[orionredwing]

There have been many threads discussed over the years on the effectiveness of fuel injector cleaners on direct injection (DI) engines. I searched, and as there hasn't been a recent thread, I wanted to share my recent experience.

I'm a big fan of Techron on my previous cars; I used it on a regular basis and treated it as periodic maintenance. BUT due to discussions in this forum, and the doubts raised on its effectiveness in DI engines, I chose NOT to use Techron on my 335i for the past 70K miles....until now. (This gives you an idea how powerful forums are in influencing behavior, especially since I'm a big believer in Techron to begin with).

With >70K miles, my car was beginning to idle rough with the occasional blurps and hiccups every 5-10 secs that indicates a minor misfire. I track my car, and despite multiple track days, with multiple 20-30 min sessions of constant WOT, no actual misfire codes were thrown.

Around 70K miles, I changed out my spark plugs. Upon removal, I noticed that the plugs for cyl #3 was black with fuel smell. I installed new plugs AND for the heck of it, also swapped coil pack positions to troubleshoot. The car was still idling rough. 10 miles later, and the next morning (after engine was cool), I pulled the plugs to reinspect, and here's what I saw. (Note: Other users have mentioned the same symptoms, and saw this in cyl 6, but mine was cyl 3)

NEW PLUGS w/ 10 MILES:


With only 10 miles, the brand new plug was black w/ fuel smell. Other new plugs next to it in the picture were fine. With coil packs swapped, it looks like I have a bad injector. That sucks!

At that point, I had an old bottle of Chevron Techron lying around, and decided to give it a shot (nothing to lose at this point). It was the smaller 12 gal treatment bottle, so I filled up half a tank and ran it through. After the treatment, I noticed an improvement. The rough idling and blurps went from once every 5-10 secs, to once every 10-20 secs. It helped, but looks like I'm stuck with the rough idle.

Recently, Chevron Techron came on sale at Kragen's (O'Reilleys - buy 1 get 1 free). It's been 3K miles and 4-5 track days since that last treatment. With the sale going on, I decided to try Techron again, and opted for the larger bottles that treat 20 gallons.

RESULT: I ran 1 bottle through.....and my rough idle is now completely gone!!!

Wow, I came in with low expectations. For years, I listened to all the naysayers saying it doesn't work on DI engines. Their arguments made so much sense that a strong believer such as myself stopped using it.

Kragen (O'Reiley's) currently has a sale (buy 1 get 1 free) good till 5/24. Sorry, it's been going on the past 3 weeks, so I was surprised nobody posted the sale. For those experiencing rough idle, I suggest giving it a try. Use 2 treatments and see if it helps you. Maybe it works, maybe it doesn't, but at $11.99 + tax for 2 bottles, it's waaaay cheaper than replacing injectors, so is a no-brainer to try in my book.

I believe the inherent problem is still there, and the Techron treatment only serves to mitigate the symptoms. It's either bad injector on cyl 3, or carbon build up. But remember, with NO misfire codes thrown after multiple track days, I can live with using Techron on a periodic maintenance schedule. I went back and bought 6 more bottles (3 + 3 free)

[blacknbean]

i like techron and usually buy it when its on sale. however it seems to make the car run crappy when its mixed with the gas ie less power etc. so i usually only use it when i go on long trips and burn through that tank of gas asap!

[dzenno]

Why not pull those plugs and post a pic again to compare?

[marv85]

Originally Posted by dzenno

Why not pull those plugs and post a pic again to compare?

+1 that would be very helpful

[Stucks]

So this is the stuff you used?


http://shop.advanceautoparts.com/web...ci_sku=7081073

[AhmEd_B_Stylin]

Need to give it a a try ASAP

[Zeph]

I use Redline fuel injector cleaner every so often. Good stuff.

... Lucas Oil makes a good one too.

[michaelalex17]

techron FTW!!!

[Express]

im wondering if i should give this a shot..

[michaelalex17]

Originally Posted by express705

im wondering if i should give this a shot..

do it, its great

[Express]

i guess it cant hurt.. whats the worst thing that happens? i lose a few bucks?

[GeorgiaTech335coupe]

When people talking about Techron not being effective on this platform, they are talking about its effects on cleaning the intake valves. The intake valves will never see fuel or Techron which cleans them.

It could be possible that the Techron is slighltly cleaning a clogged injector nozzle or maybe washing the plug from carbon prior to combustion. Although, the time it would have to do this would be very, very small.

[kjrulz]

I don't have one in my area....I don't think I can get the deal online...I don't see how at least...wack

[max]

Like the OP, I'm a long term believer in Techron, good to hear it also works for DI injectors.

[wren57]

Originally Posted by GeorgiaTech335coupe

When people talking about Techron not being effective on this platform, they are talking about its effects on cleaning the intake valves. The intake valves will never see fuel or Techron which cleans them.

It could be possible that the Techron is slighltly cleaning a clogged injector nozzle or maybe washing the plug from carbon prior to combustion. Although, the time it would have to do this would be very, very small.

+ a lot.

[Syndicategt]

Originally Posted by kjrulz

I don't have one in my area....I don't think I can get the deal online...I don't see how at least...wack

You can buy this stuff anywhere (Autozone, O'rileys, PepBoys, Walmart, Target....)

I've used it in the past, seems to help the injectors....definately can't hurt them and for $10 you can't go wrong. I always do this right before an oil change though, since it is a fuel additive it's recommended you change your oil afterwards.

I'm getting my hands dirty this weekend and doing a deep scrub of my intake mani and valves

[C4sF80M3]

If you want to clean the intake valves, jut pull the vacuum line going to the recircs, get yourself about 4-5ft of vacuum tubing and an inline connector, buy some Throttle Body Cleaner, use the straw attachment, and spray it into hose with short bursts with the car running and your foot on the gas holding the engine at a steady 3k rpms. Each time you spray the RPMs will dip a bit, and wait for the engine to stabilize before spraying again. This process will take some time to go through a whole bottle of cleaner. This method works very effectively on removing gunk from the intake plenum and the valves. Just make sure that whatever type of TB or Carb cleaner you use says that it is safe for Oxygen Sensors. Most are these days, but double check.

[Syndicategt]

^ Sorry but carb cleaner alone will not clean all that carbon build-up off.....you need to SCRUB!

[C4sF80M3]

Correct it will not remove all of it, but it does work well in removing a good bit of it, especially if done regularly.

The best way of course is media blasting, but that's a bit more involved for most here.

Originally Posted by Syndicategt

^ Sorry but carb cleaner alone will not clean all that carbon build-up off.....you need to SCRUB!

[Bakeme521]

I actually over heard a tech yesterday telling a customer to put this stuff in their 335is when I was at the stealer. I guess I will have to give it a try bc my idle bounces quite a bit.

[Clarkson]

Has anyone tried Motorvac on the 335 yet? I'm not sure if it works on DI but I have read good things about it... Just never tried it.

[etichi]

How frequently?

Every month? Every couple of months? Every time I fill up?