hondapwr

I seem to be having sensor/fuel/spark problems with my B16.

Here's the setup:
B16A 2nd Gen JDM spec
96 Civic LX body
P72 ECU (98 GSR)
Adjustable FPR
Accel 260cc Inj

The problems are intermittent, resulting in the engine running totally lean according to my Air/Fuel gauge. Looking under the hood while it's stumbling, the fuel pressure gauge looks normal with plenty of pressure.

Then after letting the car sit a bit, the car will run normal again. I can go for a few days without problems then I run into the issue again.

It seems to happen more often when I'm flooring it. I figure it will be easiest to diagnose when it dies completely, but I have no clue what it is for sure.

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I'm figuring it's either the ignition, ECU, or MAF sensor.

Can anyone troubleshoot with me to help narrow it down? Anything I should be testing?

Thanks


Modified by hondapwr at 7:16 PM 9/12/2004

hondapwr

I also have an Apexi VAFC.

I noticed that the problem happens mostly when I'm flooring it over 6000rpm now. Any help?

2lua

you might want to check your plugs, wires, rotor, and dist. cause the way you discribed sounded like you got a miss. about the a/f gauge i wouldn't trust it at all.

hondapwr

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 2lua &raquo;</TD></TR><TR><TD CLASS="quote">you might want to check your plugs, wires, rotor, and dist. cause the way you discribed sounded like you got a miss. about the a/f gauge i wouldn't trust it at all.</TD></TR></TABLE>

The A/F gauge is working fine. It's not the most accurate thing in the world, but it measures rich, lean and stoich just fine.

1. I was thinking about the ignition components being at fault. If anything, I'm losing spark entirely not just missing. Which would make sense considering the O2 sensor is seeing lots of oxygen. (Because the air AND fuel are being sent out the tail pipe without being lit)

2. The other scenario is that the fuel is cutting out. But since my fuel pressure gauge reads 20-30psi while the car is dying, it must be electronic/injector related.

So i think my next course of action is to drive around with something that can test injectors and spark, and wait for the problem to show itself again.

Opinions?

hondapwr

I should also clarify that it runs ok most of the time, only every once in awhile does it die on me completely. And it doesn't really stumble, it just cuts out. Even when it's having trouble it idles ok until you hit the gas.

-Trinitron-

Is your ECU chipped? For some reason re-chipped ecu's sometimes have idle problems like that. occasionally leaning out and sputtering. I had issues with the AF gauge. It was actually a bad connection and it wasn't getting a strong enough signal. Re-spliced it in, and everything was cool.

hondapwr

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by -TRINiTRON- &raquo;</TD></TR><TR><TD CLASS="quote">Is your ECU chipped? For some reason re-chipped ecu's sometimes have idle problems like that. occasionally leaning out and sputtering. I had issues with the AF gauge. It was actually a bad connection and it wasn't getting a strong enough signal. Re-spliced it in, and everything was cool.</TD></TR></TABLE>

It's a stock 1998 P72 ECU, with a VAFC attached. It never has problems idling, just at wide open throttle. The A/F gauge shows lean when it when the power cuts out.

I just check the igition components last night, and they all look to be in great condition. Additionally, the plugs are white around the electrode. This confirms that the fuel is cutting out, and the spark is probably fine.

All the plugs are the same level of white, so I doubt it's a bad fuel injector.

Now i'm left with wiring issues, sensor issues, or ECU issues. I'm going to try replacing the P72 with a P2E to see what happens. This problem is annoying because the car was running just fine today.

Has anyone seen a faulty TPS or MAP sensor cause problems like this?

hondapwr

I figured out what the problem was. Apparently my VAFC was getting glitchy.

I just disconnected the yellow and white VAFC wires from the ECU, and reconnected the ECU directly to the engine. I haven't had a problem since. This removes the ability for the VAFC to alter the amount of fuel.

I now use the VAFC as a monitoring tool for throttle opening, pressure, rpm's, and to change the VTEC crossover point.