Stock P13 ecu
Stock 345cc P&H injectors
Stock FPR
3" SRI with k&n filter
Cheap ebay header
Stock cat
2.5" RS*R Ex-mag cat back exhaust
Replaced within last 10k miles: Dizzy cap and rotor, NGK plug wires, NGK iridium plugs

Could a restrictive header cause the AFR to be so rich? Is it possible that the stock FPR is broken, causing too much fuel pressure at the rail?

If you have any guesses, suggestions, or need more info to troubleshoot let me know!!

Thanks in advance

 

Whats your vaccum reading?(should be 18-22hg's at idle)
Could it be an old o2 sensor?
12's is truly gates rich

 

o2 sensor (NTK) was replaced with everything else less than 10k miles ago.

i'll have to check on the manifold vacuum. It does not idle high, so i dont think i have a vacuum leak. If its greater than 22hg's at idle what would that suggest?

Thanks

 

bump

 

87 views and only 1 reply? that makes me

Anyways, i may have found the problem. I am using the fuel rail and fpr from my old h23a1 on the new h22a4 engine. after looking through the helms, it appears that h22's take about 3psi less fuel pressure than h23's and f22's.



im unsure how much difference 3 psi at the rail makes what effect it will have on the afr. When i was researching for the swap, i never read anything about having to get a new fpr, so im wondering how many other people who have done this swap have this problem and just dont know it.

your $0.02 on this issue is appreciated

 

So you're running a completely stock ecu/fuel setup?

That AF curve looks pretty reasonable for a stock setup.

 

you think afr in the 12's is reasonable? im under the impression that it should be closer to 14. . . .

 

NA should be 13.0:1

 

could 3psi difference at the fuel rail cause it to be in the 12's rather than 13's?

 

Increased fuel pressure will cause you to run richer.

 

im asking if the afr is about 12:1 at say 43psi, would it be more like 13:1 at about 40psi?

please correct me if i am getting this all f'd up

 

I follow you on that, i think the only way to see is to change it out and go back to the dyno$$ The hondy H22 engineer's run it rich for safety correct?(lean=melt=F*uck) But i agree your a/f ratio is way rich for na like stated before.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by syntax420 &raquo;</TD></TR><TR><TD CLASS="quote">you think afr in the 12's is reasonable? im under the impression that it should be closer to 14. . . .</TD></TR></TABLE>

Well, it certainly could be better, but that doesn't mean you should expect the stock fuel and computer bits to hit that. Stock maps are going to run the engine rich for safety, that's just life, and your dyno is a typical example of that.

If you want to hit the AFs for peak power, just invest in some kind of ems.

 

Swap out to an H22a FPR and see how it goes.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Finest &raquo;</TD></TR><TR><TD CLASS="quote">Swap out to an H22a FPR and see how it goes. </TD></TR></TABLE>

i wish i had one to swap it out with or i would have done it already! do you have one to donate to the cause?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Featherfire &raquo;</TD></TR><TR><TD CLASS="quote">Well, it certainly could be better, but that doesn't mean you should expect the stock fuel and computer bits to hit that. Stock maps are going to run the engine rich for safety, that's just life, and your dyno is a typical example of that.

If you want to hit the AFs for peak power, just invest in some kind of ems. </TD></TR></TABLE>

Im really not all that concerned with peak power, right now i cant pass emissions testing and to be honest the exhaust fumes stink. Plus i think ill probably get better gas mileage with the correct afr.

I'm looking into getting a fuel pressure gauge for the rail and possibly and adjustable fpr so i can lower the pressure a bit. And then ill already have the fpr if (or when) i decide to boost the biyotch

Thanks guys

 

I'm almost sure it's proportional. That is, 43psi --&gt; 40psi is a change of 7%. If you add 7% to your a/f of 12 you'd be up to 12.9. Pretty dang close to perfect... so I'd say change the fpr.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kb58 &raquo;</TD></TR><TR><TD CLASS="quote">I'm almost sure it's proportional. That is, 43psi --&gt; 40psi is a change of 7%. If you add 7% to your a/f of 12 you'd be up to 12.9. Pretty dang close to perfect... so I'd say change the fpr.</TD></TR></TABLE>

i &lt;3 h-t members that know what their talking about. . .

im about to post a wtb for a stock 4th gen h22 fpr

and your kimini rocks

 

You can use that theory but there are more factors that come into play than percentage.

Basically the only way you'll know is to back off the fuel pressure and check your a/f's from there.

 

It is too rich in open loop according to that dyno graph. I do recommend lowering the fuel pressure. However, the regulator is not what is causing you to fail emissions right now. In closed loop operation the ECU has the ability to set fuel trim, and 7% is well within it's capability. If the car has been this way for a while, you may have a bad catalytic converter. I would also verify the operation of the o2 sensor.

Many stock Hondas run in the 12:1 range in open loop, especially Preludes.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PrecisionH23a &raquo;</TD></TR><TR><TD CLASS="quote">You can use that theory but there are more factors that come into play than percentage.

Basically the only way you'll know is to back off the fuel pressure and check your a/f's from there. </TD></TR></TABLE>

Fair enough, but that logic works on our aircraft ECU...

 

So what if you are running say 7psi of boost.... your fuel pressure will increase by 7psi. So if you are running a base of 40psi you are now at 47psi. But this change will not account enough to run rich enough that a turbo engine would require.

I know we are talking about NA motors here, but this is the type of application to where other factors come into play. My guess is 3-5psi should yield a 13.0:1 a/f that this guy desires though.

 

i going to install a fuel pressure gauge on the rail and see what the pressure is with my existing fpr (from and h23) and then swap it out for one from an h22 and see what the difference is.

Thanks for the help guys