poor city gas mpg unless i drive on highway for a bit?

[zedjr10]

Originally Posted by Rilas

Unless they are excessively leaking, they will only build up enough oil on the backside of the valves to burn off after sitting 8+ hours. If they are excessively leaking then I could follow that train of thought.

I still feel as though you are grasping at the wrong things hoping it will help. Or possibly are just as stubborn as I am in certain things and are not willing to listen to some sound advice.

Second if there is a rotten egg smell its one of 2 things. Either way your going to need to fix either of them.

1. Battery - Your battery is on it's way out and can give off this smell.
2. Catalytic Converter - You don't live in California, buy an $80 Magnaflow Hi-Flow catalytic converter that is bolt on. No welding of flanges, just cry as you cut your rusted on catalytic converter studs/nuts off. (I can usually get 1 of 3 on average, even with soaking it in penetrating oil for days ahead of time. Re-coating a few times a night, as I have my own garage it can just sit in. Even with a pneumatic impact gun.)

Vacuum leaks can occur in a ton of places on the intake manifold. You have something like 10+ o-rings/gaskets that are at best 25 years old, at worst 28 years old. All of them can be brittle and cracked causing minute air leaks. I've recently been rebuilding an F22A6 to put back into an Accord. I replaced every non paper intake gasket with OEM gaskets. I have absolutely no doubts that the intake is properly sealed. Every gasket that was replaced broke upon coming out due to shrinkage and brittleness. I'm sure some of them were leaking.

You have to remember that the valves on the intake also come apart and have internal o-rings to themselves that need to be replaced as well.

Third if your so overly concerned about things such as an air intake leak, you need to build yourself a smoke tester and come up with some way to provide some air flow to it. Borrow a friends pancake air compressor if possible, if you don't already have your own. This will undoubtedly let you find any leaking spots. (I had an air leak on my 3rd gen TL, and with the air leaks it had, I would have paid thousands of dollars for the amount of time/labor it took to find them all and fix them. I did it myself with a homemade smoke tester, I believe Sonik did the same thing trying to find an air leak on his Prelude.)

Fouth, have you adjusted your valves recently? If so have you verified that it was done correctly if not done by yourself? If not you can check it in a few hours with basic hand tools and a feeler gauge.

O-rings and everything else pretty has been checked or replaced. Most likely replaced. Even the fitv and the eacv(the one beside it that controls idle on electrical output). Bad stem seals = oil contamination through the exhaust system. Oil in the exhaust system = fouled oxygen sensor(s). Fouled oxygen sensor(s) = fail safe mode in the engine control unit (computer). Fail safe mode = full rich fuel mixture, which explains bad mileage. That is a possibility is it not? I've had the valves adjusted but not personally checked and done by myself. I am going to replace cylinder head soon regardless. So then i'll see wasup.

[Rilas]

Originally Posted by zedjr10

O-rings and everything else pretty has been checked or replaced. Most likely replaced. Even the fitv and the eacv(the one beside it that controls idle on electrical output). Bad stem seals = oil contamination through the exhaust system. Oil in the exhaust system = fouled oxygen sensor(s). Fouled oxygen sensor(s) = fail safe mode in the engine control unit (computer). Fail safe mode = full rich fuel mixture, which explains bad mileage. That is a possibility is it not? I've had the valves adjusted but not personally checked and done by myself. I am going to replace cylinder head soon regardless. So then i'll see wasup.

Highly unlikely, unless you have an CEL for a bad O2. They are most likely leaking so slightly that it's not having much of an effect on overall condition of the exhaust mixture.

Also you may have checked the initial ones, but the FIT valve has 4 o-rings on it alone. 2 on the face that mounts to the plenum, 1 on the top, and 1 on the bottom under the covers. Same goes for the other valve on the side of the plenum.

One of my Accords when I first got it burned oil all the time, through the valve stem seals. It still got better mileage then you are now. There is something else going on, you just need to start doing a few things, like reading your plugs. Check the work that other people have done to your car. It's not their car, so most of the time they are not going to care enough to do the best job possible. While yourself on the other hand has something at stake for doing it right. Money out of your pocket that goes into gasoline, it's in your best interest to have the car running top notch, for the engine, driver, and peace of mind.

Also a smell of rotten eggs is clearly a sign that something is wrong, no matter how much your unwilling to admit it. Your car is clearly telling you it needs some tlc... Just some food for thought.

[zedjr10]

Originally Posted by Rilas

Highly unlikely, unless you have an CEL for a bad EGR. They are most likely leaking so slightly that it's not having much of an effect on overall condition of the exhaust mixture.

Also you may have checked the initial ones, but the FIT valve has 4 o-rings on it alone. 2 on the face that mounts to the plenum, 1 on the top, and 1 on the bottom under the covers. Same goes for the other valve on the side of the plenum.

