blow-by or something else, bad MPG

mamyta · 10-09-2008, 09:10 PM

Hi,

I have a 2007 Civic LX AT with about 14k miles on it.

When I pull the oil dip-stick out - there is a lot of compressed air coming out and plenty of gas fumes. could it be a blow-by? there is no black/white smoke coming out of the exhaust...

I've been experiencing bad mpg 22-24mpg (80% city). the engine is kind of sluggish and hesitates, some kind of power loss, accelerates slow...I'm experiencing these problems few months after I bought the car July 2007...

No trouble codes so far from the ECU. I've been 7-8 times to different Honda dealers - they are unable to do anything. according to them if there are no codes - the car is in perfect condition. I got the MAF and PCV valve replaced (I even paid for that even I still have warranty on the car...). Also put a new air filter as well - nothing helped so far...Tires are at 34psi, a little bit over but...

I've reset the ECU a couple of times - no difference at all...
Recent oil change (1 month ago) - no difference as well...

so my question is - could it be a blow-by and still it won't throw any codes?
I was baby-sitting my car during the brake in period and after that. I rarely go over 3500 revs... I can say - I'm driving it like my grandmother...

I can't make the dealers to run leak down test or compression test. they simply refuse. and I don't want to pay for it...Still have a plenty of warranty on my car...I have to open cases at Honda Motor Corporation - no assistance from them as well...

any suggestions?

BigT · 10-09-2008, 11:51 PM

A compression tester is only like $40-$50 and very easy to do. A leakdown test is a little more difficult, but shouldn't be very expensive.

Edit: See if a dealer will let you test drive a new auto LX to compare the response. Also maybe have an oil analysis performed to see if there is evidence of excessive blow-by. If you can prove that there is a problem you could possibly get the dealer to reimburse you for the testing.

BigT · 10-10-2008, 12:10 AM

There is a simply test for blow-by. It isn't 100%, but it can give you an idea. Remove the oil cap while the engine is running (be careful, the placement of the cap may allow oil to be flung out the opening). With the cap off place a piece of paper over the opening. There will be air movement in the crankcase due to blow-by (all engines have a little) and piston movement. But the PCV system should result in a slight net negative pressure in the crankcase. Once flush against the opening the paper should stay in place. If it blows away and doesn't lightly suck against the opening you could have a slight amount of excess blow-by.

Keep in mind the engine should be warmed up fully for this test because there will always be more blow-by when the engine is cold. Also, if the paper is held slightly away from the opening it will likely flutter around from the air movement. This is normal and may be what you are feeling with your hand (it's hard to tell what it feels like over the internet

).

Also, as for your question about codes. If the fuel mixture is basically correct and nothing is dramatically wrong an engine could have excessive blow-by without setting a code.

Good luck.

mamyta · 10-10-2008, 06:22 PM

thanks for your quick reply, BigT

now the interesting part.

I removed the oil cap and put a piece of paper on top of the opening. it was simply blown away from the compressed air from inside the engine.

the car was fully warmed before I performed my "test".

suppose I have to "argue" again with the managers in Honda dealerships.
should I asked them only for compression test or for leak down test as well ?

any other options ?

BigT · 10-10-2008, 06:50 PM

Quote:

Originally Posted by mamyta

thanks for your quick reply, BigT

now the interesting part.

I removed the oil cap and put a piece of paper on top of the opening. it was simply blown away from the compressed air from inside the engine.

the car was fully warmed before I performed my "test".

suppose I have to "argue" again with the managers in Honda dealerships.
should I asked them only for compression test or for leak down test as well ?

any other options ?

Just to clarify, if you simply hold a piece of paper near the hole it will most likely blow away (or just blow around). But if you push it agains the opening for a second it should stay there when you let go. It might flutter and make a lot of noise, but the PCV system will hold it there. I just checked it on my car and if I hold the paper an inch or two away from the oil fill it will seem like it is blowing away. But if I push the paper down until it contacts the opening it will stay there from the slight suction.

It is the same with the dipstick hole. If you simply put your hand above it you will feel a lot of air moving and it will feel like a constant blowing, but if you put your finger against the hole (sealing it) your finger shouldn't feel like it is being pushed away.

If your's blows the paper away no matter what then I would think you have a blow-by issue.

You could try explaining the test you did to the dealer, but that may or may not help. "But a piece of paper over the oil fill blew away"

, might not go over well. But who knows.

