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P2187 Help

7.6K views 10 replies 4 participants last post by  philrab  
#1 ·
i've had this "p2187 system too lean at idle bank 1" CEL for a few weeks now, and i've checked and double checked everything everybody says too, except the O2 sensor (since that's the most expensive).

my question is: is there any surefire way to tell if this is indeed the culprit before i go droppin $$$$$ on parts? or is this gonna be trial and error till i fix it? thanks for any input
 
#4 ·
2007 2.3 manual; 110,000 mi.
engine mods:
simota short ram intake
steeda throttle body spacer
srs catback
sure bsd

the light first came on when i installed the throttle body spacer. once i had the code read, i used carb cleaner to check for leaks and there weren't any. then i checked/adjusted the purge solenoid valve and the CEL stayed off for 400 miles, then came back on.
now that i think about it, the common sense thing to do would be take the spacer out and clear the code, then see if it comes back on. duh. any other thoughts?
 
#5 ·
steeda throttle body spacer

the light first came on when i installed the throttle body spacer

I hate to sound like a smart@ss, but it sounds like you know the problem. Either you have an air leak at the last part you installed before this happened, or something about that mod is pissing off your ECU.

Anyone else have experience with throttle body spacers? I haven't seen many use them.
 
#7 ·
If it were me, I'd untinstall and replace the gasket. If your issue disapears, then something about that part was making the ECU unhappy. These cars are fairly sensitive to MAF and airflow changes.

Any other symptoms other than the light? Bucking, stuttering, hesitation? Anything else to indicate you're running lean? could always pull your spark plugs and check color. Black is usually rich (or dirty as Hell) and white/grey is typically lean (if I remember correctly.)
 
#8 ·
sounds like a plan. thanks for your input.
the only other symptom is that whenever i let off the gas pedal after riding at cruising speed for a while, it lopes 3-4 times before stabilizing at idle. it has never stalled, though.
 
#9 ·
Fluctuating idle is a symptom with a few possible causes:
1. vacuum leak - single most common reason

2. air bubble in cooling system - not as common, but not unheard of either. Basically, the air bubble causes the water temp sensor to send a false reading to the ECU, telling it to engage the cold start map which raises your idle and richens your mixture. This is not necessarily followed with a CEL. Again, the only time I'd go this direction is if you recently messed with your cooling system, or if you notice you're low.

3. disconnected battery, ecu reset - resetting the ECU by disconnecting the battery on these cars is known to cause a period of idle upset while the ECU relearns several variables about your engine (I suspect mainly throttle body behavior, which it uses to control idle). Unlike older engines which used cable throttles and a bypass valve in the throttle body to maintain idle, our electronic throttle body is manipulated by the ECU directly, and holds the throttle open a precise amount to stabilize idle. It apparently takes the ECU a little time to relearn how much to hold the throttle open, which leads to idle dips and surges until it gets its mind right.
 
#11 ·
Not necessarily. If it's intermittent, or very slight, you could miss it over valvetrain noise. You could try spraying carb cleaner around the junction though. If it gets sucked in, there's your leak, but if it's intermittent you may be better off just removing the spacer and seeing what happens.