[dont have one yet]

Well I was bored at work today so I decieded to do a test on my insight.

With all this talk about Herky Jerkies (which I have been experiencing). I tested the theory with a controled experiment.

I created an EGR blockoff plate, basically a gasket that blocks recirulated gas from entering the manifold but allows the valve to move freely.

For the 20 mile test I experienced:
The same hesitation (in lean burn) as described on other threads.
This was about 70% highway and 30% city driving.
I did not encounter a Check engine light (NONE), and it ran fine (20 miles test of-course).

So I concluded with this test:
The recirulated gas has (entering or not) probably has nothing to do with the hesitation problems.

Anyway, let me know what you guys think, in the meanwhile I'll think of more test to do while at work. :twisted:

 

[Insightful Trekker]

Cakely did the same test way back when in a post with the same result (he later sold it and has been inactive for quite a while now).

It IS an issue of degree. Some _slight_ harshness is _NORMAL_. It seems that the best indicator of abnormal _ENGINE_ harshness is MPG (low).

HTH!

 

[tuna1]

Not a valid test>>>>>>>

EGR gases are designed/required by the engine to lower the temperature in the combustion chamber.Your test is not valid. I don't have a CVT model,but i feel it's not a transmission problem,but most likely a lean air/fuel ratio problem that's causes a lean surge problem.I need to get a hold of a CVT and put a scan tool on it a watch the values of a few items to really know if this could is the problem.

If you change your precat O2 LAF sensor, it would be a cost effective way to find this out for yourself,rather than purchase a scan tool.The Honda's OEM NTK brand,5 wire wideban O2 sensor is availiable private labeled here in the USA: from Walker as their OEM replacement part#250-25001,also from it'savailiable from AC Delco as their OEM part #213-1542.Bosch has their own 5 wire OEM replacement as their part#15393.

NTK is NGK's O2 sensor brand made in Japan.Over here it not promoted as a NGK product line.NTK inspects their O2 sensors 100%.The Bosch unit may be a better unit,but as yet i have not handled one.The Honda/Acure products also use this NTK O2 sensor,but the of lenght of wire leads is different.

When it comes to 4 and 5 wire O2 sensor the info out their can't be trusted,too many mistakes in the printed literature.

 

[dont have one yet]

Re: Not a valid test>>>>>>>

EGR gases are designed/required by the engine to lower the temperature in the combustion chamber.Your test is not valid.

I don't think it works quite like that? Exhaust gases = hot.

I didn't experience any overheating issues.
Not all motors have egr's (example: B16/B18/D-series), nor would they need them. I believe they are mainly benificial for emissions (like a cat).

 

[joecvt]

It seems to me that most of the people that have the "herky jerky"
problem (when it is not transmission related - example accelerating
from a stop) own manual transmissions. Since 5 speeds do lean burn,
I think it is a combined problem between the EGR and LAF because of
the constant changing of air / fuel ratios and purging...These parts as
well as the CAT may get more carbon build-up because of the lean burn
cycle. How many CVT owners have to change or clean these parts to
fix the problem?

I only have 50,000 miles on my CVT so far so I may have to eat my
own words later if I run into this problem...I'll supply this phrase so
someone will be able to find this response with ease:

CVT never needs EGR replaced herky jerky

JoeCVT - Just your average CVT owner

 

[tuna1]

EGR's purpose

Basically exhaust gas is a inert gas,in that it contains no/little oxygen to promote combustion.It's purpose in the chemistry of the combustion prosess is upon introduction back into the combustion chamber it lowers the temperature of the combustion process below which NO(nitrogen oxides) are formed,app. 1400*C.The temperature at which the engine operates at would not show this change on the instrument panel gauge,but it would show on a EGT if the car had one.My comments about the test preform by a member today,are valid.The test was invalid.The control of the combustion process by the onboard engine controls; very well,most likely is the causes of the discribed "Herky Jerky" engine operation.A very good scan tool might be able to display the engine control data too confirm this.Again a cost effective proceedure would be to change out the precat wideban O2 LAF sensor to see if it helps.

A online source to confirm my point is " http://www.ngksparkplugs.com/techinfo/o ... country=US "

In this posting under NGK's FAQ's about "When do i need to change my O2 sensor" it states a to do under "surging and/or hesitation" conditions.

 

[Insightful Trekker]

Tuna 1's done his EGR homework.

If EGR cleaning (low cost) dosen't fix the problem another member in here also identified its internal position sensor as the fault (and a resulting incorrect amount of EGR flow)

The LAF O2 Sensor is a strong possibiliy, but don't forget there is a long list of "simple" things that can cause engine harshness too :!: (one size dosen't fit all) One member found loose spark plug(s), probably incorrectly tightened after the eariler owner took a peek.

And there is a relatively straightforward and simple LAF "test". Propane enrichment. If it passes it could still be bad, but if it fails...no more guesswork :!:

HTH!

 

[Aaron Cake]

I've done the same test. The end result was the blockoff made no different to the hesitation and roughness I was experiencing. I also just unplugged the valve and while the car did throw a CEL, it drove exactly the same (with the same problems).

My issue was cured by replacing the LAF sensor (after a 6 month battle with Honda....but that's another thread).

