Stock (mostly) KA24E runs very rich at high RPM?

[Nanaimo]

Hi,Sorry for cross-posting AGAIN, but I've still had no response.

The dyno says my AFR is 10.8@4300 RPM. Is this normal? Is it good? I'm using 92-94 octane gas, so there's little risk of knock. Why is the engine shooting so much unburnt fuel out the exhaust?

See this thread ( zerothread?id=162069 ) for more info and graphs.

[InsanityInc]

With the stock engine management system, I wouldn't doubt it. I know the KA24DE runs very rich at WOT and high RPM levels by design. Didn't know it ran THAT rich, but who knows.

Unless you're having some kind of emissions-test problem, just chalk it up to an over-protective fuel map. Devious can probably tell you more.

[Nanaimo]

Umm, yeah, I have to pay (~$1.10/L) for that gas, so is there any easy way to fix it?

[InsanityInc]

Yeah: don't drive around at wide-open throttle.

Alternatively, invest in a standalone engine management system.

[deviousKA]

Something a little more along the lines of 11.5:1 would be normal, but that does seem a bit rich. The ka24e is tuned much richer than the de in original form.

First thing you should do is run the codes on your ecu. If all of that checks out (code 55=all good) then you should check your fuel pressure. If that checks out well, time to retune your ecu.

Ive posted a free NA tune over at eccs.hybridka.com that should save you some money at the pump, not to mention the power increase

[Nanaimo]

Something a little more along the lines of 11.5:1 would be normal, but that does seem a bit rich. The ka24e is tuned much richer than the de in original form.

I wonder why my car gets mileage so bad on regular then...

First thing you should do is run the codes on your ecu.

Ugh... I had to do that last summer. I imagine it's hard enough to access, but when your wrist doesn't bend it's a real SOB. I'll do that today.

Ive posted a free NA tune over at eccs.hybridka.com that should save you some money at the pump, not to mention the power increase

Great! Thanks, I'll check it out... If I want to buy a spare ecu (incase I lift traces on the desoldering... done that before... to a unique prototype (non-automotive)), what's the difference between these:

Elec Cont Unit (ECU), (right kick panel), MT, Fed and Canada, thru 9/88Elec Cont Unit (ECU), (right kick panel), MT, Fed and Canada, from 10/88 thru 1/89Elec Cont Unit (ECU), (right kick panel), MT, Fed and Canada, from 2/89

And if I get the California one will it give me a functional check engine light but still allow me to use the same maps?

Can I put the original chip back in if I want to sell the car to someone who's going to put 89 octane in?

[deviousKA]

Yeah checking the codes on the nissans isnt real easy, you have to unbolt and lay the ecu down on the floor pretty much.

If you can obtain the actual part numbers on those ecus you could find precisely, but the FED MT ecus from 89-90 had 2 basic versions.

One for 9.1:1 CROne for 8.6:1 CR

The "high compression" ecu doesnt use the iat (air temp sensor) in its fuel trim calculations quite like the later version does, but that is about the only difference. All will work fine in your car and can be tuned using the same methods.

The california versions of the ka24e ecu use the egr temp sensor input and compare to a threshold to throw a code, the federals dont (but have the same egr temp sensor, not used). You will probably want to stray away from the cali ecu, you might have to put a dummy resistor in place of the egr temp sensor to keep it from throwing a code. That is, assuming you have egr removed (or plan to remove it at any point in time). It wont give you a functional check engine light on your dash, codes will have to be read in the same fashion.

The california ecu can use the same maps as the others, and with the nissan ecus you can install the original chip reverting the ecu back to stock any time you would like. Its not like the other ecu tuning platforms where you need to run special code or modify your ecu in order to tune, remove your stock eprom and install a tuned version, done deal.

You might want to look into using a 90-92 stanza ecu. These are plug n play in a 89-90 240sx and offer the diagnostic/monitoring system known as consult, with this you can hook your laptop up to your ecu with a certain adapter to monitor all input sensors, logging of various data, and even do maptracing for tuning purposes. Lots of other cool things to but not really the topic at hand. If you read around a little bit on that eccs forum you might find some things of interest.

Oh, btw, with the stanza ecu and the said consult adapter, you can check and erase your codes with a click of a button on your laptop , or even palm pilot/pocket pc for that matter.

[deviousKA]

Just for reference, here is a table of the A/F target values that the ka24e ecu will run when operating properly. This is not a VE table.

Rpm is the Y axis, Load is the X axis.

Low rpm/load load areas leaner than 14.59 have been set to 14.59 btw, this is the area that the ecu is running in closed loop with o2 sensor feedback and will normally run 15.3-14.7. A value of 1 on the fuel target table designates 14.7:1, a negative value means leaner. During tuning these closed loop areas are usually removed (values set to "1") and thats what your seeing here.



As you can see, in the higher rpm high load areas the ka24e is set to run rather rich.

[Nanaimo]

Oh, btw, with the stanza ecu and the said consult adapter, you can check and erase your codes with a click of a button on your laptop , or even palm pilot/pocket pc for that matter.

Sweet!!! is there MacOS X software for this? Can it tune the ECU, or just check/clear codes?

[deviousKA]

Sure is, it is called Consultan

Ive never used it personally, I have a copy of the software here on my computer but let me see if I can dig up a website for it.

You can do some tuning adjustments in real time, some basic rich/leaning by percentage. These settings will be cleared each time ecu is restarted iirc, I have never personally used them on a KA ecu but they are part of the consult system.

You can also shut down individual cylinders, turn fuel pump/fan on/off, all kinds of stuff.

I dont know about the features of consultan, ill take a look.

This here is probably the best windows software available, take a look at the page and it will give you a basic rundown of what you can do with the consult system. http://home.curl.aunz.net/tpkolo/DataScan.htm

[deviousKA]

Consultan link.

http://home.sandiego.edu/~epoo...ultan