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1987 firebird? again


gordesky1

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this realy aint a big deal but i like too get this car too 100% when i was changeing the airfilter. while i was at it i cleaned the thoutelbody and when i was spraying theres was alot of black stuff comeing out i got most of it but im shure theres more. and i was wondering what whould cause this? is it normal? or? like when we push the pedel too go theres like something trying too hold it back than it goes the car has alot of power even more when we change the air filter. but i whould like too get it too top shape.by the way the car is mutiport fuel injection 2.8 v6. and the car pops when we start it up after awhile like 3days.

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Look into some combustion chamber cleaner, like SeaFoam, or my personal fav, Mopar Combustion Chamber Cleaner (even if your car isn't mopar, IMO it's the best.)

 

You just let your car idle, open up your thottle body, and spray it in just enough to not kill the car... Then turn the car off, and let it sit for a couple hours then take it out for a drive... There should be a HUGE brown/black smoke coming out of your tailpipe... Just drive around 'till iut goes away... Try doing a couple WOT runs.

 

While you're at it go ahead and take out all your spark plugs, and get a table spoon or two full and drop it in where the spark plug goes.

 

If it hasn't been done before you'll see a BIG difference. Not only in performance and less hisitation but gas mileage.

 

On a side note, if you have any sort of oil leak, use caution because the cleaner can clean up the deposits that are keeping the leak small, and may open them up.

 

Also note, after running the cleaner I would HIGHLY reccomend changing your spark plugs, and oil, and oil filter at least.

 

Other things that can cause the hesitation, spark plugs, spark plug wires, clean oil, quality oil filter, check for any corroded 'tubes' that can cause air/fluid leaks and replace as necesary.

 

There's a lot more that can e done, but that little bit should make a very noticable difference.

 

: all4sma :

 

EDIT: fixed a couple typos, and added a litle more info.

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thanks all4sma when i go back out i pick that up:) were do you get it will it be in any auto shops? by the way i forgot too say when the car sits idel sometimes the car will rev up and down alittle bit not alot but you can hear it. than sometimes its on the 2 on the rpm thing instead of the 1 or below that as it should.

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Check for broken vacuum hoses especially the small ones, that could cause the idle problem.

 

A lot of black in the throttle body is probably accumulated oil as PCV hose runs to the throttle body a 3/8 hose or so. This would be normal considering the age of the car.

 

And like all4sma said change plugs and wires and check rotor and cap if it has one.

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SeaFoam you can usually pick up at a regular auto-parts store, but the Mopar Combustion Chamber Cleaner you'll need to get from a Dodge/Chrysler dealership directly from their service dept.

:: IIRC it cost's about $6.00 for the can.

 

For the crazy idle, that could very well be an air leak. But there are literally TONS of things that can caused apoor idle.

:: Get a squirt bottle, put a little tiny bit of soap in it, and fill it up with water. Turn the engine in, spray a mist all over the place (avoid electrical connections and air filter(s)... Look for bubbles forming as this can be a sign of an air leak (or you put too much soap in the bottle :P .)

:::: Replace any hoses that may have a leak, or if they even look corroded.

 

Another cause I have heard of with a weird idle could be related to poor battery strength/connections.

:: Clean off you battery posts and inspect the wires for any corrosion.

 

Check Spark Plugs

Check Spark Plug Wires

Check Coil Pack

 

Check to make sure your fuel injectors are firing.

:: The way I was told to test this was by starting the car, let it idle, and while it's running pull the electical connector to each injector one by one. The idle should change drastically if it's working properly (or at least firing), plug it back in and pull the next one and so forth.

 

: all4sma :

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is the car a high miler?....if so id be careful about cleaning the inside of the motor to much...as bad as build can be the parts are wore to that buildup...cleaning it can cause a whole lot more problems...the black build up is a combination or oil fumes drawn in via the pcv and unburnt fuel evaporating after shut down. if your car has a carb looking device in the center of the intake its call throttle body, if its all closed intake coming to a butterfly valve then it multiport injection...cleaning that plate will help in idle quality and initial throttle response.

