fuel injector cleaner

[pat q]

Would a Shell fuel injector head cleaner liquid product work for
an 86' 560 SL. It has 291,000 miles but the motor was reconditiion at 250,000 and it's running well.
With warm wether, I have noticed slight hesitation when the acelerator is pressed to start moving. Will this cleaner work

[slsmag]

The ONLY fuel injector cleaner that I have found to work well is TECHRON (made by Chevron). Make sure you get the conentrate, not the cheap stuff... the concentrate runs anywhere from $5 to $8 a bottle.

The first time you use it it, when your tank is ready for a fill-up, pour the bottle in and THEN fill-up with about 10 gallon. On subsequent uses (like every other or every third or fourth fill-up, you can fill the tank to normal.

With regular use it will keep your injectors from clogging... and if you're currently getting sluggish performance on take-off's (hesitation), unless an injector is damaged (or the problem is elsewhere) you will see a huge improvement.

(PS Another common cause for hesitation is a filthy air filter - easily checked and remedied!)

- michael

[maheath]

Every mechanic I've talked to only recommends Techron. But there are a few different products. Look at http://www.chevron.com/prodserv/nafl/auto/content/fueladd.shtm for a description of the products.

The Pro-Guard Fuel Injector Cleaner is sold at Costco, ~$10 for 4 bottles. I've only seen the Concentrate Fuel System Cleaner at auto parts stores, $8-$10 per bottle.

[cbdo]

An additional point with Techron (or any similar product, really), is that if you use it in higher concentration, eg with less gas, you get a stronger cleaning effect but should change oil just afterwards. Sometimes there may be some leakthrough into the oil with all that grunge-dissolving going on!

[pat q]

Thanks for your recommendation Michael !

I used the Chevron product today and I already can see the difference. The car is running much smoother and there is no hesitation. Should I change the oil soon??

[slsmag]

Originally posted by pat q
I used the Chevron product today and I already can see the difference. The car is running much smoother and there is no hesitation. Should I change the oil soon??

Hi Pat -

The concentrate really is good stuff... I'm glad it's working for you. After that initial use, if the acceleration has smoothed out and the car is both idling and responding as it should, remember to add a bottle before fill-up on a somewhat regular basis... once every 3,000 miles or so should be fine.

Since the stuff is added to the fuel the only opportunity it would ever have to mix with oil is if you're experiencing ring failure now (and finding fuel in the oil)... otherwise it gets combusted in the cylinder with the fuel - so I wouldn't worry about doing an oil change unless it's time for one anyway.

If you're using dino oil instead of synthetic oil then your oil change interval will coincide with the 'regular use schedule' of Techron (3,000 miles) so it wouldn't be a bad practice to run a tank of gas with Techron right before you're do for the oil change... it would be an easy way to remember to do both.

Also, if you find that your injectors are clogging up again quickly (say, within 500 miles) you might seriously consider pulling the fuel rails and sending the injectors out for cleaning and inspection:

Marren Motor Sports
49 Burtville Ave., Unit 3A
Derby, CT 06418
Phone: (203) 732-4565
http://www.injector.com/
(they charge around $25/injector)

or

B & D Fuel Injection Service, Inc.
4800 Stamp Road
Temple Hills, MD 20748
Local: 301-899-1626 Fax: 301-899-2051
Toll Free: 1-800-603-1626
E-mail: info@dieselpump.com
http://www.dieselpump.com/
(they charge around $15/injector)
http://www.dieselpump.com/

- michael

[cbdo]

Pat,
Mike's points well taken and logical. Search this site on Techron and you'll get a number of hits. Some have suggested that if you use a higher-concentration approach, say 5-6 gallons of gas rather than 10-12, there may be some improvement in cleaning due to the higher concentration of solvent, but there's also an increase in the amount of cleaner that may get past the rings even though unadulterated gas doesn't. That's the rationale advanced for changing oil afterwards.
No particular expertise on my part--just the messenger!

[slsmag]

Originally posted by cbdo
Some have suggested that if you use a higher-concentration approach, say 5-6 gallons of gas rather than 10-12,

Personally, I would not use a full bottle of Techron concentrate with less than 8 - 10 gallons of fuel. That's already using it at a higher concentration than reccommended (full tank).

Mixing with only 5 gallons could indeed do some damage to other seals in the fuel system: remember, from the tank the fuel mixture and fumes will pass through the fuel filter, the emissions control shut-off valves, the fuel accumulator and charcoal cannister, the fuel rails, the injector connections - and all of their related assemblies and connectors - not just the combustion chambers. Start breaking down those seals and you'll be dealing with one headache after another.

While a higher concentration won't hurt the rings, it will remove any carbon that has built up on them which *may* be what is covering up a faulty ring already - so a good cleaning could, theoretically, expose some wear and tear that wasn't rearing its ugly head before cleaning.

That's why I suggest just a slightly higher concentration on the first use ONLY... then following the instructions for use in all future applications.

(I should practice what I preach... tight now I am buying time on my Q45 by using a bottle every 1000 miles instead of having the injectors pulled and cleaned!)

- michael

Try running a search for "BK44", works much better than most anything out there.