Since today's knock sensors detect and the ECU/PCM pulls timing all in milliseconds, the human ear cannot detect this. Only by logging with HP Tuners/EFI Live or similar can show the actual rate of timing pulled. In the old days it was "Ping" r the "marble rattle" we could hear and then add premium or retard timing at the distributor.

Interesting to see how he is tracking it also.

The additives can be harmful to GDI high pressure injectors. The Techron is apparently a good one as is Lucas and my always favorite are the Amsoil products "Quickshot".

The ones that are really strong solvents can damage the internals of the injector over time, but this is an area that I am not an expert and defer to those that do injector cleaning and flow balancing like this guy:

"Owner/Presidemt/Technician
As New Injectors Inc. & High Performance Injector
December 2008 – September 2011 (2 years 10 months)Sarasota, Florida
Our Company Tests, Ultri Sonic Cleans, Retests,Replacing filters and O Rings to Refurbish Gasoline Injectors, Bringing them back to factory Spects.

New to the Industry is Our High Performance Injectors, These Injectors are New top feed Bosch Long Stroke Injector made for the the Performance Industry. These Injectors have Multiple Applications with a large range of Fuel volumes (up to 2000cc per min) and spray patterns from a varied assortment of Spray Tips. These Injectors Atomize the fuel better to obtain the highest Performance from the fuel volume.

hpinjectors@yahoo.com"

He really understands what does and does not harm them.

Top tier fuels have detergent additives in addition to what is mandated in all street fuels.

 

The other forum member I mentioned told me he had an upper induction cleaning and no real detonation change. The mechanic just told me I have very minimal oil in the intake but I have not had a cleaning. We both think the issue is not the oil but maybe something in the ECU or maybe a knock sensor that is not coding. You are probably right in that its degrading, but I haven't noticed anything power wise and do have an increase in MPG's, 32 strictly highway as compared to 30-31 last year.

 

I understand your point about how the FEDERAL government is concerned about the standards being met when the car is new. However, many states require periodic emission testing. If the GDI vehicles in fact have worse emissions then they age then they will not be able to pass the factory standards that the state test stations use.

This will make it impossible to renew the car registration until the problem is fixed and the tailpipe once again meet the original FEDERAL standards. However, this will be an expensive fix perhaps, if the owner is lucky, just a full cleaning of the heads. If they are unlucky all new valve guides etc. If they are really unlucky, as mileage mounts on the vehicle, the guides get so sloppy that a valve is dropped etc.

All of this is potential cost that will probably be out of warranty. It may fall on the original owners but more likely will fall on those who bought the vehicle used. So, while the Federal gov't may not care NOW about degradation of emissions as GDI vehicles age some states certainly will. Eventually, and the process is almost certainly underway now, the value of these vehicles used must drop as owners know what they may be in for down the road etc.

For the present, since used values have not yet started to drop, the best strategy seems to be to buy new, run the heck out of the car, and sell prior to the expiration of the warranty. I would think that many used car buyers in the future are in for a very rude awakening perhaps much more so than the original owners who are insulated from the problem by the warranty and by manufacturers who are in no hurry to expose the problem for what it is.

 

What is the "readiness test" and "readiness mode" you are quoting in your statement? Is that unique to diesel engines?

Isn't the VW emissions compliance issue only with the diesels and not with their gasoline engines?

 

Any oil is an issue if you have a GDI engine. Even port injection oil ingestion, even in small amounts will cause pre-ignition and slow/disrupt the burn of the A/F mixture. You only want air & fuel in the combustion chamber at the time of ignition/combustion. ANY contaminate affects burn pattern, flame front, creates hot spots and other detonation causing conditions. AN upper induction cleaning will do little to correct any of this (a Seafoam/BG, etc. solvent based) as they only can loosen up to 40% (generally in the lab we see 20% or less is removed) and then the damage caused when they are DI hard carbon deposits make this a risky procedure. Rarely do these hard abrasive crystalline deposits not cause scouring of the pistons and cylinder walls and further damage.

