly known it was there. That space was never much good for rectangular things anyways.
Max
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- vwfye
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Re: Going under the knife
Cool. I was just remembering what I was told for my stand alone and I remember my buddy had major interference in his buddy and the CB efi until he relocated the system.
Sorry I can't be more he'p!
Sorry I can't be more he'p!
- Max Welton
- Posts: 3023
- Joined: Mon Jun 03, 2002 12:01 am
Re: Going under the knife
No problem Brian. This is actually V2 of my system. V1 was in my old squareback. In that car the ECU was under the rear seat and the MS wiring did run alongside the stock harness inside the left rear fender. FWIW, I experienced no inference. Drove it daily all season from 2012 to 2016.
Max
Max
- GS guy
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- Joined: Wed Nov 06, 2002 12:01 am
Re: Going under the knife
I'd definitely get rid of the "clamp-on" wire connectors, may be OK for testing purposes but trouble waiting to happen for any kind of long term usage.
Relay trigger wiring direction shouldn't make any difference (unless it is some kind of non-typical relay) - just activating a small coil in the relay so very low current. For the 30/87 connections go with large gauge wire, probably #12(?) or at least same gauge as supplied with the relay pigtail and come directly off the fuse for that circuit - especially for the fuel pump. Maintain wire gauge through pump and all the way back to the main ground connection with sturdy lugs at any bolt-on connections. Grounds have to be nice and clean bare metal to metal connections (no paint!). I like to use a small bit of di-electric grease on all mechanical connections - where ever anything bolts or plugs together - to minimize corrosion/oxidation at the connection.
Jeff
Relay trigger wiring direction shouldn't make any difference (unless it is some kind of non-typical relay) - just activating a small coil in the relay so very low current. For the 30/87 connections go with large gauge wire, probably #12(?) or at least same gauge as supplied with the relay pigtail and come directly off the fuse for that circuit - especially for the fuel pump. Maintain wire gauge through pump and all the way back to the main ground connection with sturdy lugs at any bolt-on connections. Grounds have to be nice and clean bare metal to metal connections (no paint!). I like to use a small bit of di-electric grease on all mechanical connections - where ever anything bolts or plugs together - to minimize corrosion/oxidation at the connection.
Jeff
- GS guy
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Re: Going under the knife
Max, looked again at the pic of the mounted relays and IMHO you should supply the main 12V feed (to the relays) with at least 3 fused circuits (maybe 4?). OK to daisy chain a couple of the relays together to come off one fuse - I'd use (minimum) crimp-on butt connectors to branch the fused circuit to multiple relays. I like the bare/un-insulated ones you can use your own shrink tubing over to insulate. One option would be combining: (1) ECU & IGN, (2) FP & O2, (3) INJ A & INJ B (although I'd just run both INJ feeds off one relay). I've read you don't want to power the O2 without the engine running so combining with FP works for that. You want a large gauge wire for the FP, the others can get by with less (14 ga). I'm using Blue Sea fuse boxes for circuits like this, compact and excellent quality with integral covers:
https://www.bluesea.com/products/5045/S ... 4_Circuits
They have several sizes - purchase off Amazon. If you decide to use something like this, feed (+12V) the fuse block with a large gauge wire, around 8 gauge. The ground sides use appropriate wire gauges depending on circuit current demands.
Jeff
https://www.bluesea.com/products/5045/S ... 4_Circuits
They have several sizes - purchase off Amazon. If you decide to use something like this, feed (+12V) the fuse block with a large gauge wire, around 8 gauge. The ground sides use appropriate wire gauges depending on circuit current demands.
Jeff
- Max Welton
- Posts: 3023
- Joined: Mon Jun 03, 2002 12:01 am
Re: Going under the knife
I took a shot at making a bus-bar from material I have on hand. Covered the solder joints with RTV. Then I tied the trigger-wires with a similar approach. More solder. I may or may not keep this.
But now I'm having a WTF moment joining the supply (blue?) from the relay to the wire running forward to the pump. I was using one of the little bullet connectors and was getting the now-familiar high-resistance behavior. So for the time being I went to simply soldering the two wires together. That resulted in no improvement. So then I unsoldered the joint and just used a simple jumper ... and it worked!
