Really gummed up intake, under the intake manifold. Advice?

[Rock_Rat]

I'll need to remove the plenums again to get at the injectors, won't I? Then, I will need to use new plenum gaskets to reinstall?

First verify if that's where the fuel smell is coming from. You should be able to see fuel around the injector that's leaking. It could also be a fuel line that isn't connected correctly.

If it is a sliced o ring, then the plenums need to come off. As for buying new gaskets, that's your call. A good rule of thumb is anytime a gasket is "crushed" you should replace it. Since there's no coolant running through the upper and lower plenums I would go ahead and re-use the ones you have. Chances of a vacuum leak on new gaskets are pretty slim. (I replaced mine...saved my old "brand new" gaskets as spares.) Just respect the torque sequence and the torque value (13 ft lbs).

Don't get in a hurry. Cover up the holes and don't drop anything.

BTW - I used a can of starting fluid and sprayed a small amount around my manifolds the best I could to ensure I didn't have any leaks. You'll hear the car rev up if you have a leak.

 

[ShooterMcGavin]

Thanks Mike!

 

[ShooterMcGavin]

Sitrep: I have at least 2 leaking fuel injectors, of the ones I can see. I can only see the front injector on the driver's side and not the 2 behind it. I'm going to need to take the plenums off again to access all of them. If an O-ring is torn, will it be obvious or is there a chance it can look fine and still be leaking? Should I just replace all O-rings on any leaking injector? When re-installing them, what is the best lube to use? Regular engine oil?

I feel like I have traded the smell of burning oil for the smell of gasoline fumes

 

[A.Wilson013]

Sitrep: I have at least 2 leaking fuel injectors, of the ones I can see. I can only see the front injector on the driver's side and not the 2 behind it. I'm going to need to take the plenums off again to access all of them. If an O-ring is torn, will it be obvious or is there a chance it can look fine and still be leaking? Should I just replace all O-rings on any leaking injector? When re-installing them, what is the best lube to use? Regular engine oil?

I feel like I have traded the smell of burning oil for the smell of gasoline fumes

If an O-ring is torn or otherwise damaged it'll likely not be attached to the injector when you pull it out. However, unless it's somehow broken in to a bunch of little pieces, you'll be able to just grab it out of the manifold, or use a small pick if it's stuck on the rail side. Hit up [MENTION=123572]TheToyotaGarage[/MENTION] to get some factory O-Rings from you. He's right down the road at Michael's.

I have always used vaseline when I have done injectors. I've had an injector leak ONCE and it was with fel pro O-Rings and WD-40. I don't recommend either for this. Also, when I removed these same injectors a week later, the o-ring was so tight that I had a LOT of trouble pulling them out. In fact, one injector broke off inside of the manifold.

When you're replacing them, try to spin the injector as much as possible while you're seating it. Once they're all in and you've tightened the fuel rail down, you should be able to still rotate them pretty freely side to side. If one doesn't want to move, or gives notably more resistance than the others, I'd be willing to bet you pinched another ring.

I apply a pretty hefty amount of vaseline around the o-rings when I install them. Never had a problem. I don't even want to thing about how many times I have done injectors on these 4Runners. Probably getting close to a dozen now. I think that's pretty high for someone who isn't a freaking mechanic.

 

[ShooterMcGavin]

Thanks Alex. All of the O-rings came out with the injectors and looked intact. They were damp with gasoline and easy to pull out. Putting them back in, dry, was a struggle. I know that some O-rings can swell when a petroleum based lube is used on them, but Vaseline is petroleum based. I'm somewhat surprised that the WD-40 caused issues.

Thanks for all the tips. That will help.

 

[St Runner]

Not to stir up trouble but I have always been told not to use petroleum grease(vasoline) on rubber orings as the petroleum will eventually degrade the rubber. I usually use a silicone grease on orings. This is just what I have been taught and I don't want to start a flame war on a very informative thread.

 

[Rock_Rat]

Not to stir up trouble but I have always been told not to use petroleum grease(vasoline) on rubber orings as the petroleum will eventually degrade the rubber. I usually use a silicone grease on orings. This is just what I have been taught and I don't want to start a flame war on a very informative thread.

