A while a go , I borrowed my friends JDM ecu. I just wanted to get rid of the CEL . my CEL went on due to secondary O2 sensor default .and

I didn't want the CEL to be on since a mechanic friend of mine said the car goes to safe mode and becomes slower if the CEL remains on after a period of time.
(NOT SURE IF HE IS RIGHT ABOUT THAT.)

However the car feels slower ever so slightly.
What do u guys think about that.

Does JDM ecu make a usdm ITR slower?

My mods are only bolt ons like 4-1 SS header, N1 apex'i catback, intake.

thanks

 

you know what dude:
you need to learn,how to drive
and put evrything back together

problem its not the ecu at all
jdm ecu its even sending more fuel
you have out-put problem and thats from your(exhaust setup) your not making any power with 4-1 header on stock 8,500rpm
4-1 power its starting from 7000------10000RPM and up

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mehdiR &raquo;</TD></TR><TR><TD CLASS="quote">A while a go , I borrowed my friends JDM ecu. I just wanted to get rid of the CEL . my CEL went on due to secondary O2 sensor default .and

I didn't want the CEL to be on since a mechanic friend of mine said the car goes to safe mode and becomes slower if the CEL remains on after a period of time.
(NOT SURE IF HE IS RIGHT ABOUT THAT.)

However the car feels slower ever so slightly.
What do u guys think about that.

Does JDM ecu make a usdm ITR slower?

My mods are only bolt ons like 4-1 SS header, N1 apex'i catback, intake.

thanks
</TD></TR></TABLE>


You also need to learn to seach because there was a thread that would have answered this question and more just yeterday!

----&gt; https://honda-tech.com/zerothread?id=1303653 &lt;----

S-E-A-R-C-H is your friend! Use it!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fast break &raquo;</TD></TR><TR><TD CLASS="quote">you know what dude:
you need to learn,how to drive
and put evrything back together

problem its not the ecu at all
jdm ecu its even sending more fuel
you have out-put problem and thats from your(exhaust setup) your not making any power with 4-1 header on stock 8,500rpm
4-1 power its starting from 7000------10000RPM and up
</TD></TR></TABLE>

thanks for the info, but irrelevant and still no good answer for my question.

Thanks for the bump though,

(F.. ing guy, revving high)

 

jdm ecu: 11:1 COMPRESSION + 290cc INJECTOR = right Pw FOR STOCK
JDM MOTOR NOT USDM
GO BACK TO YOUR USDM ECU TRUST ME DUDE
AND SEND ME THE JDM ECU........

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fast break &raquo;</TD></TR><TR><TD CLASS="quote">jdm ecu: 11:1 COMPRESSION + 290cc INJECTOR = </TD></TR></TABLE>

Where does everyone get this 290cc size from?

ALL B-SERIES INJECTORS ARE 240CC

I'll also say this again...

THE JDM P73 ECU HAS IDENTICAL FUEL MAPPING AS THE USDM P73 ECU

The JDM P73 ECU has a slightly revised ignition map, and that is it! Besides having a 125mph speed limiter, the only difference is the lack of emission checks.

And to answer your question about the CEL, only a handful of CEL's will throw the ECU into limp mode, and the secondary O2 is not one of them. I ran w/the secondary O2 CEL for over a year.

 

JDM's apparently have 290...that what my ECU is tuned for when my car was stock. My tuner also confirmed this.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MiraiZ &raquo;</TD></TR><TR><TD CLASS="quote">JDM's apparently have 290...that what my ECU is tuned for when my car was stock. My tuner also confirmed this.</TD></TR></TABLE>

Funny, every B-series injector I've come across, non-VTEC or VTEC are 240cc.

I did a back to back baseline using a JDM ECU and USDM ECU, both AFR's mirrored eachother almost identically. If the JDM ECU was actually for a 290cc injector size, the duty cycle on the maps would make the USDM injectors run lean.

I have a folder of all my dyno's, it will take me a while to dig through them to find the ECU comparison, but when I do I'll post it up.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 92TypeR &raquo;</TD></TR><TR><TD CLASS="quote">

THE JDM P73 ECU HAS IDENTICAL FUEL MAPPING AS THE USDM P73 ECU

</TD></TR></TABLE>

Nope, not true.

1996 JDM P73 is different from 1998 JDM P73 AND is different from 1997 US P73 (I am not sure on 2000 JDM or 2000 US P73 as I have not seen those maps) in all of the maps.

