Top Tier 87 still pinging/spark knock

[mightymousetech]

Originally Posted By: WhizkidTN
Originally Posted By: mightymousetech
Best way to clean out the engine is to take it out on the highway for an extended period and cruise in a lean burn condition, this will get the exhaust temps nice and high. So, get on the highway, set the cruise at 120 km/hr and drive for a couple hours.


Can you detail more about how to get this lean burn condition?


Steady highway cruising with the engine fully warmed up will provide the leanest running condition.

So just set the cruise and go for a drive.

 

[oilpsi2high]

Originally Posted By: L_Sludger
Originally Posted By: oilpsi2high
Run a bottle of Techron through it and stop whining.
Are ya gonna pay for the bottle when his car keeps knocking after the 'treatment'?

If it's knocking then he has other problems that lie ahead.

 

[SatinSilver]

The 05 Matrix was pinging under light load. Kind of annoying. Anyway, filled up with some Shell 87 which I do most of the time but added Gumout Regane HM fuel system cleaner. Took about 130 miles into the fill to notice no more pinging. I would have picked up Techron but Walmart was out of it.

Two prong attack per one of guys on here is to run a second tank with some B12 Chemtool which I'll do. The oil did seem to darken even more all of a sudden which is probably a good sign of cleaning going on.

 

[OilSwag]

Nissan DE engines almost always need 91+ octane to run better. In my experience all of them in the early mid 2000s specifically called for premium gasoline. Even cars like a Crown Vic that says regular 87 can run a little better on 93 octane. I know on my 03 Infiniti 91+ is required because base timing is at 15-17 degrees and as high as 42-44 degrees timing is the reason. Using a OB2 Bluetooth adapter and a data app like Dash command or Torque Pro you can look at short and long term fuel trims, timing, etc and notice huge differences in how your car is running. A difference even with ethanol 10 and 100% gas is more noticeable than you would think. I think to many people are trying to defeat what engineers have proved or only use gas mileage and audible noises as an indicator of what they should do.

In simplest terms Nissans ecu programming mainly with timing is the reason 93 octane is required. Different ecus can adjust and whatnot. Some can run great on 87 but perform better on 93 some aren't that lucky.If an engine is pinging I'm cringing at what's going on inside an engine

 

[Olas]

Knock only happens when the fuel you use is not appropriate for the cylinder pressures generated.

Use the correct fuel.

 

[brave sir robin]

You would be surprised how many "octane boosters" contain a lot of PEA in them. Crack them open and take a whiff.

Originally Posted By: Olas
Knock only happens when the fuel you use is not appropriate for the cylinder pressures generated.

Use the correct fuel.

not always true

I have run 100 octane unleaded racing fuel in the Buick and still had light pinging under certain conditions like merging onto the freeway with the AC running on a hot day. I drive almost exclusively in the city and only use the freeway when on trips out of town and every single time I do this the car runs noticeably better afterwards.



430ci (7 liter) V8
cast iron heads (Buicks used a more "fast burn" style chamber that required a lot less timing than Fords and Chevys)
I am currently around 30-32* total mechanical advance with another 12* coming from my modded vacuum advance
10.25:1 compression ratio (actually closer to 9.8 due to 60s manufacturing techniques)
NGK UR5 V-power spark plugs (slightly colder)
180* "high flow" thermostat (195* stock)

My particular engine was rebuilt so the compression ratio is slightly on the higher end. It is also tuned into within an inch of its life through countless hours of trial and error re curving the distributor and tweaking / modding the quadrajet. Stock this 2.5 ton beast ran 17s but after tweaking and tuning it runs 14s and hits 60mph in a little over 6 seconds on the stock 2:78 peg leg rear end.

From the factory it required what would today be considered 95ish octane but I am stuck with 91 octane here in California and the Buick runs fine on it as long as the combustion chambers are kept clean with periodic freeway runs or the old water decarbonization trick.

 

[555]

Originally Posted By: brave sir robin
You would be surprised how many "octane boosters" contain a lot of PEA in them. Crack them open and take a whiff.

Originally Posted By: Olas
Knock only happens when the fuel you use is not appropriate for the cylinder pressures generated.

Use the correct fuel.

not always true

I have run 100 octane unleaded racing fuel in the Buick and still had light pinging under certain conditions like merging onto the freeway with the AC running on a hot day. I drive almost exclusively in the city and only use the freeway when on trips out of town and every single time I do this the car runs noticeably better afterwards.



