Hi I have a 86 GT and I have had it started but it seems to load up run rich then thats it wont start again. I have put new plugs ,vacume lines,coil & gas but it will start and run for a bit but way to rich thats what I get for $500
have you checked your O2 sensors? and what motor is in it? is it fuel injected or throttle body?
My first guess would be the O2 sensor is giving a bad reading so it makes it think the engine needs alot of gas..... but i guess you would need more info then that....gve more info on the car and we might be able to help
------------------ 88 Fiero Formula 2.8L - 5 Speed - - - A work in progress....
it is 2.8 and the fuel presure is 44 pounds and it holds for the 10 to 15 min the plugs are wet when i pull them and black . I cleand the plugs and let it sit over night with no plugs I hope it will dry out and just run for a bit
[This message has been edited by engine man (edited 10-05-2008).]
Got it to i run but wants to run rich so i pull the fuse to the fuel pump and it runs right till it runs out of fuel then the fuse back in need to check fuel pressure reg make sure the diafram is not bad i need a vacume pump. Oh ya one more ? is this OBD 2 or 1 i have a scan tool for 2 is there another way to get codes
[This message has been edited by engine man (edited 10-05-2008).]
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08:08 AM
86stealthfiero Member
Posts: 667 From: zanesville ohio Registered: Aug 2008
ive had this problem before first check to make sure the right amp fuse is in the fuse box if its higher than whats reguired it will flood out he engine or one side of the engine. my car runs a little rich too i also replaced my o2 sensor. if the plugs are wet as u indicated then there is definetly a fuel issue you might want to check for a faulty pressure regulator too. dont give up it could be worse.
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10:26 AM
katatak Member
Posts: 7136 From: Omaha, NE USA Registered: Apr 2008
How long has this car sat without running? Cold start injector, injectors could be stuck or leaking fuel. Turn the key on, let the fuel pressure build, turn off key and see how long it takes for the pressure to bleed off. My bet is that you have an injector problem.
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11:06 AM
katatak Member
Posts: 7136 From: Omaha, NE USA Registered: Apr 2008
ive had this problem before first check to make sure the right amp fuse is in the fuse box if its higher than whats reguired it will flood out he engine or one side of the engine. my car runs a little rich too i also replaced my o2 sensor. if the plugs are wet as u indicated then there is definetly a fuel issue you might want to check for a faulty pressure regulator too. dont give up it could be worse.
Please explain? I do not understand how the amperage of a fuse can cause an engine to run rich. You either have 12 volts to the fuel pump or you don't. The amperage of the fuse does not regulate fuel pressure?
I have checked the fuel pressure it stays at 45 psi for about 4 min then drops a little but holds about 40 for 15 min . I think thh fuel pfes reg is bad and not releving fuel pressure when runing like it suppose to do to it go's so rich it wont even run hardly wont even come close to idling. I will never give up it will run
[This message has been edited by engine man (edited 10-05-2008).]
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11:45 AM
86GT3.4DOHC Member
Posts: 10007 From: Marion Ohio Registered: Apr 2004
Well, just check the pressure with the engine running. If its anywhere near 40, its probably fine, but you can find the testing specs in the repair manuals.
As far as the fuses, the amperage of a fuse is completely irrelevant to the output of the pump in this respect. Doesnt matter if its a 10a or a 200a, it doesnt change anything.
the book said to put a vacume on it to see if it will drop the fuel pressure it is not supposed to have as high a pressure at idle the diaphram could be bad
i dont know i changed the fuse and it stopped i just was stating that it was something to check because one side of the engine (plugs) fouled out right after i changed them and i had a higher amp fuse and when i replaced it with the correct amprage it was fine.
[This message has been edited by 86stealthfiero (edited 10-05-2008).]
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03:50 PM
tjm4fun Member
Posts: 3781 From: Long Island, NY USA Registered: Feb 2006
A clogged cat will also foul out a motor. when it does run, cover the exhaust tips with your hands. if there is almost no flow, your cat could be shot. the fact that it holds the fuel pressure fairly well sort of rules out a stuck open injector, it would drop very fast if one of more where leaking.
I cant even get back there it wont idle so i think more than the cat is pluged but it could be i will know latter in the week when i get paid i will get a vacume pump to test the other part of the fuel prssure regulator
More than likely it's the injectors, BUT, it doesn't HAVE TO be too much fuel, Could Be too liitle SPARK ! what kind of spark do you have at the plugs ?? If you have a weak spark, the plugs Will Look like they are drowned with fuel because therer wasn't enough spark to totally burn it !
I changed the coil bought a brand new one no change i have a fiero service manual and just because you have 40 pluse pounds of fuel pressure dosent mean it is working corect at idle you should have a lower fuel pressure. If the diaphram is bad it could suck fuel right into the intake and i dont think I will be selling it but nice try LOL
[This message has been edited by engine man (edited 10-06-2008).]
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06:13 PM
edmjay Member
Posts: 111 From: Edmonton, AB, Canada Registered: Aug 2008
A clogged cat will also foul out a motor. when it does run, cover the exhaust tips with your hands. if there is almost no flow, your cat could be shot. the fact that it holds the fuel pressure fairly well sort of rules out a stuck open injector, it would drop very fast if one of more where leaking.
