1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Losing acceleration

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Old 03-25-09, 12:42 AM
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Losing acceleration

I'm having problems with my car accelerating. I'll be driving and within a couple of mins my engine sputters when i hit over 2500 rpm in any gears then if i try to give it more gas it just dies out or goes into idle. I've tryed tweaking with the air intake adjuster and it still does the same thing. Anyone have any ideas on why it may be doing this?
Old 03-25-09, 01:39 AM
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Fuel filter and/or the fuel tank may have debris/rust that's plugging the pickup filter or fuel filter.
Old 03-25-09, 02:28 AM
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buy a new filter, empty the tank. this is on an se?
Old 03-25-09, 08:56 AM
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+1 on fuel filter, if problem persists after that clean your fuel lines and gas tank and replace fuel filter again.
Old 03-25-09, 09:28 AM
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I ran into several fuel issues on my car (84 gsl-se) due to the fact that i have crud in my tank. the problem i was having was that the small intake screen in the fuel pump was getting clogged. there was not that much debris coming out of the tank, but the screen is so small that it would only take a couple days to get clogged up. My solution was to buy a universal inline filter to install between the tank and fuel pump. its go alot more area inside to fill up before it restricts suction than the small screen does.

another problem to look into (im assuming we are talking about an efi car) is the fuel pressure regulator. whatever your issue is, it sounds like you are starved for fuel, and the fpr is one of the first places i would look. the plastic nipple on it is very prone to break it off. if its broken, you can drill out the hole and insert a steel roll pin and seal it with rtv. this method will work on all of the plastic "solenoids".
Old 03-25-09, 10:58 AM
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Thanks guys i'll check it out tomorrow but yes it's an SE. So it is fuel injected =)
Old 03-28-09, 01:22 PM
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i replaced the fuel filter and i'm still having some problems. But the fuel filter definetly needed to be replaced. I'll post some picks of how bad it was later but i'm still losing acceleration until it dies out or goes into idle.
Old 03-28-09, 01:22 PM
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Where is the FPR and and the pick-up filter at guys? Thanks
Old 03-28-09, 02:22 PM
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Originally Posted by Drifting_Fool
Where is the FPR and and the pick-up filter at guys? Thanks
the FPR is on the rear of the fuel rail underneath the upper intake manifold. you have to remove the upper intake manifold to access it.

my pickup filter im going to assume you mean the filter on the suction side of the fuel pump. remove the hose on the suction side (drivers side) of the fuel pump. there is a sall conical filter that slides into the fitting. Mine was very bad about clogging and it caused problems similar to what you are describing. I removed it completely and installed a universal plastic filter in the hose between the pump and the tank.

You need to check your fuel psi. If you have FPR problems, the fuel PSI will reflect it. My car has 45-50 psi at idle and it increases as the engine revs up. when my fpr was not working properly, i could hold the pedal to the floor in nuetral and the engine would start studdering and slowly lose rpm starting at around 8k rpm. If trying to accelerate under a load it would never make it over 4k rpm without a serious studder/engine dying problem.
Old 03-29-09, 11:02 PM
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Thanks buddy i'll check on it on tuesday. I'm looking for that memory card to post the pics in the mean time =P
Old 03-30-09, 12:42 AM
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sounds like it could be an ignition issue...
Old 03-30-09, 09:22 AM
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my pickup filter im going to assume you mean the filter on the suction side of the fuel pump. remove the hose on the suction side (drivers side) of the fuel pump. there is a sall conical filter that slides into the fitting. Mine was very bad about clogging and it caused problems similar to what you are describing. I removed it completely and installed a universal plastic filter in the hose between the pump and the tank.


The filter that you installed, was it specifically for FI or doesn't it matter?
Old 03-30-09, 10:42 AM
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Originally Posted by perfect_circle
sounds like it could be an ignition issue...
Agreed. I'd continue checking your fuel filters (in line and the screen), but i'd also check and make sure your ignition system is up to snuff.
Old 03-31-09, 02:00 PM
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fuel ppump
Old 03-31-09, 06:25 PM
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...or clogged cat.
Old 03-31-09, 10:12 PM
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or mice......
Old 04-02-09, 04:30 PM
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This is how dirty the old fuel filter was. I replaced it with a new one and it kept doing the same thing as before but not as bad. So i dumped out the fuel filter again and i haven't gotten a chance to really get on it but it seemed to run better.
Attached Thumbnails Losing acceleration-fuel-filter.jpg  
Old 04-02-09, 04:31 PM
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Black death, right where my cat was i saw the there was like smoke kinda pouring out of it like there was a small fire on the inside of it. Could that be it?!?
Old 04-02-09, 05:55 PM
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Originally Posted by Drifting_Fool
This is how dirty the old fuel filter was. I replaced it with a new one and it kept doing the same thing as before but not as bad. So i dumped out the fuel filter again and i haven't gotten a chance to really get on it but it seemed to run better.
judging by that picture id say your tank is pretty nasty, you have two options. remove tank, clean/replace, change BOTH fuel filters, and you should be good. the other option is the one i took. Remove the line from the suction side of the fuel filter, check the screen, its probably clogged, remove it. reinstall the line. now put a fuel filter inline between the tank and the fuel pump, the bigger the better so it takes longer to clog. then just clean/change as needed and the tank will basically just clean itself out.
Old 04-02-09, 06:19 PM
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Originally Posted by Drifting_Fool
Black death, right where my cat was i saw the there was like smoke kinda pouring out of it like there was a small fire on the inside of it. Could that be it?!?
it could be, i know the symptoms of a clogged cat are similar to a clogged fuel filter, it's gonna run like crap and you won't be able to get up to speed. but i don't know how to check for a clogged cat besides taking it off and looking right through it.
Old 04-02-09, 07:13 PM
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One easy way to check for a clogged cat is to have a witness observe from out of the car as you do some full throttle drive by's. You've heard before where an exhaust "hiss's", like it is trying to blow through a straw? If your cat is clogged that's what it will sound like.
Old 04-02-09, 07:18 PM
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If you don't have emissions testing than replace the cat's and exhaust manifold with a racingbeat header and pre-silencer.
Old 04-02-09, 07:31 PM
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Originally Posted by slow5oh
judging by that picture id say your tank is pretty nasty, you have two options. remove tank, clean/replace, change BOTH fuel filters, and you should be good. the other option is the one i took. Remove the line from the suction side of the fuel filter, check the screen, its probably clogged, remove it. reinstall the line. now put a fuel filter inline between the tank and the fuel pump, the bigger the better so it takes longer to clog. then just clean/change as needed and the tank will basically just clean itself out.

He has an SE, so he cannot put one of those in-line fuel filters in like you can with a carb, unless he buys one that specifically is made for FI.
Old 04-02-09, 07:44 PM
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Originally Posted by mjm4jc
He has an SE, so he cannot put one of those in-line fuel filters in like you can with a carb, unless he buys one that specifically is made for FI.
notice I said on the suction side, NOT the pressure side. you can do it just fine on the suction side, I have one on my car with no problems (84 GSL-SE). Now on the pressure side, yes, it will crack the filter from the pressure and blow fuel everywhere.
Old 04-02-09, 07:45 PM
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You could always put some pressure to the line coming from the tank (if you have a compressor) to see if the screen is plugged without dropping the tank.


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