Injectors Out - Lots of Carbon Buildup - How to Clean Internals?

pgilliam1

pgilliam1

Experienced Member
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I removed my fuel injectors to send them to RC Engineering. They were coated with black carbon buildup that easily wiped off. I was wondering if there was a way to clean the inside of the manifold without removing it (through the injector holes somehow :confused:)? I don't want to loosen a bunch of crud by shoving a rag soaked with cleaner into the holes. Just thought maybe someone came up with an ingenious method for this :rolleyes:.
 
May be the Sea Foam protocol (ie. throttle body, vacuum line, intake manifold, etc') can clean things up?

There are many insightful/informative & creative D.I.Y.'s online & on all/most automotive enthusiast forums w/ regards to Sea Foam - regardless the make/model. However, you'd need your fuel injectors in, as you have to run the product through while playing w/ the throttle.

Not sure how relevant/useful to us, but an inexpensive after-market oil catch can / breather-vapor bypass whatever can also help prevent or lessen future occurrence of the intake/throttle-body gunk. . .
 
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I would hate to run all that crud through my engine - the injectors were heavily coated with it so my manifold has to be the same. I just got off the phone with a guy who's done this before and he said taking the manifold off is the only way to clean inside it. Not what I wanted to hear, but what I needed to hear. I just hate doing it the first time and "learning" my way through it :confused:.
I've heard of Seafoam but never used it. What I've read sounded fairly positive though.
 
I just got my RC-cleaned oem injectors back this afternoon. They have 80k miles and 5 were Good spray pattern and 1 was Dripping. Avg. flow for all 6 was 239.8 cc/min.
This is AFTER I had 1/2 can of Seafoam in the tank and the other 1/2 sprayed into the TB slowly during idle.(to clean the intake carbon build up) and THEN an oil/filter change.

With RC cleaning, now they Avg. 250.2 cc/min and the spray pattern is Excellent of all 6. I am installing them tomorrow morning. Would I feel any difference with my butt dyno? probably not but at least they are working like they suppose to. This Dripping could be one of the reasons the car did not pass smog with my 2yr old Random cats but with OEM cats as my HC was high.

I used Seafoam on my high mileage Miata sprayed into the TB on a windy day slowly and created LOTS of white smoke. I have done this a few times and the car runs great still. There were no white smoke coming from the NSX @ 80k miles.
 
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I'm looking forward to my results from RC. My car i a 1991 and has 118K miles with plenty of them being 5 to 8 mpg track miles. Engine has no smoke and good compression but the injector o-rings were flat and I'm glad I took them out for a looksy. From other posts here I read where they become a fire hazard and even new injectors aren't balanced like what RC does.
Happy Motoring!
 
That's good to hear. I hope to have similiar results. Did you check your daily drive mpg's before and after? I would think this would help the mpg's, especially if the injectors were just dripping. Maybe just wishful thinking.
Thanks for posting and Happy Motoring!
 
pgilliam1 said:
That's good to hear. I hope to have similiar results. Did you check your daily drive mpg's before and after?

I avg. 25-26 mpg on my last tank b 4 the clean. 80/20 freeway/city.
I'll see what this tank would do. If anything else, it should help the smog test next time.
Click to expand...
 
I would recommend RC Engineering to anyone! I just installed my injectors after getting them back from RC and they look like new with all rubber parts replaced and new filters (actually they are better than new because they're balanced now). I had 2 that were "dripping" and the others weren't 100% either. The car starts much better now (it used to take 3 seconds to start from cold - now it fires right up). It seems smoother at all speeds, but that may just be psychological. An easy DIY and a comfort to know they won't leak and cause an engine fire :eek:. Happy Motoring!
 
I've got a spare set of injectors i'd like to have done.
What's the info on RC Engineering?
Cost for cleaning and flowing a set?
What's their address for shipping?

Cheers
nigel
 
I used WitchHunter instead of RC Engineering. I've used RC Engineering in the past, and both do the same - just WitchHunter was ~$40 cheaper total. You can put that $40 towards the freaking fuel rail crush washers :eek:
http://www.witchhunter.com/injectorserv1.php4

To be clear - I didn't have any problems with driveability before these were serviced. I just had some downtime on the daily driver to take advantage of and thought it was good preventative maintenance to have the o-rings replaced. Also, with a '92 and 110k on the clock, it couldn't hurt to have them cleaned!

One of the injectors was reading 10% lower flow than the others pre-cleaning. After cleaning, they were all close to each other with good spray patterns (a subjective test). So, it was an expensive exercise, but the peace of mind (new rubbers and they are all matched) is worth it. Your results may vary of course. The engine seemed to run a little smoother with them cleaned. The effect is kinda like replacing your spark plugs with new ones.

Be prepared for the fuel rail crush washer price shock at your Honda dealer! I need to start a business making those things....

I used Danoland's website and the service manual for the procedure - worked great! Work in a well-ventilated area with no ignition sources, and disconnect the battery. I think the service manual says to remove the fuel line from the fuel filter, but I didn't need to do that if you've depressurized from the gas cap. Now would be a good time to do the filter to unless you don't need to. There's a bunch of fuel in the lines though so be careful removing them.

Other than that, it was basically just following Danoland's guidance. Pretty easy job.

Dave
 
pgilliam1 said:
I removed my fuel injectors to send them to RC Engineering. They were coated with black carbon buildup that easily wiped off. I was wondering if there was a way to clean the inside of the manifold without removing it (through the injector holes somehow :confused:)? I don't want to loosen a bunch of crud by shoving a rag soaked with cleaner into the holes. Just thought maybe someone came up with an ingenious method for this :rolleyes:.
Click to expand...

Unless excessive, it shouldn't have any impact on engine performance. In fact, a smooth coating of crud throughout the intake manifold is actually beneficial to smooth out the rough casting. You basically get extrude-honed performance for free :biggrin:

Dave

P.S. Just be glad you don't have all the valve crud buildup issues that the DI engines are having now (especially Audi). Running normal engine cleaner additives through your gas tank is ineffective since the fuel is directly injected into the cylinders - it doesn't flow around the intake valves to clean them before entering the combustion chamber. Pretty wild. It's amazing this wasn't noticed during development.
 
You can easily pull the injectors without removing any of the fuel lines and avoid the crush washer replacement.
RC charged me $166 including shipping. It takes them about a day to do the work and they ship them back the next day with a detailed before and after summary. The injectors are better than what you can buy new when you get them back. A real person will answer your calls and they have the answers. All their info can be found at: rceng.com. I was very impressed.
Happy Motoring!
 
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Mac Attack said:
P.S. Just be glad you don't have all the valve crud buildup issues that the DI engines are having now (especially Audi). Running normal engine cleaner additives through your gas tank is ineffective since the fuel is directly injected into the cylinders - it doesn't flow around the intake valves to clean them before entering the combustion chamber. Pretty wild. It's amazing this wasn't noticed during development.
Click to expand...

I have heard the same thing about DI. Just when you think you have the "next best thing" it turns out to be the "next worst thing".
Happy Motoring!
 
+1 on RC Engineering. I sent in a low mileage set and had them done. My tech installed them last weekend. The o-rings were pretty flat on my original ones so I am glad I had them done.
 
FWIW, I filled the car today and I got almost 30 more miles per tank compare to before the injector clean. The engine does sound smoother at freeway steady state. I am so glad I had them cleaned and flowed by RC. Well worth it.
 

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