Cleaning fuel injectors

[Decolliber]

I suspect I may have some clogging in fuel injectors (88 Carrera). I ran a can of BG44K through the tank and the idle did improve somewhat. An Audi BB I frequent recommends a BG44K injector cleaning kit ($40 at my local Ford dealer). Has anyone tried this kit? Do you have to remove the whole fuel rail, or just the injectors, to use it? Would it be inadvisable for a neophyte to remove and attempt to clean injectors? Can you put compressed air from an air pump, through them?

[JDaniel]

Since your car uses Pulsed injection I don't think compressed air would do much good (other than remove surface debris... or possibly damage the injectors). They need to be chemically or sonicly (sp) cleaned.

I pulled mine last year and had them all professionaly flow tested, cleaned, and then re-tested. The cost was about $25 each. There are a few places online that do the service for about the same price. I can mail you the link if you want.

I'd suggest this route if you are sure there's clogging/flow problems. The removal proceedure is relatively easy, and the cost is minimal compared to total replacement.

------------------
Dan Tolley
1987 911 Coupe
http://www.cheaterswayside.com/911/gallery.asp?sort=0&userid=294

[canyonlands]

Dan,

Just curious but what was the result of your tests? Were any injectors clogged badly and what was the mileage on your car?

[stlrj]

The best way I found to clean them was to remove them, give the tips a good squirt of carburator cleaner, put them in a ziplock bag to soak overnight or longer and then put them back on.

I go through this at least once a year as part of my tuneup.

Oh yea, I found out about this trick from a GM Goodwrench tech, who really knew his stuff, back in the mid '80's when clogged injectors were a big thing.

Joe

[JDaniel]

The injector flow rates (pre-cleaning) differed by almost 10% (from lowest to highest). Most were within 5% of each other. I had one injector that was all gummed up.
After cleaning they were all within 2% of the same rate. They sent me a nice printout of the results.

Did I notice a difference?
Well, I seem to have several things going on that keep the car from running in tip top form. For now I'd say there is less "cold" stumble when first driving, and the rich condition I was suffering in #6 has apparently been cured. I also now know that the injectors are within spec of each other, and all operating as they should be.

oops, car had 56k miles when I sent the injectors off.

------------------
Dan Tolley
1987 911 Coupe
http://www.cheaterswayside.com/911/gallery.asp?sort=0&userid=294

[This message has been edited by JDaniel (edited 10-11-2001).]

[Victor]

Originally posted by JDaniel
......the removal proceedure is relatively easy, ...............

Hi Dan, I have checked around the archives to no avail. You wouldn't know if this procedure is documented online somewhere? I am thinking of ripping into this on the weekend.

[JDaniel]

I know of no online documentation, but it's pretty simple. Keep some rags handy to catch any spills, and use flare wrenches.

Remove snorkle side of air intake, remove heat tubing, unbolt a/c compressor and move out of the way, loosen and disconnect fuel rails on both sides (you should disconnect fuel pump beforehand), unclip electrical line from each injector (usually zip tied to fuel rail), pull straight up on fuel rail until injectors "pop" out (you can also disconnect the injectors one by one and pull them out individually.... but I found it easier to pull up on the rail).

This is the easy and short version typed under the influence of a good single malt.. if you would like pics or a better description send me a P.M.

[jluetjen]

I recently had my family-car's injectors done at Marren Fuel Injection in Connecticut. I've dealt with them in the past when I had the same service performed on my old ITB car. In both cases I've found Marren to be helpful with information - both before and after they cleaned my injectors, prompt (3 day turn) and reasonably priced at $25 per injector plus shipping. As part of their normal service they provide a before and after report of the injectors' performance so that you see how bad they were prior to service. I've found this very helpful in troubleshooting any drivability issues with the car.

BTW - I had run a bottle of Techron through the car prior to sending the injectors back and 2 of them were still out of spec prior to Marren working on them.