The OEM O Rings are actually made out of high grade Neoprene or Chloroprene (synthetic rubber). It's oil resistant, and compared to natural rubber, it's more gas permeation resistant and can tolerate higher temperatures up to 200 degrees Fahrenheit (F). Neoprene will not physically degrade.

I'm pretty sure most "generic" after market O rings are medium grade neoprene.

 

[St Runner]

Thanks Rock-Rat, good to know the difference in materials.

 

[ShooterMcGavin]

The OEM O Rings are actually made out of high grade Neoprene or Chloroprene (synthetic rubber). It's oil resistant, and compared to natural rubber, it's more gas permeation resistant and can tolerate higher temperatures up to 200 degrees Fahrenheit (F). Neoprene will not physically degrade.

I'm pretty sure most "generic" after market O rings are medium grade neoprene.

The fuel injectors must be able to handle petroleum products since they come into contact with gasoline.

When I take things apart to fix up the leaking injectors, should I re-seat only the ones that are leaking now? Should it be assumed that non-leaking injectors will continue to be safe from leaking?

After I install the injectors, is there any way to confirm that they aren't going to leak before I put the plenums back on and get everything put back together? I'm guessing not.

 

[Rock_Rat]

The fuel injectors must be able to handle petroleum products since they come into contact with gasoline.

When I take things apart to fix up the leaking injectors, should I re-seat only the ones that are leaking now? Should it be assumed that non-leaking injectors will continue to be safe from leaking?

After I install the injectors, is there any way to confirm that they aren't going to leak before I put the plenums back on and get everything put back together? I'm guessing not.

(Keep in mind, if they're the ones on the pax side (1,3,5) you don't need to remove the plenums.)

If they're not leaking, might as well leave them alone. Your call. If they're the original O rings, you may want to replace them anyway. I don't recall in your thread if you replaced them or not.

Be sure to check each one of the rings seated in the fuel rail. Like [MENTION=63487]A.Wilson013[/MENTION] said, they should move freely in the manifold and the fuel rail.

No way to check and see if they leak without putting pressurized fuel through the injectors that I'm aware of.

Just take your time. Don't drop anything. Masking tape and rags works wonders.

 

[ShooterMcGavin]

(Keep in mind, if they're the ones on the pax side (1,3,5) you don't need to remove the plenums.)

If they're not leaking, might as well leave them alone. Your call. If they're the original O rings, you may want to replace them anyway. I don't recall in your thread if you replaced them or not.

Be sure to check each one of the rings seated in the fuel rail. Like [MENTION=63487]A.Wilson013[/MENTION] said, they should move freely in the manifold and the fuel rail.

No way to check and see if they leak without putting high pressure fuel through the injectors that I'm aware of.

Just take your time. Don't drop anything. Masking tape and rags works wonders.

The injector O-rings are original, as far as I know. I'll take the plenums off to check each of the injectors on the driver's side. ...I mean, as long as I am doing this work to get rid of engine odors Thanks again!

 

[ShooterMcGavin]

Ok, making progress, slowly. I took it all apart again and found the leaking injectors. I replaced 4 of the O-rings; luckily the dealership near me had exactly 4 in stock. I was careful to lube the rings before assembly, so I think I have solved the leaking fuel problem. I put all the intake parts on and filled the cooling system with cooling system flush; might as well, since I will be draining and filling it again. It rev'd up to 2,000 rpms, which didn't concern me too much, especially when it dropped back down to under 1,000 after warming up. It is still too high, but that's not my biggest concern. It runs like it is not firing on all cylinders. I have checked and double-checked the spark plug connections. Besides doing all that again, is there anything else I should check?

 

[mtbtim]

Ok, making progress, slowly. I took it all apart again and found the leaking injectors. I replaced 4 of the O-rings; luckily the dealership near me had exactly 4 in stock. I was careful to lube the rings before assembly, so I think I have solved the leaking fuel problem. I put all the intake parts on and filled the cooling system with cooling system flush; might as well, since I will be draining and filling it again. It rev'd up to 2,000 rpms, which didn't concern me too much, especially when it dropped back down to under 1,000 after warming up. It is still too high, but that's not my biggest concern. It runs like it is not firing on all cylinders. I have checked and double-checked the spark plug connections. Besides doing all that again, is there anything else I should check?

