I HAVE AN 88 IROC Z AND HAVE RECENTLY REPLACED THE 305 TBI MOTOR WITH A 383. WHEN IT'S IDLING, IT WANTS TO DIE. AFTER I GET GOING AT MODERATE SPEEDS, IT DOES OK. BUT IF I PUNCH IT, IT HESITATES LIKE HELL AND HAS ALMOST NO ACCELERATION. I WAS TOLD THAT THE FUEL TABLES IN THE COMPUTER WERE SET WAY TOO LOW FOR THE 383 TO BE FED THE GAS IT NEEDS. AND THAT I NEED TO GET A CUSTOM CHIP MADE FOR IT. I CAN AFFORD IT, BUT IT IS IT REALLY NECESSARY.

DID YOU LEAVE THE FUEL ING.OR DID YOU USE A CARB

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TONY PARDUE
74Z28

<BLOCKQUOTE>quote:</font><HR>Originally posted by 74Z28:
DID YOU LEAVE THE FUEL ING.OR DID YOU USE A CARB

<HR></BLOCKQUOTE>
i left the throttle body on there.

Is it TBI or TPI?
An IROC should have been a Tuned Port Injection system not a Throttle body Injection.
IF it's a TPI system, you'll probably have to change the injectors to higher flow injectors and get a new chip for it.
Be careful not to run full throttle or you could burn a valve.
Post more info and you'll get more help.
David

[This message has been edited by davidpozzi (edited 12-08-2000).]

a TBI 383? whoooooooo that has got to be underpowered as hell. I would have stuck a road Demon 750Cfm on that bad boy.

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Chris's 67 RS can be seen at http://www.67rs.com
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<BLOCKQUOTE>quote:</font><HR>Originally posted by Chris Edwards:
a TBI 383? whoooooooo that has got to be underpowered as hell. I would have stuck a road Demon 750Cfm on that bad boy.

<HR></BLOCKQUOTE>

What is a Road Demon 750cfm?

I have a buddy with and IROC and his kinda has a hard time idling sometimes too, he took it in and I think it had to do with the mass airflow sensor. I could see if you were running lean, but if more gas doesn't fix it, you should check that out too.

[QUOTE]Originally posted by SPEEDLVR:
Well the Demon 750Cfm is a carborator and it will bost your cars performance and with a good manifold it will be better maybe even NO2

Speed,
Stick with the Fuel Injection it will be much better in the long run. You are just going to have to find someone who can tune it properly. I am pretty sure that with the 350 injectors, the system should supply enough fuel for the 383. Try this site or call LTS at 317-487-9460 for more advice: http://www.lindertech.com
Hope this helps,

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Bill Koustenis
Owner
Advanced Automotive Machine
Waldorf Md

[This message has been edited by BillK (edited 12-10-2000).]

<BLOCKQUOTE>quote:</font><HR>Originally posted by BillK:
Speed,
Stick with the Fuel Injection it will be much better in the long run. You are just going to have to find someone who can tune it properly. I am pretty sure that with the 350 injectors, the system should supply enough fuel for the 383. Try this site or call LTS at 317-487-9460 for more advice: http://www.lindertech.com
Hope this helps,

<HR></BLOCKQUOTE>

IF I HAD A 305 BEFORE, WILL I NEED TO BUY 350 OR HIGHER FLOW INJECTORS FOR THE THROTTLE BODY? OR WILL INSTALLING A CUSTOM CHIP TAKE CARE OF THE FUEL FLOW. THANKS.

<BLOCKQUOTE>quote:</font><HR>Originally posted by davidpozzi:
Is it TBI or TPI?
An IROC should have been a Tuned Port Injection system not a Throttle body Injection.
IF it's a TPI system, you'll probably have to change the injectors to higher flow injectors and get a new chip for it.
Be careful not to run full throttle or you could burn a valve.
Post more info and you'll get more help.
David

[This message has been edited by davidpozzi (edited 12-08-2000).]<HR></BLOCKQUOTE>

THE VIN E 305 ENGINES HAVE A THROTTLE BODY. THE F 305 ENGINES HAVE TPI. I HAD IT HOOKED UP TO A SCANNER AND NONE OF THE SENSORS ARE BAD. FUEL TRIMS WERE SHOWN AS:

RPM 2500 1500 625
SHORT TERM 134 134 129
BLOCK LEARN 172 172 161