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Bf150 dtc 14 iacv troubleshooting, honda gurus help please??

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Bustedknuckle

Member
[FONT=&quot]2019 honda bf150 with 70 hours. Trying to diagnosis an dtc 14 - iacv problem. Port Engine throws a code as soon as it starts, but runs. Sometimes it stalls as cranking, but once it gets running, idles fine, and no performance issues. Its only throwing code 14 when starting up.[/FONT]

[FONT=&quot]Before pulling vst, im trying to see what else it can be. So far if the iacv is unplug it will start up and runs just barely 600rpms but no dtc light. If I start the engine with the iacv plugged in, it throws code but does the normal rpm range from high to low at idle. I have an 2nd running engine with no cel, and i swapped iacv and iat sensors around to the problem engine with no difference.[/FONT]

[FONT=&quot]2nd thing is if I advance the throttle just little bit, and start the the engine w/everything plugged up, it stumbles for a brief second while firing up but no dtc light and runs fine. I think this ones electrical, something is immediately throwing my code during startup which seems sensor related. Honda gurus??[/FONT]
[FONT=&quot]videos as a reference point.

1.https://youtu.be/mRBfBUUSlCg
[/FONT]2.
[FONT=&quot]https://youtu.be/mRBfBUUSlCg
[/FONT]
 
test fuel pressure if ok, then try cleaning IAC valve? I you are having to advance the throttle, and it starts and runs then good chance its IAC valve.
 
I changed the IAC valve, spark plugs, and mechanical fuel pump. Im going to have a brand new engine by the end of this fiasco. It seems as if the problem is at the initial starting.. when I turn the engine sometimes it just clicks...or doesn't do anything.. other times it turns over starts and for a second and drops out..sometimes it starts and sometimes I get the beeping noise other times I dont. I cheaned the battery terminal and connections..still same issue.
 
what you just described, sounds like your starter or starting system could be issue. Pull your starter off engine, and reconnect wires, hold it in in your hand, have someone turn the key for it to spin over try this couple times. Also look down starter hole at flywheel see if you see water or oil in there.
 
HonDan said:
what you just described, sounds like your starter or starting system could be issue. Pull your starter off engine, and reconnect wires, hold it in in your hand, have someone turn the key for it to spin over try this couple times. Also look down starter hole at flywheel see if you see water or oil in there.
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Thanks for taking the time to reply! My neighbor came over with his meter yesterday and determined it seems to be the solenoid!
 
what year or Serial number is your engine and how many hours and what is your engine doing lights on the key switch buzzer alarm? Is the starter turning? is there voltage at the exciter wire the speaker wire that hooks to the starter solenoid when turning the key? you will need multimeter with some extension cables to see the voltage while your turning the key to start. exciter wire should be zero volts in run position when you hear fuel pump and maybe 6-12 volts when key is then turned start position.
 
I am referring to the IAC problem with the fault 14. My motor starts, sometimes runs rough at first with the alarm but clears up in a few seconds then idles and runs great at the full RPM range. After it runs for 10 min I can turn it off and restart with no problem and no alarm. I have already replaced the IAC with no success.
 
how many hours do you have on the engine? could be the 'heater portion of your 02 sensor, cleaning sensor won't fix heater portion of sensor.
 
800 hours. I replaced the Idle Air Control Valve. I believe the DTC 14 I'm receiving is for the Idle Aire Control Valve.
 
page 5-57 did you clear the IAC code after new IAC install?
since you replaced the IAC and light is still on look at page 5-80 and 5-81 in service manual to test IAC wiring.

with the engine at 800 hours good chance it is A/F 02 sensor heater I'd test that as well its DTC is 41-4 page 5-44 thru 50
 
Agreed, sounds like O2 sensor issue. Ideally you need the proper diagnostics to find the issue, throwing parts at a problem can get pricey. The fact that it runs okay.The other thing to check is that your temp sensor values, could be telling the ecu it's at operating temp and has a lean cold start.
 
I think he is asking about the IAC error code 14. Several people seem to have this problem, check the resistance and voltages per the manual, replace the IAC and still have the same problem.
 
iang6766 said:
There's a whole lot of duscussion in this thread, what problem ate yoi referring to and have you checked your fault codes?
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Thanks for the reply the IAC code is showing after i have replaced it with a brand new one. The links on the first thread show the exact same issue I am having
- Engine starts but when the key is retunes to the ON position the stalls straight away but if I hold the key on start it will continue to run but with the IAC code ''Idle Air Control Valve Failure" ...
 
Craig, this is exactly what ours does. But if we get it running for a while shut it off and restart it, it runs fine the rest of the day or for several days with no problems.
 
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