Puzzled- Excessive Oil in Throttle body (1 Viewer)

[blbuck88]

Hello All,
This website has been a tremendous help to me in rebuilding my 1997 LX450 but after hours of searching and no real explanation, I’m turning to you all for help.

I recently rebuilt the 1Fz-Fe engine (roughly 3010 miles on rebuild) and I am having major oil consumption issues. What do I mean by “major”- it will consume anywhere from 1-1.5qrts of oil to go 100-120 miles! But it only seems to burn oil when it’s on the freeway at sustained RPM for a decent length of time. It doesn’t seem to burn any oil around town or off roading?

For the rebuild I purchased all new OEM parts and lots of them. The head was rebuilt by a reputable machine shop along with crank, rods, block etc. all new OEM seals, HG, exhaust studs/nuts, timing chain, timing chain guide, ARP head studs, etc. I replaced all vacuum lines, new OEM fuel injectors, spark plug seals. I set timing at roughly 5-6* (with the jumper wire in diagnostic plug).

I read on another post a guy had a similar issue and found his valve cover had blockage/bent tabs in the baffle. So, I took valve cover off and checked for blockage and to make sure the vents were open. I didn’t find any significant blockage but the vents on the underside of the baffle were slightly closed off. Thinking that must be my issue I opened them up and hit the road but no resolution.

The majority of the oil seems to be coming from the throttle body (see picture below). So, I replaced the PCV and hose with another new OEM PCV but it’s still using oil. Next, I did a Compression test, all cylinders were good and with in 3-5 psi of each other.

While driving around town - I never see any smoke. The only time I see smoke is after driving 80-100 miles on the interstate, I stop to get fuel, check oil level, etc, shut it off and restart it. When I restart it after being shut off 5 minutes or so, it smokes a good amount for roughly 15-20 seconds then clears up and goes away.

I’m at my wits end here (thank you for getting me my parts Joey) What am I missing?

 

[Fj80oregon]

Maybe install a catch can it’s A good mod to keep oil out of the throttle body/intake. If it catches all your oil than you know the culprit if not it’s under $50 and will keep that area clean once you figure out the issue. If your getting smoke and oil Consumption like that you might have a stuck valve. With that much oil being lost something is majorly wrong.

 

[gummycarbs]

The head was rebuilt by a reputable machine shop along with crank, rods, block etc.

Pistons and rings? Bored? Honed? You should probably be really specific about exactly what work was done.

I'm no engine rebuilder, but I'm trying to think of how you could have good, consistent compression yet puke out so much oil. Have you contacted the shop that did the work?

 

[blbuck88]

Correct- new .50 over pistons, new rings, bored and honed the block for the pistons, turned the crank, new larger crank bearing, reconditioned rods/new rod bearings. Surfaced/cleaned and inspected the block. Head was cleaned, inspected, multiple valves were replaced, a few valve buckets and all new seals. New timing chain, timing chain guide. All new OEM seals (rear main, oil cover, oil cooler, front crank seal, distributor, etc, every seal I saw I replaced from Toyota). I used Toyota sealant, No visible oil leak anywhere. Two new Denso O2 senors, new oil pressure sender and temperature sensor. All new radiator lines, PHH, all new OEM radiator clamps, Aisin water pump, blue fan clutch and I topped it off with a new OEM Engine Wire Harness.

It runs better now than ever. I can maintain highway speed (I didn’t know an 80 series with 35s could go actually go the speed limit). Sometimes it has just a bit of a rough idle (it’s inconsistent though) but even when starting after it’s sat all night- no smoke.

For the first 300 miles I varied the speed/RPM around town, kept my eyes glued to the oil pressure and temp gauge. Changed the oil at just over 300 miles (Valvoline 5w-30) and went on its first road trip. On the first road trip I varied the RPM/speed, No Cruise control, etc and about 150 miles into the trip my oil light came on. I pulled over, shut it off and checked- sure enough it was about 1.5qts low. Then when I started it back up, the smoke appeared! Smoke Lasts for roughly 15 seconds then goes away. Drive another 100-150 miles on the interstate and oil light comes on. Pull over add oil, smokes when you restart, then drive on. I thought maybe the 5w-30 was too thin so at about 530ish miles I changed back to Rotella 15w-40 while on my road trip in the parking lot of WalMart. Didn’t seem to make any difference in consumption, just a slight increase in oil pressure as one would expect.

I’m super frustrated; what’s the deal here?!?! Thank you for your advice all!

