VTEC issues. Looking for suggestions for my calibration

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ITR 1102
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Joined: Sun Sep 10, 2006 9:52 am
Location: Topeka, KS

VTEC issues. Looking for suggestions for my calibration

Post by ITR 1102 »

The low cam has been completely tuned for fuel.

My issue arises once I try to accelerate into VTEC (to datalog some values and tune). It seems as though it is cutting in and out of vtec rather quickly. Taking a look at the datalog, it does not look like the VTP or VTS are turning on. The AFR's do get rather lean and I am trying to figure out why. Sometimes this problem is worse than others. I have tried to richen the entire high cam map, but the problem still persists.

I didnt start recording until the engine was warmed up over 177, where the open loop fuel correction stops. Some of the recorded AFR's in the table are from warmup, however.
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ITR 1102
Posts: 144
Joined: Sun Sep 10, 2006 9:52 am
Location: Topeka, KS

Post by ITR 1102 »

The car is an 1998 Integra Type R
AEM short intake
2001 ITR intake cam
Kamikaze header
Gutted Carsound Cat
SMSP exhaust
Hondata Intake Manifold Gasket

When viewing the tables, make sure you tell SManager to Show Boost Tables; I have added in more columns.
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Hondata
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Post by Hondata »

There is something odd occuring at 1:25 What appears to be happening is that the MAP is dropping once the cam switches - from 89 to 38 KPa even though the throttle is wide open still. This is reducing the injector duration and then the engine is not making enough power to keep running.

Check cam timing. Check that the throttle gasket is on the right way up so that the MAP sensor is seeing manifold pressure correctly. Try changing the VTEC point conditions (throttle esp) to see if that makes any difference.
Hondata
ITR 1102
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Joined: Sun Sep 10, 2006 9:52 am
Location: Topeka, KS

Post by ITR 1102 »

changing minimum throttle does not seem to help, neither does minimum load.

i saw the afr spike up to 19:1 once in vtec, so i let off abruptly. I am stumped.
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Spunkster
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Post by Spunkster »

If you load a stock itr calibration, does the problem go away?
ITR 1102
Posts: 144
Joined: Sun Sep 10, 2006 9:52 am
Location: Topeka, KS

Post by ITR 1102 »

I tried, but the problem is still present.

I did adjust vtec engagement points and throttle tip in.... It seems that the easier the transition into vtec (by lower throttle settings) allows it to work. I was able to get a couple more datalogs with the map corresponding to it respectively. Please take a look. The throttle tip in is aggrivating me as the adjustment works great for the low cam but I am afraid it is hurting me on the high cam profile.

with vtec lowered I am able to stay in vtec a lot longer. Close to 6k rpm it does the same thing and leans out. I am continuing to add fuel where it leans out to see if that fixes it or if something else is wrong.....
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ITR 1102
Posts: 144
Joined: Sun Sep 10, 2006 9:52 am
Location: Topeka, KS

Post by ITR 1102 »

Hondata wrote:There is something odd occuring at 1:25 What appears to be happening is that the MAP is dropping once the cam switches - from 89 to 38 KPa even though the throttle is wide open still. This is reducing the injector duration and then the engine is not making enough power to keep running.

Check cam timing. Check that the throttle gasket is on the right way up so that the MAP sensor is seeing manifold pressure correctly. Try changing the VTEC point conditions (throttle esp) to see if that makes any difference.
in response to this: The car runs perfectly fine on the factory ecu and even a different chipped ecu with a Crome map. It has to be something in the calibration. The gasket and map sensor are installed correctly.
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Spunkster
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Post by Spunkster »

It actually sounds more like a problem with the ecu. It is the one thing you have not ruled out by process of elimination. If you have tried a different calibration and the problem is till there then it is not the calibration. If it were a software problem, everyone would be having the problem.
ITR 1102
Posts: 144
Joined: Sun Sep 10, 2006 9:52 am
Location: Topeka, KS

Post by ITR 1102 »

I can rule out the ecu as this problem appeared on me last night with my stock computer as well.

after going home I checked the map sesnor per the hlms manual. i know that the wiring is short free judging by the voltage. i will test the map sensor with a honda diagnostic computer today wih the stock ecu installed.

the funny ting is, today vtec was working with the chipped ecu. the datalog stills shows drops in pressure in the manifold, so I think the MAP is on the way out. does this sound like a good assumption?
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