4age on bike carbs

mr2mk1hero
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4age on bike carbs

Postby mr2mk1hero » Wed Jul 05, 2017 2:08 am

My engine got the knocky rods. Want to do something entertaining with the new one I'm building. Thinking about bike carbs from a kawasaki zx6r. Should be fine with my mild cams. I know many people think carbs are not a smart mod etc. need constant fiddling and adjustments etc. I agree with all that, but I want the carb experience under my belt as well. My car is a 1987 mr2.


I'm in the possession of a early bigport (bluetop) map sesnored, non-egr ecu, dizzy, wiring harness, etc. from an at160 european celica. I have all the parts except the map sensor, which I am having a lot of trouble finding. Will any toyota 1 bar map sensor work? Any known Toyota I can get this off?

For now I want to run the bike carbs with the stock ecu. Will get msd or some other standalone ignition later.

I'm thinking about how to connect this.

There are three sensors on the intake manifold:
1. MAP - Is MAP the same as AFM in the sense that the engine will not start without a signal from it? Can I hook it up to the carb intake manifold that I will get fabricated. I think I will need the vacuum balancing thing for this.

2. Intake air temperature sensor. Do I need to plug this too into the carb intake manifold somehow as well? Or can I ignore it?

3. TPS. How will the ECU behave without a TPS connection?

The other thing is the fuel. Here I'm thinking about getting the tank out and removing the efi fuel pump and installing a fuel pump from the same bike that I get the carbs from. Any better suggestions for this that don't involve a million fuel lines and fuel pressure regulators and what not?
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frostvectron
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Re: 4age on bike carbs

Postby frostvectron » Wed Jul 05, 2017 9:14 am

Stock ecu? Not going to work.

No tps? No map?

http://jalopnik.com/how-electronic-fuel ... -499902815

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Re: 4age on bike carbs

Postby Jayrdee » Wed Jul 05, 2017 10:58 am

I think you need a refresher on how carb setup works ... you don't use the ECU with carburetors haha

Here are some links I've found useful.

http://www.club4ag.com/forums/viewtopic.php?t=4076

http://www.club4ag.com/forums/viewtopic.php?t=4076
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mr2mk1hero
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Re: 4age on bike carbs

Postby mr2mk1hero » Thu Jul 06, 2017 1:26 am

Jayrdee wrote:I think you need a refresher on how carb setup works ... you don't use the ECU with carburetors haha

Here are some links I've found useful.

http://www.club4ag.com/forums/viewtopic.php?t=4076

http://www.club4ag.com/forums/viewtopic.php?t=4076



Read this thread. Both links are to the same thread. In this thread the guy uses an MSD standalone ignition controller. I'm not using that so it's different.
Check out my YouTube channel: https://www.youtube.com/channel/UCwosUn ... xtqkNJ3Fbg
Check out my blog: http://www.driving4answers.com/
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mr2mk1hero
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Re: 4age on bike carbs

Postby mr2mk1hero » Thu Jul 06, 2017 1:28 am

frostvectron wrote:Stock ecu? Not going to work.

No tps? No map?

http://jalopnik.com/how-electronic-fuel ... -499902815


Did you even read what I wrote?
I'm asking how to connect the MAP, TPS, and intake air temp sensor to the bike carb intake manifold so they work with the stock ECU.
Check out my YouTube channel: https://www.youtube.com/channel/UCwosUn ... xtqkNJ3Fbg
Check out my blog: http://www.driving4answers.com/
Heaps of 4A-GE nad MR2 mk1 aw11 content on both.

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Re: 4age on bike carbs

Postby Jayrdee » Thu Jul 06, 2017 6:33 am

mr2mk1hero wrote:
Jayrdee wrote:I think you need a refresher on how carb setup works ... you don't use the ECU with carburetors haha

Here are some links I've found useful.

http://www.club4ag.com/forums/viewtopic.php?t=4076

http://www.club4ag.com/forums/viewtopic.php?t=4076



Read this thread. Both links are to the same thread. In this thread the guy uses an MSD standalone ignition controller. I'm not using that so it's different.


mr2mk1hero wrote:
frostvectron wrote:Stock ecu? Not going to work.

No tps? No map?

http://jalopnik.com/how-electronic-fuel ... -499902815


Did you even read what I wrote?
I'm asking how to connect the MAP, TPS, and intake air temp sensor to the bike carb intake manifold so they work with the stock ECU.




Lol once again, I think you need a refresher on how carburetors work.