2000civic · 10-10-2008, 07:23 PM

Are you loosing alot of oil? That is another sign of blowby. My buddies 2000 Si consumed a half quart in like 100 miles, oil was just blowing through the piston rings and being combusted.

mamyta · 10-10-2008, 07:27 PM

there is no oil loss at all.

I'm gonna "visit" the dealer on Monday... $150 per hour for the labor (compression test)...
but hopefully if they find a problem - I'm not going to pay for that...

BigT · 10-10-2008, 07:54 PM

Quote:

Originally Posted by mamyta

there is no oil loss at all.

I'm gonna "visit" the dealer on Monday... $150 per hour for the labor (compression test)...
but hopefully if they find a problem - I'm not going to pay for that...

Good luck. Let us know what you find out.

Where do you live if you don't mind me asking. Just the general area. Maybe someone on here could recommend a reputable shop that could perform the test for a lot less than that.

mamyta · 10-10-2008, 08:07 PM

Chicago, IL
western suburbs

It would be nice if someone can recommend me a shop...

mfisher1967 · 10-12-2008, 11:04 AM

Catch a sample during your next oil change and send it to Blackstone Labs or Dyson Analysis for testing. A Used Oil Analysis (UOA) from Blackstone Labs only costs ~$22 plush shipping and it usually takes less than one week to get the results. They even send you the sample bottle and mailing kit for free when you request one from their web site. Blackstone Labs tests for the presence of fuel in the oil, which is listed in percent. Terry Dyson, the owner of Dyson Analysis is considered by many to be the premier expert when it comes to accuracy. Dyson Analysis charges ~$50 for a UOA, but the results will be much more accurate and Terry will often make recommendations to improve or correct problems. Performing a UOA is easy and will arm you with some facts when it comes time to get the issue addressed at the dealership.

Your issue sounds like a common problem known as Fuel Dilution, which is common in engines that are frequently used for short distance trips, idle for long periods of time, or use gas treatments too often. If these match your engine use, take the car out for a 30 minute drive at freeway speeds about every other week to help get rid of fuel in your oil. As for gas treatments, I use non-solvent based Lucas Fuel System Treatment in each tank of gas, but use Redline SI-1 in the tank of gas before each oil change. I make sure to wait until the tank containing the Redline SI-1 is almost completely used up before topping off the tank and then I change the engine oil.

mamyta · 10-13-2008, 09:52 PM

next Oil change probably will be in 3000 miles.. I just changed it ...
don't you think that if the oil is "fresh" I shouldn't have these issues ???
fact is that I have them....

may be I can try the "Lucas System Treatment" next fill up...

mamyta · 10-13-2008, 10:03 PM

just came back from the dealership...

here are the results from the compression test (but I paid for it).
1st Cylinder: 200 psi
2-nd Cylinder: 198 psi
3-rd Cylinder: 202 psi
4-th Cylinder: 201 psi

according the Service Advisor it should be 200 psi
so it looks that the compression is perfect...

so I'm much more "relaxed" that at least the engine is fine..
still wondering what can cause the excessive air coming out of the engine, power loss and bad mpg?

according Honda dealership :
- average combined MPG on low end = 24.5 mpg
- average combined MPG on high end = 36.5 mpg

looks pretty low to me...

P.S.
2 PCM updates were performed. I couldn't get more information what exactly these updates were for.

BigT · 10-13-2008, 10:10 PM

Quote:

Originally Posted by mamyta

next Oil change probably will be in 3000 miles.. I just changed it ...
don't you think that if the oil is "fresh" I shouldn't have these issues ???
fact is that I have them....

may be I can try the "Lucas System Treatment" next fill up...

If you have a blow-by issue "fresh" oil won't really do much about it.

Are you talking about the Lucas fuel system cleaner, or the oil additive? Although I seriously doubt there would be an issue after only 14k miles, carbon deposits can cause the compression rings to stick in the piston and cause blow-by. If that is the case the fuel system cleaner could help. I stress could because there is no guarantee it would help even if that is the problem, and I doubt you have that big of a carbon deposit problem after 14k miles. But the fuel system cleaner won't hurt.

