Hello all, so my 2004 accord 5 speed has 286,xxx miles and i rebuild the complete engine like 5k miles ago. im burning alot of gas(I THINK).. last couple times ive been getting like 290-320ish mpg and before it was roughly 380ish-410ish mpg
only thing i have installed is tsx manifold
amazon air intake.
valve cover breather hose is venting

No check engine light. live data shows me -2% to -8%. sometimes it will jump to like -13% on decel. will include video of autel live data tomorrow.
do you folks think that with the tsx manny and the intake, its reading alot more air than it should, which would mean more fuel? car drives extremely well, and has good pick up with the tsx manny.

i have the opportunity to buy ktuner already installed in an 2005 accord ecu. i have autel scanner than can write vins and program keys. should i buy this ktuner and get a tune?thanks

 

bump

 

Here is the first video

And second video
any insight would be nice

 

Between the two videos, it appears that the fuel adaptation values are higher at idle and low RPM/light throttle operation. This is likely a bad FPR in your fuel pump assembly.

 

Ok, I will look into that. I don't see a Schrader valve to check fuel pressure. Car doesn't give data for fuel pressure.

 

I also want to make note, I have a stored p420 cat below threshold code. I have replaced the cat once with a universal cheapy and it lasted like a month. Bought another that was more expensive and a bolt on fit. Seems ok. Replaced that again with the same once since I bought 2 by accident. This was all done before the rebuild (burned a piece of the valve

You can see the piece missing from the valve. Think this was done by over fueling?

 

Failure to keep the valve lash in spec is the typical reason for a burnt exhaust valve on a Honda. The second most common is burning oil. Carbon builds up on the seat and prevents heat transfer out of the valve to the head.

 

There isn't one. You could create a test port at a fuel fitting junction up near the fuel rail. I didn't check pressures, but my suspicion would be that at idle and really light throttle, the pressures would be higher since demand by the injectors is small. However, once fuel demand is higher, high fuel demand would lower the fuel pressure. I have run into this issue in multiple Civic Si's in the last few years and now you describe the same symptom.

 

Well I purchased a new fpr, and filter so once I get those, I will slap that bad boy in, and I'll report back!

 

so i purchased a new fpr, and it didnt fit, so i have to send it back. i ordered another in the meantime, so that should be coming soon. so check engine light actually came on for p0420(cat below threshold) is it possible that due to the possible failed fpr, it was dumping fuel down the exhaust and its whats been killing my cats?

i have a new high flow cat because im building custom exhaust. just saving my pennies for the plm tsx header. i dont want to mess up this new cat so id like to figure this issue out. once its installed, ill do another video of the live data and ill see how it acts.

 

Hey everyone, so new fpr and same thing.

My brother said since I have that tsx manifold, that's my problem potentially, so I'm going to order a thermal gasket and see what happens.

 

Are there some other things I should check?Im thinking of putting my factory manifold and see if it goes back to normal... My manifold is powder coated, that would hold more heat?

Would the thermal gasket help? Or should I get that ktuner and get a tune? If I do the thermal gasket and it helps, should I go ahead and get a tune? I plan on swapping tsx head and headers so I'll need the ktuner for that obviously but for now??? I am mechanically inclined but this is my first k series. I work on them but this one I'm invested in because it's mine😆😆

 

BUMP

 

Poor gas mileage with good running car, I tend to look at compression, tire pressures, and check to see if the brakes are partially engaged by jacking up the wheels and check for resistance while spinning. Be sure to chock the wheels because you will need to have it in.Neutral for the fronts and hand brake released for the rears