Very rich idle and stalling
Apr 26, 2017, 01:22 AM
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Very rich idle and stalling
Hello. I'm having a very annoying problem with my jdm evo 7. Basically, whats happening is the car will idle fine until it has warmed up to about 80 degrees celsius then the car will start running richer and richer and richer until eventually it will start hunting (idle dropping and finding itself then dropping again). Then it will stall and be very hard starting, while it is running after warming up it will miss/backfire quite badly and blow out a lot of unburnt fuel. Now what I find to be the weird part.... after the car has warmed up and stalled and ran like a bag of **** the only way to get it to run semi-decent is to unplug the front 02 sensor. which I understand does something to the fuel maps?? not too sure. Also at startup, the front 02 sensor reads 0.00v for around maybe 2 minutes then starts slowly working its way up to 1.70v which I understand is very rich. once it starts receiving that voltage is when it will start to play up. I dont have a wideband yet so this is all I have to go off of
The only recent change I have done is converted to coil on plug and changed the spark plugs to br8es from bpr7eix but that was around 2 weeks before i started having this issue. I have tried changing the spark plugs back again but not the coils because they were knackered and I removed the plug and just wired them straight in.
Other relative mods are Apexi power fc with the hand controller
Walbro 255
kelford 272 cams
some cone filter... and a bov
stock injectors and turbo
Not a single code stored for the check engine light and the idle air control valve is functioning properly. Also have done a boost leak test and there was a couple leaks but stopping them didnt help the problem.
Any input appreciated, I can usually figure things out but this one is driving me to drink
The only recent change I have done is converted to coil on plug and changed the spark plugs to br8es from bpr7eix but that was around 2 weeks before i started having this issue. I have tried changing the spark plugs back again but not the coils because they were knackered and I removed the plug and just wired them straight in.
Other relative mods are Apexi power fc with the hand controller
Walbro 255
kelford 272 cams
some cone filter... and a bov
stock injectors and turbo
Not a single code stored for the check engine light and the idle air control valve is functioning properly. Also have done a boost leak test and there was a couple leaks but stopping them didnt help the problem.
Any input appreciated, I can usually figure things out but this one is driving me to drink
Apr 27, 2017, 12:44 AM
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Its definitely getting up to 1.7v. So you say it shouldn't physically be able to read that high? I was getting terrible gas milage before this started happening... how can I make the voltage read higher or lower? Ive noticed pulling the fpr vacuum line off while the car is running bad seems to smooth things out and actually makes it idle faster. Would pulling off the fpr hose make the car leaner or richer? The 02 voltage doesn't respond to the hose coming off also.
What is a leak down test? Like a boost leak test because I have already done that and fixed the leak I had with not really any change... probably actually made the car idle worse strangely
What is a leak down test? Like a boost leak test because I have already done that and fixed the leak I had with not really any change... probably actually made the car idle worse strangely
Apr 27, 2017, 12:56 AM
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A quick Google revealed that letting in unmetered air should make the voltage go down towards 0.1v so I pulled the bung for the bov in the factory air intake off and the voltage didn't even budge and the car ran a lot smoother. Strangely the voltage is now sitting flat around 0.42-45 only changing every few seconds.... is this enough indication that the 02 sensor is ****ed?
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Apr 29, 2017, 12:14 PM
#9
He doesn't really know, dude thinks he knows more than anyone on this forum, yet often spews absurd comments that are so far off base it isn't funny. If someone doesn't know how something works or a spec he'll belittle them with nonsense or tell them to sell their car for not knowing, calling them dumb. Meanwhile he has no clue what the **** he's talking abut 1/2 of the time anyway.
Pay him no attention and he'll leave eventually
Pay him no attention and he'll leave eventually
Apr 29, 2017, 03:43 PM
#10
He doesn't really know, dude thinks he knows more than anyone on this forum, yet often spews absurd comments that are so far off base it isn't funny. If someone doesn't know how something works or a spec he'll belittle them with nonsense or tell them to sell their car for not knowing, calling them dumb. Meanwhile he has no clue what the **** he's talking abut 1/2 of the time anyway.
Pay him no attention and he'll leave eventually
Pay him no attention and he'll leave eventually
Apr 30, 2017, 01:19 AM
#11
Account Disabled
Normally when it starts hunting it's because it's too lean , not too rich.
With the faulty O2 sensor, the fuel trims will be getting pulled full lean as a result.
Then it'll run lean.
As far as blowing out lots of unburnt fuel........that's a new one.
Never seen that.......got to be worth a video?
Unless you mean lots of black smoke in which case the back of the car will be all sooty.
But you'll know that when you look at the sparkplugs.
You say that pulling the vac hose off the FPR makes it better.
That increases the fuel pressure, makes it run richer.
So it's running lean, not rich..........as per my first statement.
What does the inside of the o2 sensor look like.
Because everything fails for a reason, o2 sensors fail from either from too much soot or from too much oil or just old age.
With the faulty O2 sensor, the fuel trims will be getting pulled full lean as a result.
Then it'll run lean.
As far as blowing out lots of unburnt fuel........that's a new one.
Never seen that.......got to be worth a video?
Unless you mean lots of black smoke in which case the back of the car will be all sooty.
But you'll know that when you look at the sparkplugs.
You say that pulling the vac hose off the FPR makes it better.
That increases the fuel pressure, makes it run richer.
So it's running lean, not rich..........as per my first statement.
What does the inside of the o2 sensor look like.
Because everything fails for a reason, o2 sensors fail from either from too much soot or from too much oil or just old age.
Last edited by RightSaid fred; Apr 30, 2017 at 03:34 AM.
May 15, 2017, 08:45 PM
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Normally when it starts hunting it's because it's too lean , not too rich.
With the faulty O2 sensor, the fuel trims will be getting pulled full lean as a result.
Then it'll run lean.
As far as blowing out lots of unburnt fuel........that's a new one.
Never seen that.......got to be worth a video?
Unless you mean lots of black smoke in which case the back of the car will be all sooty.
But you'll know that when you look at the sparkplugs.
You say that pulling the vac hose off the FPR makes it better.
That increases the fuel pressure, makes it run richer.
So it's running lean, not rich..........as per my first statement.
What does the inside of the o2 sensor look like.
Because everything fails for a reason, o2 sensors fail from either from too much soot or from too much oil or just old age.
With the faulty O2 sensor, the fuel trims will be getting pulled full lean as a result.
Then it'll run lean.
As far as blowing out lots of unburnt fuel........that's a new one.
Never seen that.......got to be worth a video?
Unless you mean lots of black smoke in which case the back of the car will be all sooty.
But you'll know that when you look at the sparkplugs.
You say that pulling the vac hose off the FPR makes it better.
That increases the fuel pressure, makes it run richer.
So it's running lean, not rich..........as per my first statement.
What does the inside of the o2 sensor look like.
Because everything fails for a reason, o2 sensors fail from either from too much soot or from too much oil or just old age.
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