As far as the oil additive is concerned I'm not a fan of Lucas oil stabilizer. It is extremely thick and is unnecessary. It also isn't likely to do anything for a blow-by issue.

intoflatlines · 10-13-2008, 11:44 PM

My girlfriend has an 07 LX sedan AT and she used to get around 24 MPG driving in Chicago traffic. Not "Chicago" traffic (like the suburbs), but actual pure stop and go bumper to bumber traffic for three hours a day every day. We changed her oil and put in synthetic, and changed the air filter.. that seemed to help her mileage noticeably.

mamyta · 10-14-2008, 07:26 PM

I have no idea what kind of oil they put at dealerships when they change it...

10-09-2008, 09:10 PM	#1 (permalink)
mamyta Junior Member Join Date: Apr 2008 Posts: 11 iTrader: 0 / 0%	blow-by or something else, bad MPG Hi, I have a 2007 Civic LX AT with about 14k miles on it. When I pull the oil dip-stick out - there is a lot of compressed air coming out and plenty of gas fumes. could it be a blow-by? there is no black/white smoke coming out of the exhaust... I've been experiencing bad mpg 22-24mpg (80% city). the engine is kind of sluggish and hesitates, some kind of power loss, accelerates slow...I'm experiencing these problems few months after I bought the car July 2007... No trouble codes so far from the ECU. I've been 7-8 times to different Honda dealers - they are unable to do anything. according to them if there are no codes - the car is in perfect condition. I got the MAF and PCV valve replaced (I even paid for that even I still have warranty on the car...). Also put a new air filter as well - nothing helped so far...Tires are at 34psi, a little bit over but... I've reset the ECU a couple of times - no difference at all... Recent oil change (1 month ago) - no difference as well... so my question is - could it be a blow-by and still it won't throw any codes? I was baby-sitting my car during the brake in period and after that. I rarely go over 3500 revs... I can say - I'm driving it like my grandmother... I can't make the dealers to run leak down test or compression test. they simply refuse. and I don't want to pay for it...Still have a plenty of warranty on my car...I have to open cases at Honda Motor Corporation - no assistance from them as well... any suggestions?

10-09-2008, 11:51 PM	#2 (permalink)
BigT Senior Member Join Date: Jun 2007 Location: Duff Beer Krusty Burger Buzz Cola Costington's Department Store Kwik-E-Mart Stupid Flanders Park Posts: 1,984 iTrader: 1 / 100%	A compression tester is only like $40-$50 and very easy to do. A leakdown test is a little more difficult, but shouldn't be very expensive. Edit: See if a dealer will let you test drive a new auto LX to compare the response. Also maybe have an oil analysis performed to see if there is evidence of excessive blow-by. If you can prove that there is a problem you could possibly get the dealer to reimburse you for the testing. Last edited by BigT; 10-09-2008 at 11:55 PM.

10-10-2008, 12:10 AM	#3 (permalink)
BigT Senior Member Join Date: Jun 2007 Location: Duff Beer Krusty Burger Buzz Cola Costington's Department Store Kwik-E-Mart Stupid Flanders Park Posts: 1,984 iTrader: 1 / 100%	There is a simply test for blow-by. It isn't 100%, but it can give you an idea. Remove the oil cap while the engine is running (be careful, the placement of the cap may allow oil to be flung out the opening). With the cap off place a piece of paper over the opening. There will be air movement in the crankcase due to blow-by (all engines have a little) and piston movement. But the PCV system should result in a slight net negative pressure in the crankcase. Once flush against the opening the paper should stay in place. If it blows away and doesn't lightly suck against the opening you could have a slight amount of excess blow-by. Keep in mind the engine should be warmed up fully for this test because there will always be more blow-by when the engine is cold. Also, if the paper is held slightly away from the opening it will likely flutter around from the air movement. This is normal and may be what you are feeling with your hand (it's hard to tell what it feels like over the internet). Also, as for your question about codes. If the fuel mixture is basically correct and nothing is dramatically wrong an engine could have excessive blow-by without setting a code. Good luck.

10-10-2008, 07:27 PM	#7 (permalink)
mamyta Junior Member Join Date: Apr 2008 Posts: 11 iTrader: 0 / 0%	there is no oil loss at all. I'm gonna "visit" the dealer on Monday... $150 per hour for the labor (compression test)... but hopefully if they find a problem - I'm not going to pay for that... Last edited by mamyta; 10-10-2008 at 07:29 PM.

10-10-2008, 08:07 PM	#9 (permalink)
mamyta Junior Member Join Date: Apr 2008 Posts: 11 iTrader: 0 / 0%	Chicago, IL western suburbs It would be nice if someone can recommend me a shop... Last edited by mamyta; 10-10-2008 at 08:39 PM.

