Hello again all, well I’ve rebuilt my engine and put everything back together. She will start beautifully and run great for about 1-2 mins. Then stall out with any throttle. Replaced fuel pump during rebuild, but upon checking I get 11 psi on start slowly dropped to 3-4 while running and that’s when it bogged out. Put a new fuel pump in again and it ran better I guess made it about 5 mins before bogged out, and stuck around 4-5 psi. Clamped off return,no diff. Shut engine off and with just priming fuel pump I can’t get it above 5 psi until everything is cooled down?what am I missing?

I would suspect a leak inside the tank. Do you still have the original pulsator installed, or did you replace it with a short length the proper submersible hose?

[This message has been edited by Patrick (edited 08-13-2018).]

Thanks for reply, never seen a pulsator either time I’ve pulled tank. I have replace the rubber hose from pump to steel pipe both times. Um I just primed pump it bit 12 psi, then dropped fast, did this a few times. Then clamped of return, primer and hit 14psi and stayed. Unclamped and only dropped to 11. Still sitting there minutes later

quote Originally posted by Dmitchell80: I have replace the rubber hose from pump to steel pipe both times.

With the proper submersible hose? And clamped tightly at both ends?

Those figures in your second post sound fine to me. Are you saying it's only when the engine warms up that the fuel pressure becomes low?

Hey Patrick,I am horrible at explaining things via writing. I see you are in BC with me. Although a lot lower and out of fire danger lol. I’d love to call you for a sec or you call me?

[This message has been edited by Dmitchell80 (edited 08-13-2018).]

I'm just on my way out the door. If this doesn't get resolved in the meantime, it's possible we can discuss this later.

[EDIT] Last word before I run. Look in the TB and make sure the injector isn't leaking.

[This message has been edited by Patrick (edited 08-13-2018).]

Those figures in your second post sound fine to me. Are you saying it's only when the engine warms up that the fuel pressure becomes low?
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It was, fuel pressure drop to about 4-5 psi after warm. Will need to check again in am, but seems adding back pressure from clamping hose has changed something. It’s holding steady at 11 psi now throughout rpm range. Can’t add load yet as I’ve had a few while working. Excited to see what happens in am though

quote Originally posted by Dmitchell80: Can’t add load yet as I’ve had a few while working.

Ummm.... I think it's all becoming clear to me now.

quote Originally posted by Patrick: Ummm.... I think it's all becoming clear to me now.

I was a military mechanic for many many years. Autocorrect is my enemy still. Meant to say can’t check under load yet

quote Originally posted by Dmitchell80: Which would have been “can’t under load yet” Drink didn’t effect my work, just saying I can’t road test today

Oh, I knew what you meant.

Replacement pumps "bad" are often:
Ebay/Amazon Counterfeit pumps. Buy local or use a AZ etc online.
Bad wiring to the pump.
Bad plumbing or TBI / fuel rail.

You pinched off return line eliminate TBI problems but not most others.
Fiero FP are Grounded in the Cabin and iffy Relay etc can "brown out" the +12v... See my Cave, Electric Motors and Wire Service

4cyl Does Not use the pulsator. Low pressure systems often don't need them.
6V/V8 high pressure systems does from factory but many aftermarket units do not need them because how their made.

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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