The whole point of carburetors is to get rid of EFI and your ECU. The carburetor(s) are what mix the air/fuel together, replacing your fuel injectors. I am fully aware that the dude in the thread I posted uses the MSD. Your ECU uses your MAP and TPS to determine how much fuel to inject into your cylinders, but your carburetor will be doing that so ..............

btw, this is the other link I meant to post.
http://web.archive.org/web/20120508012619/http://forums.club4ag.com/zerothread?id=359

These are good ones too
http://club4ag.com/tech-data/carburetors-for-the-4a-ge/
http://www.lcengineering.com/LCTechPages/techpages/carb3.html


Are you sure you aren't getting individual throttle bodies confused with carburetors?
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Re: 4age on bike carbs

Postby jondee86 » Fri Jul 07, 2017 12:15 am

This is something I have thought about before... why not use the factory ECU for
IGNITION ONLY when an engine is converted to carbs ??

Basically it just amounts to removing the injector wiring and providing an alternative
method of supplying fuel to the engine. The ECU does not monitor the injectors so it
will not know that they have gone, and stay happy just clicking its transistors.

It will be necessary to hook up a TPS or apply a fixed resistor to keep the ECU in "run"
mode. May have some small effect on idle quality, so maybe a resistor and an idle switch.
The IAT sensor can be mounted anywhere that it can sense the temperature of the air
reaching the carbs.

The MAP sensor is necessary to provide the load axis for the ignition map. Any MAP
sensor from 80's or 90's Toyota should work... just check that the output voltage is
in line with the test values in the FSM. Tapping all four throttles and averaging the
vacuum reading with a small reservoir, then using a pulsation damper in the line to
the MAP sensor, will work best.

The ECU will get the rpm and crank position signals from the distributor and ignition
will be sequential via the OEM coil, igniter and HT wiring. Never got round to doing
it myself, but I'd love to see it done :D

Cheers... jondee86
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Re: 4age on bike carbs

Postby mr2mk1hero » Fri Jul 07, 2017 12:46 am

jondee86 wrote:This is something I have thought about before... why not use the factory ECU for
IGNITION ONLY when an engine is converted to carbs ??

Basically it just amounts to removing the injector wiring and providing an alternative
method of supplying fuel to the engine. The ECU does not monitor the injectors so it
will not know that they have gone, and stay happy just clicking its transistors.

It will be necessary to hook up a TPS or apply a fixed resistor to keep the ECU in "run"
mode. May have some small effect on idle quality, so maybe a resistor and an idle switch.
The IAT sensor can be mounted anywhere that it can sense the temperature of the air
reaching the carbs.

The MAP sensor is necessary to provide the load axis for the ignition map. Any MAP
sensor from 80's or 90's Toyota should work... just check that the output voltage is
in line with the test values in the FSM. Tapping all four throttles and averaging the
vacuum reading with a small reservoir, then using a pulsation damper in the line to
the MAP sensor, will work best.

The ECU will get the rpm and crank position signals from the distributor and ignition
will be sequential via the OEM coil, igniter and HT wiring. Never got round to doing
it myself, but I'd love to see it done :D

Cheers... jondee86


Thank you jondee86! Yours was a reply I was hoping to see. I'm really happy you're interested in this. I am really keen on getting this to work.

The only part I'm still kinda confused is the TPS. I was naive enough to think that the ECU only needs it for the injectors and that I can just ignore it. So now the most ghetto solution possible would be to fit the ECU, move it to any open throttle position and fix it in that position somehow.

I'm kinda crappy with electronics, so how would the idle switch and fixed resistor thing work, where to get them and how to hook them up?. Would it make sense to look for bike carbs that already have a tps on them?
Check out my YouTube channel: https://www.youtube.com/channel/UCwosUn ... xtqkNJ3Fbg
Check out my blog: http://www.driving4answers.com/
Heaps of 4A-GE nad MR2 mk1 aw11 content on both.

mr2mk1hero
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Re: 4age on bike carbs

Postby mr2mk1hero » Fri Jul 07, 2017 12:56 am

mistake double post
Last edited by mr2mk1hero on Fri Jul 07, 2017 3:02 am, edited 1 time in total.
Check out my YouTube channel: https://www.youtube.com/channel/UCwosUn ... xtqkNJ3Fbg
Check out my blog: http://www.driving4answers.com/
Heaps of 4A-GE nad MR2 mk1 aw11 content on both.

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Re: 4age on bike carbs

Postby jondee86 » Fri Jul 07, 2017 2:30 am

The TPS is a variable resistor which tells the ECU the throttle position and the rate
of change. The latter is used for an accelerator pump function which will no longer
be available. The former is most likely used to apply corrections to the ignition timing
to help the engine accelerate. Being able to attach a TPS to the accelerator linkage
somewhere would be the best solultion.

