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What Fuel Injector cleaner is the best to use for 2003 bmw 325?

70K views 37 replies 29 participants last post by  Bigc2016 
#1 ·
Hey guys,

I have searched the web but for some reason I cant find anything about fuel system cleaners...

my mechanic told me to use the SI-1 Complete Fuel System Cleaner, putting it in the gas tank when its on empty... and i remember my brother had an old 1988 audi and these cleaners messed his fuel filter.. is this the same for the e46 engine? Just wondering if its good to do, and what is the best cleaner possible for the motor?

Thanks guys!
 
#2 ·
Techron has worked for me for years...add to empty tank when at the gas station and then fill up...don't run with it as fuel...if that's what you were advised.

Also, BMW fuel system cleaner 'with Techron Technology' if you want to spend more for what is almost undoubtedly exactly the same stuff...different label.

Anyway, three or four times a year I'll use it. If you never have, you might run two consecutive tank fulls with it added...or skip one tank and follow up with another in the third tank to ensure you're pretty clean...then just maintain every three months or so.

Doug
 
#5 ·
No, you add to tank before you fill it up...you don't drive with it as fuel, straight.

It's on the label...though in real fine print! I've added it when car is half full...even more...just top it off afterwards so it mixes in tank.

Also, you shouldn't let tank get down that low...according to fanatics bible, chapter 12, verse 3! I've heard mixed opinions of this...mostly from guys measuring their mileage by how far they can go on a tank!

Fuel not only lubricates fuel pump...it cools it...and there's also this issue, I've heard and believe, that the lower you go, the more likely you'll pull up gunk from bottom of tank...and if not slowly damage impeller in pump...clog fuel filter.

Me, whatever the truth...rarely let it get below 1/4 tank...and when I've done 250 miles...will fill up shortly thereafter. Rarely add more than 12.5 gals in a 17 gal. tank...so try to keep well clear of 'low.'

Anyway...think that's why you got bad results...it's not a fuel...it's an additive.

Doug
 
#7 ·
^ Yeah I did add it, then fueled half tank.
I don't know why, but somehow my car gets horrible gas mileage when it's full tank.
When I had full tank, OBC showed 400ish miles, then I drove 15 miles, dropped to around 370ish. asdofjapsdofjpoadsjfposd Full tank didnt even last a week..That's why I always fuel 5 gallons. At least it lasts 3-4 days.
I never let it go below 1/8, but maybe that's why I'm getting trouble with fuel efficiency? uhhh...sdapfogjagpoafpomasfpadp
 
#10 ·
I have had really good luck with techron as well. There have been posts in the past that have discussed the really aggressive fuel system cleaners, such as sea foam, and some have recommended that you add it shortly before an oil change as the deposits that it clears can get into the oil. There really seems to be just as many opinions on this topic as there are products, but Techron has worked out really well for me so far.
 
#17 ·
I've used Techron for years ... many years ... in Volvo's, Porsche's, and now BMW's. I've been pleased with the results. Buy it at Autozone/Advanced Auto/etc. I use the 20 gallon bottle and dump it in, then fill it up, as DMAX said, and drive the piss out of it.
 
#22 ·
BG 44k is an additive that is poured into the tank and run with the gasoline available. It works. I just add a bottle of Techron to my tank about 3-4 times per year. Keeps everything clean. I think that the Techron is a good maintenance cleaner, but the 44K really does work on a gummed up system better.
 
#26 · (Edited)
Lord, fuel cleaners are going to be the next oil threads! :tsk: Anyway, I've almost as much work with cleaners as I have with oil and here is how I break it down:

High maintenance (ie; every tankful)- Redline SI-1, Lube Control FP+, RLI BioPlus.

Casual Maintenance (ie; couple times a year)- Techron (or BMW stuff), Regane, Lucas, Gumout etc.

Low Maintenance (ie; aggressive one time use)- BG44K, Berryman Chemtool, Seafoam (or Deep Creep) Ventil Sauber.

Obviously the high maintenance ones are the mildest. They are slow cleaners and will clean over time/miles. They are good maintenance doses to keep an already clean system clean and provide some fuel lubricity. They also have the least effect on the oil when used in proper dosage. Basically wait til the low fuel light comes on, add proper dose, and fill tank the remainder til full. It does not hurt the fuel system to get to the warning light, there is plenty of fuel left to pump, cool, and lube the fuel pump. Our tanks are saddle style and have pick-ups on both sides to draw fuel evenly. There is a function in the OBC that will show how much fuel is left in either side. Look in the "easter eggs" thread to see how to do it and have a little fun.

The casual ones are a little more aggressive and should be used sparingly. Best used in conjuction with an oil change (use them BEFORE changing the oil) to keep the cleaning residuals out of the oil. Not good to have a fresh oil change get contaminated and keep it in the sump for the duration. IMHO, the Techron/ BMW stuff has shown better results. Plus it's easy to find.

The low maintenance stuff is very aggressive. They are usually the dump/ 20 minutes idle time varieties. The oil MUST be changed afterwards or you run the risk of having these strong solvent compounds literally eat the softer metals out of you engine internals. Their favorite snack is bearing babbit since its primarily lead, copper, or tin alloys. Also a good idea to change out the fuel filter too since it will most likely contain a good bit of contamination. These are best to use on higher milage cars that have had "neglected" fuel systems. Get them clean and then switch to a high or casual maintenence cleaner. Usually one or two treatments does the trick.

Modern fuels are really complex these days, not only is there just ethanol to worry about. There are drying agents and competitive aromatics to boost/reduce fuel vapor pressures, and high tech detergent additives like amines or nitrogen based compounds. All of this stuff must be in careful balance to provide the end user benefit. Throw in some dirt or moisture and the resultant stew can wreak havoc on any components that come in contact with fuel or fuel byproducts. Also, modern fuels are cutting compounds that add lubricity like metallic ashes for emissions reasons. The newer cleaners have either bio-based or non-metallic additives to give fuel some additional lubricity. This the the primary reason I use a "high maintenance" cleaner in every tank.
 
#27 ·
Techron triggered SES

I added Techron to my nearly empty car this morning and filled up to 12 gallons with premium fuel. I hit the highway and about 70 miles into my drive, my SES light came on. My car never had this light come on and was running perfectly smooth up to this point. I checked vitals (oil/coolant temp 93-95/ect) and everything seemed fine. Idles smooth, accelerates smooth, runs great.

In short, I think the Techron is playing tricks on the ECU.

Unfortunately, it is illegal for auto stores in CA to run diagnostic tests on cars (or so they say), so I am staring at $65 to have codes pulled by BMW Indy in Sacramento.

I would say that Techron has improved the feel and mpg so far, but causing SES codes is not a good trade-off.
 
#28 ·
So I received my Peake (r5/fcx-3) tool from BimmerTools (highly recommend them btw) to deal with my Techron-initiated SES light. I pulled the codes and got the following:

20 - c -28-83 - mixture preparation bank 2
- c -28 -82 - mixture preparation bank 1
-c -27-61 - secondar air system

This more or less confirms that the Techron was the culprit (light came on 70 miles into my drive after adding Techron to empty tank).

Reset my light and it's been fine for the last few days. I think after the Techron was out of tank, the fuel/air sensors were back to normal. Now that I have the reset tool, I'll leave it in my glove box to help me keep my sanity.
 
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