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Rough idle when cold by gofast250
Started on: 12-14-2007 12:15 PM
Replies: 9
Last post by: uhlanstan on 12-15-2007 08:40 PM
gofast250
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Report this Post12-14-2007 12:15 PM Click Here to See the Profile for gofast250Click Here to Email gofast250Send a Private Message to gofast250Direct Link to This Post
I swap out a 2.8 for the 3.4 in my 87 Gt T top with a 440T4 Trans ,but seems to runs a little rough when cold .
After it is warmed up ,it runs great .
any idea on what would cause this ,maybe the cold start injector (were can those be purchased).
What i mean by runs rough ,It seems to bog a little while pressing down on Gas pedal when cold.
But again once it's warmed up ,very response's(bogging is gone).
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Report this Post12-14-2007 12:52 PM Click Here to See the Profile for DodgerunnerClick Here to visit Dodgerunner's HomePageClick Here to Email DodgerunnerSend a Private Message to DodgerunnerDirect Link to This Post
Are you running the stock 2.8 prom on your 3.4?

On my 3.4 I had to increase the cold start table due to running lean on startup when it was cold. Didn't have issue during warm weather.
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gofast250
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Report this Post12-14-2007 03:01 PM Click Here to See the Profile for gofast250Click Here to Email gofast250Send a Private Message to gofast250Direct Link to This Post
Yes ,still running stock 2.8 prom ,Should i get a prom for the 3.4 from the 95 camaro or how do you raise the cold start .

[This message has been edited by gofast250 (edited 12-14-2007).]

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Dodgerunner
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Report this Post12-14-2007 04:59 PM Click Here to See the Profile for DodgerunnerClick Here to visit Dodgerunner's HomePageClick Here to Email DodgerunnerSend a Private Message to DodgerunnerDirect Link to This Post
No don't think you can use a Camaro prom would not work. You need to get a reprogramed one.
There is someone on the forum that does them, can't recall who. I'm sure someone will know, or if you do a search you should be able to find a post on it.

I'm doing my own for my 85 and didn't purchase the mask for your year so can't help you out...

Also forgot to ask if you used the 3.4 inj. Am guessing you did...

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gofast250
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Report this Post12-14-2007 05:19 PM Click Here to See the Profile for gofast250Click Here to Email gofast250Send a Private Message to gofast250Direct Link to This Post
I used the stock 2.8 injectors ,But i think i should have put the 3.4 injectors in(i have a few sets),so hopefully that will help as well .
Thanks for the help
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project34
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Report this Post12-14-2007 05:58 PM Click Here to See the Profile for project34Send a Private Message to project34Direct Link to This Post
 
quote
Originally posted by gofast250:

I used the stock 2.8 injectors ,But i think i should have put the 3.4 injectors in(i have a few sets)

I agree with you.

The standard size injectors for the 2.8L Fiero V6 are 15 pounds.

The standard size injectors for the 3.4L V6 are 17 pounds.

One shouldn't intentionally seek to purposely do either, but generally speaking, running slightly "too rich" is, if anything, better for engine longevity than is running slightly "too lean."

I suggest going with 17-pound injectors for your 3.4L engine swap, as those represent the standard size injectors for that engine.
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Dodgerunner
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Report this Post12-14-2007 11:32 PM Click Here to See the Profile for DodgerunnerClick Here to visit Dodgerunner's HomePageClick Here to Email DodgerunnerSend a Private Message to DodgerunnerDirect Link to This Post
What I and I believe other do find with the 3.4 injectors is you run richer at idle. That is what I've been tuning on my prom. \\
Off idle the ecm adjust for the inj. just fine. And the extra fuel give the engine some nice zip...

[This message has been edited by Dodgerunner (edited 12-14-2007).]

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project34
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Report this Post12-15-2007 10:33 AM Click Here to See the Profile for project34Send a Private Message to project34Direct Link to This Post
 
quote
Originally posted by gofast250:
I swap out a 2.8 for the 3.4 in my 87 Gt T top with a 440T4 Trans ,but seems to runs a little rough when cold .
 
quote
Originally posted by gofast250:
...still running stock 2.8 prom ,Should i get a prom for the 3.4 from the 95 camaro....


 
quote
Originally posted by Dodgerunner:
No don't think you can use a Camaro prom would not work. You need to get a reprogramed one.

In order to eliminate the at-idle/cold temp roughness issues mentioned earlier in this thread, does anybody know who specifically --- if anybody --- offers a reprogrammed Fiero 2.8L PROM for a Fiero that's now running the pushrod Camaro/Firebird 3.4L V6 engine?
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Dodgerunner
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Report this Post12-15-2007 11:22 AM Click Here to See the Profile for DodgerunnerClick Here to visit Dodgerunner's HomePageClick Here to Email DodgerunnerSend a Private Message to DodgerunnerDirect Link to This Post
You might ask Loyde at FastFieros@FastFieros.com
If he does not have them he will know where you could get one....
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uhlanstan
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Report this Post12-15-2007 08:40 PM Click Here to See the Profile for uhlanstanClick Here to Email uhlanstanSend a Private Message to uhlanstanDirect Link to This Post
Check with darth fiero he has a post that is at the top of tech right now so it should be easy to find when you read this..
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