Oil in the intake plenum and exhaust smells rich. What could my problem be?

You mean gas in the air intake??

hey matt in order to help you better I need for you to do a couple of things here///// going by what you have been told I need these answers (a) the size motor you have in the truck? (2) can you take out each spark plug and see if any have motor oil on them and which one's? this is very important you must write the cylinder #'s down on each plug you find wet with oil/ or extremely coated in black or white soot/ashes the sequence of the plugs is left side of engine as you are looking at it from standing in front of the truck O.K. if it's and 8cylinder it will be left side 1 2 3 4 //// right side 5 6 7 8 this will be the 4.6/or 5.4 motors you must tell me which one? and if it's turbocharged? if it's the 6 cylinder it will be Left side 1 2 3//// right side 4 5 6 so this is very important //// and how much mileage is on the truck///on the 4.6/5.4 motors if you find oil on any of these plugs #'s 1/4-----5/8 the intake manifold gaskets could be leaking the oil if you find other cylinders other than these we could have (a) leaking valve cover gaskets ////look for oil running down the side of the head and are you smelling burning oil? if yes we found part of the problem---if no while the truck is warm and running do you smell burning oil in the exhaust and is it smoking If no that's good if yes there could be real problems here but if the exhaust just smells very rich with no oil smell or smoking that is just the oxygen sensor code for the 1st. sensor in the front not so bad it just went maybe from usage remember this is an old truck now so some things are going to fail on a 15 year old truck(released in the fall of 2000 maybe your door sticker will tell the month) we just have to find out exactly what's going on I don't want to shoot from the hip here and take guesses of what this could be I will be able to tell you a lot but I need to know anything else you can tell me remember I'm not there at the truck so there are things you must be able to tell me or anybody else here who is trying to help you and as you can see I'm trying instead of not answering because you are lacking specific information so a little bit more info from what I have asked you to do will help a lot I know you sound desperate and also you don't want to spend a lot of money here so I'll do the best I can for right now if there is smoking oil burning coming from the exhaust this could be your valve seals on the top of the valves in the cylinder heads / or your rings it depends how much mileage is on the motor if it's the valve seals there is a way to fix it but I don't think that your a mechanic and are lacking the proper tools for this so when you post back please be as specific as possible and have done the checks asked and we'll take it from there these are simple things to do no $$$$$ spent just a little investigation time to get a better Idea O.K. and in your post say hey! Stephen it's matt & I'll get to you as fast as I can and just so you know I've been a mechanic for 40 years and have taxi fleet experience with ford motors 4.6/5.4 and all others so the right person found you we just need a little extra information I'm doing suspension work on a town car and will get to you just be patient I have a little bit of running around to do to for 2005 crown Victoria police car so I'll get you later on or when you can post back don't worry if it takes you a few days I'll see the hey! Stephen in the post O.K. just take your time and write down everything!

This is tricky without a great deal of additional information. If it runs rich there is a possibility that the oil is becoming diluted and thus losing viscosity. Check the oil dipstick and see if the level is high and smells like gasoline. This will indicate that there is fuel mixing the oil. That's the first thing that comes to mind.

Check your fuel pressure regulator. It may be ruptured allowing too much fuel into the system.

Hi.

Check the fuel cap. It is often responsible for the problem. ICheck for leaks at the fuel pump, charcoal canister and throttle body. If there is no leak, then the fuel smell may be given by a too rich mixture. In that case you often have more problems because of engine flooding. Try doing a code scanning and see if there is any code stored (e.g. rich mixture, misfire, or indications of other problem. If problem is rich mixture you will smell gas at the exhaust. If mixture is too rich, check the sensors in the air intake (MAF, IAT) and temp sensor. If the problem is none of the ones I mentioned, check the EGR system. Recirculated gas smells the similarly to liquid fuel.

Regards.

Ginko

P0305 code is a cylinder #5 missfire. The codes last digit is the effected cylinder, i.e. P0305 is cylinder #5 and a P0302 is cylinder #2 and so on. A P0300 is a multi-cylinder missfire.
Thoery 1: Ignition system! If the cylinder is being injected with fuel and not getting spark, the un-burned fuel would simply be pumped out the exhaust system and can be the source of the fuel smell. Check the ignition system and the firing order. I know you said you already did this, but I have to include this for other people in the future who might be using this to help them with a simillar problem.
Theory 2: Bad injector! If #5 cylinder injector is stuck at full fuel (leaking badly due to an internal mechanical failure) it will be pumping way too much fuel into the cylinder for the cylinder to burn. The outcome is the same as before, it just pumps the raw fuel out the exhaust system. Just as before, compare 2 cylinders by inspecting the spark plugs of #3 and #5. If an injector is stuck, that cylinder spark plug will be soaked with fuel. Injectors cannot be repaired, just replaced.
Theory 3: Low compression! If #5 cylinder is low on compression it will not fire the fuel as it is injected. A simple compression test is needed to tell if there is a mechanical failure internal to the engine causing low compression.
Theory 4: Bad intake plenum gasket! The intake manifold has a steel plate bolted onto the bottom of it with a gasket called a plenum. This plate is inside the lifter valley. If this gasket fails it will cause a vaccume leak into the intake manifold that will create a lean mixture condition for the cylinder that is nearest the failed spot. This lean mixture does not light or burn effectivly and can cause an unburned mixture to enter exhaust manifold causing the same sympoms as above.
Obviously this problem needs further diagnostics to pin-point the source of the failure. These are simply starting points and there can be many other things that can cause this type of problem, but these are the most likely. Hope this can be of some help, have more questions? Just ask!

