Possible Fuel Injector Issue

Had to take the work Tacoma in to the dealer today for it's first true issue. 2013 with 65,000 miles and I've been having rough cold starts, surging cold idle, terrible throttle response, stumbling during acceleration when cold, terrible fuel economy and diesel level soot buildup. Today I noticed a puff of dark gray smoke on the second cold start and the oil level is significantly higher than the last time I checked and smells of gas. Best guess is a stuck injector or two.

I haven't heard of any real injector issues on the forum so I thought I'd start this thread to document symptoms and the eventual fix for anyone else down the road.

Picture for the hell of it.

 

All pretty much classic symptoms with emphasis on the oil level and gasoline smell. Injector leakage is a very real possibility. At least there was no hydro-lock. Keep us updated.

I have to add this, that it is extremely rare for an engine to get 65K Miles on a defective injector. Saying that most if not all leaking injectors are due to internal contamination from manufacturing and not from any external source. It usually occurs within a very few miles say less than 1000.

 

So I called the dealer. The techs have been poking around and test driving and although they can tell something is wrong (bouncing idle, puff of smoke on startup), the truck is not throwing any codes and TechStream isn't giving them any good info. Looks like I'll be rolling the spare 2005 Colorado for the rest of the weekend.

 

Well, Sierra Toyota Lancaster can burn in hell. Their people noticed all of the issues I complained about, but because their precious and magical TechStream didn't record any abnormal data, they kicked the truck back to me without making any repairs or recommendations. At least they didn't charge me diagnostic fees. They did have the nerve to tell me that the oil level was fine and didn't smell like anything was wrong.

This morning, after not driving the truck for a few days, I checked the dipstick and the oil was as far over the top dimple as the distance from the bottom of the stick to the top dimple. I drained out a full GALLON of oil that was as thin as water and smelled like 2 stroke mix, and the dipstick now reads just a mm or two over the top dimple. Looks like I'll be taking it to a mom and pop shop that will actually diagnose by looking at each injector (should be obvious which one's bad by a quick visual).

 

Dealers...unbelievable! Reason why I avoid them when at all possible. They should have never let that vehicle leave without a proper diagnosis and repair. Unbelievable!!

 

Pull each injector out, rig up an easy injector test and without power applied to the injector and see which one leaks.

https://www.youtube.com/watch?v=zlO4krw2h8o

 

If it was my own personal truck I'd be all over it, but I'm really not supposed to be wrenching on the state vehicle, primarily for union reasons (doesn't mean I haven't done it in the past).

 

The mom and pop shop was also unable to find anything specifically wrong. They checked each injector and none are leaking. The emissions sniffer doesn't show any abnormal exhaust gasses, even on startup before the catalytic converters heat up. There are no trouble codes, not even pending. Something is still wrong with the truck. I took the below video this morning on the cold start. Note the bouncing idle before I put it in gear (A/C is not on), then notice the throttle surge and near stall as I try to drive it with steady throttle, I was not pulsing the gas pedal.

 

MAF sensor??

 

I was gonna say, sounds like a bad TB. Given that these trucks are all fly by wire, hence no idle air control valve, the bouncing idle would be directly related to a bad TB.

 

I was thinking next thing on my list to try is cleaning the TB and MAF myself. It's possible that this is all a culmination of multiple issues. The mom and pop shop did find the injector on #6 had the wire insulation boot shifted and was possibly allowing the wires to touch. If they were touching and causing the injector to run constantly with engine on, it would have filled and diluted the engine oil, the thinner engine oil could have increased deposits in the throttle body and PCV, which could have gummed up the whole works and caused the throttle response/idle issue. Maybe...

 

Plot twist! I now know why neither the Toyota dealership nor the mom and pop shop charged me diagnostic fees...they didn't actually take anything apart! I started removing the air filter housing and intake resonator and noticed that they were still covered in dust...with no fingerprints or signs of being moved. The bolts and vacuum lines were also still caked in pristine dust. I was under the impression you could not possible get to the injectors without removing the upper intake manifold, so either they had some fancy trick or they never actually looked at the injectors.

Anyway, upon inspection, the MAF/IAT sensors were absolutely filthy and the throttle body had mild to moderate grunge buildup. I cleaned everything and reassembled and now the truck, so far, idles and accelerates smoothly as it should. I'll keep an eye on everything for now.

I have to wonder, would a dirty MAF/IAT/TB really cause the truck to run so rich that it would cause all of the symptoms I noticed, including the fuel diluted oil? And if so, what caused the symptoms be be so acute? There was no degradation of performance until recently and the onset was very sudden.

 

No active codes and none pending. I believe I'm on the third air filter since I picked up the truck new, but it's still in good shape. I may pull it and look more closely, I've had pack rats chew holes in my personal Tacoma's air filter, causing me to stuff 1/2" wire mesh in the intake.