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intake manifold and TBI

i have a 1994 Z-71 with the vortec V-6 and 210K miles. it is losing about a quart of oil per week (about 250 miles) from the top of the engine, apparently the intake manifold gaskets. i am up for trying to fix this myself but have a few questions:

is it easy??? (ha ha) i assume i can get a gasket kit from the dealer. obviously, i need to replace the gaskets between the manifold and the heads, but what about the TBI? i am only getting about 15mpg and power seems low but after a gradual decline over

10 yrs its hard to tell how much as i am not a leadfoot. a mechanic told me that i could be getting air leaking into the TBI and the computer compensates by adding more fuel. therefore it follows i need a new gasket between the TBI and manifold. but - if the vehicle is running fine otherwise, hopefully this is all i need to do and there is no need to rebuild the TBI or anything else? i am hoping there is nothing to complicated with the TBI, like needing to rebuild it or replace any internal parts or gaskets.....

are there any fine tuning adjustments i will have to make?? i am hoping that all i have to do is take things off (linkages, throttle springs, vac hoses, wires, etc), label them, and put things back the way they were and all will be fine.

i have a chiltons to follow, although they can be a bit vague - and have taken off intake manifolds and heads etc. in old ford 289's and such years ago, but have shied away from anything other than water pumps, alternators, starters, etc with newer cars. this job seems doable and i have a 3 day weekend ahead. further, i successfully replaced a distributor in a 350 last week with my son after he took it off without marking anything (finding TDC, etc) so i am not a total idiot with engines, just a little behind the times.

any advice/warnings/support/cheering-ons or even a "you poor bastard" or two is appreciated!

david in houston.......

Reply to
Surfgeotwo
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Before you spend a lot of time replacing gaskets, I would wash the engine down good and try to see exactly where your oil is coming from. If your TBI/manifold gasket is leaking air the truck would very likely have a fast idle. JR

Reply to
JR

it's all pretty much straight forward, just make sure to clean the lifter valley after removing the gasket material from the heads. also if it has the quick disconnect fittings on the heater hoses, you might want to replace them too as they corrode and leak quite often. an oil & filter change is a good idea too after the repair just in case there are small particles that got into the engine.

Reply to
®

is it a good idea to run the engine a minute to wash the particles into the filter then change? or maybe better to just do 2 back to back changes?

as for the other response, i plan on washing down the engine tonight. i can drive one mile to a car wash so the engine wont be too hot, then i planned on washing it not running with a plastic bag wrapped around the distributor. i may even try that flourescent dye to make it easier to see the leak, does anyone know if it works in oil and if it is safe to do so?

Reply to
Surfgeotwo

i usually vacuum the valley then pour a quart or two of oil into it to flush any remaining particles into the pan. after reassembly of the intake, i change the oil & filter before starting. depends on if ya think the small particles may get sucked into the pump.

yeah, there are several differnt types of dye for the type of liquid used. you may want to use a bit of brakecleen to get it degreased really well.

Reply to
®

nooooooo... do not run the engine. dump the oil to get rid of any particulates that washed back into the pan, *then* you can go buy some wal-mart oil and do an extremely short OCI, if you want but I don't think it's neccessary unless the engine was rediculously dirty.

-Bret

Reply to
Bret Chase

I would plan on putting a new TBI gasket on as the TBI more than likely needs a good cleaning. That could be some of your lost gas mileage as well.

nospam

Reply to
NoSpam

Don't overlook the EGR passages in both the maniflod & the TBI. Mine were plugged solid. 223,000 miles & smooth as butter.

Reply to
Stephen Young

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