Low compression piston relation to RPM's

[WilliamW]

As some of you know I've built my block for boost using Aries Piston (bisimoto) 8.2:1 cr. I got the car built and tuned. I'm using a light flywheel weighing 8 lbs and I'm noticing that it will get stuck in the RPMs. When I mean stuck what happens is this: I drive through first gear to second, push in the clutch and the rpms drop from 4 thousand to 3 thousand but instead of going down to an idle it is just pegged at 3 thousand RPM for maybe 3 seconds. I've seen it stay at 3 thousand for as long as 14 seconds... which is really annoying!

When i got it tuned the tuner said that the car likes to be wound up, I wasn't quite sure what he meant by this until now but I was wondering if this was an issue with the tune, the low compression pistons (which all make 170 psi dead on, when using a compression tester), or possibly my light flywheel?

I'm not too worried over it since driving the car like this is way better than not driving at all, but it's just annoying.

[Joey GT-R]

I'd say if it was fine pre-tune and now messed up post-tune, a re-tune is definitely necessary. How much power you makin now with those things? Did you overbore any? Using a cam?

[WilliamW]

It's a stock F22B head non-vtec no cams, overbored to 86mm and I'm making 107 hp and 112 tq.

[WilliamW]

If what was done was a pre-tune, 300 bucks seems expensive.

It may be time to learn the in's and outs of street tuning.

[dbsharp]

That should not be happening. Can you post a map or data logs? what software?

[WilliamW]

I sure can. I'm using AEMTuner with the AEM Series 2 EMS. I'm kinda getting a feel for all the info after hours of reading, however timing is still sketchy. I'm at work right now but I can throw up the fuel map, ignition map, and any other information I might have.

[WilliamW]

Here are the maps . The size is 1440 x 900 I believe since it's a screen shot.

Fuel Map


Ignition Map


Limiters Page


O2 Feed Back Map


I'll slowly be adding or removing fuel to achieve the 14.7 at cursing since now I'm at about 13.5 some times 12.0 AFR. WOT I hit 12.5-11.0 AFR.

[brian91accord]

i am using the same pistons and i'm not having that problem. I would def get your car tuned again and see what happens.

[dbsharp]

I think your problem is possibly an IACV issue. That being said it sounds like you might also have some settings that need to be changed.

You should have a fuel cut that happens when you come off the throttle. This is generally set to happen below a certain TPS voltage or pressure. There should be a rpm this starts at and a rpm that it is disabled below. It doesn't sound like this is set right to me.

[Sarthos]

I've had a similar issue with my car when I would hit the gas in park it would want to stick at about 1500 RPMs. The problem turned out to be the tension in the throttle cable, so I would just check to make sure the throttle actually closes when you let off the gas.

[dbsharp]

yes. check tps voltage to make sure the throttle plate is closing.

[Reignstarz]

I've had a similar issue with my car when I would hit the gas in park it would want to stick at about 1500 RPMs. The problem turned out to be the tension in the throttle cable, so I would just check to make sure the throttle actually closes when you let off the gas.

Correct, This is happening to me and I have a stock car.

The issue is my throttle. It sticks, When I hit the gas and slam it into gear and then let off the gas the throttle sticks.

But I dont think it's your tune nor your build. It's throttle.

[GhostAccord]

If it isn't your throttle cable. Record the datalogging info during the situation and save it. That should show you if it is a sensor or possibly a tuning issue. TPS voltage, IACV setting, moving idle setting etc..etc....

[Sarthos]

If it's the throttle, what's the solution to that? Adjusting the cable or getting a better throttle spring?

[GhostAccord]

If it's the throttle, what's the solution to that? Adjusting the cable or getting a better throttle spring?

The solution really depends on what part of the throttle it is...

Most throttle body issues can be resolved with a good cleaning or a quick cable adjustment. Maybe even a new return spring. If those don't work then you will be looking at replacing the cable or throttle body. Which ever of the two is defunct. Finding where the issue lies is a good place to start.