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Author Topic: F-Body 3.4 Swap into a 2.8 Fiero  (Read 40911 times)

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GTXVette

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Re: F-Body 3.4 Swap into a 2.8 Fiero
« Reply #30 on: June 24, 2018, 08:08:47 am »
I am still dealing w/ insane high idle rpm 2800-. I HAVE A SET THAT ARE 17#  3 holes in the bottom .the ones in it are30#. could they be adding too much fuel.

Raydar

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Re: F-Body 3.4 Swap into a 2.8 Fiero
« Reply #31 on: June 24, 2018, 09:16:26 am »
Aren't you running a turbo? You probably need larger than 17s. But I would think the program would have to be tuned to accommodate.
Too much fuel at idle would tend to flood the engine, and make the idle speed hunt.
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Fierofool

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Re: F-Body 3.4 Swap into a 2.8 Fiero
« Reply #32 on: June 24, 2018, 09:19:56 am »
30# is way over for even a 3.4, let alone a 3100.  My experience tells me that too much fuel will drop the rpm.  Too much air will increase the rpm.
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GTRS Fiero

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Re: F-Body 3.4 Swap into a 2.8 Fiero
« Reply #33 on: June 24, 2018, 09:29:37 am »
Vacuum leak?

Fierofool

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Re: F-Body 3.4 Swap into a 2.8 Fiero
« Reply #34 on: June 24, 2018, 02:00:47 pm »
Yes.  And I still think it's in the area of that throttle body. 

With a turbo, is the wastegate operating properly?  As I think I understand, doesn't the wastegate dumps excessive air pressure from going into the engine?  Maybe based upon input from the throttle position sensor? 
There are three kinds of men:

1.    The ones that learn by reading.
2.    The few who learn by observation.
3.    The rest of them have to pee on the electric fence and find out for themselves.    Will Rogers

GTXVette

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Re: F-Body 3.4 Swap into a 2.8 Fiero
« Reply #35 on: June 24, 2018, 02:50:45 pm »
It is pressure activeatied and though it blows pretty hard at an Idle (2500rpm) I don't have it plumbed in I took of the Hose

Raydar

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Re: F-Body 3.4 Swap into a 2.8 Fiero
« Reply #36 on: June 24, 2018, 06:42:29 pm »
30# is way over for even a 3.4, let alone a 3100.

It is, if it's not boosted. Boost (more air) requires more fuel to accommodate.
Larger injectors are required, but must be accounted for in the tune, to accommodate idling, and other situations that occur when boost is not present.
This is a whole different situation - and set of parameters - than the "rich/hunting idle with the 17# disk type injectors" situation.

This is why I don't normally mess with boosted engines. It's a whole 'nother learning curve. Fan's is going to be an... experience. :-/
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GTRS Fiero

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Re: F-Body 3.4 Swap into a 2.8 Fiero
« Reply #37 on: January 04, 2020, 12:12:06 am »
My Fiero is now running on the stock 3.4 injectors, and that seems to be the best set, thus far.

Fierofool

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Re: F-Body 3.4 Swap into a 2.8 Fiero
« Reply #38 on: January 04, 2020, 08:35:45 am »
But you are using the 7730 ECM.  More tuneable than the stock Fiero ECM. 
There are three kinds of men:

1.    The ones that learn by reading.
2.    The few who learn by observation.
3.    The rest of them have to pee on the electric fence and find out for themselves.    Will Rogers

GTRS Fiero

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Re: F-Body 3.4 Swap into a 2.8 Fiero
« Reply #39 on: January 04, 2020, 08:38:00 am »
True, but it was tuned for the 15/17# injectors that TFS sells.

GTRS Fiero

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Re: F-Body 3.4 Swap into a 2.8 Fiero
« Reply #40 on: March 14, 2020, 09:14:31 am »
I "band-aided" one of these cars by opening up the window to allow the BLM to go higher, adding more fuel. (I burned a chip for the other car, but the owner said that it "didn't work" when he installed it. I offered to do another one for him but he wasn't interested.)

Both owners described the "excellent fuel mileage" that they were seeing with these injectors and a stock tune. Upper 20s to low 30s.
RIGHT! Because their engines were not getting enough fuel.

This may not be a big deal, right now, but at some point I wouldn't be surprised if some pistons or exhaust valves got damaged, over the long term. Or maybe not. Who knows?
At the expense of a bit of fuel economy, there may even be a few horsepower locked in there, if they ran a little richer.
 

I've sent several logs to Ryan, and he doesn't seem to see any lean condition.  With the latest chip, my MPG have dropped a bit, but I am a bit worried about running lean.  Judging by my exhaust, I'm running rich.  For sure, it's peppy.  Any other way to tell if it's running lean?

TopNotch

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Re: F-Body 3.4 Swap into a 2.8 Fiero
« Reply #41 on: March 14, 2020, 10:43:18 am »
Exhaust manifolds glow in the dark when running lean.
The more complex the mind, the greater the need for the simplicity of play.

GTRS Fiero

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Re: F-Body 3.4 Swap into a 2.8 Fiero
« Reply #42 on: March 14, 2020, 10:47:06 am »
Thanks.  I'll check if my Fiero has acquired this glow-in-the-dark feature. :)