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Discussion Starter #1
First of all, thank you for everyone who shares and posts their experiences and advice/updates. I've done a lot of searching related to the issue I have right now, but still not sure what to do.

I've got a 2000 Insight at 99K. Live in the city but commute out to the country (about 110mi a day) I've had the Insight since 54K. In any case, I've had all the maintenance and oil changes done, but at 63K I did need to have the CAT replaced after a CEL and 0420 code at the dealership.

Well, the problem now is I'm only at 99K and I've got another 0420 according to the same dealership and also 0720 popping up. I know a few other folks have had CAT issues, but I'm just surprised that new CAT at 63K would last such a short time. I drive highway miles 90% of the time and am a fairly gentle driver, if that matters (avg. 60-65mpg). I've got the 100K Care warranty but CAT isn't covered.

I'm actually I'm not driving the car, though, just in case Honda changes their mind and they let me use my 100K warranty...

Does anyone think I have a fair shot at getting support from Honda customer service or should I give up and assume I'm on my own? I noticed the links/ideas for shopping around and getting cheaper parts, but any other ideas (like way to convince my Insight that it really doesn't need another new CAT and just to snap out of it ...

Thanks for any input you've got!
:)

Brad (FYI sorry but my sig is wrong--car has 99K)
 

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I don't know what 0720 is off hand and my service manual is not at the office.

But it's not a cat issue. At least, orginally it was not. It's a LAF sensor issue which is causing a rich fuel mixture and is plugging up the cats. Been there, done that. Good luck getting Honda to replace a LAF sensor without a code.
 

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Discussion Starter #4
Thanks to both Insightful Trekker and Aaron for your replies. I spent the last hour+ understanding what Aaron meant by "been there, done that" :) I'm assuming that the link Aaron provided in reply during that thread...

http://www.insightcentral.net/forum/vie ... php?t=2429

...provided the "there" and "that". I definitely am going to be careful on my current issue until I figure out whether the LAF/O2 sensors are working.

Fortunately, I've got a close friend who is a(n independent) Honda mechanic helping me with this (he's been popping in and out of the forum himself). I'll keep forwarding/discussing some of your experiences and the other related threads--may be easier to just go over some of the past posts with my friend than re-hash it again here. I'll need his help as I'm not nearly as familiar with this car as everyone else.

FYI--He did let me know today (actually yesterday, Sat.) that he checked the LAF sensor (O2 sensor #1) and he said the sensor is reading between 0.1 and 0.6 (volts, I assume), never above 0.6. He and I will probably look at it together soon.

I miss driving my Insight (trying to avoid going over 100K until I confirm problem is not a warranty issue). Anyone like to guess the difference I pay in gas between the Insight and my '94 Chevy 1500 driving 110 miles a day?

Will try and get back with any updates.

Brad

: :) [/quote]
 

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Checking the LAF sensor for appropriate voltage will not prove anything. :) If the sensor is reading wrong, it will be supplying the wrong output voltage and you will have no way of knowing since there is no other sensor to compare it to. A wideband O2 sensor might be of some help if someone has posted the A/F ratio to voltage conversion chart but of course this will be useless during lean burn since most widebands only go to 18:1 or so.
 

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Discussion Starter #6
Well, I guess that makes sense about the voltage not proving anything. Thanks for the warning. My friend mentioned that he may try running the propane enrichment test to check for obvious problems just the same. The idea I think would be to show the sensor is capable of registering readings across the entire range of operation.

I've printed out about 30+ pages of old threads including the current feedback and will share with my friend tomorrow. Thanks for sharing this information.

Again, the main issue I have is CEL light on and the associated codes (0420 and 0720 as I understand). I have _not_ actually noticed any MPG or IMA or driveability problems yet (which is unlike several others' problems apparently)...I've been getting 60-65 mpg for months ever since I started getting lazy...(my first tank of gas after getting the car was about 70-80mpg, and then I was doing 65-75mpg for a while.) In any case, I'm assuming the drop is just laziness since I have been less careful in recent months.

FYI--the main questions I currently have that I will be asking:

1. When the dealer replaced the CAT at 63K, what exactly did they replace?

2. Confirm the codes. My friend reset them yesterday, but when they return, what are they? (0420 and 0720 as well--I never found 0720 in the Service Manual, though)

3. Is the LAF/O2 sensor working properly? (I may just have to replace it there's no way to know for sure. Maybe since I'm at 99K this isn't a bad idea anyways--only have to assume any new sensor is good too, of course, which is not necessarily a good assumption!)

My friend says that most dealers with my car would just replace the CAT again, but I still don't know the root cause, so that's why I'm careful of course (along with all the issues other folks like you guys have had).

Please let me know if you see any basic questions that you think I'm missing above (to make a diagnosis) and have time to reply. Thanks!
:)
 

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Codes P0420 and P0720

Can feel your pain/confusion. Code P0420 is for:"Catatyst System Effeiciency Below Threshold"go see Pg.11-264 in Service Manual, Code P0720(see Service Manual page 11-11,codeP07XX) is a code for a for the automatic transaxe (CVT)in relation to a problem with the output shaft speed sensor ?
OK,what does that mean? 1st off,Why does the ECM(Engine Control Module) think there is a CVT transmission in the car,strange?Looks like you will have to go to a dealer and have a Honda "HDS"scantool do a complete system scan and see what software the ECM has running?

