Low RPM Hard Acceleration - Pre-detonation

[Richbot]

How is this a 4page thread when switching fuel solves the problem

[Scharbag]

Originally Posted by Richbot

How is this a 4page thread when switching fuel solves the problem

Lol. Yeah.

Thing is,94 is not always available AND this has not always happened when using 91.

And I have OCD.

[Scharbag]

Originally Posted by ItsGary

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

New crappy tire agm installed last night.

It starts, so at least I did not fuk that up... Group 49 batteries are heavy AF. Is this a sports car or a highway tractor?

Long journey. If nothing else, I have a new battery now.

Cheers,

[Scharbag]

Well, new battery did absolutely nothing for the Shell 91 pre-det. But it is a new battery and it was about time anyway. Got 9+ years out of the factory battery - it owes me nothing.

Still at a loss here but I will continue to think on it...

Chevron 94 it is for a while though.

[ItsGary]

Originally Posted by Scharbag

Well, new battery did absolutely nothing for the Shell 91 pre-det. But it is a new battery and it was about time anyway. Got 9+ years out of the factory battery - it owes me nothing.

Still at a loss here but I will continue to think on it...

Chevron 94 it is for a while though.

Not much of a price difference between Shell 91 and Chevron 94. At least on the mainland. Its usually about 2-3 cents every time I've seen it.

[m3jala]

Have you tried using chevron Techron (the concentrate) to clean things up? Not sure if you daily the car but I also find that long weekend drives do wonders for me. Had the same experience in my old E46, these engines need to be warmed up and spun out every once in a while.

[ItsGary]

Originally Posted by m3jala

Have you tried using chevron Techron (the concentrate) to clean things up? Not sure if you daily the car but I also find that long weekend drives do wonders for me. Had the same experience in my old E46, these engines need to be warmed up and spun out every once in a while.

Not available in Canada.

[m3jala]

Originally Posted by ItsGary

Not available in Canada.

Talking about this:

https://www.amazon.ca/Chevron-67740-.../dp/B000CCOL3I

[ItsGary]

Originally Posted by m3jala

Talking about this:

https://www.amazon.ca/Chevron-67740-.../dp/B000CCOL3I

I know, you can get it from Amazon only. No one else to my knowledge carries in store

[Scharbag]

Originally Posted by m3jala

Talking about this:

https://www.amazon.ca/Chevron-67740-.../dp/B000CCOL3I

I cleaned my injectors with carb cleaner when they were out, and I used other injectors. So, i am pretty sure it is not the injectors.

And once again, Shell gas pings. Add a cheap STP octane boost and problem solved, Or use Chevron 94...

FML

[m3jala]

Originally Posted by Scharbag

I cleaned my injectors with carb cleaner when they were out, and I used other injectors. So, i am pretty sure it is not the injectors.

And once again, Shell gas pings. Add a cheap STP octane boost and problem solved, Or use Chevron 94...

FML

The fact stp works for you tells me the issue is the gas nothing to do with your car. Like I said my experience is that Bmw engines are just sensitive. I had pinging on my 17k mile m3 when I bought it pumping Virginia 93 gas. 17k miles. 93 metropolis suburb crap gas. I haven't tried the below but I would look into torco over stp. Dump half a bottle every second fill-up is what I would experiment with and I personally wouldn't look back once I got the formula working. Get your car in shape and enjoy the v8!

https://www.amazon.com/Torco-F500010.../dp/B07BC9N77K

[like2short]

Originally Posted by m3jala

The fact stp works for you tells me the issue is the gas nothing to do with your car. Like I said my experience is that Bmw engines are just sensitive. I had pinging on my 17k mile m3 when I bought it pumping Virginia 93 gas. 17k miles. 93 metropolis suburb crap gas. I haven't tried the below but I would look into torco over stp. Dump half a bottle every second fill-up is what I would experiment with and I personally wouldn't look back once I got the formula working. Get your car in shape and enjoy the v8!

https://www.amazon.com/Torco-F500010.../dp/B07BC9N77K

Torco and any additive using MMT reduces pre ignition and effectively increase octane, but there are side affects. The MMT leaves deposits on pistons, valves and cats. I've read research papers on this and it unfortunately does leave deposits.

I recently read bmw tech documents for the s58 engine and it said not to use fuels with metallic additives (MMT).

In terms of Hp production, MMT does not really add much. A hot rod magazine test in the early 2000s showed tiny hp gains on high compression using octane boost on 87 octane and small Hp loss on octane boost with 91 octane. 100 octane was better and 110 leader even better.

https://www.google.com/amp/s/www.hot...omparison/amp/

[m3jala]

Originally Posted by like2short

Torco and any additive using MMT reduces pre ignition and effectively increase octane, but there are side affects. The MMT leaves deposits on pistons, valves and cats. I've read research papers on this and it unfortunately does leave deposits.

I recently read bmw tech documents for the s58 engine and it said not to use fuels with metallic additives (MMT).

