You'll have to buy the same expensive equipment they're using. Most gas today has a lot of high-quality additives to keep injectors clean. What symptom are you trying to solve?
April, 12, 2012 AT 4:13 AM
Reduced gas mileage. I don't know why dealer thinks they need cleaning other than miles on car. Normal maintenance?
April, 12, 2012 AT 4:31 AM
Just to add to this one for gas that has great additives in it why does gm have a bulletin for dirty injectors and if you dont use top tier fuel you will end up with dirty injectors?I have ran into dirty injectors causing missfire codes even.I have also seen the gas leave a lot of carbon behind also. That great fuel also has been destroying fuel sending units there is a bulletin for that also. If you want to clean the injectors with a fuel additive you can use a good bottle of chevron techron gm uses that and its even in there bulletins to clean them. Also what works really good is a product made by the bg company called 44k it goes in your gas tank. But to get a really good cleaning you would use a pressure canister with a chemical that you run the engine with from the pressure canister. We used them a lot at the dealer I worked at.
April, 12, 2012 AT 5:40 AM
Another problem I've been told about numerous times is mismatched injectors but this is always related to GM vehicles. As the story goes, GM doesn't flow-match their injectors on the assembly line. They just grab a handful from the bin and stuff them in. When you reach high mileage, an injector that flows less than the others will make that cylinder lean. The oxygen sensor detects the unburned oxygen in the exhaust and the Engine Computer interprets that as all cylinders are lean. In response, it adds more fuel to all of the cylinders, but no matter how much extra fuel it keeps adding, there will still be that unburned oxygen. You may smell the extra fuel at the tail pipe, but the oxygen sensor still tells the computer the mixture is too lean, hence the drop in fuel mileage. That's why I was asking about the symptom.
This story came from Jim Linder of Indianapolis. He puts on very expensive classes all over the country talking about fuel injection systems and problems. He owns one of the few companies in the nation that rebuild injectors, then they sell them in flow-matched sets. Many of his customers comment that their GM engines never ran so smoothly even when they were new.
There's a few other things to consider. First of all, how many people remember how their engine ran 100,000 miles ago? Second, those engines must have run fine when they were new or people wouldn't have bought those cars. He also said the biggest percentage of their sales were for GM injectors, but there's more GM cars on the road too.
Chrysler buys their injectors from Bosch in flow-matched sets and problems are extremely rare. You don't hear much about other manufacturers having injector trouble. I have to wonder if all injectors suffer from the same deposits but GM's are more susceptible to the results of those deposits. The next question is if rebuilt injectors were really needed in most cases or if cleaning would have restored the flow rates enough to solve any problems. Naturally when you get rebuilt injectors they're going to be perfectly clean. So what solved the problem, the clean of the new injectors or the matched flow rates?
I doubt GM would issue a service bulletin that blames a running problem on mismatched flow rates but if cleaning gets them back to working better, you can't argue with success. Obviously people are having some good results with the cleaning machines and the canisters of "soap" that the engine will run on for 20 minutes that saturntech9 is referring to, otherwise no one would be buying the products or selling the service to their customers. Try the products saturntech9 referred to first, particularly if the drop in fuel mileage was gradual and over a long period of time. If the drop was sudden, you might look for a cracked or dry-rotted vacuum hose or some other vacuum leak. That will also introduce extra oxygen in the exhaust leading to more fuel being commanded by the Engine Computer.
April, 12, 2012 AT 6:05 AM
A lot of the gas out there doesnt have the cleaners that are need to keep the injectors clean. Also the stuff they are putting in the gas is damaging fuel sending units on other cars besides just gm brand cars. For supposed miss matched gm fuel injectors they sure run good and are getting great fuel mileage. Chevy has a lot of high fuel mileage new cars out I have seen the injectors clog up way under a 100,000 miles.
April, 12, 2012 AT 7:13 AM
By "sending units", do you mean the fuel gauge is causing trouble or did you mean to say the pickup screen? I have heard of Chrysler fuel pumps locking up from "microscopic debris" in the tank. A new NAPA or Carquest pump also fails in a few weeks, along with the third of fourth replacement, then out of frustration people buy a pump from the dealer and have no more problems. As that story goes, it's not that the dealer's pumps are better, in fact NAPA pumps come from the same supplier Chrysler buys 'em from, it's that by the fourth or fifth replacement pump, all the gunk in the tank has been collected and the next one doesn't get clogged with that stuff. Supposedly the cure is to have the tank steam-cleaned at a radiator repair shop before the new pump is put in. The pumps are built to very close tolerances to make them quiet, but that leads to them locking up easier too.
Recently had a friend who owns a small engine shop show me the mold that grew in a jar of gas with ethanol. I wonder if that's the stuff that's clogging pumps, and maybe injectors. He's seeing it eat away the rubber diaphragms in small engine fuel pumps and gaskets. I haven't run into any fuel-related problems up here in Wisconsin, but people were getting sick in the southern seven counties were they are required to use reformulated gas. Guess that's one of the few advantages to living where I do.
Also, am I correct in assuming injectors are getting plugged with varnish buildup? I can see chemicals dissolving that but not fine dirt that would collect in the screens in the injectors. I've always bought the cheapest gas I can find, even on cross-country trips with my old rusty trusty minivan and have never had a problem, ... Yet.
April, 12, 2012 AT 4:00 PM
Fuel sending unit aka fuel level sensor lol its attached to your fule pump module to tell you how much gas in your tank. They are getting damaged by the gas were putting in our tanks. The injectors are getting clogged by the carbon etc in the engine. Not the sediment/silt from the gas stations underground fuel tanks. So the bulletin says to use top tier fuels like unocal 76 philps 66 chevron texaco bp fuels wernt on that list last I saw.
April, 12, 2012 AT 7:30 PM
I see. So much for the theory ethanol cleans the fuel system, huh?