Bent valve

I have a 97 dx d16y7 sedan 5 spd, I have too much fuel pressure! It is at 47 at idle w regulator connected. I have hooked up a wideband sensor to see correct stoich, it seems anything past 5-15 % throttle it goes and almost pegs the sensor at 9.2 - 1 afr at any speed. If the car is idling it stays about stoich, if you rev and hold it it'll go anywhere from 9.0 - 14.7 . I understand I have too much fuel pressure, I have also blown air through the return line and rerouted the return fuel line into a bucket, to monitor consumption at idle

ezone

What makes you think there is a problem?
What would a REAL scantool say about the fuel trims? (not your gauges)
Do you know that there is all kinds of fuel enrichment programmed in during acceleration, when it needs power? At WOT, the O2 should go to full rich voltage, and mix will end up with around 10:1 (give or take a little bit) at max enrichment.

You got 47 PSI with the vacuum connected, what is it without the vacuum connected?

If the return lines are clear, high pressure almost has to be a bad regulator.
Did you replace the pressure regulator yet?


The specs I got:
all except B16A2 engine 38-46 psi

How accurate was your pressure gauge? You sure about that?

The low number is usually what I see when the vacuum is present, the high number is usually seen without vacuum connected.
Specs are at sea level.

HTH

Bent valve

Yes the regulator has been switched twice with a new one two months ago and another the other day, both are genuine Honda parts. Yes on the 02 sensor q, it does go to 1 volt on wot, so the only option is a crushed hard return line, or switching to a adjustable regulator?

ezone

I would need more answers before I did anything:

You said you had the return hose in a bucket. If that made no difference in pressure, then the rest of the return lines on the car aren't the problem.

After 2 regulators with no change, I'd seriously think your pressure gauge is wrong.

What on earth got you to even think about fuel pressures?
CEL-- codes?
The add-on gauge swinging all over the place?
SOMETHING got you to look at fuel pressure. What was it?

Bent valve

Ok so the fuel pressure running was at 47 w the regulator hooked up and 57 w reg disconnected " vacume hose" . There were two codes p0170 & p0172 . I have had a walbro 255 in there for three months and have finally put the stock pump back in yesterday, do you know the correct tps voltage I set it around .31 to try to get the afr more lean and it seemed to work but only about a full point on the lambda gauge

ezone

You got other mods on this?


When did this problem start happening? Anything changed immediately prior to this? Any work done?

Yes, if that gauge is accurate, then the fuel pressure is too high.
Where are you tapping the fuel pressure gauge into the system at? If you are on top of the filter or right at the rail, then the only thing I can think of that controls fuel pressure is that regulator. I'm thinking of strictly stock though, and something that has had people monkeying with it could have any number of unnatural causes. You got trash in the rail that might be clogging the regulator?

Closed throttle TPS is normally exactly at 0.49v on 99.9% of the cars I see. Having it set at .31 shouldn't make it do what you want, all that would do is make the PCM use its idle programming until the throttle is opened to about 0.55v.

I don't see P0170 code at all.
P0172 is rich.
What is the Freeze Frame data from when the code set?

I would want to see all of this info on a real scanner

What is MAP Voltage at idle? High MAP would cause it to add fuel, and a few things can make the MAP read high. Tight valves, cam timing or non-OE cam, EGR stuck open, stuff like that can make MAP read too high and lead to rich codes.

What is the EGR value when closed?
ECT? Accurate?
IAT? Accurate?
BARO accurate for the altitude?
MAP and BARO match KOEO?

I would want to watch the fuel trims and O2 readings at idle, 2500, and while driving. Also see what the data looks like under the same conditions as the Freeze Frame set criteria.

You got wrong fuel injectors? You had a fuel pump mod, why wouldn't you have the wrong injectors too?
More flow than what was programmed in the computer would certainly cause rich codes.


Random thoughts, HTH

Bent valve

Alright I have replaced the walbro fuel pump with the stock pump again and tested the pressure it is within spec w vaccume connected and disconnected, so I'm back to where I started! The car still hesitates as it climbs rpm its most noticeable at part throttle up into 4k ish, I'm sure it's there in higher rpm but I don't feel it as much, just the car not accelerating as hard as it did before without this problem, I checked with all data on the whole procedure about a p0172 and I have no idea where to go, I have been through all the steps, and I'm up to the point where it says replace the injectors, but my source says they are good and they will work without issue, also have you ever ohm'd a 02 sensor and found that a lot of aftermarket sensors don't meet the minimum required amount ohms between the two same color wires? Jrt

ezone

Let me hear this again:
Ok.....

Now that fuel pressure is corrected, have you erased the codes and driven it? Does it reset the same code now?


Have you considered misfires?


What else have you done?
A logical approach is needed, not randomly replacing parts according to a shopping list.
I'm at work, no time to elaborate.



That is why the PCM rejects so many.