mystery gas mileage drop, sluggish motor
11-23-2005, 05:33 PM
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mystery gas mileage drop, sluggish motor
So lately, I have been experiencing horrible gas mileage and sluggish acceleration. I usually get 260-300 (30-35mpg or so) per tank, but lately I have been getting around 200 (around 22-25mpg). Also, my part and WOT acceleration is seriously lacking. I have made no changes to the car at all. Fuel filter, plug wires, cap/rotor are all very new. I replaced the plugs on the last tank with no effect. I have a new o2 sensor to put in this weekend (no CEL, replacing just to be sure, current one has 150k miles)
air filter is not visably damaged
old plugs came out looking perfect
fuel pressure is set at 42psi
no CEL whatsoever
no change in gas or driving habits
stock ECU
edit - I am trying to get my hands on a timing light to check timing. My reasoning for that is that when I went through inspection last month, all my readings were 1/2 the legal limit or less, but NOX was over twice the legal limit.
air filter is not visably damaged
old plugs came out looking perfect
fuel pressure is set at 42psi
no CEL whatsoever
no change in gas or driving habits
stock ECU
edit - I am trying to get my hands on a timing light to check timing. My reasoning for that is that when I went through inspection last month, all my readings were 1/2 the legal limit or less, but NOX was over twice the legal limit.
11-25-2005, 03:31 PM
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Re: mystery gas mileage drop, sluggish motor (743power)
That's true, since the EGR valve lift is monitor by a dedicated sensor.
You'd also think that a stuck in open position EGR valve would not make NOx emissions worse, and a stuck closed wouldn't be detrimental to performance.
You'd also think that a stuck in open position EGR valve would not make NOx emissions worse, and a stuck closed wouldn't be detrimental to performance.
11-25-2005, 07:36 PM
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i started getting really crappy milage a while ago, and i hadn't done anything to my motor recently. i checked everything and couldn't figure it out. i live in the seattle area, and we just started getting our winter weather, its very cold outside. it turns out that the low temperatures brought down my tire psi, 15 psi to be exact. check your tires! mine are up to max psi now, and my regular milage has returned.
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11-27-2005, 07:24 AM
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Re: (LudeyKrus)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by LudeyKrus »</TD></TR><TR><TD CLASS="quote">Compression test.
Check timing, both spark and cam.
You may have skipped a tooth. It could also be a few other things. Help us narrow it down a bit.</TD></TR></TABLE>
i'll see about checking the cam timing
timing belt was replaced about 5k ago, all was well
forgot to say I did a compression test and it was good
Check timing, both spark and cam.
You may have skipped a tooth. It could also be a few other things. Help us narrow it down a bit.</TD></TR></TABLE>
i'll see about checking the cam timing
timing belt was replaced about 5k ago, all was well
forgot to say I did a compression test and it was good
11-28-2005, 11:54 AM
#12
Re: mystery gas mileage drop, sluggish motor (743power)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 743power »</TD></TR><TR><TD CLASS="quote">edit - I am trying to get my hands on a timing light to check timing. My reasoning for that is that when I went through inspection last month, all my readings were 1/2 the legal limit or less, but NOX was over twice the legal limit. </TD></TR></TABLE>
Advanced timing could explain your emmissions numbers. Is it possible that the shop retarded your spark timing to make NOx pass?
Definitely get your hands on a timing light. What year/model is your car?
Advanced timing could explain your emmissions numbers. Is it possible that the shop retarded your spark timing to make NOx pass?
Definitely get your hands on a timing light. What year/model is your car?
11-28-2005, 03:33 PM
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Re: mystery gas mileage drop, sluggish motor (JimBlake)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JimBlake »</TD></TR><TR><TD CLASS="quote">
Advanced timing could explain your emmissions numbers. Is it possible that the shop retarded your spark timing to make NOx pass?
Definitely get your hands on a timing light. What year/model is your car?</TD></TR></TABLE>
I do all my work myself. Timing has not been "adjusted" Don't know where it was to begin with. . . .
getting my hands on a timing light is at the top of my list right now
Advanced timing could explain your emmissions numbers. Is it possible that the shop retarded your spark timing to make NOx pass?
Definitely get your hands on a timing light. What year/model is your car?</TD></TR></TABLE>
I do all my work myself. Timing has not been "adjusted" Don't know where it was to begin with. . . .
getting my hands on a timing light is at the top of my list right now
12-06-2005, 10:30 AM
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I got a CEL code to replace the primary 02 sensor, which I did it myself. However, I'm still getting terrible gas mileage.