Only a proper manual cleaning can properly remove the deposits w/out damage to the engine. If you do a controlled test of before and after dyno with a manual intake valve cleaning like this guy at 20k miles, you should see similar. But as soon as the deposits start forming on the valve stem they are cycled into the softer brass alloy guides and begin to wear them, and they start at 1000 miles or less. Just something to think about for the future. If you are in a State that has a shop interested in removing your IM for inspection of the valves, it will help all to see at your miles what they look like.


Excellent worded reply. And that is where the consumer gets stuck in the middle. The first years Colorado started mandatory testing even back then there were several stories in the Denver Post on new cars not passing. Again, your right on that until the consumer see's this with accurate news reporting and repair shops getting educated, it will be "out of site, out of mind". Keep up the intelligent contributions here.

Readiness test is for all vehicles subject to testing gasoline or diesel. Here are some good articles to read up on just what it is and does look for:

https://www.google.com/#q=Readiness+test+fail+emissions

A diesel vehicle may take far longer driving just prior to the electronic side of the emissions test accessed through the OBDII port, so as I understand they "cheated" on this by defaulting to "all ready" when detecting when the test computer was plugged in to query the computer. The tail pipe side (real emissions) pass fine. The hassle to the vehicle owner of repeatedly having to re-schedule or keep coming back was what they were attempting to (and did very well) avoid.

But, it was "cheating" just the same, just had no negative effect on the environment. And the Feds get $10 billion.

Hope that helps!

 

The following is a news worthy announcement from Ford:

Second-generation 3.5-liter EcoBoost engine

The engine features an all-new, Ford-first dual-direct and port fuel-injection system. Two injectors per cylinder – one mounted in the intake port where air enters the cylinder and one positioned inside the cylinder – work together to improve power output, efficiency, and emissions.

This seems to be Ford's answer to the DI intake valve coking problem we have been discussing. Their announcement makes NO mention of issues/problems related to their intake valves. Is this the wave of the future?

 

Great link! Yes, this was released a few months back. They still officially take the same stance as GM that " There is no issues with valve coking etc." yet they have followed Audi and Toyota in adding in small port injectors to help with "off idle throttle response" and attempt to keep valves cleaner. The problems with this is now that a combustible mixture is present during the compression stroke, detonation and knock retard are now more prevalent and the efficiency of a GDI engine is reduced. Then we look at the real World results of this hybrid injection engines and there is a small reduction in the rate of coking, but not enough to be an acceptable trade off for the true GDI efficiency IMHO.

 

Wanted to update we just went through a GM LGX engine (the 3.6L V6) and GM deleted the intake manifold vacuum source for evacuation so they now only evacuate properly when accelerating and at WOT VS in the past at idle, cruise, and deceleration. Colorado Speed and Elite Engineering have been using both IM and area just upstream of the TB, to provide the best evacuation both most be utilized, and this is another trade off of engine wear and longevity while attempting to reduce intake valve coking. You cannot leave these contaminates in the crankcase w/out significantly increasing engine wear.

 

Bumping this back up for more discussion all!

 

 

What I read is that these engines need A so called valve job every 20K-40K miles at best

 

Were not seeing wear to the seats as in the old days, just the guides by 20-40k miles and most wont notice that w/out running high RPM's. But cleaning the valves manually with only removing the intake manifold your pretty accurate on a cleaning to retain as new performance.

 

As time goes on and miles accumulate on these cars, more will understand how different GDI engines are from port injection.

Bumping this up for continued discussions.

 

I agree... don't let this thread die

 

interesting that this thread is buried in Transactions Feedback... shouldn't it be in C7 Technical subject area?

 

Yes...it seems it got moved somehow.......weird. It was created in C7 tech...

 

Steps to reduce coking on intake valves, as I understand it include:

1. top quality tier 1 gas
2. running the engine more aggressively, keep revs up
3. top quality hi performance synthetic motor oil (i.e., Amsoil, Redline or ?? what would qualify) Mobil 1 5w-30 meets the GM recommendation but I know it as a mid level oil)
4. Elite catch can as described and sold by COSPEED.

If I have left any pertinent info out please make additional comments. I look forward to more feedback on this thread.

 

 

Those are the best steps so far!! As we learn more there will certainly be other steps as well I anticipate.

 

Thank you for your response... I am very interested in purchasing the Elite catch can...