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Engine dying on me while driving by Josh86gt
Started on: 08-21-2025 04:50 PM
Replies: 7 (104 views)
Last post by: Josh86gt on 08-24-2025 09:03 AM
Josh86gt
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Report this Post08-21-2025 04:50 PM Click Here to See the Profile for Josh86gtSend a Private Message to Josh86gtEdit/Delete MessageReply w/QuoteDirect Link to This Post
So I was taking my fiero out for a cruise I did this yesterday with no issues today I go out and as I'm taking off from a stop I go to shift to 4th and the engine dies in the middle of shifting I go all the way into 4th I let the clutch back out and it starts back up and goes I'm cruising along and it happened a second time this time I tried starting it with the starter it started back up but died again nearly instantly this happened a total of four times across 1 hour does anyone know what is causing this?
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Dennis LaGrua
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Report this Post08-21-2025 08:30 PM Click Here to See the Profile for Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
My guess would be that you are losing fuel pressure or that the battery is not charging. First step is to check if the fuel rail measures a steady 39-42 psi at idle and rises as the RPM's go up. BTW have you changed your fuel filter lately?

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

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Josh86gt
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Report this Post08-21-2025 08:36 PM Click Here to See the Profile for Josh86gtSend a Private Message to Josh86gtEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Dennis LaGrua:

My guess would be that you are losing fuel pressure or that the battery is not charging. First step is to check if the fuel rail measures a steady 39-42 psi at idle and rises as the RPM's go up. BTW have you changed your fuel filter lately?



I have only owned the car for about 6 months and in that time I've put at most 600 mi on it I don't drive it much so I've never changed the fuel filters and I did notice the battery gauge seems to be reading barely above 12 volts even while driving I had recently done an alternator test and it seemed to be working fine but maybe it is just now giving out on me and I don't know how to check the fuel pressure or if I have the tool to do so it only happens in fourth gear though I've tried it in every other gear and it had no issue
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Dennis LaGrua
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Report this Post08-22-2025 08:36 AM Click Here to See the Profile for Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Josh86gt:


I have only owned the car for about 6 months and in that time I've put at most 600 mi on it I don't drive it much so I've never changed the fuel filters and I did notice the battery gauge seems to be reading barely above 12 volts even while driving I had recently done an alternator test and it seemed to be working fine but maybe it is just now giving out on me and I don't know how to check the fuel pressure or if I have the tool to do so it only happens in fourth gear though I've tried it in every other gear and it had no issue


Not to be critical but when you own a 35 yr old car it must be given great care and maintenance. Members are here to help you but learning basic diagnostic tests required to pinpoint problems should go along with ownership of a Fiero. I would buy a Fiero repair manual and start reading. Many of the procedures on diagnosing engine problems are listed there. You could also try You Tube and hooking up with Fiero owners in your area. Fiero owners are good people and many are willing to help but you will need to do learn basic tests before a solution can be found. BTW, is the check engine light on?

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

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Mickey_Moose
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Report this Post08-22-2025 01:08 PM Click Here to See the Profile for Mickey_MooseSend a Private Message to Mickey_MooseEdit/Delete MessageReply w/QuoteDirect Link to This Post
You don't need to buy a manual, the factory service manuals are available as a free download: https://www.boomtastic.com/files/

Checking fuel pressure, you could probably borrow one from AutoZone/etc. These places usually "rent" tools like that out (you give them money, take it home, and get your money back when you return it). Should be some videos on youtube on how to check the fuel pressure.

Some people have also found some ignition control modules to be intermittent - I have never seen one like that, just usually fail. So that COULD be the problem, but it COULD also be many other things (anything in the ignition system, power issue, fueling system, etc). You need to track down the issue by testing thing. Don't start throwing parts at it because someone on the internet said to change this, or change that.

The factory service manual has step by step procedures for finding faults. Just look up the section that has your symptoms and follow the steps.

Some basic things you can check are:

Battery connections clean and tight?
Ground connections tight?
Spark plug wires in good condition?
Are you getting spark?
Fuel pressure good?


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Josh86gt
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Report this Post08-22-2025 01:15 PM Click Here to See the Profile for Josh86gtSend a Private Message to Josh86gtEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Dennis LaGrua:


Not to be critical but when you own a 35 yr old car it must be given great care and maintenance. Members are here to help you but learning basic diagnostic tests required to pinpoint problems should go along with ownership of a Fiero. I would buy a Fiero repair manual and start reading. Many of the procedures on diagnosing engine problems are listed there. You could also try You Tube and hooking up with Fiero owners in your area. Fiero owners are good people and many are willing to help but you will need to do learn basic tests before a solution can be found. BTW, is the check engine light on?



Yeah when I bought this thing I wasn't expecting it to run perfectly and no the check engine light is not on I am just figuring everything out as I go and picking up the tools as I need it probably is in my best interest to pick up a repair manual
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Dennis LaGrua
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Report this Post08-24-2025 02:32 AM Click Here to See the Profile for Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
First step and test::
First change the fuel filter -an easy task. When old they can clog depending on where the gasoline was bought and pumped from
Using a fuel pressure test gauge, screw the hose fitting on to the Schrader valve on the fuel rail. Start engine and read the pressure. It must hold steady around 39-43 psi at idle and when running.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

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Josh86gt
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From: Millton
Registered: Oct 2024


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Report this Post08-24-2025 09:03 AM Click Here to See the Profile for Josh86gtSend a Private Message to Josh86gtEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Dennis LaGrua:

First step and test::
First change the fuel filter -an easy task. When old they can clog depending on where the gasoline was bought and pumped from
Using a fuel pressure test gauge, screw the hose fitting on to the Schrader valve on the fuel rail. Start engine and read the pressure. It must hold steady around 39-43 psi at idle and when running.



Alright thank you
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