Hi All,
I know it's been mentioned before, but I thought I post this just in case..........
Having installed MJ, everything seemed to be working, until I took the car for a drive......at just over 4000rpm, the car popped and and lost drive, but then as the rev's climbed, it was ok again.........
Anyway, turned out to be the VR sensor mounting.....I checked this before taking the car out, and all seemed well, the bracket seemed solid.....however, when I looked at the bracket when the revs were up, there was a specific point at which the bracket resonated, this caused the vr sensor to vibrate so much it was hitting the toother wheel!!!!!..An easy mod, and all is now working very well indeed, car has must more low down urge, and is so much smoother throught the rev range...I just need to get a good map sorted out on the rolling road...
Anyway, just something to be aware of.....Again, it has been discussed before, so this is a reminder....
Cheers.
Paul.
Interesting info on VR sensor.....
Moderators: JeffC, rdoherty, stieg, brentp
Yes, this is somewhat common and the topic comes up from time to time. You'll see another recent thread on this as well. Anytime I see a problem regarding mis-fires, stumbling or backfires in the 4000 RPM range I think of resonating brackets.
The VR sensor bracket needs to be rigid enough to resist harmonic vibrations across the RPM range. In other words, the harmonic frequency must be higher than vibrations produced by the engine across it's operating RPM range.
If you are familiar with building loudspeaker enclosures, especially for subwoofers, the rule of thumb is to design your speaker enclosure so that the resonating frequency is higher than the speaker's operating frequency. Otherwise the enclosure itself becomes part of the loudspeaker.
If you suspect a vibrating bracket, you can inspect the trigger wheel teeth or the sensor for strikes and abrasions- a tell-tale sign that the bracket was excessively vibrating.
Regards,
The VR sensor bracket needs to be rigid enough to resist harmonic vibrations across the RPM range. In other words, the harmonic frequency must be higher than vibrations produced by the engine across it's operating RPM range.
If you are familiar with building loudspeaker enclosures, especially for subwoofers, the rule of thumb is to design your speaker enclosure so that the resonating frequency is higher than the speaker's operating frequency. Otherwise the enclosure itself becomes part of the loudspeaker.
If you suspect a vibrating bracket, you can inspect the trigger wheel teeth or the sensor for strikes and abrasions- a tell-tale sign that the bracket was excessively vibrating.
Regards,
Yes, this is somewhat common and the topic comes up from time to time. You'll see another recent thread on this as well. Anytime I see a problem regarding mis-fires, stumbling or backfires in the 4000 RPM range I think of resonating brackets.
The VR sensor bracket needs to be rigid enough to resist harmonic vibrations across the RPM range. In other words, the harmonic frequency must be higher than vibrations produced by the engine across it's operating RPM range.
If you are familiar with building loudspeaker enclosures, especially for subwoofers, the rule of thumb is to design your speaker enclosure so that the resonating frequency is higher than the speaker's operating frequency. Otherwise the enclosure itself becomes part of the loudspeaker.
If you suspect a vibrating bracket, you can inspect the trigger wheel teeth or the sensor for strikes and abrasions- a tell-tale sign that the bracket was excessively vibrating.
Regards,
The VR sensor bracket needs to be rigid enough to resist harmonic vibrations across the RPM range. In other words, the harmonic frequency must be higher than vibrations produced by the engine across it's operating RPM range.
If you are familiar with building loudspeaker enclosures, especially for subwoofers, the rule of thumb is to design your speaker enclosure so that the resonating frequency is higher than the speaker's operating frequency. Otherwise the enclosure itself becomes part of the loudspeaker.
If you suspect a vibrating bracket, you can inspect the trigger wheel teeth or the sensor for strikes and abrasions- a tell-tale sign that the bracket was excessively vibrating.
Regards,