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Location:
Sydney
Registered:
January 2004
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Replacing Engine
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Sat, 24 January 2004 13:02
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Just a general question/s. If you buy a Jap motor (motor only) and then preceed to bolt it up ot the existing intake exhaust etc , how will the injectors know to "inject" at correct time in engine cycle. Do they get a signal from the distributor or what? Did some work on race car last year but was running batch fuel injection - a dodgy EMS computer. DO the jap motors usually come with distributor, water pump etc? Are these jap motors usually good enough to just bolt straight up - changing timing belt of course. Thanks
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Replacing Engine
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Sat, 24 January 2004 15:12
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ahh ummm....
do you know how motors work??
if not, then i suggest a crash course in fuel injected motors at www.howstuffworks.com
or just look at my sig for search links.
Cya, Stewart
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Location:
Sydney
Registered:
January 2004
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Re: Replacing Engine
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Sat, 24 January 2004 21:41
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fair call. but if you know so much about motors couldn't you have given a sentence description! Of course i know how motors work, i thought it was a bit of a dumb question but hey I don't pretend to know it all...like some. I'll check the links and see if i can make some sense. But the engines don't have individual cylinder sensors, you've only got the 02 sensor in exhaust manifold - operating in closed loop, i don't know how it can then make indidual adjustments to cylinder injection timing. Will think about it some more
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Club Member
Location:
sydney
Registered:
May 2002
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Location:
Sydney
Registered:
January 2004
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Re: Replacing Engine
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Sat, 24 January 2004 23:02
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Right. Thanks Michael. You don't usually need to take the head off though do you? Piston rings usually ok?
About the motor...does that mean the injectors run off signals from the ECU based on signal from distributor..like I mentioned in first place but wasn't sure?
PS I just dont think people should post reply if they aint going to help
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: Replacing Engine
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Sun, 25 January 2004 00:54
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it depends on the car
for an older jap car, yes the dizzy tells it what the pistons are doing (sort of)
on newer engines, the CAS (Crank Angle Sensor) does that, and the engines dont have a distributor
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Location:
Lost in the K hole
Registered:
May 2002
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Re: Replacing Engine
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Sun, 25 January 2004 05:23
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| HighRolla wrote on Sun, 25 January 2004 10:02 |
PS I just dont think people should post reply if they aint going to help
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http://www.howstuffworks.com IS helping.
doing some background reading of existing material yourself, then asking specfic related questions (as opposed to spoon feeding the whole concept from the get go) saves a LOT of effort on everyones behalf.
but, alas...
buying a 'jap motor' and 'bolting on the manifolds' is hardly going to get the motor even close to starting. the engine and electronic engine management system must be fully integrated and functioning properly, and this incorporates a wide variety of sensors, as well as the tuning maps of the ecu itself to co-ordinate fuel and spark delivery.
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Location:
Sydney
Registered:
January 2004
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Re: Replacing Engine
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Sun, 25 January 2004 05:58
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True, research is good..All I required was "yeah the distributor helps to 'time' the injectors and allows injectors to open when intake valves open or about to open, while in a newer model car the CAS does this job"...and not learn the engine cycles and what EFI is...Thanks for the reply though.
One more thing at the risk of getting ridiculed.. aren't most of the sensors etc external to the actual engine (bar CAS). SO provided you were running the existing EFI system (ECU) reusing old injectors etc (i.e if the jap motor is same as one replacing), assuming the timimg was correct etc shouldn't the motor run. Maybe I'm missing something totally. Thanks..sorry this post turned into a bitch fest - i feel like a big girl or a naughty boy being repramanded and trying to justify himself 
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Location:
Lost in the K hole
Registered:
May 2002
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Re: Replacing Engine
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Sun, 25 January 2004 06:11
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| HighRolla wrote on Sun, 25 January 2004 16:58 |
provided you were running the existing EFI system (ECU) reusing old injectors etc (i.e if the jap motor is same as one replacing), assuming the timimg was correct etc shouldn't the motor run.