[JDaniel]

Mine were also done at Marren, but I think he could find something a bit closer to home.

[silver912e]

I sent my 25 year old injectors to this place, and they did a very nice job. They provide a before and after profile of your injector's performance:
http://www.rceng.com/service.htm

[CRH911S]

You can send your injectors to EBS or ANDIAL and they will clean them and test them. If the discrepency {flow} is too low or too great between any of the existing injectors I would consider new. You can purchase new injectors, matched, from EBS and they will assure you little to no discrepencies. I am considering this and planning to contact John Walker to see if he provides this service. Just my two cents 8)

Regards,
Clinton R Hodges II

[Mike Kast]

The best way I found to clean them was to remove them, give the tips a good squirt of carburator cleaner, put them in a ziplock bag to soak overnight or longer and then put them back on.

Is this a good idea for starters? I mean before I send them off. I think my injectors are fairly new, I have to check reciepts, but with all the nastyness I cleaned out of my fuel tank last month I'm thinking they need a cleaning.

[Sunroof]

Try a cheaper method first............
Chevron Techron (full big bottle) in 1/4 - 1/2 tank of high test. Try it twice, back to back to see if that cures the problem. Change the oil though within 500 miles of that kind of dosing. I only suggest this because when I had my 1985.5 944 for 12 years I got 345, 000 out of it with never having to remove the injectors or any major engine work. Chevron Techron was part of the diet on a routine basis and continues to be in all my cars. Many here swear by it as its successful when removing tenacious deposits. My 2 cents worth.


Bob
73.5T

2000 Mazda Miata
1998 Plymouth Voyager
1990 Plymouth Laser - rainy day car

[Mike Kast]

Thanks Bob,
I have run some through as per the instructions that said 1 bottle to 12 gallons of gas. I have heard about the change the oil soon after running it through, do you know why?
I am doing so much oil line and tank work right now I think I may change the oil fairly quickly this time just to flush it out. I may do it just before I change the oil again. I have changed the oil 3 times since march... with all the time its been being worked on I sure have driven it a lot since I got her...
I may clean the injectors with carb cleaner anyway while I have it all apart. Then one more dose of techron and if I'm still having the intermittent high RPM hesitation I'll send them out to be cleaned.

[Sunroof]

Mike.
The thing about Chevron Techron and the other cleaners is that they are petroleum ditillates that have a high flash point and do not burn in the combustion chamber. Rather it weeps past the rings after washing the cylinder and injector and makes its way to the oil sump. You can smell it on a dip stick and with cars that are water cooled and use less oil, the oil is definitely thinned down.

Years ago Porsche put out a bulletin advising those who use Techron to change oil within 500 miles of use as a precaution from weakening seals. When you consider that the 911 takes an average 10 quarts of oil, it would take alot of Techron to thin it down. I have been using it for many years and it can make a difference in performance.

You may want to get the gas down to 1/4 tank and add Techron and only fill the gas to less than half. Run it down and try it again. Thats when it does well to dissolve tenacious deposits. Its worth the effort to save on having them cleaned at a shop for starters.

Changing the oil within the recommended time is good insurance.

Good Luck

Bob

[Mike Kast]

Thank you sir!

[Speedy1]

My wrench at Bev Hills recommended 2 bottles of techron on ½ tank of the best fuel money can buy, just before a trip to see him for a tune up. He also changes the oil at that time regardless. A Union 76 station in town sells Racing fuel 103 Octane 4.99 per Gal. That’s a bit much for me but once in a wile I'll shoot it 20 bucks worth . I like to think that is what keeps her running great. Maybe not though.

[dd74]

Speedy - is that the Union 76 on San Vicente? Hmmm...though I swear I wouldn't, I might put in about 20 or 30 bucks worth again before my next Reseda dyno run.

[Speedy1]

dd74 I'm not sure of the cross st. but the main st is huntington dr. in san marino. sorry if that is too informative.