Wiring injectors

For discussing injector selection,manifold modifications, throttle bodies, fuel supply system design and construction, and FIdle valves and IACs.
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Metalfab_101
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Wiring injectors

Post by Metalfab_101 »

My previous MS experience is with a TBi setup, and now that i'm going to multipoint i'm faced with trying to figure out how to wire my injectors.

MY problem is I can't figure out if I should fire all four, or split them into 2 batches of 2 firing alternatly. Wiring them isn't the issue, it's knowing what difference each makes and deciding what will work best for me.

I hope this hasn't been covered in the manual because i've been looking with no luck! I'll be happy to read more if someone points me in the right direction though.

OR is it just a matter of try it and see what works for me?

thanks!

Damo.
trakkies
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Re: Wiring injectors

Post by trakkies »

Metalfab_101 wrote:My previous MS experience is with a TBi setup, and now that i'm going to multipoint i'm faced with trying to figure out how to wire my injectors.

MY problem is I can't figure out if I should fire all four, or split them into 2 batches of 2 firing alternatly. Wiring them isn't the issue, it's knowing what difference each makes and deciding what will work best for me.

I hope this hasn't been covered in the manual because i've been looking with no luck! I'll be happy to read more if someone points me in the right direction though.

OR is it just a matter of try it and see what works for me?

thanks!

Damo.
Obviously wire them in two groups since there are two drive circuits in MS. Then try them both - it's only a simple change via software. On my V8, I found alternate best.
Dave P, London UK.
Rover V-8
MSII V3
EDIS
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Metalfab_101
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Re: Wiring injectors

Post by Metalfab_101 »

Thanks Dave!

I'm going to do as you mentioned and wire them in 2 groups, I do need to decide which pairs to group. I think to even out the distribution the best they should be 1&4 and 2&3. That's what I came up with in my head, and read that others had used the same (assuming a 1342 firing order). From what i've read most people have good results with alternating, but as you say it can be changed in the software once it's wired up.
trakkies
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Re: Wiring injectors

Post by trakkies »

Metalfab_101 wrote:Thanks Dave!

I'm going to do as you mentioned and wire them in 2 groups, I do need to decide which pairs to group. I think to even out the distribution the best they should be 1&4 and 2&3. That's what I came up with in my head, and read that others had used the same (assuming a 1342 firing order). From what i've read most people have good results with alternating, but as you say it can be changed in the software once it's wired up.
You could leave the wiring long enough so you could experiment with the grouping - then tidy it when you're happy. But I think any difference will only be at very low revs.
Dave P, London UK.
Rover V-8
MSII V3
EDIS
Tech Edge Wideband
kjones6039
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Re: Wiring injectors

Post by kjones6039 »

IMHO you are on the right track Damo. I used a similar scheme for a SBC w/TPI that worked very well for me.

Firing order is 1-8-4-3-6-5-7-2
Bank 1 1-4-6-7
Bank 2 2-3-5-8

I used the alternating setting so that only the bank that needed the fuel was turned on.

If you draw this out on paper you will get a better idea of how it works

There use to be a schematic one of the forums that illustrated this quite well. I will try to find it again for any one who might want it.

Ken
1979 Corvette - 383 CID SBC w/ Holley Pro-Jection 900 CFM TBI, 4-85 lb lo-z injectors & Walbro 255 pump
MS2 v3 w/ms2extra 3.4.0 Release
36-1, Delphi LS2/7 coils in wasted spark, driven by v2.0 logic board from JBPerformance
Spartan Lambda Sensor from 14point7
kjones6039
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Re: Wiring injectors

Post by kjones6039 »

I found it........

This is a little schematic i found useful when i was wiring up my TPI several years ago.
IMHO it worked better than straight bank for bank wiring.
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1979 Corvette - 383 CID SBC w/ Holley Pro-Jection 900 CFM TBI, 4-85 lb lo-z injectors & Walbro 255 pump
MS2 v3 w/ms2extra 3.4.0 Release
36-1, Delphi LS2/7 coils in wasted spark, driven by v2.0 logic board from JBPerformance
Spartan Lambda Sensor from 14point7
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