G35 Sedan V35 2003-06 Discussion about the 1st Generation V35 G35 Sedan

Fuel Injection Service - Recommended?

Old 02-20-2019, 04:34 PM
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Fuel Injection Service - Recommended?

Dealer is recommending performing a Fuel Injection Service on 2006 G35x because they found it not clean or contaminated or whatever they found - I am not sure how they worded it. Is this recommended or it will do more harm than good? And if I decided to do it, should I keep doing it at specific intervals?

Old 02-20-2019, 08:20 PM
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What was your car at the dealer for in the first place? They will always have something they "recommend" doing even if you're in for an oil change. First time I went to the dealer I got a book of recommended service worth thousands.
Fuel injection cleaning is not something considered preventative maintenance. Sounds more like busy work. If you're not having any issues then I wouldn't change anything
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Old 02-20-2019, 08:23 PM
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I'd like to know how they determined it was contaminated lol. Maybe they have a magic lens that lets them see inside an injector while it's still installed on the vehicle

Personally I wouldn't waste the time with a fuel injection system cleaning, it's a bit of a gimmick to be honest. Yes it can clean out SOME of the gunk that accumulates on a vehicle with just a PCV system but it's really designed more for vehicles that also have an EGR system sucking dirty exhaust soot into the intake plenum, the G35 doesn't use exhaust gas recirculation though.

If the vehicle has carbon deposits on the valves then yes it can help, I'm just going to assume that's what they're charging to clean since cleaning the injectors is literally as difficult as pouring a bottle of Seafoam into the gas tank.

Does your engine lack power, does it have a miss at idle, are your spark plugs new, do you have light pinging under full load? If you answered YES to ALL of those questions you may have dirty valves. If so then yes a Seafoam treatment will help fix the problem. However I don't recommend paying a shop $125 to do what almost every capable human on the planet can do for under $10. The method shown on this Nicoclub link:


is almost exactly what I do on my G35 except I pull the other end of the PCV hose on the plastic intake tube (the one directly under the throttle body on the driver valve cover) so it washes past the throttle body as well. I have my wife hold the throttle at 2500rpm and I suck the entire bottle, never tried to intentionally stall the engine with seafoam... that seems like maybe a bad idea but who knows?

I run 1 bottle of seafoam in the gas tank after every oil change on every vehicle I own, I'm also pretty good about getting 250k+ miles out of an engine, that's mostly due to doing oil changes on interval but I like to think the seafoam is what keeps the engines running GOOD during it's lifetime.

Fuel injectors however... wait until one fails and replace them all at once. As for paying a shop for the service, if you know for sure they're using Seafoam then there's probably no harm as long as they plug the vacuum lines back in but if they're using John's Proprietary Snake Oil Injection Cleaner™ then I personally wouldn't let them touch my car.
Old 02-20-2019, 08:28 PM
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Old 02-20-2019, 09:37 PM
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Interesting. I've heard of using the seafoam SPRAY on the intake through a vacuum line, but never the original liquid product. Only in the crank case and gas tank.

On top of that, I've heard about an equal amount of bad stories with seafoam in the crank case as I have good stories.
Old 02-20-2019, 10:48 PM
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I strongly suspect people using it in the crankcase are using the wrong ratio per quarts of crankcase oil, OR they don't respect oil change intervals and run the seafoam for far too long.

Personally I only use it for less than 1000 miles in the crankcase because it's going to break down faster and I run my engines fairly hard. I try to do my first oil change of.the year with seafoam and just drain/fill the crankcase after 1000 miles. Never been too concerned about changing the filter early because I don't use cheap filters.
Old 02-21-2019, 02:35 AM
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It's a scam if you want to do a fuel system cleaning just buy some BG44K off the Internet for like 20 bucks. You can use SeaFoam too, but it will smoke like crazy. I've used it once in my car to find exhaust leaks. I put a 1/3 in the tank, 1/3 in the crank (oil change couple hundred miles later), and the last third through the brake booster line sucked very slowly.
Old 02-22-2019, 09:01 AM
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I have had some injectors fail to the point that they have to go into the ultrasonic cleaner and get reverse flowed several times. They will spray weird and hit the sidewall because of contaminants clogging the holes. Sometimes they will stick open or closed too. But it's really hard to diagnose this without pulling all of the injectors and putting them in a flow test machine like we have at work.
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