Sounds like a plugged converter to me... I know i'm new to posting on here, but I'm a licensed GM tech, and have run into the same problem many times, gets you chasing the wrong things when its fouling plugs and looks like its running rich.. With your pressure still at 36 after 1/2 hour, it's not leaky injectors causing the problem, that would be considered an acceptable drop in pressure. Easiest way to confirm that it's the cat, is remove your O2 sensor and fire it up, it'll be a bit noisy but should keep running.. If it does, then head down to the local exhaust shop and either have it swapped out for a resonator or replaced.
EDIT - wasn't thinking when I wrote it, I'm guessing in FL you need to pass smog... so a resonator in the cat's place probably would not be such a good idea... don't have to worry about that up here
still no good only way it will run if I pull the fuel pump fuse dont know what to think could some one check there fuel pressure while idling it should be lower than when it is runing but how much lower is what i need to know
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01:54 PM
pswayne Member
Posts: 1282 From: Lawrenceville, GA USA Registered: Sep 2006
Got it to i run but wants to run rich so i pull the fuse to the fuel pump and it runs right till it runs out of fuel then the fuse back in need to check fuel pressure reg make sure the diafram is not bad i need a vacume pump. Oh ya one more ? is this OBD 2 or 1 i have a scan tool for 2 is there another way to get codes
Actually, it's neither OBD 1 or 2. It's ALDL (Assembly Line Diagnostic Link), and it's under the cigarette lighter cover. To get the scan codes, short terminals A and B together and turn the key to ON (but not Start). The service engine light will blink the scan codes. First it will blink once, followed by a short delay, and blink twice. After a longer delay it will do this again. This is code "12", which is the normal code you should see. After 3 code 12's it will blink any error codes stored in the ECM. If it repeats 3 code 12's again, there are no errors.
i'll try to think of anything else to check... do you have access to a noid light? be nice to see if the injector pulses are reasonable or if it's commanding the injectors to open to much...
have you checked the coolant temp sensor? if it is disconnected it will read at the coldest temp, and then the pcm will be overfueling big time... if you can, test the resistance of the sensor and get back to me... I'm fairly certain those sensors are cheap, so maybe try a new one or a known good used one. just a thought...
how do you know its reading the temp? are you going by the temp gauge or do you have a scanner hooked up now? (i didnt think it ran long enough to get a temp reading on the dash, and just because it's showing there doesn't mean the pcm is seeing the same thing..)
if i pull the fuse to the fuel pump it will idle for about 5 to 10 min before runing out of fuel but i think i hurt the engine due to i got it to rev and it had fuel in the oil maybee time for a engine swap
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05:39 PM
edmjay Member
Posts: 111 From: Edmonton, AB, Canada Registered: Aug 2008
I have idea 4.3 1996 or up vortec put a carb on it drop in a hei and go 96 and up have the best heads they have the same design as the 350 vortec heads
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06:05 PM
86GT3.4DOHC Member
Posts: 10007 From: Marion Ohio Registered: Apr 2004
I dont know how to say this, but it seems to me it would be impossible for the engine to run 5-10 minutes on just the pressure in the rail. I know, because I often pull the fuse pump fuse to prevent theft, without the fuse, the engine will start and idle for a few seconds, then spudder out, then spit and spudder.
Did you mean 5-10 seconds? Thats perfectly normal. If its really 5-10 minutes, your fuel pump is getting power from somewhere else, the oil pressure bypass still uses the fuse as the power source.
well i started it this morning no knock i feel it was detination this thing is going to be a good little car once i get it runing corect could it be a bad TPS thinking im giving more throttle but i have no check engine light Pleas Help dont know where to look any more
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11:10 AM
86GT3.4DOHC Member
Posts: 10007 From: Marion Ohio Registered: Apr 2004
If the pressure is bleeding to 0 in 5-10 minutes with the engine off, thats a little quick, you probably have a leaky injector. I dont know that it is fast enough to cause your problems, but it is definitely a problem, so its a lead. You'll have to pull the injectors and check them.
If could also be the fuel pump, but I dont know how to test it in this case.
Start with the Cold Start Injector, remove it, then turn it around and put the line back on. Pressureize the fuel system and watch.
Then pull the upper and middle intake, remove the fuel rail, hook the lines back up and pressureize the system.
To check the TPS, check the grey wire for 5v, and the black for ground. Then check the other wire, it should read .5v at closed throttle and 4.5 v at WOT, with a smooth transistion in the middle.
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01:06 PM
86GT3.4DOHC Member
Posts: 10007 From: Marion Ohio Registered: Apr 2004
Thats the problem it hold pressure for 20 min 42 LBS not runing every thing off so not leaking injector its not a pluged cat tried pulling O2 sensore to releive any back pressure dint help
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01:23 PM
86GT3.4DOHC Member
Posts: 10007 From: Marion Ohio Registered: Apr 2004
my 3.8 swap was doing a similar thing with the tps incorrectly hooked up, but i also couldnt get it to rev for anything, i would invest in an aldi connector it should help you figure somethings out quickly, i would hope.
