Replacing injectors

[Mr. C4]

Hello M3 E9X community!

If I am replacing the injectors, are there any other parts that I should consider doing at the same time?

Thanks!

[smokinjoe64]

Lots of posts, info already exists on topic...suggest

[Honda]

Originally Posted by Mr. C4

Hello M3 E9X community!

If I am replacing the injectors, are there any other parts that I should consider doing at the same time?

Thanks!

I just did this job. It is very simple DIY. There is nothing else you need to replace. Just make sure you clean around injectors before removing so that no debris enters cylinder

[DW_CT9A]

I just did this last weekend. While I was in there, I also decided to clean and lube the ITB linkage, clean the ITB inlets, and replace the fuel tank vent valve. You may not need to do any of those things, but my car definitely needed to have that valve replaced and the ITBs needed some love.

[LKN624]

I would replace the clips too but that's just me.

https://www.leebmann24.com/de/de/pro...ammer-10100853

[khoivo408]

Did the injectors this past summer for the 2nd time (free thanks to FCP Euro!) due to thinking it was causing high negative fuel trims on both banks. Turns out the ITBs needed thorough cleaning since the carbon build-up appears to clog the throttle plates and restricting free movements that can also lead to premature TA failure.

You don’t have to go to town like I did and took everything apart to clean but definitely lube the ITB linkages (springs and plate shafts) if yours squeaks when actuating. ITBs 1,4,5, and 8 have the needle bearings where the linkage rod passes through that is hard to lube unless you remove the rod. But if you want to take them apart, be careful DO NOT touch the throttle stop screw on each of the ITBs. These are set from factory to sync properly and have black plastic caps on them to prevent tampering. I def learned the hard way 😂.

While doing injectors, I also replaced spark plugs, coils, PCV (freakin impossible to reach unless bank 2 ITBs are out), starter, Rebuilt TAs, MAP sensor, thermostat and sensor, and rubber intake couplers.. because my car has 125k miles and I was “already in there” and didn’t want to take everything apart again.

Oh yeah also cleaned the shit out of the ICV, air rails, ITBs, and everything in and around the “V” of the engine. Lucky found no dead rodents! 😂

Maybe some or all of the above components didn’t need to be replaced but I’m happy to say my fuel trims are now down to -2 and -4 and the M drives like a brand new car with super crisp throttle response. Butt dyno feels like +20hp lol.

[Honda]

Originally Posted by khoivo408

Did the injectors this past summer for the 2nd time (free thanks to FCP Euro!) due to thinking it was causing high negative fuel trims on both banks. Turns out the ITBs needed thorough cleaning since the carbon build-up appears to clog the throttle plates and restricting free movements that can also lead to premature TA failure.

You don’t have to go to town like I did and took everything apart to clean but definitely lube the ITB linkages (springs and plate shafts) if yours squeaks when actuating. ITBs 1,4,5, and 8 have the needle bearings where the linkage rod passes through that is hard to lube unless you remove the rod. But if you want to take them apart, be careful DO NOT touch the throttle stop screw on each of the ITBs. These are set from factory to sync properly and have black plastic caps on them to prevent tampering. I def learned the hard way 😂.

While doing injectors, I also replaced spark plugs, coils, PCV (freakin impossible to reach unless bank 2 ITBs are out), starter, Rebuilt TAs, MAP sensor, thermostat and sensor, and rubber intake couplers.. because my car has 125k miles and I was “already in there” and didn’t want to take everything apart again.

Oh yeah also cleaned the shit out of the ICV, air rails, ITBs, and everything in and around the “V” of the engine. Lucky found no dead rodents! 😂

Maybe some or all of the above components didn’t need to be replaced but I’m happy to say my fuel trims are now down to -2 and -4 and the M drives like a brand new car with super crisp throttle response. Butt dyno feels like +20hp lol.

wow you definately have gone above and beyond. I also wanted to clean between the V and ITB, however, I couldn't afford the car to be down for long time.

[KawBoy]

Hello Everyone,

What is the consensus regarding fuel injectors; BOSCH or genuine BMW? I've seen that as far as ignition coil goes, BMW brand is the choice, but don't know about injectors. I just had #5 locked open last night. Going to replace the set.

Thank you.

[Honda]

Originally Posted by KawBoy

Hello Everyone,

What is the consensus regarding fuel injectors; BOSCH or genuine BMW? I've seen that as far as ignition coil goes, BMW brand is the choice, but don't know about injectors. I just had #5 locked open last night. Going to replace the set.

Thank you.

BOSCH is the OE supplier of these injectors to BMW. So when you buy the Bosch you are just paying for the same injectors without the M Tax

[KawBoy]

Understood.