How can that be?? I have dozens of soldered joints just like this and now I don't trust any of them. Not to mention all the little bullet connectors.
Max
But now I'm having a WTF moment joining the supply (blue?) from the relay to the wire running forward to the pump. I was using one of the little bullet connectors and was getting the now-familiar high-resistance behavior. So for the time being I went to simply soldering the two wires together. That resulted in no improvement. So then I unsoldered the joint and just used a simple jumper ... and it worked!
How can that be?? I have dozens of soldered joints just like this and now I don't trust any of them. Not to mention all the little bullet connectors.
Max
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- GS guy
- Posts: 909
- Joined: Wed Nov 06, 2002 12:01 am
Re: Going under the knife
I use the "white trigger wire" technique routinely for daisy chaining - just have to be sure the wire at the end is big enough AWG to handle the current.
I'd guess a cold solder joint on the bad connection? Were you able to check the resistance of the joint? You're in deep enough to justify an inexpensive VOM (Volt Ohm Meter) for checking your circuits post assembly. The pic of the joint above looks dull - like maybe the parts moved a little while the solder was solidifying? Soldering - requires clean, clean, clean(!) wires, good flux and a joining/clamping technique that doesn't allow part to part movement while the solder is molten. Best to let it cool enough to touch before any movement. Do all 3 and you're golden.
I usually try to mechanically twist the wires together (no dirty fingers!) to prevent movement, then either a good flux-core solder or flux then solid core solder.
The red power wire daisy chain should work OK - just a PITA to insulate the joints!
I'd guess a cold solder joint on the bad connection? Were you able to check the resistance of the joint? You're in deep enough to justify an inexpensive VOM (Volt Ohm Meter) for checking your circuits post assembly. The pic of the joint above looks dull - like maybe the parts moved a little while the solder was solidifying? Soldering - requires clean, clean, clean(!) wires, good flux and a joining/clamping technique that doesn't allow part to part movement while the solder is molten. Best to let it cool enough to touch before any movement. Do all 3 and you're golden.
I usually try to mechanically twist the wires together (no dirty fingers!) to prevent movement, then either a good flux-core solder or flux then solid core solder.
The red power wire daisy chain should work OK - just a PITA to insulate the joints!
- GS guy
- Posts: 909
- Joined: Wed Nov 06, 2002 12:01 am
Re: Going under the knife
FWIW - a bad solder joint will have a sort of frosty look. A good joint should look similar to the solder on the reel when cooled.
I've used alligator clamps and hemostats to hold the wires/parts together while soldering - anything to keep them from moving at the critical solder-solidifying moment.
Jeff
I've used alligator clamps and hemostats to hold the wires/parts together while soldering - anything to keep them from moving at the critical solder-solidifying moment.
Jeff
- Max Welton
- Posts: 3023
- Joined: Mon Jun 03, 2002 12:01 am
Re: Going under the knife
I really need (to make) something to hold the two wires while I solder. It's very hard for me to work at odd angles due to back problems.
Max
Max
- Max Welton
- Posts: 3023
- Joined: Mon Jun 03, 2002 12:01 am
Re: Going under the knife
Part of the problem here is that every time I start over with a connection, I have to cut the wire back a little more. I am now out of wire on the second set of pigtails.
This is beyond frustrating. This engine should have been running at least two weeks ago. This car exists to support my megasquirt habit. What I love is working with the control parameters and the resulting data. I am not an electrician. But I can't move forward until this bit is functional. The things that work and do not work are counterintuitive to me.
I do have a couple of cheap volt-ohm meters but neither has test leads with alligator clips so they are impossible to use at arms length.
Tomorrow I will remove the panel from the car and see I can tell using the ohm meter. Unfortunately that now means cutting some wires.
This is very frustrating.
Max
This is beyond frustrating. This engine should have been running at least two weeks ago. This car exists to support my megasquirt habit. What I love is working with the control parameters and the resulting data. I am not an electrician. But I can't move forward until this bit is functional. The things that work and do not work are counterintuitive to me.
I do have a couple of cheap volt-ohm meters but neither has test leads with alligator clips so they are impossible to use at arms length.
Tomorrow I will remove the panel from the car and see I can tell using the ohm meter. Unfortunately that now means cutting some wires.
This is very frustrating.
Max