 

Well the JDM P73 I used on the dyno was from a '96spec (OBD2A) and of course mine is a '97 USDM P73. But I know for certain, the fuel mapping on the '96spec JDM ITR P73 is identical to the USDM P73.

If they are different, how can you explain the identical air-fuel curve recorded by a wideband on a dyno? Fluke?

EDIT: Heres the dyno of the USDM P73 and JDM 96spec P73 on a stock USDM motor w/JDM 4-1 and T1R exhaust. Only change was the ECU.




Modified by 92TypeR at 1:06 AM 7/14/2005

 

https://honda-tech.com/zerothread?id=1242980 Resolve your cel & convert to obd1

 

Well ..Ive talk to several people about this, including a guy who reprograms ITR timing maps on the stock JDM ecu. He said that the injectors are 290cc. I self-tuned my PFS based on thinking that my injectors were 240cc and it ran like total crap. After recalculating based on 290cc, it ran tons better.

 

I have seen the actual P73 maps (96 JDM, 98 JDM, 97 USDM) overlayed. Four maps: VTEC fuel, VTEC timing; NonVTEC fuel, NonVTEC timing. They are not the same. (Maps are not located at the same address in the chip; BUT that could be just due to the fact that the JDM does not have the Emmisions that US has on the chip; although the 98 JDM is also located at different addresses.)

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 92TypeR &raquo;</TD></TR><TR><TD CLASS="quote">

If they are different, how can you explain the identical air-fuel curve recorded by a wideband on a dyno? Fluke?

</TD></TR></TABLE>

Keeping the fuel maps as a constant, take away timing, and A/F will show rich. A/F reading is affected by timing. Is it possible that Honda had a target A/F ratio in mind, and with the added fuel or less fuel they changed the timing to maintain that target A/F ratio.

Its been a while since I viewed the programs but if I recall, JDM P73 has less fuel and more aggressive timing than USDM P73(NonVTEC map). JDM P73 has more fuel (especially when VTEC kicks in) and slightly less timing compared to a USDM P73(VTEC Map).




Modified by ITR#132 at 9:42 PM 7/14/2005

 

So you've examined the actual OBD2a/b ROM's?

OR

Did you download the .bin's that people made to resemble the OEM maps for OBD1 chipping?

If you're looking at the .bin's, that is not the actual ECU ROM's that are on the OBD2 ECU's, as the 302 ROM based OBD1 .bin's are completely different than OBD2a/b ROM's.

All I know is that I did that back to back dyno that I posted above, the air-fuel's aren't EXACT, but pretty darn close IMHO, especially below VTEC. Thats the raw evidence I have supporting my case...

Also, with the air-fuels so identical, that adds another supporting fact that ALL B-series injectors are 240cc. If the JDM ECU I dyno'ed was designed to run with 290cc injectors, the equivilent duty cycle on the 240cc injectors would make it run lean, not the same.

I know '97+ Prelude VTEC injectors are 290cc, which is why many people with mild builds seek those out because they are plug-and-play (saturated), and allow a little bit more tunability compared to the 240cc.

I'm not doubting some of the references that suggest that the JDM ITR's are equiped with 290cc injectors, but I've never seen any actual evidence to support that. It wouldn't make sense for Honda to use 290cc injectors for the Japense makes but not for the rest of the world. If I really wanted to prove that all B-series injectors are 240cc, I'll take some automatic B16 injectors, GSR and JDM ITR injectors, send them to Dr. Injector and and show they will all be equal. But I don't care to spend $150 to prove a point

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
ALL B-SERIES INJECTORS ARE 240CC
</TD></TR></TABLE>

Correct! You can even call RC Engineering and they can confirm it as well. They have tested and flowed just about every injector out there. From gas to alcohol, auto to marine...even industrial and aerospace.

All B-series injectors, JDM or USDM are 240cc.

RC Engineering: 310-320-2277 ask for Wayne.

-Brandon

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ITR#132 &raquo;</TD></TR><TR><TD CLASS="quote">Nope, not true.

1996 JDM P73 is different from 1998 JDM P73 AND is different from 1997 US P73 (I am not sure on 2000 JDM or 2000 US P73 as I have not seen those maps) in all of the maps. </TD></TR></TABLE>

When I run my 2000 usdm p73 ecu for my 96 spec jdm itr motor I get a too lean/too rich cel when I drive slow, if I drive a little more aggressively the cel doesn't come on often. When I use a 96spec jdm itr ecu I don't get any cel at all which leads me to believe that perhaps the jdm itr motor run richers not just because of the fuel maps but because of 290cc injectors vs. 240cc. Could it be the usdm ecu is only used to normally running 240cc injectors?


