skip to main content

intake leak

16 years ago

96 cadillac seville. changed intake due to leak at blow off flap. bad gasket. put on used intake. new intake gaskets. 6 months later i get a p0171 and p0174 code. bank 1 and 2 lean condition. i checked every vacuum line and hose and pcv valve. brake booster too. nothing seems bad. than i got a code p0131, O2 sensor. think these are related? the plenum is dry. no coolant passages to deal with. the intake gaskets are heavy molded plastic with silicone ribs. almost impossible to put in gaskets wrong. attach gaskets. lower intake. how hard is that? i know the torque is low as i cracked the original intake 2yrs ago. any ideas?

Sort by:Oldest

Comment (1)

john_g
16 years ago
Pull the freeze frame data to identify whether the leak occurred at idle or under a load. (Engine RPM PID and Load Pid, you could even use the vehicle speed as part of the reference)

If it occurred at idle, then a vacuum leak could be at play, if it occurred under a load then a vacuum leak is NOT indicated as a cause.

Once you identify under what operating conditions the failure occurred, driving the car though differing conditions (Idle, part throttle, cruise, heavy throttle) and watching how fuel trim is compensating under those different conditions will be an important piece of information. It's not beyond expectations that the problem could still be a random occurrence. If fuel trim isn't making a correction and there are no hard faults causing open loop, then the problem simply might not be there at the moment.

Lastly using VE (volumetric efficiency) calculations against the MAF sensors reading helps to prove if the MAF air sensor isn't reporting the airflow correctly.
You need to do a snapshot and capture engine RPM, MAF in grams/second, and ambient temperature all under wide open throttle and from there I could calculate the reported VE for you.
Related Discussions
'86 Lawn Boy F Series - Fuel Leaks From Intake?
Q
Comments (7)
Assuming the needle and seat are sealing and the float level is correct this is not unusual with a F engine.It happens from the combination of too much reed clearance and sustained high rpm. Reeds tend to get bent slightly open with long use allowing a tiny amount of reverse flow before closing on the piston down stroke. Now there is a fuel fog which is present in the carburetor of all reed engines, even when new and this tiny amount of reverse flow pushes this fog closer to the air cleaner end. The degree of this fog depends on the condition of the reed and how quick it closes. High rpm aggravates the condition creating a fog that will reach the air filter and soak it. Check the maximum rpm and adjust if necessary, but you probably will need to replace the reed. I think Lawn Boy made a plastic part that was made to fit in the carb to help control the fog, but I don't know the part number or if it will fit your carb. Also check the exhaust ports if you haven't done it in a while.
...See More
craftsman mower bizarre!
Q
Comments (2)
Maybe an air intake leak? Sealing itself after the engine warms up. Check the carb mounting to the block to make sure the bolts/screws are tight. Check the gasket if you can see it too. With the mower running, spray carb cleaner around areas where gaskets would be (carb to intake, etc). if the engine RPMs change, your leak might be there.
...See More
4-hp tec engine starts nice runs ok, but dies when
Q
Comments (7)
A sticky throttle plate, one that does not turn freely, would cause that problem. When you load up the engine, the rpm's will drop off, releasing pressure on the air vane. The throttle spring should pull the throttle plate open, quickly, before the engine stalls. If the throttle is stuck, due to some mechanical defect, it will not open, and the engine stalls due to lack of fuel.
...See More
homelite 360 SL
Q
Comments (3)
Sounds low side carb blocked if have low side screw you can screw in then back out don't for get to count turns dry gas at small space at seat stopup idle side if don't have idle side screw use some seafoam addtive to gas to clean it. open low side sometime help them when self cleans go back to old setting. check mounting screws for losing up to. Tickleing throttle cause vaccum rise in carb so it pull more gas into engine may take kit and cleaning passages to get run right with this heat its good time year for gas dry fast.
...See More

Related Stories

REMODELING GUIDES Know Your House: The Steps in Finishing a Basement

By Bud Dietrich, AIA

Learn what it takes to finish a basement before you consider converting it into a playroom, office, guest room or gym

HEALTHY HOME Get Cleaner Indoor Air Without Opening a Window

By Mariana Pickering (Emu Building Science)

Mechanical ventilation can actually be better for your home than the natural kind. Find out the whys and hows here

KITCHEN APPLIANCES Love to Cook? You Need a Fan. Find the Right Kind for You

By The Sky is the Limit Design

Don't send budget dollars up in smoke when you need new kitchen ventilation. Here are 9 top types to consider

HOUSEKEEPING What's That Sound? 9 Home Noises and How to Fix Them

By Mitchell Parker

Bumps and thumps might be driving you crazy, but they also might mean big trouble. We give you the lowdown and which pro to call for help

MATERIALS Insulation Basics: What to Know About Spray Foam

By Mariana Pickering (Emu Building Science)

Learn what exactly spray foam is, the pros and cons of using it and why you shouldn’t mess around with installation

REMODELING GUIDES Top 10 Tips for Choosing Shower Tile

By By Any Design Ltd.

Slip resistance, curves and even the mineral content of your water all affect which tile is best for your shower

HOUSEKEEPING How to Clean Your Range and Oven

By Bonnie McCarthy

Experts serve up advice on caring for these kitchen appliances, which work extra hard during the holidays

ORGANIZING 21 Tips for Organizing Your Stuff

By Laura Gaskill

Restore order at home with these ideas for tidying up cupboards, shelves, doors and more

HOUSEKEEPING 20 Things You Might Be Forgetting to Spring-Clean

By Laura Gaskill

Clean these often-neglected areas and your house will look and feel better

FUN HOUZZ Technicolor Solutions to 3 Popular Home Peeves

By Vanessa Brunner

Imagination runs wild in these illustrated solutions for Houzzers' home dilemmas

Sponsored

Structural Remodeling

Franklin County's Heavy Timber Specialists | Best of Houzz 2020!