 

[Scott]

Honda replaced my EGR valve in my 02 CVT in 10/05 ( under warranty) after my CEL came on with a P1456 code. I was experiencing some hesitation prior to replacement and it was no better after replacement.

 

[dont have one yet]

I've done the same test. The end result was the blockoff made no different to the hesitation and roughness I was experiencing. I also just unplugged the valve and while the car did throw a CEL, it drove exactly the same (with the same problems).

My issue was cured by replacing the LAF sensor (after a 6 month battle with Honda....but that's another thread).

Honda replaced my EGR valve in my 02 CVT in 10/05 ( under warranty) after my CEL came on with a P1456 code. I was experiencing some hesitation prior to replacement and it was no better after replacement.

A online source to confirm my point is " http://www.ngksparkplugs.com/techinfo/o ... country=US "
In this posting under NGK's FAQ's about "When do i need to change my O2 sensor" it states a to do under "surging and/or hesitation" conditions.

Awsome! Well, replacing the LAF was going to be my next step. I'm working with some NTK vendors now to get a good price, (under $200) as my warranty has expired (130K miles).

 

[dont have one yet]

 

[BillClark]

laf purchase

priced a sensor from Majestic Honda at 210.00 and my Honda dealer matched the price, coming down from 275.00;

 

[Dave Rowley]

I repeated the test by blanking the EGR to confirm for myself what you guys are saying. I found that the car was more responsive and much smoother BUT the engine check light came on after about 30 miles . I think my next step is to put the EGR valve into an ultrasonic bath and see how it goes on. Do I need to supply power to the valve to extend the valve whilst its in the sonic cleaner?

 

[Insightful Trekker]

The unusual fact that you noticed a smoother engine operation makes me _suspect_ a more difficult to fix problem. *If* the EGR plumbing system gets clogged (the 3 individual runners rarely clog equally) then one cylinder will get an abnormal proportion of EGR causing a power imbalance (read, harshness). This will _require_ intake removal for access to the EGR distribution plate for a thorough cleaning. Sometimes a cleaner (there are several to choose from) injected directly into the plumbing (with the EGR valve removed) can do the job, but IMO its a rarely long term fix.

Actuating the valve will improve the cleaning process by exposing the valve's stem better. And that's where the carbon will be causing any sticking of its proper motion.

SEE:

EGR VALVE DISCOVERY
http://www.insightcentral.net/forum/vie ... php?t=3287


EGR valve cleaning, instructions please
http://www.insightcentral.net/forum/vie ... php?t=1978
PICS :!: :!: :!:


Honda recognizes EGR valve's potential for engine roughness
http://www.insightcentral.net/forum/viewtopic.php?t=653

HTH!

 

[dont have one yet]

I repeated the test by blanking the EGR to confirm for myself what you guys are saying. I found that the car was more responsive and much smoother BUT the engine check light came on after about 30 miles . I think my next step is to put the EGR valve into an ultrasonic bath and see how it goes on. Do I need to supply power to the valve to extend the valve whilst its in the sonic cleaner?

Yeah, unfortunatly my computer recently noticed it too and threw a P0401 code (insufficient EGR flow). LOL, I was hoping to leave it that way because it did run better.

Insightful Trekker,

I have an idea to clean the egr passages w/o taking the manifold off:
Rotate the engine to get the intake valves open for one cyclinder, taking out the spark plug for that cylinder, shooting some carb cleaner in the EGR port then force it through with compressed air. With the valves closed in the other two cylinders as well as the Throttle body, I would think the only way out would be the sparkplug hole on the isolated cylinder. Sounds simple enough huh? jk (NOT)

 

[dfiore]

With all this talk about Herky Jerkies

When I get the herky jerkies, I know it's time to replace my air filter! :lol:

 

[Dave Rowley]

I don't like the sound of pressurising carb cleaner in the bore, I suppose it would always find the easiest way out which would be the spark plug hole but could it not blow past the rings and start to contaminate the oil?

I've just put a new gasket on my EGR valve and its made a real difference, I just averaged 84mpg on the way to work this morning over 120 miles and it feels smoother.

 

[Insightful Trekker]

There are several variety of cleaners to choose. Not all are HC (Hydro Carbon) based. At the quantity potentially entering the oil any HC or water based cleaner would rapidly "boil" off with normal engine operation.

The biggest problem in getting this to work is outlined in the links I gave earlier. Another factor is that if you leave the spark plugs installed (which is a reasonable option), should you add a volume of cleaner (any type) greater than the volume of the cylinder at top of compression hydrostatic lock will occur. A liquid can't be easily compressed and somethings got to give, usually a connecting rod $,$$$ :!: :shock:

To prevent this as a possibility the engine should be cranked over several times with the spark plug(s) removed to "pump" any excess liquid out of the hole. Some of the better cleaners for such an attempt are highly flammable and in clearing the cylinders you are misting this liquid. Failure to disable the spark or have any other ignition source and your Insight could be toast :!: :shock:

 

[BillClark]

I dont think

Ok, dealer ordered and installed 02 sensor; the wrong one; there's one for manual trans and one for auto trans; engine light still on; what a cluster .... these guys are. In shop for two weeks today. Unbelievable.

 

[Dave Rowley]

What about the Cat? There must be some possibility of the cleaner escaping through the exahust valve and into the exhaust system, surely its not going to do it any favours?