Hi guys finally doing my own wrenching - I have lots of knowledge of the theory, but my real-practical knowledge is really limited. But I hope I'm dodging the painfully obvious questions and only asking specifics & clarification.

As part of this tune-up, I changed: Spark plugs, coolant temp sensor, cleaned the throttle body and tightened my throttle cable (again) another half turn of the nut to take up even more slack. Took me about 3 hours, as before now the most I'd ever done is changed a battery. Some suggested the connector clips would break as the plastic would be brittle. I had no issues, none of mine broke. But then again, this car has been garaged it's whole life and pretty well taken care of.

Took it for a drive after I was all done, car runs great, no issues no codes. Idles fine, full throttle feels great. I didn't drive it enough to determine differences in drivability - but I'm sure I'll post later if I notice anything.

Couple of questions.

1) Car didn't want to start at first. Took about 15 seconds of cranking, getting ever closer to catching before it finally painfully crawled into life. After it caught, it idled stable and was perfectly fine after this. I let the car idle for a few minutes, turn it off. Next time I started it, it caught instantly precisely as it should. Is this because of the throttle body cleaning? Residual cleaner in the intake causing harsh start? I didn't squirt any into the engine, I only cleaned the outside of the butterfly valve so I'm surprised there would be that much residual left...

2) Two of my spark plugs were loose. And by loose, I mean hand tight. Both of them were on the cylinders against the firewall. It's like whoever did it last didn't bother torquing the ones back there. Is this normal? All of the rest felt like they had the required 13lb\ft.

3) Of those two loose spark plugs against the firewall #4 was covered in oil. Even on the nut itself. Is this valve guide\stem seals? Or is this a result of the spark plug being loose.

4) One of the other spark plugs, #6, was significantly tighter than the rest, and as a result, both it and the coil had a very mild amount of corrosion along the porcelain. Should I be concerned?

5) Engine is completely sealed, doesn't leak or burn any oil. None. 160,000 miles, it's actually incredible. Passenger valve cover is utterly dry and clean. However, driver side has a huge oil splotch. Is this because of people spilling oil when it's being filled up over the cars lifetime? It's my best guess as it's centered around the oil fill cap. I don't see any evidence of it coming from anywhere else unless I don't know what to look for.

6) Final picture. Are there supposed to be holes in this rubber tube? It connects the top of the valve cover on the driver side to the intake manifold, above and behind the throttle body.

The plugs that came out. Left to right, they are in order of where they came from. #1 is passenger front, #4 is passenger at the firewall. #5 is driver front, #8 is driver against the firewall.


One of the normal spark plugs. Dirty, but I don't see evidence of the gap being incorrect or there to be wear\pitting of either side of the tips. All of the tips across every spark plug look the same.


#6 coil


Passenger valve cover


Driver side valve cover w\ oil stain


Are there supposed to be... holes?

 

That hose is the PCV Valve hose and I just bought one new from Bell and it has holes, but I think they're only in the outside sleeve that covers the real vacuum hose inside.
The oil on the valve cover might be some blow-by from the oil filler cap gasket that Aptoslexus talked about in his Valve Cover Gasket post. And your oily spark plug issue might be because you need to do the spark plug seal job that he did in that same post.

 

Uhm... I also just found this on the floor next to where I put all of the plastic trim pieces (intake, vanity cover, etc).

I have no idea where it came from.

 

Looks like a spacer/support sleeve that goes into a plastic hosing.

 

Question 3. as cj mentioned is more than likely a tube seal.
Replace it before the oil seeping through kills the coil.
Of course, replace all 4 WYIT…

 

I have my '98 engine in readiness for timing belt/water pump job. I just looked at the parts pulled out of the beast and I saw four of the sleeves inserted into rubber bushings, three attached to the Air Cleaner Cover (17705-50060) and the other on the driver's side end of the Engine Air Intake Hose(17750-50020) where the unit bolts onto the radiator support thingy (yes, a technical term) Maybe one of the rubber bushings has given up the ghost and that's what you've found.

 

Alright, I'll have a poke around those bits tomorrow. I still have to do the idle air control valve cleaning as well so I gotta take the vanity plate off anyway.

I'm also going to give the valve cover a good cleaning, to get rid of that oil and see if it's an ongoing blowby issue, or, if some smooth brained person didn't tighten it properly however many years ago and it isn't an ongoing problem. Because that would be quite strange to have the oil filler cap be my first leak out of this engine, ever

Thanks everyone!

 

idk if you're using terms interchangeably but the VVT-i engine doesn't have an idle air control valve the same way that the previous gen LS models did

despite having a throttle cable it's still electronic throttle control, and the idle speed is controlled with the opening of the throttle plate

 

Sorry the air mix passages:

https://www.clublexus.com/forums/ls-...ttle-body.html

I actually don't fully understand the purpose of these passages if I'm honest.

P.S Does anyone have any opinion on why the spark plugs were extremely loose?

 

13 ft-lbf is not a lot of torque. Even when torqued properly they are not overly tight.

 

They were hand tight. I unscrewed them just by the gnarring on the shaft, I didn't even use the wrench.

The rest needed a wrench for the first couple rotations.

 

Kelvin at Cartune NZ has a video on the air passages, says they're for the Air Assisted Injectors. From what I understand the airflow from the passages comes out right near the injector nozzles and aids in the atomization of the fuel as it gets injested into the intake ports.

 

That looks like the spacers (don't know what else to call them) that are in the bolt/stud holes in the engine cover. Check there.

Judging from the oily grime, it was probably something that was near the cam covers - the air cleaner duct/air chamber or something on the driver's side.

 

I've seen him over the years, and man he is just a wealth of knowledge. Truly incredible.

So they sort of are a form of idle control. But not like the traditional system. Just air assisted injectors to aid in the atomization of fuel at low rpm (idle).

I'm now worried about the AVIS system in my car lol. I've never seen it discussed here - never even knew it was a thing. The default position is open for low-end power, but I wonder how many people's cars are failing to open for the shorter intake runner at high rpm's.

 

Nope, not that. Doesn't fit on the long embedded screws, too tall. And it doesn't fit on the underside of the vanity cover.

It does appear to be the same brassy-goldish metal as the supports for that vanity\engine cover however. I don't see any other metal of this type anywhere else around the engine.