D16y7 not idling after warm

bobby lee

New Member
Ok when I crank the engine it idles smooth until it is warmed up and then it hunts for idle between 200 to 1000 rpms.. if I'm doin 30 mph and push in the clutch the rpms drop and the engine dies.. it'll crank right back up it just sounds like it has a miss until the rpms get past 500 then it's smooth again.. but if I take the vaccum line off the FPR it finds idle and runs smooth... if I drive it the rpms still die off but doesn't kill the car it just drops to 200 or so and slowly comes back up.... I'm not sure what this mean??
 

HeX

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I don't know what "FPR" is, but as research would show you, try cleaning the idle control valve (IACV).
 


bobby lee

New Member
Tested the TPS. New spark plug wires , spark plugs, cap and rotor
 


Otto85

New Member
Iacv only holds your idle until the car is at operating temperature then your fast idle control valve takes control. Open your fast idle control valve and tighten the inners back up unless your cars throwing a code that should fix it

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MotorMo

Respected
Iacv only holds your idle until the car is at operating temperature then your fast idle control valve takes control. Open your fast idle control valve and tighten the inners back up unless your cars throwing a code that should fix it

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--Negative, that info is backwards. The wax pellet in the Fast Idle valve (if adjusted correctly to factory specs) should allow air to by pass the Idle Control Valve only when cold, before the engine is warmed up. Once the coolant get hot enough, it melts the wax and the valve closes, much like the operation of a thermostat.
I would put my money on a failing Idle Control Valve---Using a factory scan tool, I have noticed that while cruising at speeds, the IAC closes it self- If the IAC is 'sticky', the valve tends to stick closed even though it is being commanded open by the ECU during gear change or what not. This is more than likely the reason why it dies if you engage the clutch while driving. ---Try this, once your car gets up to operating temp, put it in neutral, or park and raise the RPM's to 2,500 for 20 -30 seconds. Quickly release the gas pedal and see if the IAC can open fast enough to catch the idle in time before it dies. You can do this test at a stand still.
Pulling the FPR vacuum hose off allows for extra air to enter the manifold, thus increasing your RPM's and smoothing out your idle.
As far as the slight misfire when all this is going on, I would look into your ignition tune, perhaps there are several areas that are effecting your drivability.
No codes stored yet?
 

Otto85

New Member
--Negative, that info is backwards. The wax pellet in the Fast Idle valve (if adjusted correctly to factory specs) should allow air to by pass the Idle Control Valve only when cold, before the engine is warmed up. Once the coolant get hot enough, it melts the wax and the valve closes, much like the operation of a thermostat.
I would put my money on a failing Idle Control Valve---Using a factory scan tool, I have noticed that while cruising at speeds, the IAC closes it self- If the IAC is 'sticky', the valve tends to stick closed even though it is being commanded open by the ECU during gear change or what not. This is more than likely the reason why it dies if you engage the clutch while driving. ---Try this, once your car gets up to operating temp, put it in neutral, or park and raise the RPM's to 2,500 for 20 -30 seconds. Quickly release the gas pedal and see if the IAC can open fast enough to catch the idle in time before it dies. You can do this test at a stand still.
Pulling the FPR vacuum hose off allows for extra air to enter the manifold, thus increasing your RPM's and smoothing out your idle.
As far as the slight misfire when all this is going on, I would look into your ignition tune, perhaps there are several areas that are effecting your drivability.
No codes stored yet?
That makes more sense thank you for clearing that up, everything I've seen says it the way I suggested

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XpL0d3r

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I don't know what "FPR" is, but as research would show you, try cleaning the idle control valve (IACV).
Research would also show you what FPR is ;)
 

HeX

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Research would also show you what FPR is ;)
True, but I'm not gonna research acronyms to help someone, especially with as much info as is now apparentbthat he forgot to add to the initial post.
 

bobby lee

New Member
Not positive what the ecu is I'll take it down and look tomorrow. but this car ran fine for 3 years and all of a sudden this is happening.. I decided because it was burning alil oil when i bought it I would rebuild it.. new rings bearings gaskets water pump and oil pump and pickup tube.. threw in the motor and ran for 3 years now this
 

bobby lee

New Member
So the p28 ecu is good for the d16z head or the d16y block?? I'm still lost with the electrical side of the hondas..what tranny should I have?
 

MotorMo

Respected
You are now experiencing the result of an engine/ECU mismatch. The engine was slowly being destroyed because it wasn't running properly.
Always amazes me how many people don't know what they are running. Its endless. Being a geek I have always loved to further my understanding of how things work so I can make them go faster. I used to have a 'break it so I can learn and make it go faster' mentality. I wouldn't ask questions lol. these days I still research info on the daily because its my passion for cars that burns a fire with in me. At least people have found a place full of knowledge to learn from. I guess we all start somewhere.
The point of this being is I wanted to give Boofoo a high five, because he's always giving good advice with correct knowledge. Lots of bad info on the web, nice to have people that know what they are doing, and to be humble enough to share that knowledge with beginners. He seems to be answering ever technical question that gets posted lol.
:beer:
 

bobby lee

New Member
So that pw8 will plug right in to wat I have now? And yes I do appreciate everything I grew up SB and BBC is how u make power but I'm getting into this 4 banger stuff really love it just gonna take me a minute to get there
 


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