Discussing LSPI (Low Speed Pre Ignition)

[tigeo]

Hey, all. Hoping you can help shine some light on a similar issue I am having.

I found some VP Octanium octane booster at a local Canadian Tire and decided to give it a try. Reason being, I am about to do a DSG tune and wanted to compare TCU maps (stock vs. TVS) with some octane booster in the car to rule out any knock or timing pull in the CVT-like feeling of the stock 7-speed software. Though slightly better with octane booster in low-RPM range, the factory DQ381 software still sucks.

Where things get interesting is after running a few tanks with octane booster and then switching back to straight premium fuel, I noticed what sounds like a knock or fuel ping in the 2-3k rpm range at higher loads.

My guess - which is purely a guess - is that a few tanks of what would be 102 octane was enough for the ECU to adapt timing / boost and now the car has what sounds like LSPI.

Mileage is 95,000 kms and the car has been well-maintained and never tuned. My only other guess is that any crap that’s come out of the injectors is causing it.

It’s strange to think it’s just coincidence because the car ran completely fine until I used the VP Octanium — and to be clear, it was not the ‘Unleaded’ version that’s advertised as safe with catalytic converters and O2 sensors. Unfortunately, I did not know about this one until after I ran the ‘off-road racing’ blend.

Hoping someone out there can help with a possible solution. Plugs are new, coil packs are new, fresh oil, and still the same issue. VW did a live scan and no knock (apparently) but it did register some misfires. Same knocking / pinging noise described throughout this thread. Super frustrating. Car has good compression straight across the board and pulls hard up top, it’s just at low-rpm under high-load that I am hearing the noise.

I am wondering whether there are fuel trims or anything in the ECU that can be reset to factory. Any help is much appreciated.

LSPI is a different animal (pre-ignition) than standard run-of-the-mill spark knock/ping/detonation and our engines don't really have an issue with it - that's mostly v. small displacement Asian engines and is a v. specific situation. Why are you putting it under high-load at low RPMs? Never good for any car. Have you just logged it to see what is going on? I'm still confused as to what you are trying to accomplish here?

 

[tigeo]

LSPI is a non-issue for VAG engines, as far as selecting special oil, or even for running less than 91 octane. GM, Hundai and Subaru are the engine brands that had any known problems.

Also, it looks like Castrol 0w-40 is now back to a high calcium formula >2000ppm. So, for the rest of my cars, I'll use the same old oils I have stashed; Pennzoil Ultra 0w-40, Mobil 1 0w-40 and my other oddball oils like Liqui Moly 0w-40 and Valvoline SynPower 0w-40, which has a bit of sodium in the formula, another element that is bad for LSPI.

For the new Sportswagen, I'm leaning back towards reduced SAPS, like VW 504 or Pennzoil Euro L 5w-30, which is a winner at $22/5q

https://www.walmart.com/ip/Pennzoil-Platinum-Euro-L-5W-30-Full-Synthetic-Motor-Oil-5-qt/495194903

At least it can help reduce intake deposits, which is the bane of VAG DI engines. I literally do not understand people using K&N gauze filters on these engines, they are KNOWN to pass dirt....onto the hot dry valves....good luck with that

So you want a lower Ca oil but will use M1 0W40? It's got ~3200 ppm!

K&N for sure pass more dirt, it's a fact but the amount isn't worth the drama of the discussion that ensues. My UOAs all shows v. low SiO2 running a K&N/open element filter. The Gen 3 EA888 doesn't have the carbon build-up issues that the prev. gen engines had. I don't believe that running a reduced SAPS oil/504 will do a thing to avoid an eventual carbon cleaning maintenance at some point if you own it long enough.

 

[RabbitTwo]

LSPI is a different animal (pre-ignition) than standard run-of-the-mill spark knock/ping/detonation and our engines don't really have an issue with it - that's mostly v. small displacement Asian engines and is a v. specific situation. Why are you putting it under high-load at low RPMs? Never good for any car. Have you just logged it to see what is going on? I'm still confused as to what you are trying to accomplish here?

@tigeo it is making the noise in normal DSG modes. I am not doing anything specific to load up the engine at low RPMs. Pulling out onto the highway and rolling on the throttle did it. I am trying to figure out why.

 

[jimlloyd40]

@tigeo it is making the noise in normal DSG modes. I am not doing anything specific to load up the engine at low RPMs. Pulling out onto the highway and rolling on the throttle did it. I am trying to figure out why.

What were the plugs gapped at?

 

[tigeo]

@tigeo it is making the noise in normal DSG modes. I am not doing anything specific to load up the engine at low RPMs. Pulling out onto the highway and rolling on the throttle did it. I am trying to figure out why.

Have you ascertained the source of the noise definitively through logging?

 

[RabbitTwo]

@jimlloyd40 factory-spec. @tigeo VW dealer logged - no knock but misfiring.

 

[jimlloyd40]

@jimlloyd40 factory-spec. @tigeo VW dealer logged - no knock but misfiring.

What do you consider factory spec?

 

[RabbitTwo]

What do you consider factory spec?

Whatever the dealer gapped them at. With old plugs and new plugs, same issue. New coil packs, too. I doubt very much it is either.

 

[jimlloyd40]

Whatever the dealer gapped them at. With old plugs and new plugs, same issue. New coil packs, too. I doubt very much it is either.

Please ask the dealer what they gapped them at. Should be 028 if not tuned. Exactly how much misfiring is there?

 

[RabbitTwo]

Please ask the dealer what they gapped them at. Should be 028 if not tuned. Exactly how much misfiring is there?

Hey @jimlloyd40 dealer just emailed me back: “NGK plugs, gap is 0.8mm (done from factory, we verify)

Technical support is reviewing all your GFF logs and will have an answer for me tomorrow!”

The service manager I work with at my VW dealer is awesome.

 

[jimlloyd40]

Hey @jimlloyd40 dealer just emailed me back: “NGK plugs, gap is 0.8mm (done from factory, we verify)

Technical support is reviewing all your GFF logs and will have an answer for me tomorrow!”

The service manager I work with at my VW dealer is awesome.

They are gapped a little bit to open. Should be 028. Probably not enough difference to explain the problem. Exactly how much knock is it showing?

 

[RabbitTwo]

So a VW technical engineer got back to my local service manger after reviewing the logs.

The long and short of it is likely fuel contamination, and/or possibly a dirty injector.

Their recommendation is to try the VW fuel additive and monitor after two tanks of that have been run through the car. I am on tank one now with a fresh mix of Ultra 94.

Some details:

Misfire read on ODIS scanner. Engine is running well otherwise as it tries to perfect stoichiometry in the air fuel mixture – it is never perfect due to many influences resulting in the odd misfire here and there. O2 issue? This might make sense given the VP ‘off-road’ octane booster. They have a different additive specifically designed for vehicles with catalytic converters and O2 sensors. Unfortunately, I found this out after.

If you are going to run VP Octanium in these cars, get the ‘Unleaded’ version to be safe. Although the standard off-road blend is not leaded, it is also not advertised as safe with cats and O2 sensors. That may have caused the issue.

The car does seem to be running a little better so hopefully whatever it was is clearing up.

 

[aaronc7]

I've ran the unleaded version and Lucas octane booster--both are just MMT. Still coats everything orange and leaves behind deposits. Not recommended.

 

[jimlloyd40]

I don't know how Torco boosts octane but I have used it daily and continuously for the last 60,000 miles without any problems.

 

[RabbitTwo]

I've ran the unleaded version and Lucas octane booster--both are just MMT. Still coats everything orange and leaves behind deposits. Not recommended.

Exactly! @aaronc7 is there any way to clean that up?