JDM AE92 Harness swap questions

[Jeonsah]

So I am currently rebuilding a smallport 4age with some goodies. I have a jdm map harness/computer/dizzy to go with the swap as well. It will be going into an AE86. I am just curious as to whether or not my usdm AE86 tachometer will work with this harness/distributor? I have not done any research on how the original largeport distributor/tachometer works. Has anyone done this swap? if so, is there going to be an issue with my current tachometer and the jdm AE92 dizzy?


I really really want to keep the stock cluster with no additions except for a wideband o2 sensor.

Thanks everyone!

[dr.occa]

It should work since you'll be using the factory ignitor as well.

[Jeonsah]

I will be using the AE92 coil & ignitor. So will that setup work or do you mean the stock AE86 coil & ignitor?

[dr.occa]

Either ignitor should work but you'll need to run the AE92 dizzy w/ the hi-comp ecu for proper ignition resolution.

[morgan]

You shouldn't have a problem. My 20v coil/igniter run the oem 86 tach fine, then I swapped that out for an ae92 9000k tack, that works fine too.

[Jeonsah]

Just another question. My buddy did the same swap on a starlet but his car ended up running lean. They bought a wideband o2 sensor and bigger injectors to fix the problem. They were not able to figure out what the issue was. They also were running a MAP sensor that came from a non 4age car.... The smallport intake manifold was cut and rewelded.

I will be running the exact same setup but it'll be going into an AE86. I have the correct map sensor as well. The ecu is for an automatic jdm ae92 with a map sensor setup. Do any of you have an idea of what would cause a lean situation? I would prefer not to have to spend the money on a wideband if it is not needed....


thanks for your help guys!

ps... this site > club4ag

[dr.occa]

It's possible that the map sensor they used just wasn't calibrated with the factory ecu. The factory ECU wants specific numbers within a specific range. See if the correct factory map sensor fixes that and if not, did they ever try another ECU to eliminate that being the possible culprit?

[Jeonsah]

Yeah thats what I figured. They did not try another ecu just because the japanese ones are hard to come buy. Well, I will definitely keep you guys updated on how this thing turns out. Thanks for the help guys!!!!!!!!

[morgan]

Def look into what Jonas mentioned. Find the values for testing the ae92 JDM MAP, and find a usdm one that's compatible

[milchmann]

Fuel pressure also could have been the issue. Wide band O2 sensor requires a different fuel pump, and wiring a feedback loop to control its rate which sort of kind of suggests this was the case.

On another note, over sized injectors coupled with a wide band O2 tends to promote puddling in the cylinders, all sorts of wonky pump surging from to much and to little fuel being burned alternately.

[Jeonsah]

Basically what I did was searched a JDM AE92 on toyodiy and then got the part number for the map sensor. Then I googled that part number and found them for sale online. Thats what I ended up purchasing. As far as the wideband thing goes, thats very interesting. I never knew that. Ill keep you guys posted on how this build goes. Ill probably start posting it on here. Its pretty much just a standard rebuild with a DCR and CR planned for the future.

milchmann - Do you have an article or link about that wideband information you posted? Im interested in that now....

[milchmann]

http://www.carcraft.com/techarticles/cc ... ewall.html" onclick="window.open(this.href);return false; talks a little bit about sizing injectors.

This little guy will tell you how wideband o2's work.
http://en.wikipedia.org/wiki/Oxygen_sensor" onclick="window.open(this.href);return false;

This is a fuel pressure calculator to convert from CC/min lbs/hr so that you can size injectors to fuel pumps... or dial a pressure regulator correctly.
http://witchhunter.com/injectorcalc1.php" onclick="window.open(this.href);return false;

This is a good explanation/examples of the math.
http://www.rceng.com/technical.aspx" onclick="window.open(this.href);return false;

Did not dig anything up immediately about the low pressure / fuel surging / over sized injectors / puddling cyclical disaster ... but it was a long week and I am already kind of drunk, so I am going to have to leave you with the above starting points and your favorite search engine for the rest...

[Jeonsah]

Sweet thanks man.


Also I have one more question. The stock USDM largeport harness has the fuel pump wired up with the AFM and the COR relay. With this new map harness, how does the fuel pump work?

Thanks again!

[ashleyco]

Basically what I did was searched a JDM AE92 on toyodiy and then got the part number for the map sensor.