NGK seems to be the OEM manufacture of the ignition coils; however, those not paying the M Tax are having issues with them. I thought this could be the case here. Thank you.

[Honda]

Originally Posted by KawBoy

Understood.

NGK seems to be the OEM manufacture of the ignition coils; however, those not paying the M Tax are having issues with them. I thought this could be the case here. Thank you.

I believe it was mentioned before that NGK stopped selling M3 coils in the aftermarket and your only option is to buy them from BMW. So if you bought NGK coils, they are definitely not the same coils

[a5m]

Originally Posted by khoivo408

Did the injectors this past summer for the 2nd time (free thanks to FCP Euro!) due to thinking it was causing high negative fuel trims on both banks. Turns out the ITBs needed thorough cleaning since the carbon build-up appears to clog the throttle plates and restricting free movements that can also lead to premature TA failure.

You don’t have to go to town like I did and took everything apart to clean but definitely lube the ITB linkages (springs and plate shafts) if yours squeaks when actuating. ITBs 1,4,5, and 8 have the needle bearings where the linkage rod passes through that is hard to lube unless you remove the rod. But if you want to take them apart, be careful DO NOT touch the throttle stop screw on each of the ITBs. These are set from factory to sync properly and have black plastic caps on them to prevent tampering. I def learned the hard way 😂.

While doing injectors, I also replaced spark plugs, coils, PCV (freakin impossible to reach unless bank 2 ITBs are out), starter, Rebuilt TAs, MAP sensor, thermostat and sensor, and rubber intake couplers.. because my car has 125k miles and I was “already in there” and didn’t want to take everything apart again.

Oh yeah also cleaned the shit out of the ICV, air rails, ITBs, and everything in and around the “V” of the engine. Lucky found no dead rodents! 😂

Maybe some or all of the above components didn’t need to be replaced but I’m happy to say my fuel trims are now down to -2 and -4 and the M drives like a brand new car with super crisp throttle response. Butt dyno feels like +20hp lol.

Wow impressive! I wish warm weather stuck around longer as I think my fuel tank breather valve is on the way out and I'd want to service other things "while I'm in there".

Did you follow a guide or something that you can share?

[khoivo408]

Originally Posted by Honda

wow you definately have gone above and beyond. I also wanted to clean between the V and ITB, however, I couldn't afford the car to be down for long time.

I'm in the same boat as you so I def know what you mean. The M is my daily so any project or maintenance that I want to do has to start on Friday afternoon after I pick my kid up and finish Sunday night so I can use it Monday morning. For the above project, my wife was visiting family in Japan so I was able to use her car for two weeks to go to work while the M gets taken apart in the garage.

[KawBoy]

Originally Posted by Honda

I believe it was mentioned before that NGK stopped selling M3 coils in the aftermarket and your only option is to buy them from BMW. So if you bought NGK coils, they are definitely not the same coils

I am yet to replace coils; they are still up and running fine. Thanks.

[khoivo408]

Originally Posted by a5m

Wow impressive! I wish warm weather stuck around longer as I think my fuel tank breather valve is on the way out and I'd want to service other things "while I'm in there".

Did you follow a guide or something that you can share?

The DIY section in this forum def helped a lot in showing me what I was getting myself into for each of the maintenance items. I remember referencing back to the DIY for the starter and TAs specifically as it showed what was needed to get the wiring harness and SAP out of the way to reach down in the "V". Lots of Youtube videos as well.

For the PCV, I looked at images of S65 engines on Google and eBay to figure out where the hell it was located at as it was in a super hard to reach area on the back side of the engine.

After taking the throttle bodies apart, there is a specific BMW procedure (Throttle Valve Basic Setting TIS #1354010) to properly adjust and sync the actuating rod and arms to each throttle bodies. Again DO NOT touch the stop screws lol.

Fuel tank breather valve is easy enough that should take you less than an hour to replace if it's causing issues with your car. All you need is remove the intake and plenum and it's right there, no need to mess with harness or other components. Only issue I ran into when I did mine was that the "U" hose was seized onto the valve so I had to cut it and shortened the connection to the new valve. I eventually replaced the hose later.

[Honda]

Originally Posted by KawBoy

I am yet to replace coils; they are still up and running fine. Thanks.

Honestly, you don't need to change coils unless they go bad. There is no preventative maintenance in changing coils. So I would leave them alone until I get check engine light

[KawBoy]

Originally Posted by Honda

Honestly, you don't need to change coils unless they go bad. There is no preventative maintenance in changing coils. So I would leave them alone until I get check engine light

That's the idea. Thanks.