430ci (7 liter) V8
cast iron heads (Buicks used a more "fast burn" style chamber that required a lot less timing than Fords and Chevys)
I am currently around 30-32* total mechanical advance with another 12* coming from my modded vacuum advance
10.25:1 compression ratio (actually closer to 9.8 due to 60s manufacturing techniques)
NGK UR5 V-power spark plugs (slightly colder)
180* "high flow" thermostat (195* stock)

My particular engine was rebuilt so the compression ratio is slightly on the higher end. It is also tuned into within an inch of its life through countless hours of trial and error re curving the distributor and tweaking / modding the quadrajet. Stock this 2.5 ton beast ran 17s but after tweaking and tuning it runs 14s and hits 60mph in a little over 6 seconds on the stock 2:78 peg leg rear end.

From the factory it required what would today be considered 95ish octane but I am stuck with 91 octane here in California and the Buick runs fine on it as long as the combustion chambers are kept clean with periodic freeway runs or the old water decarbonization trick.

Well yeah you had pinging on the 68 Buick. You didn't want to back off the timing! I wouldn't either. But we're talking about a car where the timing is backed off while the vehicle is on the road, not at the shop with a timing light.

 

[brave sir robin]

Maybe I didn't get my point across correctly

I run a much faster and more aggressive ignition curve over stock but even with this I still do not see much pinging as long as the combustion chambers are clean. 100 octane racing fuel did not really allow much (I think I bumped it a whopping 2*) more additional timing over my current set up.

stock
0* at idle
20-22* maximum mechanical advance all in around 4500k rpm
add on another 20* from the vacuum advance.

My timing curve is closer to
14* at idle
additional 16* mechanical advance (30-32* total) all in around 2500k rpm
add on another 12-14* from the vacuum advance

proper ignition timing isn't as simple as just rotating the distributor. I shaved the weights used different springs and created a limiter on the vacuum canister to get everything as optimized as a I could.

 

[Olas]

A dirty combustin chamber has reduced volume, increasing pressure/temp.
Increase volume and or reduce pressure/temperature, or increase octane.

 

[SHOZ]

No E10 gas? I had a '79 Ford Mustang 4 cylinder that pinged like crazy on straight 87 octane but then they came out with E10 in the early '80s and that took care of the knock 100%.

 

[555]

Originally Posted By: brave sir robin
Maybe I didn't get my point across correctly

I run a much faster and more aggressive ignition curve over stock but even with this I still do not see much pinging as long as the combustion chambers are clean. 100 octane racing fuel did not really allow much (I think I bumped it a whopping 2*) more additional timing over my current set up.

stock
0* at idle
20-22* maximum mechanical advance all in around 4500k rpm
add on another 20* from the vacuum advance.


My timing curve is closer to
14* at idle
additional 16* mechanical advance (30-32* total) all in around 2500k rpm
add on another 12-14* from the vacuum advance

proper ignition timing isn't as simple as just rotating the distributor. I shaved the weights used different springs and created a limiter on the vacuum canister to get everything as optimized as a I could.

Point taken. Sounds like my type of car!

 

[Oil_Flunky]

Fuel up with 93 and do some full throttle on ramp runs. Fill with 87 on the next tank and see how it does. Cheap and easy first then try something else.

 

[B320i]

If in the distant past you have used 87 octane fuel without any pinging, then I'd be looking in the direction of knock sensors. If it is carrying on rather continuously, it seems obvious the engine is not retarding timing soon enough to prevent issues.

As I've noted elsewhere, pinging seems to be an issue that is affecting a lot of late model vehicles on the road which should be entirely capable of running on the "jungle juice."

The old Bimmer I harp on about does it too on high-octane fuel, but I'm quite certain that is a knock sensor, and really have to get my a$$ into gear and fix it!

 

[kpatter]

just an update...

I added a bottle of gumout regane and back on shell 93 and the truck runs like a singer sewing machine..sooo, guess I will just stick with the premium.... I dunno..

 

[Aichiguy]

I used to be a gas marketing rep for QT about the time when port injection was causing problems with carbon deposits on fuel injectors and intake valves. Chevron and DuPont developed chemicals to clean this through the fuel system vs. physically removing them by blasting them with Walnut shells. Some gas retailers started to include these chemicals as part of the additive package and eventually these were classified top tier. There is a difference in gasoline because there is a difference in additive packages. Carbon deposits on the intake valves and fuel injectors and in the combustion Chambers cause driveability issues as well as emission issues. Not addressing these can result in engine damage through pre-ignition.(knocking). If you consistently use top tier gas you will have no need for other additives or a higher octane fuel which usually is a blend of heavier hydrocarbons which tend to leave more carbon buildup.