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Fuel pressure regulator by Andrew561
Started on: 04-11-2025 10:31 AM
Replies: 13 (140 views)
Last post by: 82-T/A [At Work] on 04-19-2025 08:38 AM
Andrew561
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Report this Post04-11-2025 10:31 AM Click Here to See the Profile for Andrew561Send a Private Message to Andrew561Edit/Delete MessageReply w/QuoteDirect Link to This Post
Hey guys i need help in locating the fuel pressure regulator on my 1988 fiero 2.5 and i cant find it anywhere ive also read that its on the gas tank but im not 100% sure so if someone can help me out with locating it that would be amazing
Thank You!
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Report this Post04-11-2025 11:36 AM Click Here to See the Profile for Vintage-NutSend a Private Message to Vintage-NutEdit/Delete MessageReply w/QuoteDirect Link to This Post
I'm a V6 guy but I believe it is in the throttle body itself....

This photo is from a 1988 S10 2.5L L4

Fuel pressure regulator is circled in the red {I added a red arrow}



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Report this Post04-11-2025 11:51 AM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Vintage-Nut:

I'm a V6 guy but I believe it is in the throttle body itself....

This photo is from a 1988 S10 2.5L L4

Fuel pressure regulator is circled in the red {I added a red arrow}




100%, that is the fuel pressure regulator. It's easier to change out on the newer 87-88 Fieros than it is on the 84-86. But I want to ask... how do you know that you need the fuel pressure regulator replaced. Is this what someone told you? I've never seen one fail... not that they don't occasionally, but it's usually something else, especially in a car this old. These fuel pressure regulators usually last basically forever... and only really ever get replaced because someone is rebuilding the TBI unit for the heck of it.
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Andrew561
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Report this Post04-11-2025 11:56 AM Click Here to See the Profile for Andrew561Send a Private Message to Andrew561Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 82-T/A [At Work]:
100%, that is the fuel pressure regulator. It's easier to change out on the newer 87-88 Fieros than it is on the 84-86. But I want to ask... how do you know that you need the fuel pressure regulator replaced. Is this what someone told you? I've never seen one fail... not that they don't occasionally, but it's usually something else, especially in a car this old. These fuel pressure regulators usually last basically forever... and only really ever get replaced because someone is rebuilding the TBI unit for the heck of it.


So basically what happens is if you let the car sit for longer than let’s say two hours it takes 30 seconds to start the car but when you just turned off the car and try to turn it back on it starts right back up. I’m in a diesel mechanics class and my teacher said that it could be the fuel pressure regulator because after it sits a while, the fuel can leak back to the fuel tank but I am not sure he(my teacher) seems to be pretty confident for that to be the answer
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Report this Post04-11-2025 12:44 PM Click Here to See the Profile for 1985 Fiero GTSend a Private Message to 1985 Fiero GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Andrew561:


So basically what happens is if you let the car sit for longer than let’s say two hours it takes 30 seconds to start the car but when you just turned off the car and try to turn it back on it starts right back up. I’m in a diesel mechanics class and my teacher said that it could be the fuel pressure regulator because after it sits a while, the fuel can leak back to the fuel tank but I am not sure he(my teacher) seems to be pretty confident for that to be the answer


The fuel pump replaces that fuel in a matter of a second or 2 at most, my guess would be the fuel pump relay, I don't know if it's different on the 2.5 but on the 2.8 there are 2 seperate things telling the fuel pump to turn on, oil pressure and the ECM via the fuel pump relay, if the relay dies the car still runs, but it needs oil pressure before the fuel turns on, so after sitting the oil drains down and takes a while to build pressure, then turns the fuel pump on, then fuel flows, then it finally starts.

To test this, turn the ignition to on (engine off), you should hear the fuel pump prime for a few seconds, then stop, if you don't, the ECM has no control over the pump, and it is driven by oil pressure only. Diagnose from there.
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Filben
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Report this Post04-11-2025 03:47 PM Click Here to See the Profile for FilbenSend a Private Message to FilbenEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Andrew561:


So basically what happens is if you let the car sit for longer than let’s say two hours it takes 30 seconds to start the car but when you just turned off the car and try to turn it back on it starts right back up. I’m in a diesel mechanics class and my teacher said that it could be the fuel pressure regulator because after it sits a while, the fuel can leak back to the fuel tank but I am not sure he(my teacher) seems to be pretty confident for that to be the answer


Check to see if its spraying fuel when it does its 30 second cranks. If it sprays then I would check if the ignition is going bad(getting heatsoaked after sitting). I would also check to see if its leaking or dripping fuel out of the injector when you shut it off. Those TBIs are easy to rebuild, not sure how cheap anymore, been a long time since I messed with one.
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Andrew561
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Report this Post04-17-2025 11:02 AM Click Here to See the Profile for Andrew561Send a Private Message to Andrew561Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Vintage-Nut:

I'm a V6 guy but I believe it is in the throttle body itself....

This photo is from a 1988 S10 2.5L L4

Fuel pressure regulator is circled in the red {I added a red arrow}




Yes that was The fuel pressure regulator thank you for helping me out
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Andrew561
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Report this Post04-17-2025 11:05 AM Click Here to See the Profile for Andrew561Send a Private Message to Andrew561Edit/Delete MessageReply w/QuoteDirect Link to This Post

Andrew561

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Member since Apr 2025
 
quote
Originally posted by Filben:


Check to see if its spraying fuel when it does its 30 second cranks. If it sprays then I would check if the ignition is going bad(getting heatsoaked after sitting). I would also check to see if its leaking or dripping fuel out of the injector when you shut it off. Those TBIs are easy to rebuild, not sure how cheap anymore, been a long time since I messed with one.


