I have a DC Sports Header and I haven't noticed my MPG drop at all. Maybe your intake manifold/throttle body is clogged. I would check those along with your EGR valve before moving onto any other problems. A magnaflow cat might actually decrease gas mileage as it isn't as efficient as the OEM one but I'm not sure. Might as well pour in some Chevron Techron Fuel Injector cleaner as well as your fuel injectors might have a lot of deposits stuck in them over the period of time.
Any Others with the DC Sports 4-2-1 Header
- Thread starter WiCkeDuDe
- Start date
jcollins6
Well-Known Member
It did when my EGR was clogged to high heaven!
knighthawk1104
Well-Known Member
i believe he has new injectors.
anyway, if everything mechanical is working fine, im gonna bet it's some sort of sensor problem. have a mechanic check the car with a scan tool. check the cars parameters to see if anything is below or above what's normal.
WiCkeDuDe
Member
I have my own scan tool and checked everything. Nothing really outta norm.
jcollins6
Well-Known Member
did you physically unbolt and look in the EGR port?
that would require turning a wrench, the average person can't do that anymore.
WiCkeDuDe
Member
Yes I took the egr valve off and shot brake clean in there, then used a bunch of pipe cleaners to clean it out really well. I then seafoamed the piss outta the engine. It did run noticeably better after but mileage was not affected. I am not average BTW, as I do my own axle regears, rebuild my own engines, etc. I turn my own wrenches and more. Thats why this is so frustrating, as it is some oddball rare problem that has got me stumped.
I have so far run a compression check - 180 lbs all cyl, fuel pressure check - spot on, new injectors, cleaned egr - new egr gasket, no vacuum leaks - constant 18-20 in HG, new intake air temp, new map, cleaned TB and new gasket, new plugs, wires are pretty new - checked resistance - less than 1k ohm, new upstream oxygen sensor, new cat, checked exhaust for restrictions - none. Checked ignition timing and replaced rotor - spot on 12 degrees at 700 rpm hot.
Like I said the only thing on the scan tool thats a little wack is my downstream oxygen sensor is pretty slow to heat up and read anything. Ill prob just replace it as it is 90k old. As others have said there header is not causing an issue I dont see how that could be the cause.
Does anyone have their old factory manifold and cross over pipe for a 2.3 vtec?
I have so far run a compression check - 180 lbs all cyl, fuel pressure check - spot on, new injectors, cleaned egr - new egr gasket, no vacuum leaks - constant 18-20 in HG, new intake air temp, new map, cleaned TB and new gasket, new plugs, wires are pretty new - checked resistance - less than 1k ohm, new upstream oxygen sensor, new cat, checked exhaust for restrictions - none. Checked ignition timing and replaced rotor - spot on 12 degrees at 700 rpm hot.
Like I said the only thing on the scan tool thats a little wack is my downstream oxygen sensor is pretty slow to heat up and read anything. Ill prob just replace it as it is 90k old. As others have said there header is not causing an issue I dont see how that could be the cause.
Does anyone have their old factory manifold and cross over pipe for a 2.3 vtec?
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jcollins6
Well-Known Member
f23A1? I have a factory manifold that I will even trade you for... just sayin
WiCkeDuDe
Member
I had a very small crack awhile back a few years ago that I welded up on it. Ive checked all over for leaks and found none. When I seafoamed I didnt notice anything come out anywhere so I felt good being the seafoam will come out of about any small pore.
Its only the downstream oxygen sensor that is slow. Ive just been hesitant to replace it because it SHOULD only monitor cat efficiency, not affect fuel curve, unless the accord does things different. I did order a sensor for the hell of it being its 90k old.
jcollins6- I am totally open to swapping if you will send the manifold AND flex pipe. This is my wifes car and I dont have time to mess with it or desire. With fuel as high as it is right now mileage is the highest priority. If I cant figure it out soon Ill swap.
Its only the downstream oxygen sensor that is slow. Ive just been hesitant to replace it because it SHOULD only monitor cat efficiency, not affect fuel curve, unless the accord does things different. I did order a sensor for the hell of it being its 90k old.
jcollins6- I am totally open to swapping if you will send the manifold AND flex pipe. This is my wifes car and I dont have time to mess with it or desire. With fuel as high as it is right now mileage is the highest priority. If I cant figure it out soon Ill swap.
