Scan-tool fun

[zip]

I borrowed NuSiers OBDII scan tool for the day to find out why I keep getting a CEL 45 since the RC 310s were installed. The scantool isn't Honda specific but can read the generic SAE parameter codes. The fp currently 30psi at idle.

Here's some of the scan-tools screenshots:



This was taken when the car is at idle and at operating temps. The JR IAT trick actually lowers the intake temps to around 1 to -1F degrees under boost. The spark advance during cruising goes all the way to 40BTDC under partial load. That can't be too good for FI. Thank goodness for timing control under boost. STF1 represents short term fuel trim.


Here LTF1, long term fuel trim is -16%.


O2 sensor readouts. DOH! The CEL is on, as indicated by the MIL.



More O2 sensor readouts


Closed loop


Here's the freeze data frame of the MIL"


DTC code


Damn, the idle mixture is still too rich!


The most expensive alternative to erase CELs.


The odd part is that the short (-16%) and long (-20%) fuel trim are way below the -30% that the ECU is capable of controlling. I think the Lucas style injectors aren't atomizing at idle to well hence the CEL. Anybody have any other ideas?

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Mods

[TrustGs-R]

those things are too cool..

that part about timing being advanced to 40btdc...whoa wtf?? is that because it thinks the car is intake air is extremely cold? (jr iat mod)

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96 gsr hitting 12s
90 hybrid hatch hitting 14s

[rjaffey]

30psi at idle? With or without vacuum?

As for 30% latitude, where are you getting that number? I thought it was more like 15% either way, but don't quote me on that.

[zip]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by rjaffey:
30psi at idle? With or without vacuum?

As for 30% latitude, where are you getting that number? I thought it was more like 15% either way, but don't quote me on that.<HR></BLOCKQUOTE>

30psi w/ vac. I'm going to lower the pressures to around ~22psi. A member on CSi and NuSier are running these pressures, so I guess it's safe. Now that I think about, the 310s are ~23% larger than stock and the long term fuel trim is 20%. So I guess I still need to lower fuel pressures even more. The SI rates at about 31-37psi at idle w/ vac line connected according to the Helm. So if I take 23% off the lowest pressure indicated on the Helm, I'll arrive at 22-23psi. It makes sense.

The ECU can control the 310s but I just found out that if the fuel trim is beyond +/- 10% fuel trim then the CEL will activate. The ECU can reduce the duty to about -30% according to Hondata: http://forums.clubsi.com/ubb/Forum12/HTML/005375.html

but the 10% threshold causes the CEL to be triggered.
http://forums.clubsi.com/ubb/Forum12/HTML/005404.html

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Mods

[NuSiEr]

Looks like you're having fun with that thing.

[zip]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by TrustGs-R:
those things are too cool..

that part about timing being advanced to 40btdc...whoa wtf?? is that because it thinks the car is intake air is extremely cold? (jr iat mod)
<HR></BLOCKQUOTE>

No, the 40BTDC is during cruising at part throttle. All Hondas are programmed w/ high spark advance for better response in the flat spots of the cam and increased fuel economy. People "think" that if the base timing is set at 16BTDC, then it'll be 16BTDC throughout the rev range. That's a misconception since the ECU is always changing timing parameters according to its preprogrammed timing maps. This the reason OE Honda ECU's aren't suitable for forced induction, which is why we use BTM's and such to lower timing under boosted conditions.

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Mods