383 94 vert rough idle
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Joined: May 2004
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From: Freedom Pa
383 94 vert rough idle
just put together my 383 lt1 stroker. 11:1 cr, lt4 hotcam, 1.6 rockers, headers, 160deg thst, 32# inj, 52 mm tb . adjustable fuel pressure regulator, higher stall ati converter, Problem is it doesnt seem to idle right, it seems lagging until it hits 3rd gear and runs like a raped ape. not sure whats up, had this been a carburated engine it would be a snap.
btw the computer was reworked.
any ideas
?
btw the computer was reworked.
any ideas
?
Melting Slicks
Joined: Sep 2003
Posts: 3,326
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From: I live at www.domesticlugnuts.com I sleep in PA
The engine should pull the same way no matter what gear it is in.
Meaning 1st and 2nd gear should not seem lagging, and 3rd gear be great.
If I had to guess, I would say that you are running out of air or fuel and just notice it more in the shorter gears.
I say this because I tried my old 750 Q-Ket on my 383 and 1st and 2nd were not as impressive as they should have been.
I changed back to my 770 Holley Street Avenger and finally found the power to snap the D36 with street tires. The 770 flows a little more air and alot more fuel.
Meaning 1st and 2nd gear should not seem lagging, and 3rd gear be great.
If I had to guess, I would say that you are running out of air or fuel and just notice it more in the shorter gears.
I say this because I tried my old 750 Q-Ket on my 383 and 1st and 2nd were not as impressive as they should have been.
I changed back to my 770 Holley Street Avenger and finally found the power to snap the D36 with street tires. The 770 flows a little more air and alot more fuel.
Large Impressive Member
Joined: Jul 2003
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
So much more information is needed here that I don't know where to start. For starters throw the 160 degree stat away and your injectors are probably too large.
Melting Slicks
Joined: Sep 2003
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From: I live at www.domesticlugnuts.com I sleep in PA
I disagree about the 160 stat.
I run one in my Vette and I run a 180 in Lisa's Vette.
Today it was only 75 degrees and while driving around town and on the interstate, I held a steady 167 degree temp.
Hers was at 189. They both have new radiators, her Vette is stock and mine is a 383.
The 160 stat is "Cool" (pun intended).
But I do agree that more info would help.
I run one in my Vette and I run a 180 in Lisa's Vette.
Today it was only 75 degrees and while driving around town and on the interstate, I held a steady 167 degree temp.
Hers was at 189. They both have new radiators, her Vette is stock and mine is a 383.
The 160 stat is "Cool" (pun intended).
But I do agree that more info would help.
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From: Freedom Pa
well it was running out of fuel before the adjustable pressure regulator was installed, pressure before was only 39 psi, and 3bar for the injectors is about 45psi in my conversion book, so that pressure issue was resolved. what else would you like to know?
Safety Car
Joined: Dec 2002
Posts: 3,655
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From: Charleston SC
To help you a lot more info will be needed. As far as the injectors go as long as you have the constant in the ECM set for them they will be fine, I have 36# now and have ran 42's with no problems.
Who did the tune?
Was it on a dyno?
What are the A/F numbers?
Any data logs?
Any codes?
Vacuum?
Who did the tune?
Was it on a dyno?
What are the A/F numbers?
Any data logs?
Any codes?
Vacuum?
Thread Starter
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Joined: May 2004
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From: Freedom Pa
pcm performance did the computer work, it hasnt been on a dyno, i honestly have never heard of any dynos in my local area, ill have to get back to you on the vacuum. Im doing this a little bit every weekend when im home from college and when im not at work.
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Safety Car
Joined: Sep 2003
Posts: 3,599
Likes: 24
From: Orange County NY
St. Jude Donor '10-'11-'12-'13
Originally Posted by FD2BLK
To help you a lot more info will be needed. As far as the injectors go as long as you have the constant in the ECM set for them they will be fine, I have 36# now and have ran 42's with no problems.
Who did the tune?
Was it on a dyno?
What are the A/F numbers?
Any data logs?
Any codes?
Vacuum?
Who did the tune?
Was it on a dyno?
What are the A/F numbers?
Any data logs?
Any codes?
Vacuum?
Also, does this happen in open or closed loop? Is it going into closed loop? A real time scan will tell you / us a LOT about what's going on.For starters, pull the plugs and see what they look like. They'll tell you a lot about how the car is running.
Instructor
Joined: Apr 2004
Posts: 161
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From: fl
Yea, pull the plugs and Data log it if you can, or send the computer to another outfit like PCM's for less....I don't know much about the place you had yours programed at, but for a fact, Bryan Herter will be able to get things very very close until the day comes when you can get "hands on" tuning on a dyno.......for a mail order tune, I wouldn't trust many others......also try opening the throttle blades some more if you have'nt done so, and make sure there are NO exhaust leaks before your O2's
Last edited by 95NOSvette; May 3, 2006 at 05:06 PM.
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From: Freedom Pa
well at idle ~500 - 600 rpm it only has 10 inches of merc. and when you turn the a/c on it stumbles and wants to cut out. And i definately have a small exhaust leak around the header/pipe joint..... this thing is driving me crazy. DAMN COMPUTERS!
Safety Car
Joined: Dec 2002
Posts: 3,655
Likes: 24
From: Charleston SC
Before you mess with the set screw try this two or three times to see if the idle will bump up just by reseting the IAC, I have to do this two time normaly, sometimes three.
Reset IAC valve pintle position:
A. Depress accelerator pedal slightly.
B. Start engine and release accelerator pedal, run engine for 5 seconds.
C. Turn ignition “OFF” for 10 seconds.
D. Restart engine and check for proper idle operation.
Reset IAC valve pintle position:
A. Depress accelerator pedal slightly.
B. Start engine and release accelerator pedal, run engine for 5 seconds.
C. Turn ignition “OFF” for 10 seconds.
D. Restart engine and check for proper idle operation.
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From: Freedom Pa
after pulling the plugs it is evident the car is too rich. the plugs have a strong gas smell along with being a bit wet. this is with the 32# inj and fuel pressure set around 3-bar. (45 ish psi)
Le Mans Master
Joined: Jul 1999
Posts: 8,683
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From: Phoenix AZ
Your injectors are not too big, IMO. I'm running 42# injectors in my 383 with no issues at all. However, it does sound like the tune is a ways off...if it's as rich as you make it sound I'd drive is sparingly as you don't want to wash out the rings. If you can't get to a dyno, see if you can get ahold of a scanner or something like AutoTap to get some AFR info. Also, as stated earlier 600rpm is WAY low for idle RPM...you'll want to have the chip reprogrammed for a higher idle speed (I'd recommend about 825-850). 
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From: Freedom Pa
Ya its parked now and not gonna go anywhere until its trouble free... I'm just stuck without the proper diagnosis equipment, how i wish this was a carb / HEI setup.... anyhow, so i should find someone to see if the guy before tuned it right to what mods i have? This is quite frustrating.