Low RPM Hard Acceleration - Pre-detonation

[Scharbag]

Originally Posted by deansbimmer

You don't need to rebuild them. Any injector shop will flow test and assess them for a smaller fee. Assuming this fixed your issue, I would absolutely have them tested to know where you stood. It will identify the point of flow and injector condition that induces the ping you're seeing. That's helpful for anyone to know. Real life data are always good to have.

I will ask the shop if they can do that for a reasonable fee. I also want to know!

Just filled up with Shell 91. Will go for a rip later.

One issue I seem to have now is long cranking when starting. I have checked for fuel leaks and everything seems to be dry. No fuel smell in the engine bay at all. Have you ever had this happen? If so, something that is typically missed? Fist start after changing injectors took a while to start but that is expected as I emptied the rail. Did not expect it to persist...

Thanks again,

[jcolley]

Originally Posted by Scharbag

I will ask the shop if they can do that for a reasonable fee. I also want to know!

Just filled up with Shell 91. Will go for a rip later.

One issue I seem to have now is long cranking when starting. I have checked for fuel leaks and everything seems to be dry. No fuel smell in the engine bay at all. Have you ever had this happen? If so, something that is typically missed? Fist start after changing injectors took a while to start but that is expected as I emptied the rail. Did not expect it to persist...

Thanks again,

Wouldn't be surprised if there's air trapped in the fuel rail. Pressure builds up, but collapses the air bubble in the rail. In non-return fuel systems, you don't have constant flow of fuel to displace the air. I would imagine a few sustained high power runs would clear that up.

[Scharbag]

Verdict is in: I still have pre-det when using Shell 91...

FML

So I am a bit lost as to what the heck to do next. And I have NEVER set a single code for knock. Not once.

Open to other suggestions. Like fire, or explosives, or possibly napalm...

The frustration is real. But I will figure it cause I am stubborn.

Cheers,

[ItsGary]

Originally Posted by Scharbag

Verdict is in: I still have pre-det when using Shell 91...

FML

So I am a bit lost as to what the heck to do next. And I have NEVER set a single code for knock. Not once.

Open to other suggestions. Like fire, or explosives, or possibly napalm...

The frustration is real. But I will figure it cause I am stubborn.

Cheers,

Pop out the intake box and see if your exhaust manifold heat shield is moving around.

[Scharbag]

So, I added a single bottle of STP cheap octane boost to 3/4 tank of Shell fuel and the pre-det seems to be gone...

I think my car just hates Shell fuel. FML

And, even after some fairly spirited driving, the damn thing still long-cranks if it sits for a bit. No fuel smell in the engine bay at all.

Grumble grumble grumble...

[GORDON.M3]

Originally Posted by Scharbag

Verdict is in: I still have pre-det when using Shell 91...

FML

So I am a bit lost as to what the heck to do next. And I have NEVER set a single code for knock. Not once.

Open to other suggestions. Like fire, or explosives, or possibly napalm...

The frustration is real. But I will figure it cause I am stubborn.

Cheers,

You need Ultra94 from Petro-Canada... even then its not really 94 octane sadly.
I never got knock codes before but I could seriously tell the power was down when using 91 from shell.

[Scharbag]

Originally Posted by GORDON.M3

You need Ultra94 from Petro-Canada... even then its not really 94 octane sadly.
I never got knock codes before but I could seriously tell the power was down when using 91 from shell.

I wish... Sadly, we do not get Petro 94 here on the island...

Chevron 94 will have to do.

Now to solve the long crank problem I seem to have caused myself... FFS.

[GORDON.M3]

Originally Posted by Scharbag

I wish... Sadly, we do not get Petro 94 here on the island...

Chevron 94 will have to do.

Now to solve the long crank problem I seem to have caused myself... FFS.

Then stick to Chev94 from now on. If your coils haven't been done, look into that.

I'd also look into getting a tune from BPMSport.

[Scharbag]

Originally Posted by jcolley

Wouldn't be surprised if there's air trapped in the fuel rail. Pressure builds up, but collapses the air bubble in the rail. In non-return fuel systems, you don't have constant flow of fuel to displace the air. I would imagine a few sustained high power runs would clear that up.

How long should it reasonable take to get the air out? I have done some aggressive driving and it persists...

Anything else to look for? It always starts, just long cranks in the morning and idles poorly for a few seconds.

Thanks again for the help.

UPDATE: I swapped the injectors back to my original ones (first I cleaned them with carb-cleaner and a 9V battery). First start was waay quicker than the other injectors and after the car sits, it immediately starts again. Pretty sure one of the serviced injectors is leaking... Oh well. Took it out for a rip with Shell 91 and 1 can of octane boost and it was still fine.

Cheers,

[ItsGary]

Originally Posted by Scharbag

I wish... Sadly, we do not get Petro 94 here on the island...

Chevron 94 will have to do.

Now to solve the long crank problem I seem to have caused myself... FFS.

Chevron 94 is the only 94 Octane available in all of BC.

