Gas mileage decrease after injector cleaning...

[jwagner]

but how many times do you actually see a shop with one? most that ive seen is a bottle of cleaner or an injector R&R. (both way faster for the shop)
-granted i didnt call every shop in sea. but when i did mine i had to find a "dr.injector" franchisee (or what ever) was at a tranny shop in kirkland.

 

[bamachem]

You probably just got a bottle of B&G 44K shot in a vacuum line and a bottle added to your gas tank.

Seriously... For that price, that's all you got. Maybe even a couple cans of seafoam instead of B&G 44K.

However, it shouldn't run rough. If the above is true, then you've probably got a loose vacuum hose.

Allowing the tech that made the potential mistake to review his own work is NOT QUALITY CONTROL when an unhappy customer returns.

They need to get a senior tech involved and tell you why it's now running rough and you lost MPG's after they serviced the truck. Oh, and this should be complimnetary since it is apparently their mistake to begin with...

 

[ThirdShore]

Just trying all the different possibilities...I put it in neutral the other day, and revved the engine up to about 2000-3000 RPMs, and there seemed to be some vibration/humming at those rates. I haven't really tried this when I wasn't concerned with the way the it's running, so don't know if this is normal.

Does this mean anything at all, and could it be related?

 

[86tuning]

There are 3 types of 'fuel injector service' that are popular.

1. in-tank cleaner
2. thru the fuel rail cleaner
3. intake de-carbon service

the fourth is to r&r the injectors then send them for ultrasonic cleaning. This takes a day or two, and is not done except in extreme cases. Race cars, or cars where injectors are difficult to source, or extremely expensive. Sometimes a car that's stored for a few years can have blocked injectors, and this type of cleaning is really the only logical choice.

1. in-tank cleaner charges at the dealer are usually about $15

2. fuel-rail cleaning is $100-200 depending on the vehice and access to the fuel rail. The fuel pump is disabled and a flush machine is hooked up to the fuel rail. A 'special' cleaning solution runs thru the injectors with the engine running. This also helps scrub the intake valves somewhat, and may help with carbon buildup on the piston tops. Often includes the in-tank cleaner (#1 above) as part of the service. This is likely what was paid for.

3. not gonna get into this one, depends on how thorough etc. throttlebody cleaning also falls into this category.

As for the mileage decrease, I cannot comment as I've never tracked fuel mileage before/after on any customers cars. The vehicle usually runs better though, with noticeably smoother idle.

YMMV

 

[bluejack]

I would raise a little hell to at least find out exactly what you paid for and definitely talk to the highest guy on the totem pole to see if you can get some answers.

 

[ThirdShore]

Yeah, I definitely plan on getting it figured out one of these days.

I would expect a cleaner injector to cause things to run more efficiently. I run premium fuel, and now it feels like when I'm running 87 octane instead. There's got to be some underlying cause.

 

[jwagner]

maybe the cleaner gunked the fuel filter? only thing i can think of. its cheap and super easy to replace.

 

[ThirdShore]

2. fuel-rail cleaning is $100-200 depending on the vehice and access to the fuel rail. The fuel pump is disabled and a flush machine is hooked up to the fuel rail. A 'special' cleaning solution runs thru the injectors with the engine running. This also helps scrub the intake valves somewhat, and may help with carbon buildup on the piston tops. Often includes the in-tank cleaner (#1 above) as part of the service. This is likely what was paid for.

After giving the engine over 2 months and 2,500 miles to "adjust", I called the dealership today and this is how the service advisor described the process. I'm bringing it in again on monday for them to check. To my knowledge, no DTCs have been thrown, but it still just feels like it takes a lot more to get up to speed, and even to cruise.

Is it possible to damage the fuel injectors and cause a fuel leak or other inefficient delivery of fuel through this procedure? Anything else I need to be mindful of that could be causing this? I've seen over a 10% drop in fuel economy since it's been done (just looking out for my two kittens, don't really care about the rest).

 

[ThirdShore]

For everyone that was glued to their seats waiting for a resolution to this issue, after 3,500 miles it seems to have returned to my normal. All that it took was a tank of Chevron Supreme with Techron.

I don't know if it was the Techron that ended up degunking something or what, but the MPG is right back to where it was before the injector cleaning.

 

[OregonLC]

For everyone that was glued to their seats waiting for a resolution to this issue, after 3,500 miles it seems to have returned to my normal. All that it took was a tank of Chevron Supreme with Techron.

I don't know if it was the Techron that ended up degunking something or what, but the MPG is right back to where it was before the injector cleaning.

Had you been running 92 before, just not with Chevron?

 

[ThirdShore]

Yeah, I'd been running Supreme prior (91 where I am), but not with Chevron. There aren't too many Chevron's around where I live. I usually use Shell. It still seems as if it sucks gas down than before to get up to speed, but at a constant speed seems to have improved back to an acceptable level.

I've noticed a tear in the plastic connection of the air intake assembly to the engine. It still appears to fit snugly in place, but I'm now wondering if this is enough to let a little extra air slip through, and have a negative effect???

 

[OregonLC]

That definitely could be the source of your problem. If any air is coming in downstream of the MAS then it's going to throw off your mixture. My guess is that the O2 sensors are enriching the mixture to compensate, perhaps in open loop mode.

I wonder if your shop tore it when doing the last work?

 

[ThirdShore]

Yeah, I was wondering the same. I don't know how else it'd get torn. I've also noticed a screw was left off of the assembly that holds the intake in place on the engine...it just seems to me that they do sloppy work.

Thanks for the help, I guess I'll check to see if they'll take any responsibility for the tear, but I'm assuming I may be replacing it out of pocket if I want to see if that's the issue.