Hi guys!!

After a long winter, tried to start my 1986 Fiero V6 2.8L, 4 spd man... But it seems that she's not willing to...

2 options:
1- she has a new old friend beside her, a 1969 Oldsmobile Cutlass 350ci, and my Fiero is just jealous because I did not drive her since I got the Cutlass...
2- it really has a mechanical problem...

Usually, when I turned the ignition ON, the fuel pump made an acute and regular "zzzzzz" sound for 2sec.

Now when I turn the key, the "zzzzz" sound seems lower, hesitating as if the sound is no more as regular. (Hard to explain it with my poor English).

I guess it is a bad fuel pump?
(Assuming I still hear the "zzzzz" sound)

The engine starts, and if I try to rev the engine, it dies.
Even if I just start, the engine runs 1 sec.
As if it is not getting enough fuel?

Thanks a lot for your help!!

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Christophe - 1986 Pontiac Fiero - V6 2.8l - 4 Spd Man
Eibach lowered / Stainless perf Exhaust

Before you drop the fuel tank, test the fuel pressure at the engine. Around 40 psi with the key on is good.
It could be a plugged fuel filter or a bad relay.

low on gas?

Thanks Gall and Phone!!

quote Originally posted by phonedawgz: low on gas?

Gauge was half and also added about 6 liters of new fuel before starting!

Will try with a new relay, then filter and also check fuel pressure.


What seems weird to me is that the engine is priming well... But this "zzzzzz" sound is not at all as usually.
Will a bad relay cause this kind of symptom?
If the relay would be bad, the fuel pump would simply not prime, and would not be able to hear it? No?

Thanks again for all your help!!

[This message has been edited by DJWINNI (edited 06-01-2015).]

How do you know that the engine is priming well? There could be a low flow rate due to low voltage or a restriction in the line.

If the pump sounds funny, and there is enough gas in it the pump probably needs replaced. But I agree checking fuel pressure woudl be a good idea.

Had a similar problem a few weeks ago. Car would start, but die immediately. I checked fuel pressure, and it was bleeding off immediately after the 2 sec prime, so if I didn't get it started fast enough, so the oil pressure switch would kick in, then I got no more fuel. Turns out the "Pulsator" that is mounted on the pump was very loose, allowing the fuel pressure to just flow back into the tank. Replaced the pump with a new one ( without the pulsator), and no more issues. New pump is much quieter too!

Get a fuel pressure test gauge and test the pressures. It's a good tool for diagnosing issues. Problem could be as I described, or it could be regulator, cold start valve stuck open, hose on fuel pump in tank split, etc.

Just for grins, this is how the Previous Owner fixed the fuel pump on my '87.


The wire nuts were wrapped in Green Masking Tape. This is just above the tank- guess he didn't want to take time to disconnect the connector.

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'87 GT in process!

Thanks a lot for all your help guys!!!

As I'm in France, and so that I can save some $$ on shipping, I ordered all parts I'll need!
At least it will be a complete fuel system tune-up!

Fuel Pump Pulsator
Fuel Pump
Fuel Pump Strainer
Fuel Pressure Gauge Kit
Fuel Pump relay
Fuel filter

Thanks again!!
Will let you know once all parts here and installed!

I'd change the filter before doing anything else.

quote Originally posted by BrittB: I'd change the filter before doing anything else.

Yes!
That's what I'll do!
Will replace filter and relay first, and install the fuel pressure gauge!

Thanks!

[This message has been edited by DJWINNI (edited 06-03-2015).]

Hi guys!!

Finally installed the fuel pressure gauge!
Turning the key, pump still starts but makes the hesitating and weird "zzzzzzz" priming sound!

Checked the gauge while someone was starting, fuel gauge reads just above 5 PSi!!!

Relay is OK!
Will change the filter next week end, but I guess it will be a bad fuel pump!

Thanks for you additional comments!

quote Originally posted by DJWINNI: Checked the gauge while someone was starting, fuel gauge reads just above 5 PSi!!! Will change the filter next week end, but I guess it will be a bad fuel pump!

Since the pump runs (as it appears to be doing) but your fuel pressure is so low, I'll say it's the hose/pulsator in the tank that's failed.

Hi guys!!
Finally had the time this morning to work on the Fiero!!
Dropped the fuel tank, and replaced:
-fuel filter
-fuel pump,pulsator gasket and in tank filter
-installed a fuel pressure gauge!

Priming, pressure stands at 40psi!! Fuel pump is much quiet than before!!
Starts and runs great now!!!! Everything is OK!!

Thanks a lot for your help!!!

[This message has been edited by DJWINNI (edited 07-11-2015).]