The 1st cat you can pull the O2 sensor and look at the honeycomb to see if it's been overheated and is melted/pluged.The 2nd cat you will need to disconnect the flange and look in. All so you can use a IR gun and check them for an increase in temperature while in operation.A bad primary O2 sensor should have set a code before any cat damage was done. A good cat runs higher than the exhaust gas temperature due to it's oxidation process to burn off the gases.

I have not found a consumer scan tool that will show what the primary O2 sensor output is doing ,most of the time it's a converted reading.

Hopes this helps...
 

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Discussion Starter #8
Thanks, Tuna1. I was wondering if P07XX existed. CVT? I was sure I had a manual...:) Maybe like you say I need to use another scanner (I think my friend did tell me the one he used the other day was not Honda).

What kind of temperature would you expect to see on a normal CAT during operation? Is that spec in the service manual?

A couple more questions have come up, in case anyone has any answers:

1. If I keep driving and let's say the CEL pops back on (let's assume with code 0420), should I expect the car to run fine if I can't find anything wrong with the CAT or the LAF sensor? Should I be surprised if I run this way long-term and nothing gets damaged? (I know I asking us to make some assumptions here--maybe this is a poor question.)

2. If I keep driving and the CEL pops back on (assume the same code), does the engine go into what my friend calls "open loop" operation? Does it matter? (if you know, a brief answer is fine--I know I may be opening up a can of worms).

3. 36531-PHM-A01 (SENSOR, LAF) is the sensor at the head of the CAT that we're all talking about, right?

(FYI-- the receipt for the work by the dealer a year ago revealed that the whole catalytic converter kit was replaced (06180-PHM-A00), not just one component, which was one question I had.)

Thanks for the tips you've already shared.

Brad
 

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Re: Codes P0420 and P0720

tuna1 said:
A bad primary O2 sensor should have set a code before any cat damage was done.
Sorry Tuna1,

Both Aaron Cake and GetShocked.ca have proven that the primary LAF O2 sensor can fail without coding _and_ cause secondary CAT damage as a result. Aaron's was the "trickiest" to isolate because it was failing intermittantly.

HTH! :)
 

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Moderator-1st.Yes i beleive,Arron's story.Get Shocked-His i don't-he just tore that poor car up,and blamed it on everything and everyone else.Presently i have questions about my own 2000 with app 85,000 miles.I have carbon deposites in the tailpipe around town driving,which tells me rich mixture/cats not cleaning correctly.

Now Brad,with knowledge OBTAINED HERE,and my own car. #1 i would change the precat primary O2 sensor the LAF(Yes,your Correct on it).Either go with the Honda Stock NTK/NGK unit you list or the Bosch replacement(i have a Bosch unit on backorder thur a local NAPA).With the engine light on,your in(YES)a open loop program running fixed values from the ECU tables stored in rom. As far as IR temperature readings i will take some and report back with my results.

The design specs for the Precat/LAF O2 sensor is 100,000 miles lifetime,but thats under the best condition/fuels. It may be real world conditions ,the life is a lot less.Untill i find the proper scan tool with the correct values listed i can't comment.

Recap - change out the LAF and may be the postcat O2 Sensor's and you will be in good shape,if the cat's are not melted/damaged.IR temps will confirm if all is well with them.
 

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tuna1 said:
I have carbon deposites in the tailpipe around town driving,which tells me rich mixture/cats not cleaning correctly.
Wrong end. ;)

Carbon at the tailpipe is _normal_ and _will_ accumulate. No accurate way to judge the amount until its sooo excessive that it will be the least of your symptoms.

Black sooty spark plugs (or a color approaching abnormally black) Reading spark plugs, that's an art form :!: ;)

A DVOM will give you the direct readings you desire. But use a HIGH impedance meter. Most manufacturers recommend 10 meg ohm / volt minimum to prevent sensor damage.

Unlikely the secondary O2 is at fault. It (over) simply "wakes-up" when a CAT can no longer efficiently "scrub" the exhaust stream.

HTH! :)
 

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Discussion Starter #12
My friend checked the catalytic converter inlet and outlet temperatures for me and got about 240F going in and about 340F going out. Anyone know if this 100F differential is normal for a good CAT?

Also, he did a propane enrichment test and found the LAF sensor responded MUCH more slowly than the other O2 sensor (at the tail of the CAT) and never went past .8 or so. Since the cars at almost 100K, I'll probably just order and install that new sensor next and see if the code comes back. Like someone mentioned, the dealer probably won't replace the sensor without a code and the exhaust system isn't covered under the 100K Care warranty anyways...

Thanks for reading.

Brad
 

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Discussion Starter #13
CAT Temperature Measurements

I'm curious--does anyone have an IR sensor and a few minutes to measure IR temperature readings on a normally-operating Insight's CAT?

It looks like several folks have shot around temps for coolant with some MPG-improving mods, but haven't seen any CAT temps.

My friend got 240F inlet and 340F outlet on my CAT and was curious if these readings were in ballpark range (or at least similar to what someone else was getting). In reality, depends on a lot of factors, how long the car's been running, etc. but FYI the above temperatures were with the car warmed up and idling.

Thanks,
Brad
 
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