Help! Rpm/Accerelation Issue
03-16-19, 02:06 PM
#1
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Help! Rpm/Accerelation Issue
I’ve had this issue since I’ve bought my 08 IS250 AWD
My issue is I can accerelate my car until about 3rpm. After 3Rpm it does continue to rise but does not accerelate any faster. My car will accerelate the same way whether on 2rpm or 7rpm. I’ve changed my catalytic converter (p0420) B1S1: Now I get a code for my 02 Sensor Bank 1 Sensor 1 . I’ve done a tune up. Oil change. I’m wondering what could be the cause of the reason why my car isn’t 100%. I could floor the pedal but the accerelation isn’t there.
My issue is I can accerelate my car until about 3rpm. After 3Rpm it does continue to rise but does not accerelate any faster. My car will accerelate the same way whether on 2rpm or 7rpm. I’ve changed my catalytic converter (p0420) B1S1: Now I get a code for my 02 Sensor Bank 1 Sensor 1 . I’ve done a tune up. Oil change. I’m wondering what could be the cause of the reason why my car isn’t 100%. I could floor the pedal but the accerelation isn’t there.
03-17-19, 07:18 PM
#4
You changed the Primary CAT or B1S1 sensor?
If you had a primary cat failure, something caused that failure. Cats die from failed ignition components typically.
If you didn't change the cat but you suspect it is/they are plugged, remove the upstream O2 sensors S1/S2 and see if it revs.
If it does, yes, it is in the exhaust and now you need to confirm it is not the secondary cats that are plugged.
If you had a primary cat failure, something caused that failure. Cats die from failed ignition components typically.
If you didn't change the cat but you suspect it is/they are plugged, remove the upstream O2 sensors S1/S2 and see if it revs.
If it does, yes, it is in the exhaust and now you need to confirm it is not the secondary cats that are plugged.
03-17-19, 11:48 PM
#5
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I replaced the B1s1 cat so passenger side cat conv. I’ll do the o2 upstream sensor removals and see if it revs. But my problem isn’t that it doesn’t rev up past 3k rpm. It’s that it can rev up to 7k + and not have accerelation past 3k. The sound will be louder but the accerelatation is the same from 3k Tom to 9k rpm
03-18-19, 10:29 AM
#6
B1S1 is an o2 sensor identifier location for the USD right side upper sensor near the battery. You replaced the Bank 1 primary cat. But why? What caused it to fail?
If it were mine and a CAT failed w/say 100,xxx miles on it, I would replace the B1S1 and B2S1 O2 sensors.
In short a plugged exhaust will limit the ability to make power. The engine will Rev under NO LOAD but under load it may barely move the vehicle.
So, the easy thing to do is make an exhaust leak (remove B1 and B2 upper sensors which are ahead of the cats.
Do keep in mind there will be 1300°F hot gasses exiting those holes so plastic and other materials can burn!!!!
Protect anything near this with a metal deflector shield held in place by a hose clamp.
** You are doing this at your own risk and I am not responsible for damage to your vehicle if you use this information... **
Any chance this engine was fueled by leaded gas?
Does it consume a lot of oil and what other service history does it have?
If it were mine and a CAT failed w/say 100,xxx miles on it, I would replace the B1S1 and B2S1 O2 sensors.
In short a plugged exhaust will limit the ability to make power. The engine will Rev under NO LOAD but under load it may barely move the vehicle.
So, the easy thing to do is make an exhaust leak (remove B1 and B2 upper sensors which are ahead of the cats.
Do keep in mind there will be 1300°F hot gasses exiting those holes so plastic and other materials can burn!!!!
Protect anything near this with a metal deflector shield held in place by a hose clamp.
** You are doing this at your own risk and I am not responsible for damage to your vehicle if you use this information... **
Any chance this engine was fueled by leaded gas?
Does it consume a lot of oil and what other service history does it have?
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