There is also a circuit in the TPS that goes open (like a switch) when the throttle plate
goes fully closed. This tells the ECU to adjust fuel (function no longer available) and
ignition timing for best idle. If a TPS is not possible some experimentation with a
fixed resistance (or variable poyentiometer) could find a suitable compromise setting.
Timing would still vary with rpm as usual. Again, a small switch hooked up to the
throttle linkage somewhere could simulate the idle switch operation. I'd have to check
to see if not having a TPS causes the ECU to throw a fault and go into limp mode.

A TPS is more or less something that is only used with EFI, so you are not likely to
find one on a bike with carbs. But it may be possible to adapt one, and google will
find you examples of how it has been done. You will need to visited a friendly bike
repair shop and look at a few setups on EFI bikes to see how it is usually done.

Cheers... jondee86
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Re: 4age on bike carbs

Postby mr2mk1hero » Fri Jul 07, 2017 3:09 am

Some of the late 90s bike carbs actually do have TPS. I have no idea why but they do. For example 1999 kawasaki zx6r carbs already have a tps on them. The question is whether it can be made to work with our stock ECU. Will probably have to buy a set of those carbs or at least a tps from them to know. This is definitely going to be fun :)

So on the intake manifold I just need 1 tap on each runner for the vacuum to the vacuum canister and then to MAP. Don't need to tap the intake manifold for anything else?
Check out my YouTube channel: https://www.youtube.com/channel/UCwosUn ... xtqkNJ3Fbg
Check out my blog: http://www.driving4answers.com/
Heaps of 4A-GE nad MR2 mk1 aw11 content on both.

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Re: 4age on bike carbs

Postby jondee86 » Fri Jul 07, 2017 4:06 am

Probably had the TPS as an input to an electronic ignition box. Electronics is not my
strong suit either. But I would think that it should be possible to adapt a bike TPS by
adding a small resistor in series to scale the output to suit the 4AGE ECU.

You will need to tap one (or preferably two) of the throttles to get some vacuum for
your brake servo, They will be approx 5mm dia and teed together. The MAP sensor
tappings can be small... 2mm or so, and all four run into a small reservoir, say 20 dia
by 150 long. In-line pulsation dampers can be found (small plastic hollow plastic discs
with a vacuum tit on each face) can be found on many different cars.

The gas on bikes is usually gavity fed, but you will need a low pressure pump and
regulator. Say a pump delivering 4-5 psi and a regulator to give 2 psi to the carbs.
And carbs are usually attached to the bike engine by flexible rubber couplers and
clamps, so you will need to study both how to build your manifold and what you need
to do to get the carbs spaced to more or less match the port spacing on the 4AGE
head (saves having to extend the spindle linkages between the carbs).

Cheers... jondee86
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Re: 4age on bike carbs

Postby Jayrdee » Fri Jul 07, 2017 8:40 am

Wait ... What? Lol.

In theory this makes sense, I'd be very interested to see how this plays out. Especially toying with the TPS and MAP sensor(s).

I've never seen/heard this being done before?!
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Re: 4age on bike carbs

Postby jondee86 » Fri Jul 07, 2017 3:43 pm

I am glad that I have been able to find this forum thread again. It is from another
site but essentially mimics a long running thread that seems to have disappeared
(unfortunately) from this site :(

http://www.aeu86.org/forum/Thread-CARBU ... rt-16V-4AG

That thread will save me a lot of writing :D It covers not only how to go about
using the factory ECU for ignition only control with carbs, but the also the very
good reason for doing so. ECU control of timing is a big step up from any other
method that only provides fixed timing or a single programmable timing curve.
All the reuired components are already in the car and it just takes a bit of ingenuity
to get the MAP and TPS working with the carbs.

Of course, a fully programmable after market ECU is an even better solution,
but not everyone wants to face up to the cost and work involved in that upgrade.
Using the factory ECU is a good DIY alternative that provides reliable electronic
control of advance for minimal cost.

Cheers... jondee86
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Re: 4age on bike carbs

Postby ditn » Wed Jul 12, 2017 2:01 am

using stock ecu with carbs is a good idea.
much better like said than msd or fixed.

i remember a friend used axle for opening valves carbs to attach his tps.
so he basicly used that with a lever to make his own tps.
if i go there ill take a picture worked like a charm

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Re: 4age on bike carbs

Postby fiveten » Thu Jul 20, 2017 11:47 am

I'm selling an MSD 6AL 2 with complete plug and play for a carb'd 4AG. PM me if you're interested. Reason for selling is because I went ITBs.

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