10-10-2008, 06:22 PM	#4 (permalink)
mamyta Junior Member Join Date: Apr 2008 Posts: 11 iTrader: 0 / 0%	thanks for your quick reply, BigT now the interesting part. I removed the oil cap and put a piece of paper on top of the opening. it was simply blown away from the compressed air from inside the engine. the car was fully warmed before I performed my "test". suppose I have to "argue" again with the managers in Honda dealerships. should I asked them only for compression test or for leak down test as well ? any other options ?

10-10-2008, 07:23 PM	#6 (permalink)
2000civic Senior Member Join Date: Jan 2006 Location: Rancho SoCal Age: 21 Posts: 1,923 Robert iTrader: 0 / 0%	Are you loosing alot of oil? That is another sign of blowby. My buddies 2000 Si consumed a half quart in like 100 miles, oil was just blowing through the piston rings and being combusted.

10-12-2008, 11:04 AM	#10 (permalink)
mfisher1967 Senior Member Join Date: Dec 2007 Location: South Houston, Texas Posts: 116 Mark Fisher iTrader: 0 / 0%	Catch a sample during your next oil change and send it to Blackstone Labs or Dyson Analysis for testing. A Used Oil Analysis (UOA) from Blackstone Labs only costs ~$22 plush shipping and it usually takes less than one week to get the results. They even send you the sample bottle and mailing kit for free when you request one from their web site. Blackstone Labs tests for the presence of fuel in the oil, which is listed in percent. Terry Dyson, the owner of Dyson Analysis is considered by many to be the premier expert when it comes to accuracy. Dyson Analysis charges ~$50 for a UOA, but the results will be much more accurate and Terry will often make recommendations to improve or correct problems. Performing a UOA is easy and will arm you with some facts when it comes time to get the issue addressed at the dealership. Your issue sounds like a common problem known as Fuel Dilution, which is common in engines that are frequently used for short distance trips, idle for long periods of time, or use gas treatments too often. If these match your engine use, take the car out for a 30 minute drive at freeway speeds about every other week to help get rid of fuel in your oil. As for gas treatments, I use non-solvent based Lucas Fuel System Treatment in each tank of gas, but use Redline SI-1 in the tank of gas before each oil change. I make sure to wait until the tank containing the Redline SI-1 is almost completely used up before topping off the tank and then I change the engine oil.

10-13-2008, 09:52 PM	#11 (permalink)
mamyta Junior Member Join Date: Apr 2008 Posts: 11 iTrader: 0 / 0%	next Oil change probably will be in 3000 miles.. I just changed it ... don't you think that if the oil is "fresh" I shouldn't have these issues ??? fact is that I have them.... may be I can try the "Lucas System Treatment" next fill up...

10-13-2008, 10:03 PM	#12 (permalink)
mamyta Junior Member Join Date: Apr 2008 Posts: 11 iTrader: 0 / 0%	just came back from the dealership... here are the results from the compression test (but I paid for it). 1st Cylinder: 200 psi 2-nd Cylinder: 198 psi 3-rd Cylinder: 202 psi 4-th Cylinder: 201 psi according the Service Advisor it should be 200 psi so it looks that the compression is perfect... so I'm much more "relaxed" that at least the engine is fine.. still wondering what can cause the excessive air coming out of the engine, power loss and bad mpg? according Honda dealership : - average combined MPG on low end = 24.5 mpg - average combined MPG on high end = 36.5 mpg looks pretty low to me... P.S. 2 PCM updates were performed. I couldn't get more information what exactly these updates were for.

10-13-2008, 11:44 PM	#14 (permalink)
intoflatlines Senior Member Join Date: Apr 2008 Location: Chicago Posts: 104 iTrader: 0 / 0%	My girlfriend has an 07 LX sedan AT and she used to get around 24 MPG driving in Chicago traffic. Not "Chicago" traffic (like the suburbs), but actual pure stop and go bumper to bumber traffic for three hours a day every day. We changed her oil and put in synthetic, and changed the air filter.. that seemed to help her mileage noticeably.

10-14-2008, 07:26 PM	#15 (permalink)
mamyta Junior Member Join Date: Apr 2008 Posts: 11 iTrader: 0 / 0%	I have no idea what kind of oil they put at dealerships when they change it...

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