Lean AFR at Idle
Jan 2, 2018, 12:15 PM
#16
Account Disabled
If your afr goes leaner with the brake pedal depressed it can be a vaccum leak at the brake booster.
Go under dash and press brake pedal listen for a hiss noise from booster. Maybe spray brake cleaner at the back of the booster inside the car while pressing the pedal. See if engine stumbles
Go under dash and press brake pedal listen for a hiss noise from booster. Maybe spray brake cleaner at the back of the booster inside the car while pressing the pedal. See if engine stumbles
When you press the pedal the air goes in to relieve the vacuum.........otherwise it won't work as a booster.
So what you're seeing is a normal condition.
And like I said before, the WB sensor has to be before the cat converter.
If it's near the rear o2 sensor thern it's after the cat converter and it will always read lean.
So it's yet another normal condition.
Jan 2, 2018, 01:02 PM
#17
Newbie
Thread Starter
Did you know that a brake booster has a hole in it to let the air IN.
When you press the pedal the air goes in to relieve the vacuum.........otherwise it won't work as a booster.
So what you're seeing is a normal condition.
And like I said before, the WB sensor has to be before the cat converter.
If it's near the rear o2 sensor thern it's after the cat converter and it will always read lean.
So it's yet another normal condition.
When you press the pedal the air goes in to relieve the vacuum.........otherwise it won't work as a booster.
So what you're seeing is a normal condition.
And like I said before, the WB sensor has to be before the cat converter.
If it's near the rear o2 sensor thern it's after the cat converter and it will always read lean.
So it's yet another normal condition.
Will double check wiring though, maybe it's not installed properly. But on other hand WOT AFR looks good(meaning it's the same as tuner said he tuned for, using his wideband), wouldn't it cause wrong readings at WOT too?
Alternator version seems interesting as well, will log the voltage.
Jan 3, 2018, 04:19 AM
#19
Newbie
Thread Starter
Ok so, logged the voltage, most of the time it's 14.1-14.2, occasionally drops to 13.9-14.0. I have moved battery to trunk, and voltage on battery ports is a bit lower around 13.8-13.9, when car is idling.
As for Wideband wiring everything seems to fine. Seems like I'm back where I started.
As for Wideband wiring everything seems to fine. Seems like I'm back where I started.
Jan 3, 2018, 09:34 PM
#21
Evolved Member
check for leaks, do a boost leak test, check the injector seals run your hand on top and behind the intake manifold for any loose/broken vaccume lines...
check all the vacumme lines, some times they are split from underneath and you cant tell unless you inspect it.
check all the vacumme lines, some times they are split from underneath and you cant tell unless you inspect it.
Jan 4, 2018, 06:34 AM
#22
Newbie
Thread Starter
And don't really think it's boost leak anyway, because AFR is almost close to stoic when cruising, wouldn't it be same or worse in case of boost/vacuum leak?
Trims also look more or less fine(attached logs), at the end where low trims spikes up and afr goes around 19-20, car was still and I pressed brake 15-20times.
I'm suspecting exhaust leak, because front O2 is newly replaced(suspected it to be the cause of this issue and changed it), and if 17-17.5 was the correct AFR wouldn't it affect the trims?
But as I said can't really hear any abnormal noise or see any damage on exhaust.
Jan 4, 2018, 06:46 AM
#23
Evolved Member
Already did a boos leak test, sprayed with soapy water everything I could think of(injector seals, all the vacuum lines, IC pipes, IC itself, EGR port), also did test with running machine and throttle cleaner, no leaks. One thing though intake doesn't hold static boost, it goes to 15 psi to 0, in around minute. But I think that's ok, probably going through valves.
And don't really think it's boost leak anyway, because AFR is almost close to stoic when cruising, wouldn't it be same or worse in case of boost/vacuum leak?
Trims also look more or less fine(attached logs), at the end where low trims spikes up and afr goes around 19-20, car was still and I pressed brake 15-20times.
I'm suspecting exhaust leak, because front O2 is newly replaced(suspected it to be the cause of this issue and changed it), and if 17-17.5 was the correct AFR wouldn't it affect the trims?
But as I said can't really hear any abnormal noise or see any damage on exhaust.
And don't really think it's boost leak anyway, because AFR is almost close to stoic when cruising, wouldn't it be same or worse in case of boost/vacuum leak?
Trims also look more or less fine(attached logs), at the end where low trims spikes up and afr goes around 19-20, car was still and I pressed brake 15-20times.
I'm suspecting exhaust leak, because front O2 is newly replaced(suspected it to be the cause of this issue and changed it), and if 17-17.5 was the correct AFR wouldn't it affect the trims?
But as I said can't really hear any abnormal noise or see any damage on exhaust.
Jan 4, 2018, 08:07 AM
#24
Newbie
Thread Starter
Already did that when installed new turbo month ago, installed new turbo to manifold/outlet gaskets as well. Only thing that haven't checked is metal O ring gasket(outlet to downpipe), will try to replace that as well.
Could it be a worn valve seats or burnt valves?
Could it be a worn valve seats or burnt valves?
Jan 4, 2018, 08:10 AM
#25
Evolved Member
if you can do a leak down test aswell.
Jan 4, 2018, 09:36 AM
#26
Newbie
Thread Starter
I've done compression test last year, it's terrible, I had like 145, 120, 120, 130 psi, something like this. Car has around 150K miles. And starting to gather parts for rebuild(want to do 2.3 stroker).
What about leak down test, don't think any mechanic does that in my country, unfortunately.
What about leak down test, don't think any mechanic does that in my country, unfortunately.
Jan 4, 2018, 04:41 PM
#27
Evolved Member
I've done compression test last year, it's terrible, I had like 145, 120, 120, 130 psi, something like this. Car has around 150K miles. And starting to gather parts for rebuild(want to do 2.3 stroker).
What about leak down test, don't think any mechanic does that in my country, unfortunately.
What about leak down test, don't think any mechanic does that in my country, unfortunately.
you said that was last year, it could be even lower now, maybe this is your problem.
even if this is not the problem, still you will have to rebuild your engine because your compression is very low, it should be atleast 160 to be healthy.
i have a built engine and my compression numbers are 180,178,190,180.
maybe time for a new rebuild.
Last edited by babaz7; Jan 4, 2018 at 04:51 PM.
Jan 5, 2018, 06:12 AM
#28
Newbie
Thread Starter
your compression numbers shouldnt be more than 15 psi apart, and on top of that your compression numbers are very low, i think mitsubishi says to service your engine if they are at 130 psi...unfortunately yours are lower..
you said that was last year, it could be even lower now, maybe this is your problem.
even if this is not the problem, still you will have to rebuild your engine because your compression is very low, it should be atleast 160 to be healthy.
i have a built engine and my compression numbers are 180,178,190,180.
maybe time for a new rebuild.
you said that was last year, it could be even lower now, maybe this is your problem.
even if this is not the problem, still you will have to rebuild your engine because your compression is very low, it should be atleast 160 to be healthy.
i have a built engine and my compression numbers are 180,178,190,180.
maybe time for a new rebuild.
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sowne (Jan 5, 2018)
Mar 25, 2018, 11:18 PM
#30
Newbie
Thread Starter
Ok swapped to different engine, compressions across all the cylinders are 175PSI +/-2. It still has stock cams. But still same, 17-18AFR at idle, 14-15during cruising, 11-11.5 WOT. What elss can it be?
