Which Fuel Injector Cleaner and How Often? - The Unofficial BMW M5 Messageboard (m5board.com)

Last 03 5 · 12th May 2005, 23:03

Title says it all. Not much in the archives on this. With my old Corvette I ran GM's gasoline additive every 3 months or so.

Recommendations?

Regards,

Greg

SCORPIO · 13th May 2005, 02:14

If it ain't broke, don't fix it?...

Quote:

Originally Posted by Last 03 5

Title says it all. Not much in the archives on this. With my old Corvette I ran GM's gasoline additive every 3 months or so.

Recommendations?

Regards,

Greg

Carrera2RS · 13th May 2005, 03:36

I use STP (black bottle) every 2-3k miles and it's always a little sweeter and crisper afterwards, do it for the first time and you'll be surprised just how sweet the cars runs at a £5er it's worth every penny !

BKH · 13th May 2005, 10:34

The FI cleaner won't do anything that good gas already has. I'd suggest using a major brand of "fuel system cleaner" (which is the strongest formulation) in the last tankful of gas before an oil change. Contaminants that escape the filter are then changed out.

BmwNut · 13th May 2005, 10:41

I would worry about fuel additives. Many can foul O2 sensors and cause more problems down the road. The only car that I ever ran injector cleaner through was my Triumph, but the O2 sensors ran open loop (IIRC, after we jury rigged some problems with the wiring harness), and the injectors needed cleaning every once in awhile. I wouldnt worry about it in a beast.

Carrera2RS · 13th May 2005, 10:48

I only use Shell Optimax and when I use STP cleaner I notice a difference and I have never had any problems with STP injection cleaner on M3's M5 and various 911's

DavidS · 13th May 2005, 20:36

Interesting topic...

What are the practical differences between STP Injector Cleaner and STP Complete System Cleaner?

Which is the optimal way of deploying it: with a small volume of petrol, or with a full tank?

David

BKH · 13th May 2005, 21:21

Quote:

Originally Posted by DavidS

What are the practical differences between STP Injector Cleaner and STP Complete System Cleaner?
Which is the optimal way of deploying it: with a small volume of petrol, or with a full tank?
David

Generally the heirarchy goes from "gas treatment" to "FI cleaners" to "fuel system cleaners," weakest to strongest. Products in the latter category almost always claim to be able to be able to remove combustion chamber deposits, which is my initial screening criteria in the store. I used the STP fuel system cleaner when it was introduced in the American market and remember asking STP for, and receiving a very convincing brochure from them that depicted before/after scenarios.

Most of the FSC's call for mixing the bottle in 16 gallons of gas. I always use less gas, usually 12 gallons or so.

DavidS · 13th May 2005, 22:39

Thanks, BKH!

I wonder how the FSCs clean carbon deposits...? If the depisits fall off in chunks, there would seem to be an uncomfortably high risk of cylinder wall scoring. On other hand, if the deposits are dissolved or at least broken down into tiny enough bits not to cause problems if caught between the compression ring and the cylinder wall, it would seem to be a really good idea to clean regularly.

Anyone heard of any drawbacks with the STP Complete System Cleaner?

David

DavidS · 14th May 2005, 00:39

Just looked at the STP website (www.stp.com).

It is a nice website, but I noticed two things:

1. In the FAQ:

"Are STP® products safe for two-cycle engines? four-cycle engines?

STP® oil and fuel additives have been specifically formulated for use in four-cycle, gasoline engines. Extensive testing in these engines has covered a broad range of passenger car usage and has clearly demonstrated the value of our products in these applications. However, we have not evaluated the performance of our products in two-cycle engines. Therefore, we do not currently recommend that they be used for two-cycle applications"

If you read carefully, they do not answer their own question.
All they say is testing has clearly demonstrated value in the applications. It does in no way state there have been no issues. I wonder why...

2. In some of their product descriptions it says as a positive thing that the stuff is made from Jet Fuel. If that means normal aviation jet fuel, that is some of the worst stuff imaginable for a car engine.

Have you ever looked at the engine cowls of a turboprop aircraft? Have you noticed the soot? That is jet fuel for you. Jet fuel is basically kerosene of the lowest quality. It is all about making a fuel cheap enough to burn by the tons. An airliner uses about one ton per 100 km. (Aviators please correct this if not correct.)

STP say they "use no corosive chemicals such as alcohol in their products". Since when is alcohol corosive? You americans of the mid-west drive on about 30% alcohol when you fill the car up. That is how corrosive alcohol is to car engines.

(Anyone who remembers that US petrol is corrosive to Nikasil alloy used in certain engines from BMW and Porsche among others, should know that it is the high sulfur content of certain US petrols that is the problem, not the alcohol content.)

Anyway, although their marketing is not absolutely convincing, I doubt that a few drops of jet fuel would cause any problem when mixed with a tank of petrol, so if everone here thinks STP FSC is a good idea I might very well give a try.

David