One of my Accords when I first got it burned oil all the time, through the valve stem seals. It still got better mileage then you are now. There is something else going on, you just need to start doing a few things, like reading your plugs. Check the work that other people have done to your car. It's not their car, so most of the time they are not going to care enough to do the best job possible. While yourself on the other hand has something at stake for doing it right. Money out of your pocket that goes into gasoline, it's in your best interest to have the car running top notch, for the engine, driver, and peace of mind.

Also a smell of rotten eggs is clearly a sign that something is wrong, no matter how much your unwilling to admit it. Your car is clearly telling you it needs some tlc... Just some food for thought.

Replaced all 4 on fitv. Noone has done work on this car but me really. Have had it a while now and person before did nothing. Plugs say nothing is wrong. Perfect mixture they say. It is definitely running a little rich. I can smell it out of exhaust. I have very few possibilities left as this hunt has been going on for a while. Highly unlikely i think the ecm is bad or not doing it's job. The cylinder head has never been replaced or worked on. Another possibility i can think of is a vacuum leak but have checked that on several occasions to find nothing. So am really just left with something in the head. One other possibility is a fuel leak in a non pressured line or my fuel injectors possibly.

[Rilas]

How was your mileage prior to your valve adjustment being done?

[zedjr10]

Originally Posted by Rilas

How was your mileage prior to your valve adjustment being done?

crappy before also. The car sat for 3 years before that. Am about to replace head or replace valves. Not sure which yet.

[Rilas]

Originally Posted by zedjr10

crappy before also. The car sat for 3 years before that. Am about to replace head or replace valves. Not sure which yet.

I feel that with a bit of determination you could solve this problem without replacing the head. Or at least do enough diagnosing to ensure that, the head is for sure the culprit. But hey it's your money and your time, do as you please.

[zedjr10]

I am pretty sure the valve seals are gone. Has all the symptoms and it has been on car for 26 years now.The head itself might be fine. I might just have a valve job done as that is alot cheaper i bet. It's about 700 dollars to replace head including the parts. Is there a good reason to machine head and do all that stuff in addition to replacing valves?

[Grumpys93]

Not sure why you created a whole new head for this matter. When you can just continue the discussion in here.

Valves don’t just go bad, unless they are burnt or bent. So replacing them all just seems pointless. If you are that worried about it, I would pull the head, buy supertech valve stem seals and take it to a machine shop and have them do the works on the head...I.e. ( 3 angle valve job, pressure test, valve stem replacement, resurface). This should cost no more then $350 including the valve stem seals.

[zedjr10]

Originally Posted by Grumpys93

Not sure why you created a whole new head for this matter. When you can just continue the discussion in here.

Valves don’t just go bad, unless they are burnt or bent. So replacing them all just seems pointless. If you are that worried about it, I would pull the head, buy supertech valve stem seals and take it to a machine shop and have them do the works on the head...I.e. ( 3 angle valve job, pressure test, valve stem replacement, resurface). This should cost no more then $350 including the valve stem seals.

Pulling the head and taking it to a machine shop is just too much downtime and more expensive than just getting a reman head. How would i easily check how bad off my cylinder head is? How can i check the valves without taking head off? I know some of the valve seals are worn or bad so i thought replacing them all would be best. I am also trying to get a better understanding of what this work would take and how far should i go. I am keeping car forever so maybe that helps understand my mindset. But i am not rich and have 2 kids so some things are more important. SHould i just rebuild my engine. Pistons, rings, bearings, cylinder head, cleaning my intake. Will cost me about $1350 total(i got a cheap mechanic). Wet/Dry test on pistons are 140/160 across the board so i thought they would need replaced in next 2 years.THen i got a new engine but honestly i would rather not do that. The pistons still seem to have good punch. So maybe just replace head or even just do a valve job and clean intake. Beyond my skills though possibly I got a tranny to replace also. Once beyond doing valves i must pay a mechanic to do this. I live in an apartment so can't be working on car for 3 days. Hope this helps.

[zedjr10]

effn poor air filter caused all this crappy city mpg i believe. I just put a high quality K & N OEM Fitted air filter and my city mpg seem to have shot up dramatically. I will update in a week or two when i am 100 percent sure. Right now i am like at 98 percent sure.

[zedjr10]

My new air filter seemed to help some. About 1-2 more mpg. I had an exhaust manifold to downpipe leak. I fixed that last week and waiting to see results. From past experience when resetting the ecu it takes a hundred miles to adjust some trim values. I only have a couple more things on list that could be possible. My new o2 sensor doesn't work as it should. I have a partial blockage at intake manifold. Clogged injectors which is doubtful. I still have a vacuum leak somewhere that i cant seem to find. This is doubtful too.. I think it could be a combination of things and ill know when i get around to taking manifold off and cleaning it thoroughly. Got to get my ac system working first.