Yeah i checked everything out and saw that the fuel pressure regulator is bad cuz i saw it dripping fuel from a little hole that it hand in the housing (I’m not sure for a better way to explain that sorry)
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Report this Post04-18-2025 04:25 PM Click Here to See the Profile for Andrew561Send a Private Message to Andrew561Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Filben:


Check to see if its spraying fuel when it does its 30 second cranks. If it sprays then I would check if the ignition is going bad(getting heatsoaked after sitting). I would also check to see if its leaking or dripping fuel out of the injector when you shut it off. Those TBIs are easy to rebuild, not sure how cheap anymore, been a long time since I messed with one.


Yeah i checked everything out and saw that the fuel pressure regulator is bad cuz i saw it dripping fuel from a little hole that it hand in the housing (I’m not sure for a better way to explain that sorry)
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Report this Post04-18-2025 07:54 PM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Andrew561:

Yeah i checked everything out and saw that the fuel pressure regulator is bad cuz i saw it dripping fuel from a little hole that it hand in the housing (I’m not sure for a better way to explain that sorry)



If you haven't already bought it... this comes with everything you need: https://www.rockauto.com/en/moreinfo.php?pk=46922
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Andrew561
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Report this Post04-18-2025 08:09 PM Click Here to See the Profile for Andrew561Send a Private Message to Andrew561Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
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Originally posted by 82-T/A [At Work]:
If you haven't already bought it... this comes with everything you need: https://www.rockauto.com/en/moreinfo.php?pk=46922


So what would this whole kit be for? Does it replace all the gaskets on the carburetor?
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Report this Post04-18-2025 09:37 PM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Andrew561:

So what would this whole kit be for? Does it replace all the gaskets on the carburetor?



Yeah, it's a complete rebuild kit... so it replaces ALL of the gaskets. Not to nit-pick, but it's called a TBI unit (Throttle Body Injection), not a carburetor... hehe.

You have a 1987 model, so I don't have a video for that... but you can watch my daughter rebuild a 1984-1986 model, which is still pretty close to what you're doing... she goes through the entire rebuild process:




It looks a little different from yours, but it's basically the same thing.

But yeah, that's ALL you need to rebuild your TBI unit. The ONLY other thing you can possibly consider doing, is replacing the fuel injector if you think it's clogged.

There's one on Closeout from Rock Auto (probably an AC Delco) that's for sale for $21 bucks... which is a damned good deal: https://www.rockauto.com/en...optionchoice=0-0-1-1

Might as well since it's so cheap.


But yeah, follow the process in my daughter's video, and it's pretty easy.
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Report this Post04-18-2025 10:04 PM Click Here to See the Profile for Andrew561Send a Private Message to Andrew561Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by 82-T/A [At Work]:
Yeah, it's a complete rebuild kit... so it replaces ALL of the gaskets. Not to nit-pick, but it's called a TBI unit (Throttle Body Injection), not a carburetor... hehe.

You have a 1987 model, so I don't have a video for that... but you can watch my daughter rebuild a 1984-1986 model, which is still pretty close to what you're doing... she goes through the entire rebuild process:




It looks a little different from yours, but it's basically the same thing.

But yeah, that's ALL you need to rebuild your TBI unit. The ONLY other thing you can possibly consider doing, is replacing the fuel injector if you think it's clogged.

There's one on Closeout from Rock Auto (probably an AC Delco) that's for sale for $21 bucks... which is a damned good deal: https://www.rockauto.com/en...optionchoice=0-0-1-1

Might as well since it's so cheap.


But yeah, follow the process in my daughter's video, and it's pretty easy.


Yeah i might as well put in the whole rebuild kit cuz its cheaper and a lot better in the long run because i bought only the fuel pressure regulator at autozone and was more expensive than the rebuild kit. I didnt realize it was a TBI unit thanks for that information lol and yes i watched the whole video and your daughter did an amazing job and explaining everything and i understood everything that was going on thank you for that video as well and i think the fuel injector is still perfectly fine so as of right now i wont get a new fuel injector but id have to take a good look at it when i do take it out and thank you for helping me out you saved me some money on showing me where i could get the TBI rebuild kit
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Report this Post04-19-2025 08:38 AM Click Here to See the Profile for 82-T/A [At Work]Send a Private Message to 82-T/A [At Work]Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
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Originally posted by Andrew561:

Yeah i might as well put in the whole rebuild kit cuz its cheaper and a lot better in the long run because i bought only the fuel pressure regulator at autozone and was more expensive than the rebuild kit. I didnt realize it was a TBI unit thanks for that information lol and yes i watched the whole video and your daughter did an amazing job and explaining everything and i understood everything that was going on thank you for that video as well and i think the fuel injector is still perfectly fine so as of right now i wont get a new fuel injector but id have to take a good look at it when i do take it out and thank you for helping me out you saved me some money on showing me where i could get the TBI rebuild kit



No problem! And thanks for watching my daughter's channel!
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