Misfiring on cylinders 1-3.

[Schabzo08]

Schabzo08

The Mosfets on the MSD80 DME's do fail and an easy way to test is with a multi meter.

See youtube vid below:

Give it a try first, its free and will confirm if your DME may be at fault.

If it is the problem, you should be able to source replacement Mosfets and have them resoldered on.

Goodluck, I hope you come right

I will try that tomorrow morning and let you know the outcome. Thanks for your help

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You dont need to buy mhd to check codes.
Install the app and you can run the scan for free.

There are plenty cables for sale on gumtree and bidorbuy

I downloaded the app last night but I need to source the cable now.

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[Schabzo08]

I've followed the video and I tested the mosfets (thought I escaped Electronics when I became an auto electrician) anyway I found 1 defective Mosfet. Now the hard part is finding the replacement part. I've tried RSE electronics, Manteca, Screen Vision, Advanced Product Tech, Jico Electronics as well as communica. Non of them have this Mosfet. Any Ideas on where I should try next?

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The part number is IRF W644B

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The part number is IRF W644B

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[Kish2604]

Well done on the ground work... you have your problem isolated, do a search on the international forums, plenty 07/08 dme blow the mosfets for the ignition drivers and there were some part numbers for a stronger replacement available.

hope you come right, worst case is import it yourself using Aramex global shipping program.

 

[Danny2]

I've followed the video and I tested the mosfets (thought I escaped Electronics when I became an auto electrician) anyway I found 1 defective Mosfet. Now the hard part is finding the replacement part. I've tried RSE electronics, Manteca, Screen Vision, Advanced Product Tech, Jico Electronics as well as communica. Non of them have this Mosfet. Any Ideas on where I should try next?

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The part number is IRF W644B

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The part number is IRF W644B

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Roleen Electronics or GT Electronics
Both in Boksburg

 

[b3rg]

Great that you have found the fault....

see link below, they should be able to assist.

https://www.digikey.co.za/products/en?keywords=FDB14N30TMCT-ND

and replace all 6 while you are at it....

 

[Schabzo08]

Great that you have found the fault....

see link below, they should be able to assist.

https://www.digikey.co.za/products/en?keywords=FDB14N30TMCT-ND

and replace all 6 while you are at it....

Thanks will check it out.

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I've followed the video and I tested the mosfets (thought I escaped Electronics when I became an auto electrician) anyway I found 1 defective Mosfet. Now the hard part is finding the replacement part. I've tried RSE electronics, Manteca, Screen Vision, Advanced Product Tech, Jico Electronics as well as communica. Non of them have this Mosfet. Any Ideas on where I should try next?

Sent from my PRA-LA1 using Tapatalk

---

The part number is IRF W644B

Sent from my PRA-LA1 using Tapatalk

---

The part number is IRF W644B

Sent from my PRA-LA1 using Tapatalk

---

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Roleen Electronics or GT Electronics
Both in Boksburg

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Thanks, I will call them tomorrow morning.

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Well done on the ground work... you have your problem isolated, do a search on the international forums, plenty 07/08 dme blow the mosfets for the ignition drivers and there were some part numbers for a stronger replacement available.

hope you come right, worst case is import it yourself using Aramex global shipping program.

Hopefully I can source stronger ones. Thanks for the advice

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[Schabzo08]

Just an update. I searched all over for replacement mosfets and couldn't find anywhere. So I then decided to take my Ecu to a repair place in Wychwood and I told them that I need them to replace one Mosfet thinking that it will be easier for them to source the parts, that was on a Friday afternoon. They called on a Monday morning quoting me R5000. 00 to repair the control unit and I told them to rather leave it. Found RS components in Kyalami and ordered 4 mosfets for R27. 00 each and had one replaced on Saturday at a TV repair shop for R80 and refitted it to my car. I still had a misfire on 3 cylinders so I moved the coils around and this time the problem moved with the coils. Replaced 3 coils and all is well again. Thank you for your assistance I really appreciate it. The replacement is IRF 644 SPBF.

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[Schabzo08]

Just a question, are the injectors coded cylinder specific or does it not make a difference that 2-3 are swapped around with 4-6?

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[thegonzoman7]

Just a question, are the injectors coded cylinder specific or does it not make a difference that 2-3 are swapped around with 4-6?

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Check the numbers stamped just below the electrical connector. ...
Below is a shitshow diagram for the location of the 6 digit number needed when upgrading / changing / diagnosing etc...
IF YOUR CHASING A MISFIRE..... you can squeeze a cellphone down between each coil and injector and take a picture of each fuel injector so you have a reference for the location of injectors. If you don’t have MHD, bimmergeeks protool, or impa/ista (Model specific diagnostic and coding software tools) or access to someone who does, after you complete swapping injectors to see if misfire follows, YOU MUST RETURN EACH INJECTOR TO ITS ORIGINAL LOCATION. The 6 digit number I’m referring to is bmw’s way of making sure that the fuel system consistently delivers the correct amount of fuel to each cylinder for optimum performance, especially when it’s tuned. There are several different “indexes” of bmw injectors. They look the same, but are vastly different. each index having its own specifications and capabilities. LOOK TO SEE IF YOU HAVE TWO OR MORE IDENTICALLY NUMBERED INJECTORS FIRST! IF possible, try using injectors marked with same number code. That way, when chasing a misfire or diagnosing issues, YOU KNOW FOR SURE YOU FOUND THE PROBLEM. Interchanging injectors, even when it’s done on the same engine, can yield misleading results due to each injector having very specific values, often having vastly different specifications even when swapping injectors around on the same engine. This is why people are so redundant when saying injectors / etc. must be individually computer coded when any change is made. It’s an annoyance, any bmw owner will surely agree just how annoying owning a bimmer can be, just as he shall agree it’s the price one pays to drive a beautiful engineered high performance machine..”the ultimate driving machine”, -BMW.
Here’s my best shot at explaining where, what, when, how and why.... not easy. At all... don’t bust my balls please.... I gave it a spirited effort..-

Here’s the directions to find the BMW fuel injector CODING VALUE.

It’s a 6 digit number. printed in Two rows,
(3 digits stacked above 3 more digits),
laid out as,,

↘️ ↙️
555
555
↗️ ↖️

If the injector was
In your hand,
Maintaining the same
Orientation as is installed,


. Wire Plugin Fuel ⬇️Line
⬇ |=====|
(—-) |=====|
IIIIII. (======)
Iiiiiii. II. IIIIIII
H IIIIIII.____——____IIIIIII
E IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII
R ~> ( 573 ) IIIIIIIIIIIIIIIIIIIIIIIIII
E ~> ( 224 ) IIIIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII
IIIIIIIIIIIIIIIIII
IIIIIIIIIIIIIIII
IIIIIIIIIIIIIIII
IIIIIIIIIII
IIIIIIIIIII
IIIIIIIIIII
IIIIIIIIIII
IIIII
IIIII
IIIII
\ /
•