One point mentioned a few times is about the throttle not closing all the way. Is the spring doing it completely, or can you close it a tiny bit more by hand? Is there any tolerance in the throttle cable length? Does it close better with the cable disconnected?
How about dry throttle parts desperate for some oil? Don't be afraid to use some WD40 and a brush, with an air hose if you have one, to get every moving part moving freely.
One point mentioned a few times is about the throttle not closing all the way. Is the spring doing it completely, or can you close it a tiny bit more by hand? Is there any tolerance in the throttle cable length? Does it close better with the cable disconnected?
If we look past the dirt , it appears that the TBI's butterfly valve is fully closed.
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Originally posted by Patrick:
There's an awful lot of dirt on the "clean" side of that air filter canister/TBI gasket. It should be absolutely spotless. Your poor engine!
At one point I thought that mightve been the problem but I later confirmed that it closed completely and everything moved fine/nothing was binding. I probably will oil everything still though so thank you.
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Originally posted by Yellow-88:
One point mentioned a few times is about the throttle not closing all the way. Is the spring doing it completely, or can you close it a tiny bit more by hand? Is there any tolerance in the throttle cable length? Does it close better with the cable disconnected?
How about dry throttle parts desperate for some oil? Don't be afraid to use some WD40 and a brush, with an air hose if you have one, to get every moving part moving freely.
At one point I thought that mightve been the problem but I later confirmed that it closed completely and everything moved fine/nothing was binding. I probably will oil everything still though so thank you.
please provide more pictures of what modifications you have done to the engine and if you think you killed your ecm or tbi I do have some sitting around as long as a 84 ecu will work in an 85
OK. The throttle plate closes completely. No vacuum leaks in any of the tubes. At this point it looks like an IAC issue.
Crud in the seat not letting it close as far as it want's to? I suppose there can be a failure in the "motor" or the power to it but personally I'd clean both the valve and the electrical connector first before jumping to extreme conclusions. Most problems are actually simple stuff. Here is a link to an IAC thread.
Okay I’ll try cleaning it today and go from there. I just found another thread of someone having the exact same issue as me and the iac valve and everything just needed cleaned so hopefully this fixes it.
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Originally posted by Yellow-88:
OK. The throttle plate closes completely. No vacuum leaks in any of the tubes. At this point it looks like an IAC issue.
Crud in the seat not letting it close as far as it want's to? I suppose there can be a failure in the "motor" or the power to it but personally I'd clean both the valve and the electrical connector first before jumping to extreme conclusions. Most problems are actually simple stuff. Here is a link to an IAC thread.
UPDATE: I cleaned the IAC and it idles right around 900!!! I understand I have to drive it a few times over 35mph to get it right but this is awesome!! Thank you all for your help!
I cleaned the IAC and it idles right around 900!!!
If the IAC valve was gummed up with crud and it couldn't close, you in essence did have a vacuum leak, as a surplus of air was being allowed to enter the intake system. I bet dollars to donuts that a lot of that grit we see in your photo of the TBI has worked its way into the IAC system, and resulted in the valve becoming stuck in an open position.
If it was my engine, I'd be removing the TBI unit to thoroughly clean it, as I wouldn't want to be washing grit out of the TBI unit and into the intake and eventually into the combustion chambers.
I will start looking online for the gaskets and stuff and get to cleaning soon! Thank you!
quote
Originally posted by Patrick:
If the IAC valve was gummed up with crud and it couldn't close, you in essence did have a vacuum leak, as a surplus of air was being allowed to enter the intake system. I bet dollars to donuts that a lot of that grit we see in your photo of the TBI has worked its way into the IAC system, and resulted in the valve becoming stuck in an open position.
If it was my engine, I'd be removing the TBI unit to thoroughly clean it, as I wouldn't want to be washing grit out of the TBI unit and into the intake and eventually into the combustion chambers.
I will start looking online for the gaskets and stuff and get to cleaning soon! Thank you!
How comfortable are you with rebuilding the TBI unit? There's a rebuild kit that's about $50 bucks... it's not hard at all to do. I'd just buy some brake cleaner and after disassembling it, I'd blast the heck out of it.
I’m pretty confident I could do it after thorough research. Even if I do mess it up I’ve got a buddy that’s great with these types of things. Where could I purchase a rebuild kit?
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Originally posted by 82-T/A [At Work]: How comfortable are you with rebuilding the TBI unit? There's a rebuild kit that's about $50 bucks... it's not hard at all to do. I'd just buy some brake cleaner and after disassembling it, I'd blast the heck out of it.
I will start looking online for the gaskets and stuff and get to cleaning soon! Thank you!
quote
Originally posted by Patrick:
If the IAC valve was gummed up with crud and it couldn't close, you in essence did have a vacuum leak, as a surplus of air was being allowed to enter the intake system. I bet dollars to donuts that a lot of that grit we see in your photo of the TBI has worked its way into the IAC system, and resulted in the valve becoming stuck in an open position.
If it was my engine, I'd be removing the TBI unit to thoroughly clean it, as I wouldn't want to be washing grit out of the TBI unit and into the intake and eventually into the combustion chambers.
I’m pretty confident I could do it after thorough research. Even if I do mess it up I’ve got a buddy that’s great with these types of things. Where could I purchase a rebuild kit?