 

[BILT4ME]

Correct- new .50 over pistons, new rings, bored and honed the block for the pistons, turned the crank, new larger crank bearing, reconditioned rods/new rod bearings. Surfaced/cleaned and inspected the block. Head was cleaned, inspected, multiple valves were replaced, a few valve buckets and all new seals. New timing chain, timing chain guide. All new OEM seals (rear main, oil cover, oil cooler, front crank seal, distributor, etc, every seal I saw I replaced from Toyota). I used Toyota sealant, No visible oil leak anywhere. Two new Denso O2 senors, new oil pressure sender and temperature sensor. All new radiator lines, PHH, all new OEM radiator clamps, Aisin water pump, blue fan clutch and I topped it off with a new OEM Engine Wire Harness.

It runs better now than ever. I can maintain highway speed (I didn’t know an 80 series with 35s could go actually go the speed limit). Sometimes it has just a bit of a rough idle (it’s inconsistent though) but even when starting after it’s sat all night- no smoke.

For the first 300 miles I varied the speed/RPM around town, kept my eyes glued to the oil pressure and temp gauge. Changed the oil at just over 300 miles (Valvoline 5w-30) and went on its first road trip. On the first road trip I varied the RPM/speed, No Cruise control, etc and about 150 miles into the trip my oil light came on. I pulled over, shut it off and checked- sure enough it was about 1.5qts low. Then when I started it back up, the smoke appeared! Smoke Lasts for roughly 15 seconds then goes away. Drive another 100-150 miles on the interstate and oil light comes on. Pull over add oil, smokes when you restart, then drive on. I thought maybe the 5w-30 was too thin so at about 530ish miles I changed back to Rotella 15w-40 while on my road trip in the parking lot of WalMart. Didn’t seem to make any difference in consumption, just a slight increase in oil pressure as one would expect.

I’m super frustrated; what’s the deal here?!?! Thank you for your advice all!

Who assembled the rings on the pistons and installed the pistons?

Sounds to me like the scraper rings did not get installed properly.

It does take time for rings to wear in and seat, but this oil consumption seems excessive.

Blow-by on the rings is what you are describing, which is pressurizing the crankcase and causing the PCV system to remove the pressure through the throttle body.

That said, a serious vacuum leak could show a similar problem.

At idle, if you remove the oil fill cap, what happens? It should start to stumble hard. If not, then the computer is already compensating for a huge vacuum leak.

What RPM are you running while doing all this driving? I have found that mine starts using much more oil if I maintain above 3300 RPM because it is keeping more oil on top of the head and it's not draining back fast enough.

As I typed that, I realized that maybe your drain ports in the head gasket are blocked by a poor head gasket or a rag or paper towel that didn't get removed during assembly? This would keep oil above the head and cause it to suck a lot of oil through the throttle body.

Also, how about a few pics of the assembly on top of the engine so we can all look to see it's all plumbed correctly.

 

[jpoole]

@BILT4ME has some solid ideas to follow up on there. I'm hoping it's a leak or oil return issue that's causing this but as you know it could be a blowby and crankcase pressure issue caused by incorrect ring install or setup. At this point (over 3k miles) you have a serious oil consumption issue so you don't have to wonder if this is somehow normal or going away on it's own. The fact that you report no oil leaks may point to a blowby/internal issue but you can try to rule out all other options before focusing on that.

Oil is definitely coming into the throttle body via the vent line from the valve cover at higher rpms, and it may also be coming directly into the intake via the PCV valve/line.

• If this is caused by an air leak then as you open the throttle plate you increase possible vacuum on the vent line that runs from the valve cover to the throttle body and air can enter the leak and pass through the valve cover to the vent line and on to the throttle body at a velocity that allows the collection of oil.
• If this is caused by blowby then as you increase rpms crankcase pressure increases and pushes air/oil into the intake vent line.

It sounds like you've done some solid troubleshooting already and are headed towards a blowby focused path but maybe some new ideas will come up that help. Beyond Bilt's list here are a few related threads that may yield some helpful thoughts/ideas:

• 1FZ-FE Oil Consumption issue fixed - https://forum.ih8mud.com/threads/1fz-fe-oil-consumption-issue-fixed.1004374/
• 22re oil getting into intake after rebuild? - YotaTech Forums - https://www.yotatech.com/forums/f116/22re-oil-getting-into-intake-after-rebuild-164527/index2.html

 

[alia176]

This is an interesting puzzle to solve for sure but in the mean time, may I suggest cutting up the PCV hose on the right and install a cheap air/oil separator from a big box store to get an idea of how much oil was going into the intake? This isn't a fix but merely an objective way to measure how much oil is coming out of the valve cover. Having a clear bowl is very helpful in this regard. Peruse the Witts end turbo owner thread for some pics of mine and other catch can setups.

