Help! I'm stumped.

K-Series Programmable ECU installation questions / support issues
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park83rsx
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Joined: Thu May 19, 2005 10:15 pm

Help! I'm stumped.

Post by park83rsx »

I have no idea why my car is acting this way while I dyno tuned it. I tried many things and it would not clear up the problem. It is in the top end from 7000-8000 rpm. Specifically; 7100 and 7900. Any help would be greatly appreciated, as this is driving me crazy.

http://forums.clubrsx.com/showthread.php?t=271133

^Heres the question on CRSX with one of my dyno sheets.

Thanks in advance to anyone who helps out.
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Hondata
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Post by Hondata »

Post the calibration(s), and a datalog of the dyno run(s) if possible.

Explain in detail how you tuned the car - why is there still the bump in A/F at 7500 rpm? Did you tune the car or is this just two different calibrations compared on the dyno? What is the A/F scale on the dyno print out?
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park83rsx
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Joined: Thu May 19, 2005 10:15 pm

Post by park83rsx »

Hondata wrote:Post the calibration(s), and a datalog of the dyno run(s) if possible.

Explain in detail how you tuned the car - why is there still the bump in A/F at 7500 rpm? Did you tune the car or is this just two different calibrations compared on the dyno? What is the A/F scale on the dyno print out?
The bottom line on the dyno is the hp and tq gains.

here is the calibration...(right click save as...)

http://www.personal.psu.edu/users/b/m/b ... %20whp.kal


The datalogs are still on my laptop and I can post one of those later.

A full tune wasnt done on the car, since I only had about an hour. I tried out some different cam angles adding and subtracting 5, then I added some ignition. VTEC point at 4300 was still perfect from your cai calibration, so that wasnt messed with. Rev limiter was knocked back to 8500 because the car falls flat on its face right after 8400 anyway.

-Brian
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Hondata
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Post by Hondata »

Ignition, fuel and cam angle look OK. Check the spark plugs and check that the gap is OK.

I think you just need more time of the dyno to tune it. Try adding fuel at the lean point (7400) and see what happens. It could be the dyno - perhaps try a different gear to see if that makes any difference.
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park83rsx
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Joined: Thu May 19, 2005 10:15 pm

Post by park83rsx »

Hondata wrote:Ignition, fuel and cam angle look OK. Check the spark plugs and check that the gap is OK.

I think you just need more time of the dyno to tune it. Try adding fuel at the lean point (7400) and see what happens. It could be the dyno - perhaps try a different gear to see if that makes any difference.
Ok, i'll have to check the gap. The largest problem area is also right after the cam angle changes from 30 to 25, so maybe keeping 30 or bumping it down to 20 would do the trick.... :?

Also, the dyno owner (Bart Grande) said that he's seen this kind of thing before on newer, highly technological cars (computers can have a mind of their own).

Thanks for your help. 8)
silver rsx-s
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Post by silver rsx-s »

i'm running the same tune as him (af adjusted of course), and i notice the loss of power from 6-7k and the extreme power boost at 7k as well, i havent dyno'd but its very obviously there. AF is a constant 13.1-13.5 throught the RPMS so i dont think its an AF problem
park83rsx
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Post by park83rsx »

Spark plug gaps are fine......
park83rsx
Posts: 19
Joined: Thu May 19, 2005 10:15 pm

UPDATE!!!!!

Post by park83rsx »

Well I finally figured it out!!!!


Same thing happened to evaunit's car when tuning on that dyno. We changed the dyno's grounding point on the car and most of it went away, however, the RSX has a shitty ground system. After a few runs we were able to figure it out...

First of all, the problems always occured right after peak torque. Peak torque and higher RPMs are when the ignition system is under the most load. What was happening is it would give off electrical noise, which would interfere with the dyno equipment and momentarily (almost instantaneously) freeze the RPM signal. This caused the RPM signal to stay at a constant value momentarily, which obviously the dyno would read as a loss of torque; then when the machine caught back up, the RPM signal would rise very quickly, showing a large increase in torque. Hence the torque/power dips and spikes we were experiencing.

At first, I was wondering why I only saw this happening on this particular dyno, but I began to look more closely at other peoples graphs and i've noticed similiar (however not so bad in magnitude) trends on about 30% of other graphs posted.
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