If you have the V-8 Engine, just totally disregard this post.

If you have the 3.8L V-6 engine, your oil consumption problem is most likely to be caused by the PCV Valve if you cannot find any external leaks. These are also known for the upper intake plenum leaking antifreeze. The ports in the manifold that go to the throttle body are made of very thin plastic. The EGR tube, with its hot exhaust gasses, goes right between them. This causes the plastic to heat up and crack, causing an antifreeze leak that goes directly into the intake and gets burned in the combustion chambers.

DORMAN makes a replacement upper plenum kit to fix this problem. The kit includes the upper plenum with thicker coolant passage walls, an intake manifold gasket set, a smaller-diameter EGR orifice, and a new PCV Valve. This kit will probably fix BOTH of your problems.

The DORMAN part number for your car is 615-180 Shop around...prices vary considerably.

They are under the black plastic cover that is in the middle of your valve cover gasket. Remove the intake hose from the aluminum intake plenum on top of the valve cover and the silencer box against the firewall. Remove all the connectors from the sensors which should be 2 on the plenum and the 2 large vacuum hoses on the plenum. Then remove the 3 12mm bolts from the plenum at the throttle body and remove the plenum. You can reuse the throttle body gasket at the plenum so don't destroy it. All the other bolts are 10mm and use a screwdriver to loosen the clamps on the hose. The sensors have clips that you need to remove with a small screwdriver, then disconnect them. Remove the bolts on the cover and the cover. Then remove the bolts holding the coil packs down. Do one plug at a time. 2 of them are connected to the 2 plug wires and 2 are underneath the 2 coil packs. The connectors on the coil packs are fragile so remove them carefully. Reverse the steps to reinstall the plenum, etc.

I can tell about a couple of odors from oils that are quite indicative of the places where they oil is leaking into the exhaust though.

You've got a few internal places where oil can get into the engine and even some can get into the combustion chambers. They have distinctive odors and can really help diagnose the cause or reason for the oil consumption.

First let's start with the "sweet-smells".

This means that the oil have gone through the combustion process along with the engine's fuel (gasoline or diesels too!). It is about the same smell you get whiffing the exhaust on a 2-cycle engine with gas-oil premix.

Places where this CAN happen:

1) Cylinder walls ie; piston rings, worn or broken.
2) PCV system where the oil is sucked into the manifold under vacuum and is entrained into the combustion chamber in the normal air-flow to the engine for combustion.
3) Intake runner-to-head surface gasket(s) where the intake can actually **** oil from the cam tray area or the inner valley between the heads and the intake manifold.
4) Occasionally from changing spark plugs in "well" type plug chambers that let the plug get very close to the head through the head casting. Taking a plug out and letting the collected oil fall into the cylinder is usually a temporary situation, but can scare you when it happens.
5) Cracked head or blown head gasket: this usually has to happen where the head has a high pressure passageway for the oil to travel through the head to get to a cam tower on top of the head.
6) Now - here's something that's gonna get debated, fer sure! ONLY the intake valves can leak past their stem seals and allow oil to travel down the stem onto the combustion process. Remember that I am speaking or "sweet" oil smell here.


Now some of the "not sweet" or bitter oil smell:

1) Exhaust guides or stem seals on the EXHAUST valves ONLY can cause a very acrid smell of nasty, eye watering and cough-inducing stink.
2) CVCC or pre-combustion chambers can also cause this problem. The Honda CVCC engines were notorious for this! The auxiliary valve can leak oil into the pre-chamber and then it opens the valve and dumps the burning mess into the main cylinder head area and the results are a bad BAD stink and lots of white/blue smoke.
3) RARELY...very rarely the exhaust port AFTER the exhaust valve seat can become perforated and allow oil to get into the exhaust stream. It does NOT burn here - rather it just cooks-off with a very bad smell.

So-o-o-o

Acrid oil smell - the oil has NOT gone through the combustion process in the cylinder head but is rather "cooked" into a stinky odor. It may or may not smoke too much too.

Sweet oil-burning smell - oil that has been burned as part of the combustion process in the combustion chamber on one or more or even all cylinders.

check your engie oil. smell it and make sure that there is no gas getting into your oil.