buggy1129

Drove my car to work today, and on my way home I was entering the freeway on 2nd tried to redline MY00 and I felt a no VTEC engagement and early fuel cut off at around 8200-8500 rpms. What could cause this? MY00 is completely stock, just got 2 months ago. It now has 72k+ miles on it. CEL is not on. Anybody experience this problem before, if you did what did you do to fix it?

Kyushin

Hmmm sounds alot like what I had happen but if you are not throwing a CEL kinda hard to say, how is your oil level? Is the Vtec solenoid connected at both locations?

FISH22

there is some info here

read this

i had the same situation a few days ago. not sure if it was the same as yours. i felt an early rev limiter around 7800 rpm, but the inside of the car was still cold, not sure if everything had enough time to warm up inside, even after a 15 minute drive. if the led's are cold enough they can delay a lot.

buggy1129

Thanx, I'll try that; but i have feeling that would not be it. I live in CA so it doesnt get as cold over here compared to your area. I went to the TOPDOWN meet last nite and ask some of the guys over there, and a lot of them said it could be VTEC solenoid. From what I understand that if it was the vtec solenoid, that would cause the vtec not toengaged, i could i still reach the redline with a bad vtec solenoid, correct? Thanx for your input guys, really appreciate it!

RED MX5

You need three bars on the temp guage before VTEC will engage. Also, if oil pressure is low you won't get VTEC, so check your oil level (if you haven't already done so).

buggy1129

I made sure the there are 3 bars on the temp gauge. And oil level is all way up to full.

My friends in exospeed and I took apart the solenoid practically cleaned it. Screen filter was clean it was not clogged. We blew some air thru the solenoid and power it up using a car battery and that was working fine. I then put it back together and ran VTEC 3 times from 1st to 3rd. Wierd thing is that I got VTEC first two runs, third run no vtec, cut off at 8200-8500 rpms.

Also during the runs I took a test light and hook it up on B12 pin which is the wired leading to the VTEC solenoid, then grounded it to the car, throughout the whole runs it light up solid on all 3 gears. That should indicate that power is being sent to the solenoid.

After i came back from the 3rd run we then unhook all the harness from the ECU and kept the test light on B12 pin so see if there is a short or open connection between the ECU harness to the solenoid. We found out there is no short and the test light light up solid.

These are our assumptions, please correct me if I'm wrong. By hooking up the test light on the B12 pin (VTEC solenoid wire), and having it light up during VTEC eliminates the ECU as being faulty. Disconnecting the harness from the ECU and testing if there is a short from ECU harness to the VTEC solenoid, and resulting that the test ligh, lite up solid, concludes that there is no short. Clearning the testing the solenoid if it working properly elminates that the solenoid it faulty.

Our next test would be the oil pressure switch, that might be faulty. We did get to test that last night because it was late already. I'm pretty sure that my friend is exospeed knows how to check that, I wanted to ask anyways. How do you check if the oil pressure switch is working properly?

Also, there any other component that I could test, that relates to this problem?

Thanx for all your input...

RED MX5

It may not have anything to do with VTEC. The ECU could be cutting fuel for some reason, or you could be losing spark, etc. What have you done to narrow it down to the VTEC engagement?

buggy1129

I assume that it has something to do with the vtec because I get no VTEC when i'm suppose to around 6000 + rpms, thats the time when the VTEC in engages.

I haven't checked the spark plugs, I will do that right about now.

What else could cause this problem? Right now i'm practically doing elimination process.

Any suggestion what else could cause this problem??

buggy1129

I took off the spark plugs, they looked ok, the only thing is that the tips were white; which would mean they are running too hot. But i'm up for spark plug change anyways so i'm going to change them out on monday. Also a friend of mine mention to check the ground for ECU and around the engine bay; that might cause the ECU to send abnormal signal.

Any other input would help me out alot...thanx

RED MX5

[QUOTE=buggy1129,Feb 11 2007, 09:42 PM]I assume that it has something to do with the vtec because I get no VTEC when i'm suppose to around 6000 + rpms, thats the time when the VTEC in engages.