atomicrm

When I first bought the S about 3k miles ago (came with a vafc2 installed) it threw a cel code P1259 which is a vtec malfunction. Since then as long as I dont hold the car in vtec very long this has not been an issue and vtec still comes on strong. The other day I was jut having fun and noticed that the top of second felt slow. Yesterday rolling from 20 in first gear I went full throttle all the way to 9k and vtec did crack on. Once the car gets to about 7k the car feels choked. The acceleration is very slow, I can pretty much watch the speedo go 36...37...38. No CEL came on though. The oil is a hair below the Full line and I have cleaned the map sensor.
What could cause sluggish high rpm acceleration? Is it possible that the original VTEC CEL I got has just gotten worse?
For the P1259 code the solution Im finding on this forum is to replace the VTEC oil pressure switch, could replacing that fix both problems?

Thanks for any help guys!

atomicrm

anyone have any ideas?

zeroptzero

As long as you are feeling VTEC engage then it is fine barring any further CEL's for that code.

As far as sluggish top end I'd suspect the spark plugs first, do you know how old the plugs are ?. Secondly, what are your programmed settings for the VAFC ? - fuel and vtec point ?. Running rich can hurt top end performance, more so for ap1's. Let us know about your plugs and any VAFC settings you have.

atomicrm

I am not aware of how old the plugs are. I will pop them out when I get home and see if they show any signs of fouling.
I have vtec set at 6k. I will check on fuel when I get home from work.
The vafc settings haven't been touched by me since I have owned the car besides messing around with the vtec point a little bit and it has ran perfectly fine up until now.

zeroptzero

Yeah let us know what you find.

With the plugs it would be good to know the colour of the plugs and how large the gap is, as the plug gap grows over time. When you go to remove the plugs pay attention to how easy they loosen on removal, loose sparkplugs can be an issue on ap1's. Remember to torque the plugs to 18 -20 ft lbs when you re-install them.

A quick test with the VAFC would be to return the car to stock settings and see if it runs better, worse , or the same. You can always put the settings back after the test. A 6K rpm point is the same as stock so you aren't getting any benefit there. With fuel settings you can get a bit more power by leaning out the fuel, if the previous owner was richening up the fuel settings that could cause you to lose power on an ap1.

atomicrm

Not super familiar with the VAFC besides changing the vtec point. How do I revert to stock settings? can the vafc unit be turned off or does it need to be unplugged?
I put the vtec point back to stock to stay out of vtec a little more as I mostly just cruise around. When looking for the most power/speed what is the recommended vtec point?

zeroptzero

^ this could be part of your problem. Did you get a manual for the vafc when you got the car ?. If not try to download one.

For the fuel settings go through and see what they are set at for each rpm point. A positive number is richening (adding) fuel by that percentage, zero is leaving it at the stock fuel setting, and a negative number is leaning (decreasing) the fuel level by that percentage. Make note of the current settings, and just change them all to zero to leave the stock fuel settings.

The best way to set the vtec point is on a dyno to pick the rpm point that maximizes power, if you don't have access to a dyno I'd leave it at the factory setting. You could decrease the vtec point in the range of 5,000 to 5,500 ,but without a dyno you really won't know how it is working.

Let us know what you find out on the fuel settings and other info.

atomicrm

Here is my Wide Hvt Fuel settings
5500- 0
6000- -3
6500- -2
7000 -3
7500 -5
8000- -8
8500- -10
9000 -15

zeroptzero

hmmm, the mid-range doesn't look to bad, top end is leaned out a bit though. Try doing some runs with the settings put back to stock and see if you can notice any difference. Thanks for posting the info.

s2000Junky

The short answer is YES

1259 code will disable vtec, but you should feel it jerk a bit and not come on. A vafc can exacerbate this OEM problem, or it could be entirely the VAFC malfunction or user error. Best advice for trouble shooting this is to disconnect the vafc all together and drive the car, if the 1259 code comes up again, then you know its an OEM issues and you need to deal with this.