 

[blbuck88]

This is Great feedback guys- I really appreciate the help!

Engine assembly: machine shop did all the machine work and complete head rebuild and I assembled the block. We used Hastings Piston rings on DNJ pistons and Mahle bearings. Only one ring in my ring set had any markings, small dot (I believe it was the second ring) signifying it needed to face up. I followed the Toyota FSM to a T in ring orientation.

Removing the Oil Fill cap with engine running: Engine is fully warmed up (184*) and 650 rpm idle if I remove the oil fill cap- absolutely nothing happens. It doesn’t miss a beat, no change in rpm, stumble, nothing. So, I have a vacuum leak?

 

[blbuck88]

Here is a few pics of vacuum current vacuum routing.

It’s definitely RPM dependent, the faster I go, the more oil it pushes into the throttle body and intake. On the highway traveling at 75-80 mph it will use about double the oil versus this morning I drove from Durango Colorado to Montrose Colorado, through 2 mountain passes (some 10,910 feet elevation) pulling a 12ft V Nose box trailer all roughly the same miles and it used about half the oil.

Catch can idea: this is on my list. I think it’s a good idea but I wonder if I’ll be having to empty it back into the block every 100-150 miles?

 

[alia176]

This is Great feedback guys- I really appreciate the help!

Engine assembly: machine shop did all the machine work and complete head rebuild and I assembled the block. We used Hastings Piston rings on DNJ pistons and Mahle bearings. Only one ring in my ring set had any markings, small dot (I believe it was the second ring) signifying it needed to face up. I followed the Toyota FSM to a T in ring orientation.

Removing the Oil Fill cap with engine running: Engine is fully warmed up (184*) and 650 rpm idle if I remove the oil fill cap- absolutely nothing happens. It doesn’t miss a beat, no change in rpm, stumble, nothing. So, I have a vacuum leak?

I have a smoke tester that can be used to look for vac leaks, if you happen to need one. I sent you a PM.

 

[BILT4ME]

Here is a few pics of vacuum current vacuum routing.

It’s definitely RPM dependent, the faster I go, the more oil it pushes into the throttle body and intake. On the highway traveling at 75-80 mph it will use about double the oil versus this morning I drove from Durango Colorado to Montrose Colorado, through 2 mountain passes (some 10,910 feet elevation) pulling a 12ft V Nose box trailer all roughly the same miles and it used about half the oil.

Catch can idea: this is on my list. I think it’s a good idea but I wonder if I’ll be having to empty it back into the block every 100-150 miles?

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I don't see any OBVIOUS problems on the vacuum hoses unless the issue is under the intake manifold.

The fact that there is NO change in how the engine runs when you remove the oil cap would indicate there is a serious vacuum leak. However, to clarify, how long has it been since your EFI fuse was pulled and the ECU was reset? If it was recent, then the computer has not made all its adjustments yet.

However, if you are already pulling a trailer in the mountains, then you're working the shyt out of this engine and that's why you're sucking oil. I have noted on mine on multiple trips across Kansas through the Flint Hills on a 75 MPH interstate, if I set the cruise at 70 MPH, I use significantly less oil (as in only slight change on the dipstick) to losing a quart in 350 miles when running with the cruise set at 85 and it downshifting hard and holing at 3600 RPM for two miles at a time before it upshifts.

Very much RPM related, as that places more oil in a given time on top of the head. I also get MUCH worse gas mileage during the faster drive.

I run the same routes over and over, so I try things to see how to optimize my fuel mileage as well as oil consumption.

Also, did you use cast iron rings or chromoly rings? IDK what the factory rings are made of, but I have heard about C-M rings not seating well on engine rebuilds when they were not a "factory setup" to begin with, especially when coupled with synthetic oils because the oil is too lubricious and doesn't allow the friction needed to wear-in the rings to the cylinder walls. Not sure if that applies to Toyota Engines.

 

[FMC80]

Take this for what it is worth because you have the big brains on your case. I experienced oil consumption on my 94, 1FZ as well. I was pooling oil inside my intake tube, but I also found evidence of oil pooling inside the throttle body. I had no obvious vacuum leaks or misrouted lines; even after the oil cap removal test. My problem began after a baseline, replacing all rubber, VC gasket, PCV valve, etc. It turns out my VC gasket was chunked, which created some weird vacuum condition that pooled oil in my intake tube and throttle body. I found the culprit immediately. Of course, you were much more invasive in your maintenance, but you never know.

