RB25DET Neo - bad smell after changing spark plugs

[sledgehammer]

Hi all,

recently I changed my spark plugs. Went from heat range 6 to 7 as the previous ones were white (running too hot). Not sure why though, because the engine is stock. 

A days of driving later I noticed a bad smell coming from outside when the window is opened. Only while I drive over 60kmh. If the window is closed there is no smell at all, also not from the A/C. So my guess is that it's either because of the ignition or spark plugs.. or the catalyst. Or maybe both? From what I know is that defect spark plugs can damage the cat. On the other hand the car is running fine, no misfire, etc. Only that bad smell. 

Anyone had this before? Could it also be something else? 

Thanks!

[KiwiRS4T]

Maybe something is causing your car to run lean?

[tridentt150v]

Maybe somebody hates you and has poured milk down the front of your windscreen???

[GTSBoy]

Almost certainly running lean & therefore very hot EGTs. The hot exhaust makes the dump pipe overheat the firewall & air-con hoses etc around that part of the engine bay and it stinks.

[sledgehammer]

Thanks all. What could cause the car running lean? I may use the search function for that

[Slap]

Check nothing came unpluged or disconected when the plugs were done.
It doesnt take much.
A vacum leak, a disconected sensor or plug.

Doughtful but If the old plugs were shagged the long term trims may be out badly. If its a stock ecu do a hard wire reset to see if it helps.

[sledgehammer]

Thanks, I'm gonna have a look that everything is connected.
Could it also be caused by a boost leak? The turbo makes a high pitched sound when boosted but I'm not sure wether it's the old ceramic turbo or a leak. Also on my list of things to check. 

How about the fuel pump?

[Slap]

Arhg! I hope the turbine wheel isnt scraping the housing inlet. Turbo rebuild time if so and i wouldnt drive it like that..
Check if the turbine can pull back to the entry and see if its hitting.
A boost leak usualy causes richer than normal but still possible to throw shit out of wack.

[sledgehammer]

Then that's the first thing I'm gonna do. Just to be sure. The boost noise is there since I bought the car a year ago. So I believe it's just the bearings or a leak. If hitting, then it would be long dead I guess. First time turbo removal for me, that's gonna be fun. 

After that: Check all connections, other leaks, sensor, catalyst, change fuel filter and maybe fuel pump.

[Slap]

You dont need to remove the turbo. Just the intake pipe to it. So you can see the turbine propeller. If the shaft moves to far toward the inlet where the pipe came off it can scrape.
You been on stock boost so it may last a year.

[sledgehammer]

Even better if I don't have to take out the whole turbo. I'm gonna post the result here once I'm done. 

[sledgehammer]

Turbo seems fine. No scraping, shaft play minimal up and down, not horziontal. In and out a very very little. Feels like 0.5 mm. But again, I can't make it scrap by hand. My guess is that the whining  noise is coming from the bearing or some boost leak. 

[sledgehammer]

Here a photo of the turbo. 

Something bad that happened when I tried to remove a porous hose. The very small pipe of the breather pipe broke off (see photos). So thats something to fix now somehow.

 

[sledgehammer]

Uh, I guess I found the reason for the boost leak. Bolt was almost out completely. Turbocharger to manifold. The other bolts were lose too. I hope the gasket is fine.

Edited May 10, 2019 by sledgehammer

[Slap]

That bolt loose shouldnt cause a boost leak. Maybe a zorst leak.... wich may cause the fuel ratios to be read wrong by the 02 sensor and changing the part throttle fuel trims.

 

On the bright side the turbine prop looks ok. Is that a bit of grease on the fins?

 

Bit of rubber hose is easy to replace dont stress. It may have been perished anyway.

 

Hmmmmm tighten up the bolt and see if it helps.

 

If that turbo is highflowed and on low boost it may be a bit loud from the waste gate working harder to keep boost down.

 

I have never heard of spark plug temps causing such an issue with smell. The way you described it. Could it be wiring? Just maybe load for the plugs is making things hot~???

 

Maybe someone will chime in soon that has had a similar issue

 

 

[Slap]

Sorry to be a sad sack but.

If a car is pinging badly on boost the noise can be high pitch (not a whistle but similar) and it will eat itself from the inside. If the plugs are white that means lean...lean on boost means pinging due to less timming , heat and pressure is needed to ignite and will have increased temps leading to detonation from heat induced pre ignition.

Id be checking the fuel filter , fuel pressure , flow and regulator.

Were any old plugs different color to the others?

There is so many things that can cause a lean condition and so many driving occasions that things can occur at.
Research a lot.
Asking doesnt always help.
If your mech or tech happy you should be fine to figure this out. Otherwise take it where it can be tested and diagnosed.

From... un metered air - undelivered fuel- incorrect timming.

Un metered air-
breathing post maf pre turbo, unpluged , dirty or dead maf.

Undelivered fuel-
pump (bad flow/dead), ecu(control/tune), injectors(dirty/loose conection/dead) , filter (blocked) ,sender (can cause bad flow not switching 9v idle-12v throttle), maf(dirty/dead/unpluged) ,fuel regulator(should rise 1-1 with boost),
O2 sensor(part throttle and boost transition lean condition)

Timing out-
Tune, incorrect maf/tps/cas sensor readings to ecu.

Ok thats all that i can think of right now that is a possibilty. Im sure theres more.

Goodluck.

[sledgehammer]

Thank you for your help, really appreciate it. Now I know better where to look for. 

I tighten it up, clean the maf and see if that already fixed the problem. I read that an exhaust leak also could leak to bad smell and bad performance.