aklim

So a side question would be how much carbon is on it that we need to worry?

Not to mention having a financial ax to grind.

Going thru all the work, how is it easier than yanking the injectors out, send them for cleaning and testing every so often?

PatternDayTrader

I posted the true facts because of the digression on carbon deposits, fuel treatments, and Gm Top Engine cleaner. You should read it carefully, that way you will know what your talking about next time the subject comes up.

aklim

Actually, you posted what GM said.

Tom400CFI

^Exactly.^ Copy 'n paste. Impressive. Thanks for providing that service.

I know as much as anyone needs to know about carbon deposits in an engine. So, inspite of the fact that you never adressed any of the questions that I directed toward you, we're good.

PatternDayTrader

Well in my opinion carbon buildup is a non issue unless your vehicle is experiencing pre ignition (not to be confused with spark knock from overly advanced timing) or a knocking noise that you think could be related to carbon. Its worth mentioning that this is not something that happens often anymore.
As far as properly cleaning the injectors, the tsb makes it sound wayyy more difficult than it really is. The only real problem for non-professionals is the fact that you need a canister you can pressurize and connect to the fuel pressure test port so you can run the solution through the injectors. You either have to make one or buy one, which is kind of a pain ....

PatternDayTrader

Correct.

I am of the belief that GM is a reputable source of information for GM vehicles.

aklim

It's going to be a lot easier to believe an independent 3rd party than a party with financial interests. I mean, would you believe my wife giving me a reference telling you that it is safe to hand all your cash over to me?

So how serious an issue is carbon deposits? Is it something that needs to be cleaned or is it just going to be black because combustion is always taking place? IOW, what if I don't fix it, will it pile up to the point of hurting the engine or performance?

PatternDayTrader

That's right. I'm bored feeding the troll who think engines magically repair themselves simply by running.

Tom400CFI

Good. I'm sick of your arrogant, but essentially worthless posts. So...we're good.


Aklim, Since you quoted my post, are you looking for my input on this? I'm almost afraid to answer, for fear of being bludgeoned by motox and pages of GM marketing propaganda (not to mention insults).

Unless there is something wrong w/the the engine that specifically causes excessive carbon build up, carbon build up is a non issue. It burns and washes from the combustion chambers as fast as it is produced.

aklim

So probably a non issue unless you have oil fouling the cylinders?

Well, you do have to shut off the fuel pump also. Now how will you verify the work? Say you sweep a room wearing a blindfold. Lets even say you have a dustpan full of dirt. Is there more in the room you missed? IMO, a better method is to take the injectors out, send them for cleaning and testing and you know if it is clean or not. What you know is you are spending money to clean it, do a balance test, etc. BTW, how will you do a balance test on a bank fired system again?

PatternDayTrader

First, GM dealers and the techs absorb the costs of warranty claims with almost no reimbursement. So while they may have a financial interest in this procedure it is limited at best. I brought it up because I know for sure that both of the above processes actually work.

Second, don't even worry about carbon deposits unless your vehicle has a carburetor. Really, put the idea right out of your mind, its a non issue.

aklim

I believe they have a great deal of information. What I don't believe is that they share that information with us other than what benefits them first and you, well, if you benefit, so be it. How's your faith in VW concerning their information on VW vehicles?

aklim

Why not? I didn't think carbon was such an issue but I could be wrong.

Kinda what I thought but I haven't looked into a combustion chamber and done much testing although I have seen many a post on how an outboard motor did some "testing" with a couple of outboard motors and "proved" how their product cleans engines.

aklim

Injector cleaning via pressurizing the rail with cleaners might work. What I don't know is how to verify that it is as good a solution as taking the injectors out and sending them for testing.

Oh, God, No. I switched my ATVs and Jetskis to Fuel Injected. All my lawn equipment is 4 stroke only because I can't find an economical Fuel Injected system for my lawn stuff. You couldn't GIVE me a car with a carburetor on it.

PatternDayTrader

By unplugging each injector and testing them one at a time, but I can tell you from experience that if you think you have a restricted injector or injectors, just run the solution through the fuel rail. Don't even screw around testing them because it takes maybe ten minutes and the top engine cleaner is maybe 10 bucks. In the event there is still some sort of drivability issue then pull them out and bench test them, or replace them or send them out to whoever for cleaning.

Tom400CFI

I hear you. It's not an issue.


Why I posted the pics of two stroke pistons. You can see in those pics, that carbon build up is a non issue, even in carb'ed 2 strokes (for the most part). On a properly running engine, 2 stroke or 4, the carbon is washed and burned as fast as it's created, after some initial build up.


EDIT: Whoops...I realized that I never actually posted the 2 stroke pic, earlier. Here it is:



-Note that the richest AF ratio results in the cleanest piston. I've worked on 100's if not 1000's of these things. Never once saw "carbon build up" as an issue of any kind.

.

PatternDayTrader

I am totally with you on that ....

PatternDayTrader

Yeah they begrudgingly reveal information only through their dealership network. I don't benefit anymore, I am retired from the profession. Thankfully...

btw - I cant wait to see how VW handles there issues with the diesel emissions. The fact that they have a cheater program makes me think they straight up cant pass present nox limit tests.

crowz

As for to worry or not worry about carbon?

Yes and no

In the no column if there are no symptoms from it then it can be looked at as a non issue. I sure wouldn't put it on my list of maintenance items to do. But while not being a high priority issue if it does build up it can cause problems.

In the yes column it lowers displacement in the cylinder head. How much depends on how much it builds up. It can come loose on its own damaging valves. California vehicles have a much higher rate of problems with the carbon build up than other vehicles due to the programming and emission equipment changes for that state. Gm's tsb database has a ton of entries covering just California versions.

I usually see the problem on vortec motors the most now but Toyota had a run of vehicles with the problem. I think it was camry models but that's been so long I cant remember for sure.

Basically the motor runs like crap. Very rough idle and spark knock sounds under load. Usually the computer trips a random misfire. Its a pain to track down if you have never dealt with it before. Most mechanics throw parts at the problem then give up around here then I get a call asking for help.

The scope Ive got its the only sure fire way of diagnosing the problem without tearing the engine down. Well worth buying for all kinds of jobs but a must if you want to check for carbon build up. Again Ive never had it happen to anything Ive owned.

My 86 coupe had no issue with it either when I owned that one.

So in my opinion if the motors running fine I wouldn't worry about it. Adding some techron to the fuel system from time to time might keep it from happening. I do that once a year on all my stuff so that may be why Ive never had the problem but who knows for sure.

aklim

Testing what? With the injector in the car, all you can do is ohm the thing. That tells you the coil is working or not. Spray volume and pattern is not going to show on a DVOM.

OK. Say you run the cleaner through. It is still not going to tell you if you need to run 2 cans or 3 cans or 1 can. IOW, you don't really know. Bench testing is the only way to KNOW. That is why I do it every 3 years even for my ATVs or Jetskis. My daily driver injectors are tested more often. I used to pull the diesel injectors out every 100K since that was the interval they seemed to develop issues or the bench test shows issues. Now I know if the pintle is wearing out and that they need to be replaced about every 100K at the latest. Top Cleaner doesn't tell me that. "Cleaner in a can" is a cheap answer to a problem. Obviously, it lacks any sophistication or more concrete results but you get what you paid for.

Unbeknownst to Jon at FIC I borrowed a rig to test the injectors before sending it off. 7 were so so and 1 was off. Sent to him and he confirmed results and what the final product was. Got it back, tested it myself and it was what he said it was. This way I know what issues I have going out, FIC doesn't know what I am seeing or looking for and the did the right work as verified by my own tester