Cleaning K-jet components

[Bitsyncmaster]

While playing with my rest pressure I ran across many vendors offering cleaning of cold start valves, injectors and frequency valves. I was thinking of what would work for cleaning these components since they are sealed and can not be taken apart. I would not think ultrasonic would not do anything as far as cleaning the inside. It's just sound waves that can not pass though the metal case.

I would think forcing a solvent (acetone or MEK) under pressure while the valve is operating is the only way. The flow could be both ways.

You also should run and record test data of before and after cleaning so the customer could see the improvement. Do any vendors do this?

[Rich]

Very few shops offer cleaning of CIS (including K-Jet) injectors. They cannot be reverse-flow cleaned because of their design.

There's at least one shop that offers to (sort of?) clean them. You can read about their approach here (https://jaguarfuelinjectorservice.com/CIS%20Injector%20Cleaning%20Testing%20Service.htm) .

They start with two ultrasonic methods. Their last-ditch 3rd level cleaning involves an internal solvent-soak followed by a compressed air flush, possibly in several rounds if needed. I have no experience with this shop.

I had my 6 injectors flow tested (not cleaned) at this shop (https://injectorrepair.com/faqs/) about 10 yrs ago. You can see in their FAQ this shop doesn't clean CIS injectors.

[Bitsyncmaster]

Very few shops offer cleaning of CIS (including K-Jet) injectors. They cannot be reverse-flow cleaned because of their design.

There's at least one shop that offers to (sort of?) clean them. You can read about their approach here (https://jaguarfuelinjectorservice.com/CIS%20Injector%20Cleaning%20Testing%20Service.htm) .

They start with two ultrasonic methods. Their last-ditch 3rd level cleaning involves an internal solvent-soak followed by a compressed air flush, possibly in several rounds if needed. I have no experience with this shop.

I had my 6 injectors flow tested (not cleaned) at this shop (https://injectorrepair.com/faqs/) about 10 yrs ago. You can see in their FAQ this shop doesn't clean CIS injectors.

Thanks for that info and link. Sounds like an honest company not claiming the ultrasonic cleans the inside any. By the way, you can hold the pintle open on our injectors using a 40 AWG solid wire you stick in after lifting it with you finger nail.

[David T]

The vendors offer (or at least most of the them did) cleaning of the 6 fuel injectors. If you look in the Service Manual you will see an illustration of the cleaner and a procedure to check and clean the injectors. Once in a while you get an injector that won't clean up. Very important to use good, pliable injector seals or you get a lot of vacuum leakage and new copper crush washers so you don't have any fuel leaks. All an ultrasonic cleaner can do is pretty up the outsides. These are mechanical injectors with an internal spring loaded valve. What is important is that they open and close at the correct pressures and not leak when closed. Volvo dealers also have (had) these injector cleaners too. If you can't find anyone who can clean your injectors contact me directly. Make sure all six of your injectors have the same, proper part number on them. It's is getting harder and harder to find the proper fuel injectors, sources are "drying up".

[Timeless]

It's is getting harder and harder to find the proper fuel injectors, sources are "drying up".
I have no problem getting BOSCH injectors - in fact 1-2 arrival as well. When I was still K-Jet I got some to replace my 40+ year old units. Worked great.

https://www.amazon.com/dp/B00H2RO0QE?ref_=ppx_hzsearch_conn_dt_b_fed_asin_ti tle_7#averageCustomerReviewsAnchor

[Rich]

Odd coincidence as David T says reliable sources of these are drying up and then your handy link to an Amazon source says they have just one DMC injector left in stock.

I see Rock Auto still has them. Or something they claim is a legit Bosch DMC injector. And you can currently put 6 of them in your online cart.


I have no problem getting BOSCH injectors - in fact 1-2 arrival as well. When I was still K-Jet I got some to replace my 40+ year old units. Worked great.

https://www.amazon.com/dp/B00H2RO0QE?ref_=ppx_hzsearch_conn_dt_b_fed_asin_ti tle_7#averageCustomerReviewsAnchor

[Bitsyncmaster]

Have you seen the price of NOS frequency valves or cold start injectors? Have you seen the "rebuild" price of those? Same goes for fuel distributors, but those really can be rebuilt.

EFI guys can get a lot of money for those components they don't need any more,

[Timeless]

Odd coincidence as David T says reliable sources of these are drying up and then your handy link to an Amazon source says they have just one DMC injector left in stock.

I see Rock Auto still has them. Or something they claim is a legit Bosch DMC injector. And you can currently put 6 of them in your online cart.
It's changing by the hour. As of now it's showing 10 in stock. When I ordered the look to be legit BOSCH - box and all. Rock has always been good.

[David T]

It's changing by the hour. As of now it's showing 10 in stock. When I ordered the look to be legit BOSCH - box and all. Rock has always been good.

Just make sure they have the correct Bosch part number. It matters. While they may look the same and may even work, different numbers are for other applications and the opening/closing pressures and flow vary. The other thing is Bosch parts are now being made with much less quality than they used to be. You are better served by having your old ones cleaned and tested.

[Chris4099]

About 12 years ago a local owner's car wouldn't start anymore and it turned out she had let it sit so long the gas in it was over a year old. I checked the spray pattern and most had really bad patterns/streams. So I sent them off to John Hervey and he cleaned them. This was when you had to pay about $100 for each new injector. I think at the time he did the ultra sonic cleaning and then flushed with cleaner. Per his notes, they all tested to correct pressures and most had good patterns. The car ran fine again for the next 10 years. 2 years ago it wouldn't start again. When I checked the injectors, sure enough the patterns were bad and one injector had about half the volume of gas as some others. Since the injectors are so much cheaper now, I bought 1 from Amazon (same one linked to above, but only 1 in stock at the time) and 5 slightly more expensive ones from Rock Auto. The Amazon one was identical to the Rock Auto ones. I didn't test them after installing, but after performing a quick mixture adjustment, they have been running great.

I still have the original 44 year old injectors in my D. I haven't tested them, but my car runs really well and passes emissions tests with no issues. I just make sure to drive enough that the gas doesn't get too old and run a bottle of Techron through about once a year (along with running Top Tier rated fuel). But if I do eventually run into an injector issue, I'll just replace them. They are cheap enough now it's not worth the effort/risk of cleaning them.

[David T]

The Techron should clean up and/or keep your injectors clean. It is a good idea to run a bottle of it once a year. Best to put into a full tank and then go on a long drive. As for fuel, it is all the same now from every station, it all has to meet strict standards from the Federal Government. The K-Jet system is very reliable and rugged BUT, if you don't use the car regularly and let the fuel get old you WILL have problems. E-10 with Ethanol doesn't store well and will go bad a lot quicker than non-ethanol fuel. The other problem is letting the rubber get old and deteriorate and that causes vacuum leaks. If you don't use the car for a long period (over 6 months) the best strategy is to remove the fuel for storage. I now put Stabil into the fuel and drive the car before storing it and removing the fuel from the tank for the winter. You cannot get every drop of fuel out so I am hoping the Stabil will help preserve what is left in the lines, injectors, hoses, and the rest of the fuel system.