Check for Leaking Injector?

[actionstan]

Hello All,

I have a 2013 KIA Forte with 20,000 miles, I am running 7500 mile OCI with synthetic oil PP/Mobil 1.

Last time I changed the oil I noticed a terribly strong (what seemed like) gas smell when I drained the oil. The car is driven 30 miles twice a day, to and from work by my wife, almost 100% interstate miles. On the weekend it is our errand runner, its possible it may sit and idle while I run into a store to grab something, and my wife and kid stay behind in the car.. it also may see some short trips on the weekend, but I feel any fuel dilution should be burned out easily during the work week. Also I should mention that the car runs perfect, and usually gets 30mpg, give or take a little.

I have considered just doing a used oil analysis to see if there is excess fuel dilution, however I am currently not in a financial place to do so, also I have seen many question the correctness of Blackstone's results.

So at this point I would like to handle this from the mechanical side, I feel the only way I am getting excess fuel dilution(if I am) is if one of the injectors is leaking. Upon my reading most people recommend taking the fuel rail out of the car, and pressurizing the injectors by turning the key to the "on" position, but not actually starting the car.

My question, Is it possible to check for a leaky injector without removing the fuel rail/injectors from the car? Can I check it with a fuel pressure gauge anyway? If I found out the Injectors are not leaking I think I can stop worrying since this car sees such long trips.

Let me know your thoughts, thanks!

 

[Oldmoparguy1]

Sure sounds like fuel contamination. That's not good for your rings/cylinders. I would see the dealer for warranty service.

Good luck,

Wayne

 

[SatinSilver]

Here you go:

http://www.forteforums.com/forums/kia-fo...-smell-oil.html

 

[actionstan]

Originally Posted By: satinsilver
Here you go:

http://www.forteforums.com/forums/kia-fo...-smell-oil.html



Hahah that is my thread on the forte forums, they basically all told me to get a used oil analysis, when I am looking for a mechanical approach.(Many question Blackstones accuracy especially with the way they test fuel dilution, and it does not appear wix offers fuel dilution on there used oil analysis)

The car is mainly taken on long trips, so the only way I can imagine fuel dilution is a leaky injector. The only way I know to test a leaky injector is by pulling the injector connected to the fuel rail, and pressurizing the system.

I would prefer to avoid pulling the injectors.. and was just curious if its possible to test the injectors with a fuel pressure gauge.

 

[Virtuoso]

I would do a used oil analysis first, before pulling your injectors out.

 

[Trav]

A leaking injector will cause the ecm to lean the mixture on all injectors on the bank monitored by an O2 sensor. On a 4 cyl all 4 on a V engine the affected bank.

If it adds or subtracts too much it will trigger a CEL
Its common in cold weather to get a strong fuel smell from the oil in some engines as they can run very rich for a short time at cold start.
Letting the engine idle to warm up the car further increases this rich running period.

 

[actionstan]

Originally Posted By: Trav
A leaking injector will cause the ecm to lean the mixture on all injectors on the bank monitored by an O2 sensor. On a 4 cyl all 4 on a V engine the affected bank.

If it adds or subtracts too much it will trigger a CEL
Its common in cold weather to get a strong fuel smell from the oil in some engines as they can run very rich for a short time at cold start.
Letting the engine idle to warm up the car further increases this rich running period.


Thanks, It sounds like I shouldn't worry about a leaking injector unless I get a CEL. I wonder, even if the fuel is burned off, on a long trip, does it typically leave behind a smell?

Also is it possible a injector could leak after shut-off, but work properly during normal operation? OR typically if they leak, they leak 100% of the time? Which should also cause rough running?

 

[Trav]

A certain amount of the fuel will burn off but not all, the oil is diluted, yes it leaves a smell to the oil.
Is this direct injection?

Edit: A leaky injector will leak 100% of the time its under pressure.

 

[92saturnsl2]

If you have an Android phone, buy a $15 OBD-II Bluetooth adapter and the $5 Torque Pro app.

Monitoring the ECU's fuel trims will tell you what you need to know. If the oxygen sensor sees a rich mixture (through a leaking injector or other such problem), the ECU pulls fuel to maintain low emissions. This fuel taken away shows up as a negative fuel trim. The CEL won't light until the fuel trim passes a certain threshold-- by the time a CEL is set, there's almost always driveability issues, stumbling, misfires, etc.

If there's a slight leak, the ECU will simply lean out the other cylinders to compensate, which will often times invite spark knock, which reduces performance through the ECU retarding timing. You can monitor spark knock and ignition timing in real time as well with the Torque app.

Few things are as valuable as a scan tool with real time sensor data at your fingertips. It also reads & clears codes and a host of other things. That said, I really don't think you have any problems, judging by your description and lack of symptoms.

I don't consider oil smell to be a valid indicator of fuel dilution as there are too many variables, and it's oil inside an internal combustion engine after all-- it's exposed to blow by, fuel byproducts, etc. I've always felt that used oil on a normal engine has a sort of fuel smell to it; completely normal IMO.

 

[actionstan]

Originally Posted By: Trav
A certain amount of the fuel will burn off but not all, the oil is diluted, yes it leaves a smell to the oil.
Is this direct injection?

Edit: A leaky injector will leak 100% of the time its under pressure.


No this car is normal MPI.

 

[TFB1]

If pressure remains on the fuel rail after shutdown the injector(s) are not leaking... If they were usually cranking would be longer when cold and possibly have a flooded cylinder on a hot restart...

Likely you'd have a CEL if there were really a problem...

 

[KrisZ]

On such a new car, chances of having a leaky injector are slim to none. Also, since the car is under warranty, doing a used oil analysis or monitoring fuel trim via torque app is a much better idea than messing with the fuel system or hooking up a fuel pressure gauge.