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Running rich at idle, low idle.

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Old 06-04-2018, 06:03 PM
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Default Running rich at idle, low idle.

hey all,

just completed a b16a swap into my 1999 dx hatchback. The car started up, first time, no problem, EXCEPT: the idle seems low and the exhaust smells very rich.

some details:

engine is an sir2 b16a from hmo. Ecu, transmission and wiring harness are from an EM1. Tried to build the car as if it were a usdm em1 for emissions and drivability purposes. Installed obd2 usdm oil pump to run ckf sensor and wired up secondary 02 sensor to ecu. All sensors except knock sensor are usdm as far as I can tell. Intake and throttle body are jdm, however. Engine is otherwise stock except header. Cel isnt on (yet at least). The engine came out of a wrecked coupe I bought, and seemed to run fine before I took it out. Fuel pump is running at 28 to 30 with fpr at idle, with em1 fuel pump. Could be a tad on the low side.

Otherwise car runs good! Doesnt overheat, pulls decent. Just reeks of gas fumes at idle, and idles low (around 4 to 500). Any idea of what to check first? Waiting for a timing cover in the mail so I can check timing, but I havent touched it since the ecu and engine were in the coupe, which ran fine, so I cant imagine its changed. I’ve searched around A LOT first and havent found exact symptoms/answer.

thanks!!

Seth
Old 06-04-2018, 09:50 PM
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Default Re: Running rich at idle, low idle.

I guess I could simplify:
is it bad to use a jdm intake and throttle body with the usdm ecu? Would that with a header cause a rich condition? Would slightly low fuel pressure maybe be causing a lean miss at idle, which smells lean?

Old 06-05-2018, 04:47 AM
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Default Re: Running rich at idle, low idle.

Maybe ignition timing is off?
Old 06-05-2018, 04:57 AM
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Default Re: Running rich at idle, low idle.

Use OBDII scanner to check fuel trims. Are the JDM fuel injectors the same cc rate that the USDM ECU expects?
Old 06-05-2018, 04:18 PM
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Default Re: Running rich at idle, low idle.

Ok, so taking another in depth look today... I noticed that the evap purge valve was running to where the POV valve is supposed to run. The PCs valve itself was venting to atmosphere. I got a new PCv valve and routed the hose where it’s supposed to go. However, now the evap valve has nowhere to plug into. On usdm motors, the hose for the valve goes where my finger is going. Where would it go on jdm motors, assuming it would have one? Or can I bypass it without the cel coming on? Also, I’m not sure the jdm injectors are the same as usdm but I THINK they might be. And I’m waiting for a timing cover to come in the mail before I can check timing. I’m just checking everything else I can while I’m waiting. Also waiting on a scan tool. Any info would be crazy helpful. Also please ignore my fart sticker...
Old 06-08-2018, 06:34 PM
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Default Re: Running rich at idle, low idle.

Got my cel back off for my secondary o2 sensor.
Cel stays off... no codes.
Got a timing cover in the mail today, finally adjusted my timing. Was a little off, needed advanced. Raised the idle but it still smells super rich.
Still waiting for scan tool to come in the mail.

tried swapping my primary o2 sensor with a good working one, Same with map and iat. No change.

Replaced cap, rotor and plugs with oem stuff. Also checked for a head gasket leak for the heck of it. Head gasket is ok. Hmmmm. Still smells super rich at idle! Still no codes.

Any ideas?? Smells rich at idle all the time, cold or hot. Like, 50’s American car with a stuck float rich. Otherwise drives fine.

Thanks!

Last edited by 1999AZhatch; 06-08-2018 at 07:29 PM.
Old 06-10-2018, 02:06 PM
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Default Re: Running rich at idle, low idle.

FINALLY got my scan tool.

fuel trims are both around seven with engine warmed up. Short term sometimes fluctuates between 6 and 9.

Voltage of of the two o2 sensors seems wayyy to similar. Could this mean a bad cat?

Also so map is only reading about 8 or 9 at idle (inHg) is this normal for our cars? Seems low.

spark advance at idle is only 13.5 is this normal? I set base timing to specs already using the proper procedure.

everything else seems very normal to me.

PLEASE anyone with ay insight!?????
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