adhd316

Hello,

I've got a 2001 CRV with the auto tranny it has about 144000 miles on it. Recently I've noticed the shifting is becoming harder and not happening until later in the powerband, mainly in to 3rd and 4th gear, it does not shift until about 3000-3500 rpms. Today on my way to work it got up to this rpm range and when shifting made a sound that almost sounded like a poof of air. I pulled over and parked and noticed when in park or neutral there was no problem reeving it this high nor any other noises, only when driving and the transmission was trying to shift. I do have my check engine light on, but its the p0420 code which i do not believe has anything to do with this. I noticed some times the acceleration is a little slower than normal when i first start driving then as the car gets warmed up its fine. I only live a few miles from work so its all city driving no highway so I didn't get much over 40 but each time it tried shifting into 3rd it made this sound like air was being released. Could this be one of the transmission solenoids? I tried to google it but didn't find anything similar to this. Any suggestions on where to begin looking to get this taken care of?

Thanks

OneBadTurboCRV

Did you actually try anything yet like checking the transmission fluid level first?

adhd316

Yes I've check the tranny fluid the level is fine and it still looks pretty good colorwise. On another form I was advised a bad cat converter would cause this. I seen once a test for cats with a thermometer but am not able to find it again. Does anyone know how to do this? What kind of temp change am I looking for? Also, not to sound like a moron but does any one else think a bad cat could cause this? Does any one know why a cat would produce symptoms like this.

Thanks

tony_2018

So you have a code for a inefficiency cat, it probably is bad. What you can do is find out why it went bad. That usually occurs when an o2 sensor is sending wrong readings to your ecu. I would first check the primary o2 sensor.

OneBadTurboCRV

If that's the case then yes, it most likely is a bad catalytic converter. I know I have talked about temperature testing cats before. There are a few ways for a cat to fail - melting being the worst. If the engine can't flow (breathe) correctly it will put the ECU into funky load columns and cause things like delayed shifts to happen. Sometimes it won't even shift out of 1st gear if it is bad enough. This is due to conditions not being met for a upshift to happen.

Take a spot radiometer and take the pipe temperatures of the inlet and outlet of the cat/s.

If the Inlet is colder than the Outlet the cat is functional.
If the Inlet is the same temperature as the Outlet the cat is bad but flowing.
If the Inlet is hotter than the Outlet the cat is bad and most likely clogged / melted.

You are looking for a decent temperature delta of say 20 - 40* F or more. A couple degrees is nothing.

A EASY check to do without playing guessing games is to pull at LEAST one O2 sensor if not more before the cat. Take it for a drive and if symptoms IMPROVE (doesn't mean problem will be completely fixed) then either your cat is clogged or possibly the muffler. You can also pull the O2 after the cat and see if it gets better to check for a clogged muffler (unlikely). There is such a phenomenon of a dead cat (no not that kind). Where the honeycomb burns up and stops functioning but allows full (or close to it) exhaust flow.

The proper way to do all this is with a back pressure gauge but most people don't have them set up. Many tricks to the trade though.

adhd316

Well i measure the temp of my exhaust, and it is cooler after the cat. I knew I've been needing one but have been putting it off. I went ahead and sucked it up and ordered a new cat so I'm hoping this is all related to that.

OneBadTurboCRV

How much colder is it? As in what was the Delta T?

If you prefer not to guess then do the other tricks I wasted my time posting.

adhd316

Just an update in case any one else has or had this same issue. The new cat came and have been installed and everything has been fixed. When i checked the temperature as above there was about a 70-80 degree difference at idle, the difference increase quite a bit under load. Thursday night on the way home the car actually stalled, and after slowly putting into a parking lot finally had enough to get me a few more blocks home. Friday morning it would start but was not able to be driven, as soon as you would left off the gas it would stall out and die. I highly suggest just buying all new bolts as I had to cut two of mine of the back side of the cat off with a cut off wheel. But once they were off the replacement went on with ease and has been running great since.

tony_2018

Did you reset the ecu? Any new codes?

OneBadTurboCRV

Oh no, you are welcome...