CEL's on, Can't datalog, 4000rpm limp mode----please help

Toto · Post by **Toto** » Mon Jul 30, 2007 12:17 am

I have the Kpro on my 03 RSX-s with CAI for less than 3 months. Everything was great until few days ago. The CEL was on and car went on limp mode at 4000rpm. Could not datalog but saw "daughter board communication error" once. No other error code showed.

Please help and tell me what I should do! :(

Here is the story:
1. Original K20a2 motor and OEM spark plug with CAI only
2. Ground wire was relocated to the engine cover from IM before Kpro installed
3. CEL was on few days ago and kept coming back
4. Tried to datalog but datalog automatcally stop after ramdom seconds and show no data at all.
5. I cleared security and reload the k20a2-rsx-coldair calibration onto the Kpro ECU few times.
6. At the first few times, the CEL stayed on after the reload and datalog error like on 4.
7. With the CEL, engine went on limp mode at 4000rpm.
8. CEL finally cleared after few security clears and calibration reloads. Car drove normal all the way to redline. Datalog normal with no error code.
9. CEL came on again right after the engine restarted the next morning
10. Repeated from 4 to 9 and very frustrated.

Please please please....tell me what I should do and what's wrong with the Kpro and CEL.

Post by **Hondata** » Mon Jul 30, 2007 8:53 am

What has been changed on the car? Any wiring changes? Battery relocated? Ever had the battery go flat or had to jump start the engine?

Toto · Post by **Toto** » Mon Jul 30, 2007 10:35 am

Hondata wrote:What has been changed on the car? Any wiring changes? Battery relocated? Ever had the battery go flat or had to jump start the engine?

Nothing has been changed except the added CAI. Orginal OEM wiring and orginal OEM battery, never relocated. Battery never went flat and the battery status indicator says it is in good condition. I measured the bettery power to be ~12.8V and ~14.5V with the engine off and on.

Any suggestion, need help!

Post by **Spunkster** » Mon Jul 30, 2007 12:07 pm

Check your battery voltage while cranking...it may be about time for a new battery.

Toto · Post by **Toto** » Mon Jul 30, 2007 12:19 pm

Spunkster wrote:Check your battery voltage while cranking...it may be about time for a new battery.

I was able to clear DTCs with the KManager while the engine is running but the CEL would always come back after few seconds. If it is a cranking voltage issue, should the CEL stay off until I crank again at least?

What is the cranking voltage susposed to be? I will try to measure that. But it doesn't look like a battery problem to me. What else should I do to check on the battery?

Post by **Hondata** » Mon Jul 30, 2007 4:02 pm

Doesn't sound like battery voltage. When the DTC comes back on, can you read the code?

Toto · Post by **Toto** » Mon Jul 30, 2007 4:59 pm

Hondata wrote:Doesn't sound like battery voltage. When the DTC comes back on, can you read the code?

I could clear DTCs on KManager but I could not datalog at all. The datalog kept stopping after ramdom seconds of no data. Is there any other way to read the code on KManager?

Toto · Post by **Toto** » Mon Jul 30, 2007 11:42 pm

After reloading the k20a2-rsx-coldair calibration with OBDII disabled and clearing DTCs, I was able to datalog without Error codes. The car did not go into 4000rpm limp mode and no CEL showed.

There were few knocks showed on the datalog. Is this normal with k20a2-rsx-coldair calibration? Is it safe to drive wihtout hurting the Engine like this? I think the CEL was just disabled but the problem was still there.

Update: CEL came back this morning even with OBDII disabled. Very frustrated!!

Please help to check the datalogs and make suggestions. Thanks!

Post by **Spunkster** » Tue Jul 31, 2007 5:19 pm

What is the cranking voltage of the battery when starting the car?

Toto · Post by **Toto** » Wed Aug 01, 2007 6:04 am

Spunkster wrote:What is the cranking voltage of the battery when starting the car?

I measured the cranking voltage with a voltmeter. The lowest that I saw was around 11.80V, mostly >12V; nothing really unusual. I also tried to read the DTCs with the OBDII scanner and it didn't show any code at all.

Toto · Post by **Toto** » Thu Aug 02, 2007 5:59 am

Toto wrote: There were a few knocks showed on the datalog. Is this normal with k20a2-rsx-coldair calibration? Is it safe to drive wihtout hurting the Engine like this?

Would anyone be able to answer my question? Only few knocks on hard acceleration, no knocks on normal driving. Thanks!

Post by **Spunkster** » Thu Aug 02, 2007 9:36 am

You need to measure the voltage at the ECU when cranking the engine over as that is what is really important. If it drops too low it will cause the error you have received.

You should always tune out all knocking unless you can be sure it is not just picking up some other mechanical noise.

Toto · Post by **Toto** » Thu Aug 02, 2007 10:32 am

Spunkster wrote:You need to measure the voltage at the ECU when cranking the engine over as that is what is really important. If it drops too low it will cause the error you have received.

You should always tune out all knocking unless you can be sure it is not just picking up some other mechanical noise.

Which point on the ECU should I measure the voltage? Do you have a diagram?

Also, how do I know if it is real knock, not mechanical noise? I find the knock count on the datalog but didn't hear nor feel any knock when dataloging or driving. The CEL have never lighted up to indicate knocking neither. Thanks!

Post by **Spunkster** » Thu Aug 02, 2007 11:56 am

At the ecu plugs. In Kmanager go to help, contents, under reference you will find the ecu pinout.

Try removing 4 degrees of timing and see if the knock goes away,if it does, it's not mechanical noise.

hardcorersxs · Post by **hardcorersxs** » Sun Aug 05, 2007 2:35 pm

From what you've mentioned so far, it sounds like your battery is going out. I would definitely invest in a new battery or else something might go wrong with your motor or ecu, which in turn, can cost you 1000+ dollars.

Think about it