Could a vacuum leak cause an engine to feel like it is missing on a cylinder? My truck only has 140,000 miles and I noticed a couple vacuum hoses needed replacing since they were split a little at the connections. Your truck has a lot more miles than mine so I'm wondering if you have a vacuum leak somewhere. I can't remember, did you buy new spark plug wires? Did you double check the orientation of the plug wires too, how they run from the coil packs on the passenger side to the driver side?

 

[mtbtim]

You would be concerned for no reason. Oil vapors from the valve covers travel into the intake and over time accumulates.

The OP is way past this part of the conversation. Your comment is the same somebody already made on Page #1 of the thread. All the comments and clean-up have already taken place regarding the buildup. He's now trying to figure out why his truck is running rough.

 

[BlazeRunner]

The OP is way past this part of the conversation. Your comment is the same somebody already made on Page #1 of the thread. All the comments and clean-up have already taken place regarding the buildup. He's now trying to figure out why his truck is running rough.

you replied to a spam bot

 

[mtbtim]

you replied to a spam bot

Well, I'll be damned. Never heard of a Spam Bot. Created just to annoy people I guess.

 

[ShooterMcGavin]

Could a vacuum leak cause an engine to feel like it is missing on a cylinder? My truck only has 140,000 miles and I noticed a couple vacuum hoses needed replacing since they were split a little at the connections. Your truck has a lot more miles than mine so I'm wondering if you have a vacuum leak somewhere. I can't remember, did you buy new spark plug wires? Did you double check the orientation of the plug wires too, how they run from the coil packs on the passenger side to the driver side?

I don't know. Can someone else chime in on that point? It's certainly possible that I have a vacuum leak.

*Edit: Also, how do I find vacuum leaks? Spray some flammable substance near a suspect area? What should I use for that?

 

[mtbtim]

I don't know. Can someone else chime in on that point? It's certainly possible that I have a vacuum leak.

*Edit: Also, how do I find vacuum leaks? Spray some flammable substance near a suspect area? What should I use for that?

I did a little research and a vacuum leak can cause your engine to feel like it's missing. You went pretty deep into the engine so maybe one of the intake gaskets whether on the plenums, intake manifold, or throttle body wasn't sealed well for some reason. Then there's the injectors, which you've investigated and addressed and then the multitude of vacuum hoses to check.

I found a video that looked pretty good on checking for vacuum leaks. People either use starter fluid or carb cleaner. It's probably better to do when the engine isn't too hot to lessen the chance of a fire.

Here's the video:
<iframe width="560" height="315" src="https://www.youtube.com/embed/9CPqbaSgcok" frameborder="0" allowfullscreen></iframe>

 

[ShooterMcGavin]

Thanks Tim. I also talked to a friend who said what you said, that a vacuum leak can cause it to feel like a cylinder is missing. I put on new intake manifold gaskets, and then didn't touch them again. However, I installed the plenums with new gaskets, removed the plenums, installed them again, removed and installed them a subsequent time. It is possible that I will need new gaskets there because things have been on and off so much (I'm guessing). I also took the throttle body off and tried re-using the gasket, even though I have a new one. I shouldn't have done that, but it's not too deep into the engine to worry much. I will follow the steps in the video and see if I can track it down. I'll report back

*Edit: My friend recommended using either carb cleaner or brake cleaner. Between the two, I only have brake cleaner, so I'll try that.

 

[ShooterMcGavin]

I gotta give you all a big thank you!

I'm done with this part of the engine work. Time will tell if the valves are sealed up (really crossing my fingers), but everything intake-related has been cleaned and reinstalled. It runs smooth and has plenty of power now! The roads are wet now... I took it out for a good run-in. With my foot hard on the gas, the tires spin in 1st, 2nd, and at the top of 3rd.

"Shooter", you may ask, "what was the cause of the misfire and rough running"? I'm a dork I traced the spark plug wires before I took the engine apart and, apparently, I got the connections wrong. When I put things together, I was using a flawed spark plug wire setup. I googled it and found the correct pattern. All fixed now