weird vtec rev limit.

sq_creations · Post by **sq_creations** » Sun Aug 06, 2006 3:19 pm

Im working on a buddies car. I put my s300 in to tune while im putting together his. I set all the parameters for vtec but when its suppost to turn on the car hits a revlimit. The s300 and vtec work fine on my car but i am running out of ideas on his. So far I have tried tring a diffrent solenoid and tweeking the parameters. I am attaching a data log and the tune so far. It probably something right in front of me that im missing. any help would be apreciated. thanks

eric

Post by **Spunkster** » Mon Aug 07, 2006 10:06 am

Where is it revlimiting? What RPM? What time in the datalog? From the datalog I cannot see anywhere it is actually revlimiting.

sq_creations · Post by **sq_creations** » Mon Aug 07, 2006 10:17 pm

It happens at whatever rpm I set vtec to. if i turn off vtec it will go to my redline. the car shuts down when vtec is suppost to kick in. The logs say vtec is coming on too. The ecu, s300 and vtec work fine in my car. so im thinking its a sensor but everything checks out as far as I can tell. that is why I was hoping you might see something I missed in the logs and or settings.

Post by **Hondata** » Tue Aug 08, 2006 8:23 am

Check the main ground on the thermostat housing - often the extra current the ECU has to sink from grounding the VTEC solenoid will shut the ECU down if there is a poor ground. Also to eliminate mechanical issues trigger VTEC manually with an external switch.

sq_creations · Post by **sq_creations** » Thu Aug 31, 2006 9:22 am

Sorry it took so long to get back. It would work if I put it on a manual switch. I ended up using one the s300 aux outputs and a relay to triger vtec and the car is running great. I only get one set of maps this way though.

Post by **Spunkster** » Thu Aug 31, 2006 9:59 am

You still have a problem and need to resolve it. Chances are you have a wiring problem in the car somewhere. Are any other aftermarket electronics installed in the car?

sq_creations · Post by **sq_creations** » Fri Sep 01, 2006 9:45 am

No other electronics touching the engine harness except a lc1 wideband into the eld. I ran an additional ground from the battery to the thermostat housing and it didn't make a diffrence. The car runs great if you triger the vtec externally though. My buddy has the car now. If you have any recomendations I can get it back to try.

Post by **Hondata** » Sat Sep 02, 2006 8:18 am

What is happening is that the current from the VTEC solenoid is reducing the ECU internal voltage to a point where it will not run. This is from the VTEC solenoid drawing too much current, damaged ECU VTEC drive transistors, bad/missing power (A25/B1) or ground (A23/A24) connections to the ECU.

weird vtec rev limit.

weird vtec rev limit.

thinking out side the box