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Rev-Limit U1 blown
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Post Rev-Limit U1 blown 
Hello everyone

after 2 years of using my MJLJ, never had a problem.
now paint my car after I have many problems. what the fuck is wrong!

the last week a have problem with the MAX232 http://www.autosportlabs.org/viewtopic.php?t=2524 RPM's and no advance time, there were only connection to the laptop and showed me just the TPS to function, replace the MAX232 and the problem was solved. everything returned to normal, but my shift light not working, I checked the wires and the voltage came, everything was alright, I thought the LEDs were burned by a higher voltage.

drive to the highway 4 days ago, I stepped on 2nd gear started, to full throttle to overtake a truck and on that, explosions hit the exhaust and the engine does not work anymore ... I checked all wires incorrectly connected, etc, was everything right, waited a few minutes, and gave him starting again, the engine started, hit a few more explosions, was accelerating and decelerating until it returned to normal, I went very slowly to my house it will fail again.

2 days ago on the highway running at full throttle against a AUDI A4T Laughing , explosions in the exhaust again but this time the engine continued to operate but many explosions com until after a while, everything returned to normal. (I lost the race Embarassed fucking MJLJ Evil or Very Mad )

Yesterday I went to check the electrical diagram and follow all the lines are all well, I went back to assembly the MJLJ and...SAS! the shift light came into operation Wink


I went to greet a friend at 8km from home at normal speed, arriving at destination, MJLJ smoke started coming out ... stop the engine and take him pushing, disarmed the MJLJ and the U1 rev-limit was blown I did a bypass to get back to my house.
http://www.autosportlabs.net/Hard_rev_limiter_1.1.0

I don't know what happens, always all right, now, many problems.








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Hey Salamander

Shame you didn't beat that A4T.

From your description it seems to me that U1 chip has gotten hot, then had thermal runaway and fried. Have you ever noticed the actual unit being hot or warm??? It may need to be located in a well ventilated area.

How do you splice your wires, are they crimped, soldered or just tied together?? It sounds like you have some loose connections appearing so i would suggest going over all your connections. I personally get the soldering iron out and use some heatshrink sleeve as this has always been my preferred method.


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A4T ahead of me because the ignition failed.

t is cold, no problems.

on the cables, they are loose because yesterday when he missed the U1, I have to splice to return home.

very rare find everything, as I told them, I have several years walking with the V3 and never a problem, now I come all, I do not buy the V4 Evil or Very Mad .

I have a megasquiert II v3.0, still assemble and finish it if I work with injection and ignition MJLJ I do not need, but I want it to walk it into another car.

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Salamander,

If the ground connection going to the rev limiter does not make good contact then this will very quickly damage the Mosfet. This might have happened in your case. The Mosfet specified in the Rev Limiter has plenty of current carrying capacity for EDIS-4 operation, so this should not normally happen. Average coil current is about 4 to 6A at maximum RPM.

For U1 you can replace it with a different P-Channel Mosfet- 20A, 30-45 volt capacity. I would also eliminate the screw terminal on the rev limiter board and replace them with soldered connections, like we do with the production 1.2.0 rev limiter boards.

Sorry you lost the race!


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brentp wrote:
Salamander,

If the ground connection going to the rev limiter does not make good contact then this will very quickly damage the Mosfet. This might have happened in your case. The Mosfet specified in the Rev Limiter has plenty of current carrying capacity for EDIS-4 operation, so this should not normally happen. Average coil current is about 4 to 6A at maximum RPM.

For U1 you can replace it with a different P-Channel Mosfet- 20A, 30-45 volt capacity. I would also eliminate the screw terminal on the rev limiter board and replace them with soldered connections, like we do with the production 1.2.0 rev limiter boards.

Sorry you lost the race!
jajaja Laughing

thanks brent

I will weld the electrical terminals of the rev-limit, now, where can I buy the U1 or any replacement because there is not in chile

within all the problems I have, it may be negative terminal fault?

is possible that the explosions on the highway are the product of bad negative was that the U1 was about to burn?

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Salamander,

Lets un-solder the MOSFET, then clean up the board, to see what condition the board is in. If OK, we can replace with a similar MOSFET.

Also, be sure to remove the screw terminals (no longer present on production boards) and replace with soldered wires.

Brent


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the tracks were not burned, are good.

now remove the connectors Wink

As I say, here in Chile there is no "FDS6681Z P-Channel MOSFET and PNP transistor SMBT2907A" which serves as a replacement for another me





yesterday afternoon I went for a ride in the car, and again began the explosions in the exhaust and intake, the idle stays normal, mild to accelerate the blast sent the engine exhaust. I looked around, I found the wire VR sensor was making bad contact, it may be that the failure to burn the MSX232 and mosfet? or not has nothing to do?

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Thank you for the information. I will email you to arrange a replacement.

A loose VR sensor will cause erratic EDIS module behavior- not sure if it would cause 232A failure (likely not). Also unsure about damaging U1 on rev limiter- unless it causes the coil to be overloaded with current for a very long time- also unlikely.

Good that you found the loose connection, however!

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I sent you the e-mail by MP

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