hey all...i have had my 1990 exr fo ra while now and recently my gas mialge really sux!!! i get 400km to a tank that cost me like 53 dollars to fill at 90 cents a litre! now i know that is horrible. i just replaced the plugs...pcv valve...cleaned the k and n filter...welded up the holes in the exhaust...the car runs fine...nothing wrong with it mechanically that i know of...could it be the 02 needs to be replced??? fuel filter??? i dont know... the tranny shifts a bit funny...could that be it?? someone told me that but i wasnt to sure... any ideas...

 

o2 sensor going bad or your egr clogged up

 

same thing here latley I get like 400k to a tank in the city which is like 17mpg, im betting its the o2 senser, when I got the car it was running mega rich cause the excaust manifold was leaking and my the senser probably got all clogged up

 

where is the egr located on these cars... is it easy to clean out. or does it have to be replaced.??

 

o2 replaced still no difference...any ideas!?

 

EGR is usually located on top of engine on the intake manifold. They are usually shaped like 2 pie tins palced together and are usually silver or gold colored.


Here is a 4dr LX model's diagram your should not be too much different



You are looking for what is directly under #36

The EGR ports are between #31 and #33 in the diagram on the intake manifold

 

They rarely go bad but they will get absolutely plugged with carbon, both the valve and the ports.

 

the thing is...my car runs alright...really got to press the gas to go... no check engine light... just gas consumption and sluggish ness

 

Economy and performance are separate issues. EGR will not effect performance. Have you checked your timing?

 

when your EGR cloggs up, one of the first things to suffer is your milage. when EGR is inoperative it no longer allows exhaust gases to go into the compustion chamber. when you allow exhaust into the combustion chamber it effectively reduces displacement. Without the reduction in displacement, the car requires more fuel and therefore you get crappier gas milage. and it does affect performance in another way as well. It causes the combustion temps to rise leading to things like pinging and or knocking due to predetonation.

 

The difference is not a displacement reduction but an oxygen reduction. While the EGR does use a scavenging effect to cool combustion temps and reduce NOX emissions, the fuel economy is created by the re-introduction of Oxygen depleated gasses back into the combustion chamber. The computer sees this Air + O2 depleted air + Fuel as a rich condition as opposed to Air + Fuel. In other words, the same volume of gasses enters the combustion chamber, but, with the EGR open the volume of gas that enters has a lower O2 content. The O2 sensor sees this rich looking condition and narrows the pulse width of the injectors to compensate.

 

I will disagree based upon what EGR does. When you allow Exhaust gas back into the compustion chamber it is reducing the amt of fresh air and fuel required. this is in effect reduces effective displacemement.

Also, todays cars expect a certain amount of Oxygen in the exhaust before and after the catalytic converter as these quanties are used to effectively determine if the cat is working or not.

All EGR does is lower NOx emmissions by lowering the temp that combustion takes place at.

Most engines have a MAP or MAF mounted at or near the intake right before or right after the intake butterfly. Todays cars have no idea how much o2 actually enters the combustion chamger but they can take a very educated guess based upon how much is in the exhaust by the readings of o2 sensor in the exhaust stream. If there is too much or too little, the cpomputer will compensate by adding or subtracting fuel as needed.

 

It doesn't look like you actually read my post.

 

actually you didn't read what I said otherwise you would not have posted in response. Since I am in a nice mood today I'll spell it out for you

EGR allows the some of the exhaust gas to enter into the intake manifold.

When exhaust gas enters into the intake manifold, it reduces the amount of fresh air in the intake manifold

When you reduce the amt of fresh air, you are reducing the effective displacement

so if every time your cylander takes in 100CC without EGR, and with EGR it takes in 80CC isn't that a reduction in displacement? Why, yes it is.


Thanks for playing.

 

NO. The engine sucks in the exact same amount of air or gasses with every intake stroke. The fact that the gasses sucked in during EGR operation result in a charge that has less O2 per cc does not change this fact and if the computer did not have an O2 sensor this would not affect the economy at all because there would still be more O2 present than is necessary for complete burn of the fuel. But since they have O2 sensors, it has the ability to see this O2 depleted condition, so it leans out the motor and you save some gas. And since your being a smart *** that thinks you know something, I must point out that from what I've read of your posts, your a guy that gets all of his service done at the dealer and haunts the forums regurgitating things you've read in other posts. There isn't any displacement reduction. You are dead wrong.

 

back on topic: did you check the ecm/ecu for any trouble codes??? isn't there a code for a bad 02 sensor?...so wasted $ there...

try a compression/leakdown test as well... mebbe the rings are worn...


trouble code check would be the 1st thing to start

 

is ther ea flashing light on the ecu?? o rdo i have to do the connecty wire thing...also...do u guys kno where i can find the ecu code list fo rmy accord...i will test tomorrow and showu guyz....also...i am burning a lil bit of oil....not much...just a bit...could that make a huge differnece.???

 

It's not odd to burn a little oil on a car that old. It's also not odd to see the gas mileage drop some but it shouldn't be as bad as you are describing. Have you changed the air filter recently? You said in an earlier post that you did not ever see a check engine light. If that is true, and the car is as boggy as you say, I start to think of things such as airfilter, plugged exhaust, timing belt jumped a tooth. When was the last time that the plugs, wires, rotor, and cap were changed. You could have a combination of problems depending on how often your car has been maintained.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by amckee &raquo;</TD></TR><TR><TD CLASS="quote">I start to think of things such as airfilter, plugged exhaust, timing belt jumped a tooth. When was the last time that the plugs, wires, rotor, and cap were changed. You could have a combination of problems depending on how often your car has been maintained. </TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote"> i just replaced the plugs...pcv valve...cleaned the k and n filter...welded up the holes in the exhaust...</TD></TR></TABLE>

hmm, hopefully u didn't put too much oil on the filter; excess oil can coat the MAFs & throw off the readings... there's a special cleaner for that but I dunno if it's readily available @ parts stores...

ok, i didn't search on this board, but here's a good link for you to read up & get started:

http://www.troublecodes.net/honda/

O, i wouldn't rule out the plugged egr/exhaust, check vaccuum hoses, etc. GL!

 

I dont think 90 EXR had MAF's they had MAP sensors. Honda makes a kit that allows you to clean your EGR. IF your gettin bad mileage i would check that since its a 1990 car im pretty sure its somewhat clogged up. But jump the two pin connector and see what codes you get first as mentioned above. Might have something stored in there.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16gurl &raquo;</TD></TR><TR><TD CLASS="quote"> i just replaced the plugs...pcv valve...cleaned the k and n filter...</TD></TR></TABLE>I had just waken up and had about two sips of coffee. Sorry I missed that on my re-read of the thread.

 

what is the average mileage to be on a 93 Accord EX Automatic?? I get 18-21 on the average with mixed in-town and highway driving...all I have so far is a short ram intake on it.

 

I have a 92 EX manual and get 27 with mixed driving. In it's younger years, I could get as high as 29.

 

I was getting around an average of 25mpg with my old motor in my 92 EX manual.

 

ok guys i made a list of wat i recently replaced...
-plugs (ngk platinums)
-ngk plug wires
-cleaned the k&n filter
-new rotor and cap
-holes in the exhaust before etest last month
-02 sensor
i am gonna take apart the egr and clean it out and hopefully that will make a differnce, i am thinking of also cleaning out the throttle body...any other places....cuz i really need good gas milage and dont want to buy another civic...i like the comfort of my accord