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Yep thats the Exhaust Gas Recirculating Valve. Reduces emission by burning part of exhaust gas a second time. I suppose its the top piece with the vacuum line on it that is what is shaking and not the lower piece that mounts to exhaust manifold? You could try taking the vacuum line off and plugging it to see if that makes the idle steady.

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the egr actually is used to reduce combustion camber temps. the exhaust is basically an inert gas (non combustible). by putting it back thru the engine it takes up cylinder volume lowering the amount of air fuel going into each cylinder. the really bad exhaust gases are made at high cylinder temps. sometimes crud buildup or carbon deposits will hold the valve pintle off its seat and it acts like a vacume leak at an idle. with pliers pinch off each vacum hose 1 at a time and see if the engine changes speed. the one that makes the difference is the one with the leak. you have to go as close to the engine as possible so you dont miss the leak if its a hose that leaks.

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the egr actually is used to reduce combustion camber temps. the exhaust is basically an inert gas (non combustible). by putting it back thru the engine it takes up cylinder volume lowering the amount of air fuel going into each cylinder. the really bad exhaust gases are made at high cylinder temps. sometimes crud buildup or carbon deposits will hold the valve pintle off its seat and it acts like a vacume leak at an idle. with pliers pinch off each vacum hose 1 at a time and see if the engine changes speed. the one that makes the difference is the one with the leak. you have to go as close to the engine as possible so you dont miss the leak if its a hose that leaks.

:blushing: Sorry my bad assumption on function.

 

So by having the exhaust gas added to the mix although hot will not contribute to the next combustion lowering cylinder temps but not producing as much power as if the EGR valve was closed.

 

And I guess EGR mainly opens at higher RPMs because I know if you put your fingers on the diaphram and open it at idle it will drop RPMs or die.

 

Thanks for the info dd. Learned something today. :)

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i useing this thread again. what does it meen when the idel drops under 1000rpm like if we just ideling the rpm thing whould drop like around 500rpms too 700rpms instead of 1000 like it should be? and when it doing that the gas Gauge drops down and the battery gauge drops pretty low too and when it does that the car shakes like its going too stall and sometimes it does. i cant figure out the problem and sometimes the engine light comes on and it realy starts too ack up like it will smell bad and have no power. than we shut it off and start it up again and its fine. the car got pretty new spark plugs and wires and atlterlater and we even check for leaks when a spray bottle no bubbleing. and we change the oil last year. and we dont put much miles on it a year way less than 1000. we ony put about 7000miles on the car sence we got it like 10years ago. i just cant find the problem:(

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did you straighten the wiggly egr valve problem our? did you check for and find any other leaks either via crimp the air lines as close to the motor as possible or with a spray of some sort as mentioned before. personally i use water bottle for spray. it will stall the motor where as others types will rev the motor up. the down side to spray cans is the contents are usually flamables, see more than i fire....waters upside is if you have poor spark plug leads they will start a good light show ynder the hood (if the lighting is bad). vacum leaks are the prime source of bad running conditions. while your doing any repairs disconnect the battery for at least 3-5 mins to reset the cars cpu. and always disconnect the negative terminal first and reconnect last. power flows neg to pos. past this rgular maintenance spring fall oil change and annual plug and fuel filter,dist cap rotor and plug wires as required

 

 

 

edit: btw look for a white decal n the fan shroud about 1.25in x3.5in your idle speed will be on it my guess is 750-800....non adjustable with out a diagnostic tool. DONT try to do it...you will make a mess.....keep the throttle plate clean

 

 

 

 

when your checking for leaks there wont be bubbles cause its sucking air....you check while its running. your actually checking for change in engine speed up or down.check all hoses and mating seams along the intake manifold....there is 2 halves to the intale as well as where it meets each cylinder head..i do have a couple other ideas if these dont work.....do remember to reset the cars cpu

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what does it meen when the idel drops under 1000rpm like if we just ideling the rpm thing whould drop like around 500rpms too 700rpms instead of 1000 like it should be?

why do you think it should idle at 1000? Im just curious because unless you have a more agressive cam in the engine I dont think it should idle at more than say....700

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