And if you want, you can also replace your fuel injector while you're in there... price ranges from $60 to $120 depending on if you buy new, or a rebuilt one with a core return: https://www.rockauto.com/en...r,fuel+injector,6224
But honestly... this is one of those times where you want to figure out where you want to go with this. The car runs pretty well right now, so maybe you just fix what's broken when it breaks... but for me, I tend to go a little overboard.
I know you said you did some maintenance on it... but if you haven't already, I'd replace the fuel filter (I didn't see where you said you'd done that). I would also put back the factory air cleaner. It's going to be much better than an open-element air cleaner. If you want to get a little better air flow, you can knock out the "water separator" in the air box. You remove the little grill on the side of the Fiero, and then carefully shove a hammer handle in there, it knocks out the piece of plastic that's used as a water baffle. You can also get this from Rodney Dickman: https://rodneydickman.com/p...o.php?products_id=70
... it eliminates the water separator (not really needed, to be honest), and you get fresh air directly from a higher pressure zone on the side of the car. You're likely losing some power / drivability by having an open-element air cleaner in the hot engine back. It would be different if it was a front-engined car where the cool air was directly flowing into the engine compartment.
[This message has been edited by 82-T/A [At Work] (edited 09-22-2024).]
Thank you for the links! I did already replace my fuel filter but thank you anyway! I also like to go all out when maintaining my vehicles lol. It always starts out with “well I might as well do that while I’m in there” lol
EDIT: I did the open air cleaner bc of the look and the sound, I know it’s much less effective than the original.
And if you want, you can also replace your fuel injector while you're in there... price ranges from $60 to $120 depending on if you buy new, or a rebuilt one with a core return: https://www.rockauto.com/en...r,fuel+injector,6224
But honestly... this is one of those times where you want to figure out where you want to go with this. The car runs pretty well right now, so maybe you just fix what's broken when it breaks... but for me, I tend to go a little overboard.
I know you said you did some maintenance on it... but if you haven't already, I'd replace the fuel filter (I didn't see where you said you'd done that). I would also put back the factory air cleaner. It's going to be much better than an open-element air cleaner. If you want to get a little better air flow, you can knock out the "water separator" in the air box. You remove the little grill on the side of the Fiero, and then carefully shove a hammer handle in there, it knocks out the piece of plastic that's used as a water baffle. You can also get this from Rodney Dickman: https://rodneydickman.com/p...o.php?products_id=70
... it eliminates the water separator (not really needed, to be honest), and you get fresh air directly from a higher pressure zone on the side of the car. You're likely losing some power / drivability by having an open-element air cleaner in the hot engine back. It would be different if it was a front-engined car where the cool air was directly flowing into the engine compartment.
[This message has been edited by Scuba_steve45 (edited 09-28-2024).]
Thank you for the links! I did already replace my fuel filter but thank you anyway! I also like to go all out when maintaining my vehicles lol. It always starts out with “well I might as well do that while I’m in there” lol
EDIT: I did the open air cleaner bc of the look and the sound, I know it’s much less effective than the original.
I had a Porsche 944 once. I went to go replace the windshield wipers... $7,000 later... I realized that I probably should have just replaced the windshield wipers.
By the way, I'm really curious what it sounds like with an open-element air filter. Holley made a "performance" air cleaner lid that also came with a base... but most people simply used the new lid with the old air cleaner assembly. That allowed for the sound, some additional air, and still pulling in some of the cold air from the side of the car. Might be worthwhile looking into. You just need to order a slightly smaller air cleaner lid and keep the same bottom ... or is that what you did?
I just cut up the original air cleaner with an angle grinder and a dremel. I am planning on replacing the top of it with a chrome lid and polishing the bottom lid to semi-match. I’ll upload pics when I’m done!
quote
Originally posted by 82-T/A [At Work]: I had a Porsche 944 once. I went to go replace the windshield wipers... $7,000 later... I realized that I probably should have just replaced the windshield wipers.
By the way, I'm really curious what it sounds like with an open-element air filter. Holley made a "performance" air cleaner lid that also came with a base... but most people simply used the new lid with the old air cleaner assembly. That allowed for the sound, some additional air, and still pulling in some of the cold air from the side of the car. Might be worthwhile looking into. You just need to order a slightly smaller air cleaner lid and keep the same bottom ... or is that what you did?
I just cut up the original air cleaner with an angle grinder and a dremel. I am planning on replacing the top of it with a chrome lid and polishing the bottom lid to semi-match. I’ll upload pics when I’m done!
quote
Originally posted by 82-T/A [At Work]: I had a Porsche 944 once. I went to go replace the windshield wipers... $7,000 later... I realized that I probably should have just replaced the windshield wipers.
By the way, I'm really curious what it sounds like with an open-element air filter. Holley made a "performance" air cleaner lid that also came with a base... but most people simply used the new lid with the old air cleaner assembly. That allowed for the sound, some additional air, and still pulling in some of the cold air from the side of the car. Might be worthwhile looking into. You just need to order a slightly smaller air cleaner lid and keep the same bottom ... or is that what you did?
, it appears that the TBI's butterfly valve is fully closed.
