Fiero GT lacks power

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i recently bought a 1987 Fiero GT 5-speed and i took it to my local dragstrip and got an 18.0 my first run and a 17.7 my second. i know the fiero isnt a rocketship but everything ive seen for a stoct GT is around a 15.7. so what could be the problem?
 
Age, Mileage, condition, etc.
When was the last time the engine was tuned up? Ignition timed?
How well was the car maintained? (Exhaust, intake/injectors cleaned, etc.)
How many miles on the car?

If you are going to be racing it on the dragstrip you should also do a compression check to see how much wear the cylinders have with the mileage.
 
its got 99,000mi i just went through and checked all the spark plugs yesterday and was going to check the timing but my timing light stopped working. probably tomorrow im going to clean the throttle body and check out the rotor on the distributor. there is an exhaust leak where the rear manifold connects to the downpipe. but i dont think doing these things will help me pick up 2 seconds in the 1/4 mi. what else could it be?
 
The 2.8L is rated at 135-140hp.
You could easily lose 20-30 horsepower with a combination of items being worn/bad.
Here's a list of some of the things that can cause power losses. It may not be just one thing.
Timing to far retarded
worn piston rings
worn/carboned up valves
carboned up cylinders
carboned up exhaust manifolds. (If you look at the stock manifolds on the inside you'll notice that Pontiac only cut a slit in the log. Porting them can gain you 5-8 hp.)
Dirty Injectors
slightly weak fuel pump
Weak ignition coil
cracked/bad vacuum lines or EGR tube (very common problem on Fiero's)
slightly clogged catalytic converter


Also what RPM did you shift at when you ran it down the strip? With the V-6/5-spd shifting at 5500 will give you better times than going up to redline.
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i shifted right at redline going down the strip. i took a look at the cap and rotor they should be replaced and maybe spark plugs and coil too since they are relatively cheap. what do you mean by EGR tube? also when i pulled the spark plug out from the #5 cylinder there was quite a bit of carbon built up on it. i dont know if that means anything but it might be helpful.

is there a way i can test the fuel pump and see how much it flows?
 
FieroFanatic said:
i shifted right at redline going down the strip. i took a look at the cap and rotor they should be replaced and maybe spark plugs and coil too since they are relatively cheap. what do you mean by EGR tube? also when i pulled the spark plug out from the #5 cylinder there was quite a bit of carbon built up on it. i dont know if that means anything but it might be helpful.

is there a way i can test the fuel pump and see how much it flows?
Click to expand...

The EGR is mounted on the crossover exhaust pipe near the distributor. It has a tube that comes out just under it and goes to the bottom of the plenum. Usually there is an insulating sleeve over the tube since it passes very close to the distributor. These are notorious for developing cracks causing vacuum leaks. Some newer versions are flexible which eliminates carcking in the future. You can check the tube out by spraying WD-40 near the ends with the engine at idle. If it stumbles there is a crack.
The Fiero Store sells the flexible tubes. www.fierostore.com

There is a product called "seafoam" that helps remove heavy carbon build-up in the cylinders and on the valves. You can get it at most auto parts stores like NAPA or Auto Zone. It will also clean out the injectors and varnish in your fuel system. Here is the link to the product:
http://www.seafoamsales.com/motor-treatment/index.html

On the right side (near the front of the motor) there is a test port on the fuel rail just under the plenum. You can hook a fuel pressure gauge to this and measure the fuel pressure. At idle it should be around 32-34 psi. Typically it will peak around 40 - 42 psi at wide open throttle. (while driving) If the pressure gauge is bouncing a lot it could be a dirty filter, dirty injectors or a vacuum leak.

I would suggest running the seafoam through the engine then replace fuel filter and change plugs, wires, cap and rotor. Make sure you use AC delco plugs or NGK's as these work the best with the V-6.
 
Same issue!

I have the same problem with my 87 GT I am resurecting from the dead. Heavy blue cloud on acceleration, then mellows a bit. LARGE oil consumption.... Plugs are fine (actually got 27mpg on the first test run), oily residue in intake, did a compression test, consistent 230 on the back bank, and a consistent 130 on the front bank???? I decided to pull the heads (what a PAIN!!!). Some of the cylinders had a lot of carbon. I dropped the heads off at a cylinder head repair shop yesterday. Looks like if there is nothing major, will be about $300. Hopefully there are some bad guides that allowed the oil to get into the exhaust ports....

Next delima: Should I do anything with the bottom end? I don't particularily want to drop the engine... The is a slight ridge on some of the cylinders, but NO scoring. Anyone have any recomendations?
 
Okay so i replaced everything and it seems to run better but i wont know for sure until i can get back to the track next summer but i was looking through my HAYNES manual and i saw that it said fuel pressure should be between 42-47 psi. mine was a steady 37 psi even after i replaced the filter. i didnt seafoam the car yet but i when i do im going to give it an oil change and check the timing. is there anything else that i could give a good once over that might be causing a power loss? also i forgot to mention that ever since i bought it, its had a slight lifter tick/rocker chatter. and now there its a kinda metallic rumbling coming from inside my catalytic converter. my guess is that its clogged? should i just remove it cause in illinois any car pre 1996 doesnt need to go in for emissions testing?
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FieroFanatic said:
Okay so i replaced everything and it seems to run better but i wont know for sure until i can get back to the track next summer but i was looking through my HAYNES manual and i saw that it said fuel pressure should be between 42-47 psi. mine was a steady 37 psi even after i replaced the filter. i didnt seafoam the car yet but i when i do im going to give it an oil change and check the timing. is there anything else that i could give a good once over that might be causing a power loss? also i forgot to mention that ever since i bought it, its had a slight lifter tick/rocker chatter. and now there its a kinda metallic rumbling coming from inside my catalytic converter. my guess is that its clogged? should i just remove it cause in illinois any car pre 1996 doesnt need to go in for emissions testing?
Click to expand...

Rattling cat means its bad and restricting exhaust. You can remove it and replace it with a straight pipe. Catco also make a hi-flo cat for the Fiero as well if you just want to change the cat.

Fuel pressure is a steady 37psi when? At idle or wide open throttle? the Haynes spec is at wide open throttle not idle. If the fuel pressure stays the same even when revving the motor, It could be a bad fuel pressure regulator or the vacuum line is cracked/broken. Just under the upper plenum on the distributor side you will see the fuel rail with a round cover on top. That is the regulator. There should be a vacuum line plugging ito the top and hooked to ported vacuum.
Verify the regulator is getting vacuum, If it is you may need a new regulator. If not, Find the vacuum leak. One thing about V-6 Fiero's is GM used hard plastic vacuum lines which over time become brittle and split/crack. Rodney Dickman www.rodneydickman.com sells a replacement set that uses metal lines.

For the rocker/lifter noise, With as many mies you have I would switch to a 10W-30 oil. There is likely some slight wear in the engine. Also the V-6 valvetrain is a little noisy so it depends on how loud the ticking is.


Where in Illinois are you? I'm in Schaumburg.
 
fuel pressure is 37 psi at idle. when i revved it pressure would go up but then would drop back down to around 37 psi even if i held the throttle at the higher rpm.

the ticking is noticeable. it doesnt sound like noisy engine to me.

im in palos park
 
and i noticed sometimes under load or at startup at low rpms ill hear a loud pop from the intake. its just one pop but i dont know what it is. and when it idles it idles pretty high around 1500 rpms even when its warmed up.

and i was also planning on stepping up to 10W-30 because it burns a little oil on startup occasionally
 
anyone? this is my last couple questions, i swear
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Sounds like the ignition timing is off or you might have a slightly burnt intake valve.
 
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