 

[blbuck88]

Hum… I reset ECM when I did the compression test, maybe 2000-2500 miles ago. I would assume that’s long enough for the ECM to “relearn”??

With the towing, I held off on towing anything until today (roughly 3250 on rebuild) and surprisingly oil consumption doesn’t seem and different towing versus Not towing. In fact, it might even be slightly less oil use while towing but that could simply be because I’m only towing at 55-60mph?

I’m pretty sure the piston rings were Not CM, here’s a picture of the box.

 

[jpoole]

@blbuck88

That's more than enough time for the ECU to relearn. When troubleshooting remotely it's worth mentioning this as a reset could have just happened but not be known or mentioned (nice thinking @BILT4ME )

There seems to still be hope that it's an air leak. Keeping the valve cover gasket fully seated during install can be a tricky especially in the rear where the seal can be bumped loose during install. It's possible that you've had a leak there both before and after you re-checked the baffle/etc. though that remove/replace without impact on the oil consumption makes me wonder if the leak, should there be one, isn't somewhere else.

Sounds like your oil consumption is tied more to rpm than load.

If you get an oil catch can (or 2) get large ones and plan to empty them frequently until you resolve this issue. I'm not sure what kind of issues all of the oil may be causing but it seems like it could cause issues for the cats, o2 sensors, plug fouling, etc. so catch cans could help minimize some of that potentially.

Is there more to the label on the Hastings box, maybe a "set" #? Below are some details from the Hastings master catalog that may be able to nail down the ring types installed. There is also confirmation of the "dot up" installation approach for Hastings rings.

If I'm interpreting the "Ring Type" information correctly the first group of ring sets listed below have cast iron compression rings and either cast iron or chrome oil rings. The second group of ring sets, given their 2C prefix, have Chrome top and Chrome oil rings.

Hastings Master Catalog:

https://www.hastingspistonrings.com/wp-content/uploads/2021/10/2022-AMERICAS-MASTER-CATALOG.pdf

​

Relevant pages from that catalog:

 

[audi2nr]

You didn't remove the baffle inside the valve cover did you?

 

[blbuck88]

Unfortunately, I only took the one picture of the Hastings rings box. So, I just called the machine shop and they are going to see if they can find the original invoice with a part #.

In regards to the baffle, nope- I didn’t remove at all. All I did was open the two vents that seemed to be closed more versus the pictures I found here.

I’m pretty convinced I’ve got a vacuum leak somewhere. Possibly valve cover, maybe spark plug seals, maybe it’s a vacuum hose that I missed? Maybe it’s the PCV, I’ve had a few members tell me there are a couple different versions of PCV and some are longer than others?

 

[blbuck88]

While pulled over to add oil, I looked over all my vacuum lines again. And I found this- see picture below. There’s a small crack where the vacuum lines go into my charcoal canister. Did I find the culprit? I don’t remember ever seeing these before. I’d assume I caused it when standing in the engine compartment reinstalling the engine. Could this be the answer?!?!

 

[jpoole]

That cracked, plastic part is just a cover. The actual canister is metal and not impacted by that crack:

Charcoal canister rebuild - 80 Series

80 Series Charcoal Canister rebuild. Bench grinder removes the seal cleanly. Wrap up is clean the valves, replace the old charcoal, button it up and reseal. You can weld it closed or use a good epoxy like JB weld. I will finish mine up later today with a little rattle can paint. The problem was...

forum.ih8mud.com

I like your optimism and hope you find a leak causing this soon! The smoke tester offered above could be worth looking into though you have options for testing / finding possible leaks.

 

[AussieHJCruza]

What's the temperature like where you are? Isn't 5W30 a bit light for a 1FZ?

I realize temps here are a bit extreme but the 1FZ's we deal with here get 15W40 year round - temp range -5C to 40+C

 

[blbuck88]

What's the temperature like where you are? Isn't 5W30 a bit light for a 1FZ?

I realize temps here are a bit extreme but the 1FZ's we deal with here get 15W40 year round - temp range -5C to 40+C

Yes I agree; 5w30 seems a bit too thin for the 1fzfe. I only ran it for the first 300ish miles after the rebuild for break in, then changed the oil (Valvoline 5w30 again) for roughly another 300ish miles before I went back to Rotella 15w40. I was hoping the 15w40 would resolve my oil consumption issue, but it didn’t seem to make any difference at all, only slightly higher oil pressure (which I expected).
I ran 15w40 before I rebuilt the engine and it seemed to like it the best.