Can some one describe the proper way to reset or clear the check engine light? Does this involve the ECU or ECM? I'm confused regarding the "computer" side of this car.
Thank you.
PS. 1998, Accord EX, 4-cyl, auto, 45K, conservative driving style. Secondary 02 sensor replaced a year ago, along with spark plugs and distributor cap. Not spark plug wires though. But the poor gas mileage was on account of a bad primary 02, I thought. I didn't have this problem before the CEL. Also, all parts replaced on this car have always been genuine Honda parts. Tire pressure kept at 32 PSI.
Can some one describe the proper way to reset or clear the check engine light? Does this involve the ECU or ECM? I'm confused regarding the "computer" side of this car.
Thank you.
PS. 1998, Accord EX, 4-cyl, auto, 45K, conservative driving style. Secondary 02 sensor replaced a year ago, along with spark plugs and distributor cap. Not spark plug wires though. But the poor gas mileage was on account of a bad primary 02, I thought. I didn't have this problem before the CEL. Also, all parts replaced on this car have always been genuine Honda parts. Tire pressure kept at 32 PSI.
12-06-2005, 10:43 AM
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Re: (tony4111)
On a 1998 4-cyl, open the fusebox in the right-end of the dashboard. Open the passenger door & it's right near the hinges. Pull fuse # 13 from that box for a while.
You could also disconnect the battery, but then you gotta reset your clock & radio & stuff like that.
You could also disconnect the battery, but then you gotta reset your clock & radio & stuff like that.
12-06-2005, 09:51 PM
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Re: (JimBlake)
Thanks for the tip. After another 2 hrs of research on Google after my initial post, I discovered I missed some KEY steps when I first attempted to reset the ECU back a few weeks ago.
1. Like you mentioned, either pulling fuse 13 or disconnecting the battery is required to rid the CEL. However, I needed to maintain no power to the ECU for 5+ min to be sure.
2. After reconnecting either the fuse or the battery, and start the car, I must NOT step on the gas pedal for at least another 5 mins. This gives the ECU time to recalibrate itself and take datapoints from the various sensors throughout the fuel and emission systems.
It was in step 2 that I violated. Now that I performed all this properly last night, I have topped off the gas tank and will monitor over the next week or so the mileage. Hopefully, my gas mileage will be back to normal. I will also note if there are anything particular regarding idling.
Thanks for confirming how to reset the CEL Jim.
Tony
1. Like you mentioned, either pulling fuse 13 or disconnecting the battery is required to rid the CEL. However, I needed to maintain no power to the ECU for 5+ min to be sure.
2. After reconnecting either the fuse or the battery, and start the car, I must NOT step on the gas pedal for at least another 5 mins. This gives the ECU time to recalibrate itself and take datapoints from the various sensors throughout the fuel and emission systems.
It was in step 2 that I violated. Now that I performed all this properly last night, I have topped off the gas tank and will monitor over the next week or so the mileage. Hopefully, my gas mileage will be back to normal. I will also note if there are anything particular regarding idling.
Thanks for confirming how to reset the CEL Jim.
Tony
12-11-2005, 10:36 AM
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Re: mystery gas mileage drop, sluggish motor (JimBlake)
Jim -
I am happy to post that my MPG is operating like normal.. approx 23/33 (city/highway). Thanks for your insight.
Tony
I am happy to post that my MPG is operating like normal.. approx 23/33 (city/highway). Thanks for your insight.
Tony
12-11-2005, 07:28 PM
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Re: mystery gas mileage drop, sluggish motor (mx524)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mx524 »</TD></TR><TR><TD CLASS="quote">good for you but you jacked this guys thread....now stay out.</TD></TR></TABLE>
chill y0, I'm glad he figured out his problem
As far as my problem, I checked my timing, which turned out to be off a bit and replaced the o2 sensor. Also did the simple things like double check tire pressure and change oil. Car seems to be running alot better so far, we will see how things pan out after this tank is done.
chill y0, I'm glad he figured out his problem
As far as my problem, I checked my timing, which turned out to be off a bit and replaced the o2 sensor. Also did the simple things like double check tire pressure and change oil. Car seems to be running alot better so far, we will see how things pan out after this tank is done.
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