Modified by 2kgs-R at 6:02 PM 7/15/2005

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2kgs-R &raquo;</TD></TR><TR><TD CLASS="quote">When I run my 2000 usdm p73 ecu for my 96 spec jdm itr motor I get a too lean/too rich cel when I drive slow, if I drive a little more aggressively the cel doesn't come on often. When I use a 96spec jdm itr ecu I don't get any cel at all which leads me to believe that perhaps the jdm itr motor run richers not just because of the fuel maps but because of 290cc injectors vs. 240cc. Could it be the usdm ecu is only used to normally running 240cc injectors?</TD></TR></TABLE>

All B/D-series use 240cc injectors.

This 290cc myth is ridiculous.

 

its not.....I had a real hard time tuning my car because I thought my injectors were 240cc too... No matter what I did, the car ran like crap until someone here told me that they are 290cc. I looked all over the web for infoon this and I couldn't find anything. But I talked to three tuners,

#1 said, based on info from Apex'i, the injector size should be calculated based on 290cc.

#2 said that they are in between 270cc and 310cc based on flow tests. A garage in Yokohama..

#3. A guy who reprograms stock ECU's said that they are definately 290cc.

NONE said that they are 240cc. Its possible that the 98+ specs got larger injectors here, but I can't find concrete documentation on this.

 

I've always wondered why the Helms manual doesn't give a single number for a fuel pressure, but instead recommends 47-54 PSI.

Is it possible that USDM and JDM ITRs have differently set fuel pressure regulators as stock? (just to throw another wrench into the mix)

 

About 3 years ago...I blew my engine and had it complete rebuilt by this garage. they pulled the engine and did an engine dyno on it (with the engine out of the car -I still have videos of this ) Anyways, the garage boss, told me that he didn't trust the settings on my ECU so he used his own. He did a flow test on the injectors and said that he couldn't get exaact numbers but they were in between 270-310cc.

 

I had a tuned/chipped 99 jdm itr swap... i put in 290 prelude injectors (my 290s were cleaned and were between 285-290cc flow) and had to pull fuel everywhere to get the same afrs.

My 1999 JDM ITR motor... did not have 290cc injectors in it... straight from Japan to importer to me.

I'm with the group that thinks all B are 240cc.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MiraiZ &raquo;</TD></TR><TR><TD CLASS="quote">#1 said, based on info from Apex'i, the injector size should be calculated based on 290cc.</TD></TR></TABLE>

Friends of mine who work in Apex R&D have verified that the Apex Power FC base map for JDM ITRs is setup for 240cc.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MiraiZ &raquo;</TD></TR><TR><TD CLASS="quote">#2 said that they are in between 270cc and 310cc based on flow tests. A garage in Yokohama..</TD></TR></TABLE>

RC Engineering will confirm that they are 240cc.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MiraiZ &raquo;</TD></TR><TR><TD CLASS="quote">#3. A guy who reprograms stock ECU's said that they are definately 290cc.</TD></TR></TABLE>

That's just hearsay.

 

Its not hearsay, because they are proven to work. My ECU (PFC) is set for 560cc based on 290cc stock configuration, and they work perfectly. When I had them set for 240cc it ran like crap. This along with info from my tuner along with info from everywhere else proves that they are at 290cc. It HAS to be or my car would not be running right now.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MiraiZ &raquo;</TD></TR><TR><TD CLASS="quote">Its not hearsay, because they are proven to work. My ECU (PFC) is set for 560cc based on 290cc stock configuration, and they work perfectly. When I had them set for 240cc it ran like crap. This along with info from my tuner along with info from everywhere else proves that they are at 290cc. It HAS to be or my car would not be running right now.</TD></TR></TABLE>

The ONLY conclusive evidence there is, is flow testing.

RC Engineering has done this and proven that they are indeed 240cc. Nothing else matters, the flow testing does not lie.

 

The PowerFC is also an aftermarket peripheal. It is NOT an OEM ECU.

What sounds like a more reasonable possibility...

1) RC engineering flows are wrong. My dyno is an excel speadsheet. The PowerFC is programmed perfectly without any flaws whatsoever.

or

2) The PowerFC basemap loaded was meant for a modified ITR w/upgraded 290cc injectors. RC flows are correct. My dyno is an actual dyno.