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| IT WONT START!!! (Page 1/3) |
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BruhMans06
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JUN 30, 09:10 PM
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Whattup
So I have a 1984 automatic fiero that I have been working on for the past 8ish months and have gotten it to run pretty well... until it didnt.
A few nights ago I was replacing a valve cover gasket, EGR valve, and the throttle position sensor, afterwardss, I started it, and it ran pretty decent. The engine would surge a few 100 rpms a little bit, but I chalked that up to being minor vacuume leaks (Pretty normal) So this morning, I go to start it, and it starts like it normally would, and I take it probably a mile to the store, at which point it starts to bog down. I park the car in the parking lot and try to restart it. It fires, but no idle, dies immediatly.
I manage to limp the car back home and replace the throttle position senor with the original one I had on the car, and no dice. same problem of not wanting to idle at all. I also checked over all of my electronics and the only unplugged cables are the VSS and TCC cables (minor tranny issues) everything else is still connected.
I have absolutley no idea what the issue is right now
list of parts Ive replaced:
Throttle position sensor
idle air control valve
map sensor
fuel/air filters
fuel injector
EGR valve
ignition coil
distributor rotor and cap
ignition cables
spark plugs 6ish months ago
valve cover gasket
airbox gasket
headgasket
PLEASE HELP!
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Patrick
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JUN 30, 10:13 PM
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We appear to have been down this road previously.
| quote | Originally posted by Patrick Here:
Before you give up on this engine, see if you've got fuel pressure... and/or spray starting fluid into the throttle body.
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BruhMans06
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JUN 30, 10:47 PM
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BruhMans06
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JUL 01, 01:23 PM
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[QUOTE]Originally posted by Patrick:
We appear to have been down this road previously.
just checked the fuel pressure and have 10 psi, which is within spec. I still dont know whats going on.
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82-T/A [At Work]
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JUL 01, 02:55 PM
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| quote | Originally posted by BruhMans06:
just checked the fuel pressure and have 10 psi, which is within spec. I still dont know whats going on. |
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Did you spray starting fluid into the TBI like Patrick mentioned? You can either use carb cleaner, or even WD-40 to some extent. But if the car runs while you're doing that... then it's definitely a fuel issue.
10 PSI sounds to be at the bottom of the range... I remember reading that 10-18psi is the optimal operating range. 14-18psi is OK because it's a return-system so any additional fuel will just go back into the tank. Everything I see online says you really want 12-PSI... but the engine will likely demand more at RPM. The ECM, particularly the TBI system, has a whole bunch of emissions programming that can reduce the amount of fuel flow depending on varying conditions and temperature (besides normal fuel mapping). There's a bunch of conditions it could run into (even at idle) where it intentionally reduces fuel flow (just read a whole page on that on the 86 service manual).
I'm still curious if maybe you have an injector problem too. It could be anything.
Can you take some videos and post them? (create a YouTube account and share the link). I'd like to see what the spray pattern looks like from the TBI, and I'd also like to hear it try to start.
Definitely try what Patrick said.
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theogre
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JUL 01, 03:44 PM
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| quote | Originally posted by 82-T/A [At Work]:
10 PSI sounds to be at the bottom of the range... I remember reading that 10-18psi is the optimal operating range. 14-18psi is OK because it's a return-system so any additional fuel will just go back into the tank. |
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9-13PSI per GM.
9-10 the engine runs but may have fuel plumbing issues like small section of "rubber" line is leaking for various reasons.
Why say that? Many times GM set this regulator to 12-13PSI
Over 13psi often is something wrong w/ return line can also set "Bogus" DTC 45 because high pressure making the engine to run rich. Bad return can kill the pump as have enough flow is coolant & lube for it.
"Bad" hose often mean the rubber is "good," the pump will run & fuel will flow but even rust between the rubber & steel line mean bleeding off pressure & fuel flow for the engine. This won't kill the pump but often the regulator stays close so return line does little or nothing.------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)
The Ogre's Fiero Cave
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BruhMans06
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JUL 01, 07:01 PM
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Thanks for the feed back guys really appreciate it
i know its not the injector since I got a new one a few weeks ago.
So I did need to drop the tank previously to drain it of all the old gas a few months ago but I never replaced the pump or any of the lines.
so im guessing since I have a new filter and injector, one of the lines must be clogged or the pump is cooked.
imma get the car up in the air within the next week and check the lines near the tank and see whats up.
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82-T/A [At Work]
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JUL 01, 07:17 PM
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| quote | Originally posted by BruhMans06:
Thanks for the feed back guys really appreciate it
i know its not the injector since I got a new one a few weeks ago.
So I did need to drop the tank previously to drain it of all the old gas a few months ago but I never replaced the pump or any of the lines.
so im guessing since I have a new filter and injector, one of the lines must be clogged or the pump is cooked.
imma get the car up in the air within the next week and check the lines near the tank and see whats up. |
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Make sure you replace the fuel filter too when you change everything else out. Those need to be changed regularly as well.
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BruhMans06
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JUL 07, 05:38 PM
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So I ended up replacing the fuel pump that was rated for 13 psi rather then the stock psi, I also ended up replacingh some of the lines.
I also checked for spark which I have on all cylinders
still ahve the same issue, car wont idle. im 5 seconds away from giving up.
mind you I have a new fuel filter and injector, also literally all of the sensors on the throttle body are new. the engine might just be toast.[This message has been edited by BruhMans06 (edited 07-07-2024).]
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cartercarbaficionado
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JUL 07, 06:52 PM
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| quote | Originally posted by BruhMans06:
So I ended up replacing the fuel pump that was rated for 13 psi rather then the stock psi, I also ended up replacingh some of the lines.
I also checked for spark which I have on all cylinders
still ahve the same issue, car wont idle. im 5 seconds away from giving up.
mind you I have a new fuel filter and injector, also literally all of the sensors on the throttle body are new. the engine might just be toast.
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did you check that the new sensors are reporting correctly? also not idling is in my experience with 84s usually the computer being weird after replacing sensors
also do try the old map sensor and such until it idles again
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