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questions about ecu swap. does a carbed car have any?

sc0terdad

sc0terdad

Active member
Joined
May 1, 2020
Location
Victoria, Bc
so I am beginning to embark on the long to do list of things in order to turbo my 81 b21a, One thing I am a bit confused about, do the carburated cars actually have an ecu?
please take it easy on me as I am mostly new to all of this but aside from the spark distro are there any means of factory engine controll I should wory about taking out?

thanks very much.
 
Don't some 80s Hondas and GM cars have an ECU?

But yeah not on a Volvo. Good luck with your +t, going to be a good bit different than the normal LH +t regularly done here
 
There exist carbureted volvo engines that had ignition ecus. Look up the ez118k or tz-28 or Renix units. (obviously not in cars in the USA.) Or even the Bosch breakerless system had a magic controller box, but not really a computerized ecu per se. Stock B21a should have the normal points ignition though, iirc. And yeah, no ecu for the carb in this case, though they exist.
 
James M said:
Don't some 80s Hondas and GM cars have an ECU?
Click to expand...

Yeah, in the early-mid 80s you could find cars from those makers with 'computer controlled' carburetors, but it's not real EFI.

Technically you could do a +T with carbs, but there's probably a lot more work involved in a blow thru/draw thru setup. The upside is that you don't need to use an intercooler.
 
fatcatbestcat said:
Yeah, in the early-mid 80s you could find cars from those makers with 'computer controlled' carburetors, but it's not real EFI.

Technically you could do a +T with carbs, but there's probably a lot more work involved in a blow thru/draw thru setup. The upside is that you don't need to use an intercooler.
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thge plan is to swap in ms as well as a b230+t, would the lack of Efi make a ms swap easier or harder?
 
sc0terdad said:
thge plan is to swap in ms as well as a b230+t, would the lack of Efi make a ms swap easier or harder?
Click to expand...

Not having a lot of the wiring for various sensors does complicate things. Ideally, you'd have a whole parts car to steal wiring from, if you're starting point isn't an LH car.

You can definitely do MS without, it's just going to be a lot more work.

Someone who knows more about this should pitch in - I'm just working from the research I did last year when I decided that converting my diesel car to EFI wasn't worth it.
 
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sc0terdad said:
thge plan is to swap in ms as well as a b230+t, would the lack of Efi make a ms swap easier or harder?
Click to expand...

It will be a bit more involved, but not the end of the world. You will need to add a fuel return line, and possibly swap out the carbed fuel sender for an EFI one. The B21A doesn't have all the same ports in the head as the fuel injected cars so you may need to get creative. When I turboed my B21A I had to plug some and tap some of the available ports. You'll have to swap out the points distributor for an LH2.2 one, because the flexplate/flywheel has no teeth for the ignition setup like LH2.4 does.
 
If you buy a premade harness. The new wiring you are going to have to do from scratch is fuel related as mentioned and also you are providing power and switching to the efi. The premade harness will come with color coded wiring to help you know which sensors you are going to connect it to. Not that bad to wire up. Just take your time and always double check before turning on power.
 
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dl242gt said:
If you buy a premade harness. The new wiring you are going to have to do from scratch is fuel related as mentioned and also you are providing power and switching to the efi. The premade harness will come with color coded wiring to help you know which sensors you are going to connect it to. Not that bad to wire up. Just take your time and always double check before turning on power.
Click to expand...

Alright that sounds really helpful, can you suggest somewhere to buy a pre made harness?
Thanks
 
Dave Barton sells megasquirt harnesses?

Imho, if you?re doing ms, the closest you can get in a harness is the one from a late model lh2.4 equipped 240. Granted, you?re still going to have to cut a fair bit of unnecessary wire out of even the 240 harness to make it work with whatever flavor of ms you?re going with whether you get one from the jy or prancingmoose.

If you know what you?re looking for in ms and aren?t a fan of rolling your own harness (in my opinion a valuable part of the ms learning experience), there are people here that can make you a dedicated harness to fit.., but it won?t be cheap.

Edit?

I think you also have to know whether your plans are going to change for the car once you get it running? are you going to go and stay with a single coil setup or will you want wasted spark or sequential ignition? lots of wiring differences in that selection of choices. Boost control? Knock sensing? It?s hard to know what you?ll want a year from now but if you have a plan for the car now and you know it?s not going to change, it makes it a lot easier to design a harness that doesn?t turn into a hodgepodge.

I can?t recommend enough a microsquirt setup? for basic needs? even if for the robust harness connection it has compared to the chincy db37 connector that plagues even the best of ms setups.
 
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