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yes
what youve described is 'plug n play' : buying a low mile jap import engine, switching all your existing sensors, loom and ecu onto the new engine (if required), and driving away.
however, as michael suggested, you should replace as many seals and belts as you can, as they do perish. and when replacing the timing belt, its a v,good idea to check the cam timing for yourself to make sure all is well. whe you know the cam timing is good, check the basic dizzy or CAS timing to see if its generally in the right spot - then hook it all up, and see if it runs 
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Replacing Engine
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Sun, 25 January 2004 09:36
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oki, i apologise then 
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how will the injectors know to "inject" at correct time in engine cycle. Do they get a signal from the distributor or what?
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in one sentence?? i'll try.
the vast majority of EFI cars use batch injection, either in a single bank, or in multiple banks, although some cars actually use staged injection, and some also inject mulitple times for each bank per engine cycle, and i believe that the 4AG has two squirts for each of two banks per engine cycle, but there are also a few systems out there that are "Truly Sequential", which means that the injectors are timed to fire at a particular angle of the crank, for each cylinder, that said tho, some "sequential systems" actually have less number of banks than cylinders, but still inject at a 'timed crank position' and call themselves sequential, even tho they are not really, but getting back to the original question, what do you mean by ????????, most engines will use either a toothed or magnetic pickup from the crankshaft (crank angle sensor), or a reluctor style pickup from a cam driven toothed wheel (cam angle sensor), or other will use the coil pulses and divide by number of cylinders to work out rpm, but even so, none of these sytems are "TIMED" as such, they just inject a certain number of times per revolution, based on the rpm, number of banks, number of squirts per bank etc, and this timing/rpm information is sent for the pickup to the ECU which then uses a number of other inputs, such as load (AFM/MAP), coolant temp, air temp, O2 sensor feedback etc, to determine the pulsewidth of each injector pulse, and then the ECU tells the injector to fire.
so to sum up:
1) wtf do you mean by "correct time"????
2) signal comes from either dizzy, or crank angle or cam angle sensors, or direct from coil pulses (tach)
all of this you should have found in 5 minutes, seriously.
Cya, Stewart
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Location:
Sydney
Registered:
January 2004
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Re: Replacing Engine
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Sun, 25 January 2004 11:53
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Thanks stew... to answer
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wtf do you mean by "correct time"????
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I would use what you said in the case of sequential injecting:
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"Truly Sequential", which means that the injectors are timed to fire at a particular angle of the crank, for each cylinder
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In the above the particular angle of the crank would be considered the "correct" angle of the crank to fire the injector for that certain engine setup.
I don't think I can say it any better than you have, so might quit while I'm behind  and hopefully better luck in next post...It's all good...thanks for the help
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Replacing Engine
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Sun, 25 January 2004 12:09
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no wuckers 
most efi motors are not sequential, and it really makes little difference to power (since at WOT, max rpm, they should be pen 80% of the time anyways)
you can be pretty sure that most EFI motors willbe batch fired and do not fire at a specific time as such... well, they do, but it is of little significance
10sec_rx7 was saying he found phasing of the injector timing was helpful for rotaries, but i've heard that for piston motors, less than 5% difference could be expected.. there are more important things to worry about than sequential
Cya, Stewart
[Updated on: Sun, 25 January 2004 12:17]
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Location:
Brisbane
Registered:
May 2002
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Re: Replacing Engine
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Sun, 25 January 2004 12:16
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Sequential helps fuel economy at light load because you can squirt the fuel in only when the inlet valve is open. But when you think about it, that only gives you a pretty small window of opportunity; once the injector is firing at greater than 25% duty cycle (ie medium load) it will be firing into a closed valve anyway, so sequential makes no difference beyond that.
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Toymods Club Treasurer
Location:
Sydney
Registered:
May 2002
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Re: Replacing Engine
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Mon, 26 January 2004 03:07
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Highrolla, in your original post, if you'd said that you already had a jap EFI engine in your car, & that you wanted to replace just the motor with another of the same & bolt the existing ancillaries like manifolds, sensors, etc onto the new motor, a lot of heartache & bitching wouldn't have occured.
And yes, a one sentence answer would have answered THAT question.
Your question sounds like you wanted to replace your motor with something different, or switch from carby to EFI, or anything.
Very short on specifics.
People here are quite willing to help, but you've got to ask the right & specific questions, we can't read your mind.
Please remember this in future. 
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