I am pretty sure about this but i need to be reashured.
I have a 356 with all the 305 electronics on it.
I am wondering mainly if the idle air is different from Lb9 to L98? Cause my car idles up-down pretty bad sometimes. I've set the IAC a few times with no luck. I've checked for vacuum leaks and tps voltage is good. Would the IAC be the problem?
Also is the TPS different?
If you can tell me anything else you would recommend changing let me know please.
thanx

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'88 RS (originally 2.8)
-350, .040 over, vette alum. L98s, stock tpi.
-305 injectors & chip
-TES headers & edelbrock cat back
-3.73 gears, 700r4.
Best with 2.8-17.4@77mph
Best with 305-15.0@93mph
Best with 356-13.7@101mph
on a 2.050 60 ft.
(Damn the 2.8!)

 

I just swapped my tpi 305 for a 355 and used all the 305's electronics except the knock sensor and prom. It idles rough but steady. Whenever mine (305) would idle goofy it was usually a vacuum leak.

 

also check the coolant sensor mine disd the same thing

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89 HO formula 305TPI

 

thanks guys, ill check yet another time for vac. leaks. And change the coolant temp sensor.

 

Anybody know if the others sensors are different?

 

The only diffs I could think of are the injectors and the knock sensor.

 

I got a new knock sensor for a L98, and i don't think the injectors are the problem. They were recently cleaned before the ol 305 bit the dust, and they worked fine before- but they are still old.

 

You will need atleast a 350prom+22lbs injectors or a 350 prom customized for the 19lb injectors. Some guys say that the ESC is different also...

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1987 IROC-Z L98,SuperRam,EB 6085's,LPE 219/219 Roller, Crane 1.6RR, EB TPI Base, 58mm TB, ADS 24#, AFPR, K&N, EB TES, Catco Cat, 3" Borla Cat-Back, Accel cap,rotor,distro/other crap, MSD 6AL, MSD Blaster 3, Aluminum DS, 94 Disk Rear, Adjustable Valve, Precision 3.73 Gears, Sub-Frame Connectors, Hotchkis Lower Control Arms, KYB Shocks/Struts, Suspension Techniques Lowering Springs, Polyurethan Bushings all over the place, Moog Upper/Lower Ball joints and Tie Rods ends/Idler Arm,

To see the ROC, Check out the webpage Here

 

Leirch,
I would like to know what you are basing this on so i can understand it a littel more.
I thought the ecm's were the same, and the chips also except for the fuel and spark maps.
I don't see these defferences causing that much of a problem.
As for the injectors, well you tell me.
thanx

------------------
'88 RS (originally 2.8)
-350, .040 over, vette alum. L98s, stock tpi.
-305 injectors & chip
-TES headers & edelbrock cat back
-3.73 gears, 700r4.
Best with 2.8-17.4@77mph
Best with 305-15.0@93mph
Best with 356-13.7@101mph
on a 2.050 60 ft.
(Damn the 2.8!)

 

A hunting idle is caused alot of times by the neutral switch! If you used a factory harness did you hook the gear selector switch up to the ecm?

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87z 383,afr 190's, comp hyd roller(242/248-.540/.562,114 sep),Ported and polished mini ram, 30lb inj, 3.42 gears, tremec 5spd, , 1,3/4" slp headers, speed pro bank to bank-wb02.
"Just remember children, no man can beat you once youv'e found the cliterous." 'chef'

 

The 19lbs injectors will work on the 350 as long as your not going past 400horse i *think*. But, what i was getting at, you need a chip that is setup for a 350 so that you get more fuel where you need it... its not complicated. When i said a 350chip customed to the 19lb injectors, i was getting at you would need the 350chip set to have 19lbs injectors at the very least, i bet that would perform much better... well atleast better than whats in it now.

Brendan

 

87z-ya, Yeah i hooked up the gear selector switch i think. All the wires that whent to the shifter i hooked up and there where no left overs.
Hey i live in boerne. do you race at any of the the area strips?