Check your engine ground cable

https://www.m3post.com/forums/showthread.php?t=1444544

Also how old is your battery?

[Scharbag]

Originally Posted by ItsGary

Chevron 94 is the only 94 Octane available in all of BC.

Check your engine ground cable

https://www.m3post.com/forums/showthread.php?t=1444544

Also how old is your battery?

Ground cable is good.

Battery is from 2010... But I have NEVER had any codes set...

Grrr.

[Audioslave686]

i have a similar symptoms.
i was advised (by the person who knows these engines quite well) that it might be an idle control valve.
and i know that mine was already on a way out.
i will replace it within two weeks and will let you know if it helped

cheers

[GORDON.M3]

Originally Posted by Scharbag

Ground cable is good.

Battery is from 2010... But I have NEVER had any codes set...

Grrr.

Your battery is far too old. No codes don't mean its not weak. Average I would replace the batteries every 4 years, but thats just me. Some people would think that is a bit excessive but not for these kinds of cars. The chemistry that the battery is made up of eventually breaks down and not provide the same amount of cranking power like it did on day one. The system triggers replacement when the battery is FAR gone and on its last legs. It won't trigger for a car like yours with such little mileage on it. I would def. look into replacing the battery just cause its getting a bit too old! We're in 2019 now!

[Scharbag]

Originally Posted by GORDON.M3

Your battery is far too old. No codes don't mean its not weak. Average I would replace the batteries every 4 years, but thats just me. Some people would think that is a bit excessive but not for these kinds of cars. The chemistry that the battery is made up of eventually breaks down and not provide the same amount of cranking power like it did on day one. The system triggers replacement when the battery is FAR gone and on its last legs. It won't trigger for a car like yours with such little mileage on it. I would def. look into replacing the battery just cause its getting a bit too old! We're in 2019 now!

I will likely buy a battery. If that is the problem, I will be pissed.

Cheers,

[ItsGary]

Originally Posted by Scharbag

I will likely buy a battery. If that is the problem, I will be pissed.

Cheers,

$294 at Canadian Tire well $274 once you return the core.

H8-AGM

[Scharbag]

Originally Posted by ItsGary

$294 at Canadian Tire well $274 once you return the core.

H8-AGM

Seems like there are 2 sizes for the E9x M3. I will measure my battery and see which one I need. Thanks for the info on price.

Cheers,

[ItsGary]

Originally Posted by Scharbag

Seems like there are 2 sizes for the E9x M3. I will measure my battery and see which one I need. Thanks for the info on price.

Cheers,

Group 49 is interchangeable with H8.

H8 was the exact same thing as the OEM

[Scharbag]

Originally Posted by ItsGary

Group 49 is interchangeable with H8.

H8 was the exact same thing as the OEM

I have read that the battery can be either Group 94R or Group 49. I will have to look and see which battery is in my M3.

EDIT: battery is part number 61212353810 720CCA 90AH. It is over 13" long so I am pretty sure it is an H8/49 style. Crappy Tire has them in stock (UltraAGM M8). Likely pick one up this eve and swap it out. It is a real PITA trying to figure out BMW's part numbers for this battery. Grr - if you try to figure out the BMW part number for the M3 now, it is tedious. This is as close as I could get after a trip down the rabbit hole: 61217586962 and this is the NON-AGM version. Not sure why I wasted my time but meh, nothing better to do.

Cheers,

[ItsGary]

Originally Posted by Scharbag

I have read that the battery can be either Group 94R or Group 49. I will have to look and see which battery is in my M3.

Cheers,

Did you ever get a chance to check the exhaust manifold heat shield that's under the intake air box?

[Scharbag]

Originally Posted by ItsGary

Did you ever get a chance to check the exhaust manifold heat shield that's under the intake air box?

I will take another look just to be sure. Given the problem goes away with 94 octane or 91 + and octane booster, I do not think it is heat shielding. That said, it is worth another look!!

[ItsGary]

Originally Posted by Scharbag

I have read that the battery can be either Group 94R or Group 49. I will have to look and see which battery is in my M3.

EDIT: battery is part number 61212353810 720CCA 90AH. It is over 13" long so I am pretty sure it is an H8/49 style. Crappy Tire has them in stock (UltraAGM M8). Likely pick one up this eve and swap it out. It is a real PITA trying to figure out BMW's part numbers for this battery. Grr - if you try to figure out the BMW part number for the M3 now, it is tedious. This is as close as I could get after a trip down the rabbit hole: 61217586962 and this is the NON-AGM version. Not sure why I wasted my time but meh, nothing better to do.

Cheers,

Told you lol - just call the dealer if you want an OEM battery. Nothing wrong with the CT one though. 5 year warranty is pretty good

[BPMSport]

I avoid Shell. Nothing but bad experiences with them. If you're getting a lot of pinging on 91 that you're not seeing with the stock calibration, the one you're running is too aggressive. Surprisingly some tunes that you would expect to be conservative are in fact very aggressive in the ignition department - think 37 degrees..