In terms of Hp production, MMT does not really add much. A hot rod magazine test in the early 2000s showed tiny hp gains on high compression using octane boost on 87 octane and small Hp loss on octane boost with 91 octane. 100 octane was better and 110 leader even better.

https://www.google.com/amp/s/www.hot...omparison/amp/

Yep I saw that as well. It's the reason I would attempt to address the issue with Techron first (a clean to improve efficiency of ignition not just for injectors but the valves and heads as opposed to a bandaid of upping the octane). At least for me, combination of Techron and taking the car out for long highway drives every couple weeks has done wonders for me on two generations of Bmw engine while my wife's vw takes any sh* gas you throw at it. My experience anyway.

[like2short]

Originally Posted by m3jala

Yep I saw that as well. It's the reason I would attempt to address the issue with Techron first (a clean to improve efficiency of ignition not just for injectors but the valves and heads as opposed to a bandaid of upping the octane). At least for me, combination of Techron and taking the car out for long highway drives every couple weeks has done wonders for me on two generations of Bmw engine while my wife's vw takes any sh* gas you throw at it. My experience anyway.

Yes. The Techron additive is effective to remove carbon deposits on the pistons to help eliminate hot spots which can cause detonation.

And yes can keep the intake track clean too. It is less effective on intake valves with direct injection, because fuel does not through the intake valve.

At minimum choose a top tier rated fuel. Most major brands are top tier.

[Scharbag]

So I chased this problem for a while. I replaced the following that did nothing:

Plugs (old ones had 20K km on them)
Low pressure fuel sensor (by strut tower)
Rear O2s (did not mean to, one was stripped when I inspected them)
Injectors (used but flow calibrated)

None of the above helped.

Recently, I bought a new RKP x-pipe. I thought, what the hell, lets change out the front O2 sensors when installing the x-pipe. So that is what I did.

Nothing is for sure yet, but initial results are positive that the pre-det issue is greatly reduced. Also, I seem to be getting much better gas mileage (same kind of driving - if not more aggressive) on the first full tank of fuel that I have run with the new O2 sensors and x-pipe. I typically average 23L/100km (it is terrible). Last fill was 20L/100km and half the kms were with the new x-pipe and, well, aggressive driving to test This current tank seems to be using a lot less fuel than it has been. Here is hoping that, along with the pre-det issues going away, that I also get better mileage

Cheers,

[ItsGary]

Originally Posted by Scharbag

So I chased this problem for a while. I replaced the following that did nothing:

Plugs (old ones had 20K km on them)
Low pressure fuel sensor (by strut tower)
Rear O2s (did not mean to, one was stripped when I inspected them)
Injectors (used but flow calibrated)

None of the above helped.

Recently, I bought a new RKP x-pipe. I thought, what the hell, lets change out the front O2 sensors when installing the x-pipe. So that is what I did.

Nothing is for sure yet, but initial results are positive that the pre-det issue is greatly reduced. Also, I seem to be getting much better gas mileage (same kind of driving - if not more aggressive) on the first full tank of fuel that I have run with the new O2 sensors and x-pipe. I typically average 23L/100km (it is terrible). Last fill was 20L/100km and half the kms were with the new x-pipe and, well, aggressive driving to test This current tank seems to be using a lot less fuel than it has been. Here is hoping that, along with the pre-det issues going away, that I also get better mileage

Cheers,

Rear O2s were for monitoring anyways, PreCAT were the ones to inspect

[Scharbag]

Originally Posted by ItsGary

Rear O2s were for monitoring anyways, PreCAT were the ones to inspect

Yeah, I cleaned all 4 of them - one rear was stripped (old shop - grrrr) so I replaced both.

I drove "aggressively" today and I have gone ~200km using 5/8 of a tank of fuel. Before the x-pipe and O2 changes I would be close to empty for sure. Car ran great through some awesome roads - mostly second gear stuff.

Fingers crossed that my M3 is back in business!!

Cheers,

[jballer123]

i have experienced this with the two M3s i have had also, one with as little as 18,000 miles. I had a slight improvement with the detontation/pinging once i put the Dinan tune on that car.

[jballer123]

i wish we could see knock retard, or spark advance, i have watched the max timing using carly app with my Alex alpine tune and seem to get 32 degrees at full throttle near redline but i would really like to know if the ecu is pullling timing when the noise is heard, so we could atleast narrow down the issue for good.

[Scharbag]

So why am I so excited for this kind of mileage? I drove the car HARD this tank. Lots of 2nd gear twisty roads with a lot of full throttle.

To get this mileage while driving the car hard is just awesome. Plus no knocking.

Habit made me fill with chevron 94. Next tank I will try shell 91 to see if I get any knock. Bit of a journey...

Cheers,

[tdott]

I wonder if logging when it happens with http://**************.com/bmwlogger-2 will help figure out what is happening.

[Scharbag]

Originally Posted by tdott

I wonder if logging when it happens with http://**************.com/bmwlogger-2 will help figure out what is happening.

Hmm, that is a neat website address