I have a few little issues that I want to correct on my 86 SE, 2.8l
Car idles a little rough but runs stellar as soon as gas is applied. Currently, there are a couple of small things that may be contributing but I am not sure.
It has a cold air intake on it so the original piping coming off the firewall rocker cover is venting to atmosphere. Should I work on getting this plumbed back into the air intake to maybe help stabilize the vacuum on the car? Not sure what is affected when this pipe does not see the suction of the air intake.
My throttle body was one of the ported ones done by a Pennocks member. It works great but the idle adjust security cover was removed by him and I have no idea where this screw should be set? I am assuming it is an idle adjust but the Chilton manual says there is no idle adjust necessary for the 2.8. Is there a stock number of turns out for this setting from the factory?
Wondering if its worth putting the original air cleaner assembly back on the car and if it would help cure some of the rough idle issues. Its not bad and the car won't stall but it does hunt at idle by 2-3 hundred RPM which is just a pain more than anything else. Any ideas on getting it sorted? Vacuum is confirmed good on the car but what would great be on this engine?
The 2 above post are excellent advise I would definitely reinstall the stock air cleaner set up,, this should help performance after markey cold air systems hurt performance Pontiac got the air cleaner system on the 2.8 V6 as good as it gets there are minor improvements you can make on the V6 air system but get this right first this may help the hunting also set timing according to manual easy to do mark the proper line with white paint balancer & mark so you have the stock EGR system on the engine??? check spark plug wires at nite to see if thier is leakage of the tesla sort when checking for plug wire leakage ,,the darker the better! if your rubber vacuum lines are in good shape snip a bit off each end to assure a tight barely 18 fit
You can fill a spray squirt bottle & mist the plug wires to see if thier is an arc. if you have recently purchase a FIERO,run most of the gas out ,put just a few gallons in ,then next time fill it with gas fromastation that you feel assured there is little water in the ground tanks is there a difference between the car when it 1/2at engine operating temp & full temp ?? does the idle smooth out more when it reaches 190o to 220o?? I would definitely check the EGR vacuum hose real close learn how to check the codes This is real easy once you have done it do you have Fiero manual?? you can research almost any problem using the search feature at the top right of the page. make sure the PCV valve is operational,shake it listen for rattle you can check fuel injectors with a stethoscope,easier to just run a tank of chevron supreme !! also you can pull a vacuum hose to make sure you are not running rich.you can ajust the air intake by squeeze the hose bad injectore are a remote problem.,,I am amazed by how long most injectors last check the codes using your cars assembly line check with the plate under the giggarette lighter before you replace parts 2screws to remove if in doubt check the search featurw or a local FIERO gearhead you can clean the TBI &idle air controller.you can see a small hole just at the throttle plate if this hole is dirty spray it with carb cleaner or brake cleaner if you are askiller gearhead remove the IAC & clean it alsoclean the bevel port it fits into clean it with soft material like a Q tip or cotton shirt,NEVER AJUST THE IRC DO YOU HAVE A GOOD BATTERY?? charge it on low charge. make sure the small ground wire tha runs to the fender is clean & well connected,if the screw is corroded replace it poaaibly with onea size larger if your engineie very worn, you will not get proper vacuum thats all now class ,my new issue of ''TROUBLE!! WAY TO YOUNG FOR ME"" IS HERE
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05:26 PM
82-T/A [At Work] Member
Posts: 25713 From: Florida USA Registered: Aug 2002
I have a few little issues that I want to correct on my 86 SE, 2.8l
Car idles a little rough but runs stellar as soon as gas is applied. Currently, there are a couple of small things that may be contributing but I am not sure.
It has a cold air intake on it so the original piping coming off the firewall rocker cover is venting to atmosphere. Should I work on getting this plumbed back into the air intake to maybe help stabilize the vacuum on the car? Not sure what is affected when this pipe does not see the suction of the air intake.
My throttle body was one of the ported ones done by a Pennocks member. It works great but the idle adjust security cover was removed by him and I have no idea where this screw should be set? I am assuming it is an idle adjust but the Chilton manual says there is no idle adjust necessary for the 2.8. Is there a stock number of turns out for this setting from the factory?
Wondering if its worth putting the original air cleaner assembly back on the car and if it would help cure some of the rough idle issues. Its not bad and the car won't stall but it does hunt at idle by 2-3 hundred RPM which is just a pain more than anything else. Any ideas on getting it sorted? Vacuum is confirmed good on the car but what would great be on this engine?
I agree with what Uhlanstan is saying about the air intake.
For what it's worth, if you are missing the pieces, Rodney Dickman sells a "kit" that replaces those components for $39 bucks with ones that will actually improve on top of the factory pieces. Here's the link:
The screw on the TB is not an idle adjustment screw - it is a throtle plate stop. The IAC controls the idle! Messing with the screw can cause bad things to happen. Mainly, if it's set too low, the throttle plate can "stick" in the TB bore. If it's set too high, the car will "surge as the IAC tries to control the air going into the TB - makes it act like a bad vac leak that comes and goes. There is a procedure here on PFF for setting the screw correctly. Serach for it. You idle issue can be a number of things as the guys mentioned above. Do one thing at a time! A quick and simple way to check for a vac leak is to place your finger over the Idle Air intake hole just in front of the throttle plate in the TB bore. If you can completely close it off with your finger and the car continues to run - at all - you have a vac leak. As others have said, put your stock air cleaner back on.
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10:44 PM
Bernie Member
Posts: 410 From: Las Vegas, NV Registered: Jun 2002
The screw on the TB is not an idle adjustment screw - it is a throtle plate stop. The IAC controls the idle! Messing with the screw can cause bad things to happen. Mainly, if it's set too low, the throttle plate can "stick" in the TB bore. If it's set too high, the car will "surge as the IAC tries to control the air going into the TB - makes it act like a bad vac leak that comes and goes. There is a procedure here on PFF for setting the screw correctly. Serach for it. You idle issue can be a number of things as the guys mentioned above. Do one thing at a time! A quick and simple way to check for a vac leak is to place your finger over the Idle Air intake hole just in front of the throttle plate in the TB bore. If you can completely close it off with your finger and the car continues to run - at all - you have a vac leak. As others have said, put your stock air cleaner back on.
Great suggestions from everyone. I still have most of the original air cleaner and I am not partial to the hoover sound of the cold air intake anyway. Would just prefer the car ran solid.
Can you drop me a link to the settings on the throttle body screw? I did some searches but came up with nothing. Probably just don't know what to type in the search que.
could check for a vacum leaks with a mister bottole or a compressed can of carb cleaner? that would be my thought on the cars mis at idle see if it stablelizes when you hit it with the water in a squirt bottle etc... and spray down the vaccum lines while looking for cracks or connections that may leak even ware gasket are like uper and lower intake. spray those points see if they are leaking. these cars are so old that the parts are brittle and easy to break and can just break from vibration etc... of the engine if not that check spark plug gaps and spark plug wires see if they are leaking spark to ground like at night. or even a bad ignition coil in the car? every car is different so investigate also what about the fuel filter? it also says some thing about that in my book... only need a couple things like spark, fuel, and compression as in pistons timeing bring air in to the system etc... etc.. to have fuel ignition of fuel if it is not working right it is one of those three things. just remember if you got three thing to start a fire a car is simular air ,fuel, and spark. to casue fire. so check and inspect those systems.
