Gave up on my TBI and went Carb - The 1947 - Present Chevrolet & GMC Truck Message Board Network

AusTx68 · 04-02-2012, 11:01 PM

Long story short, I had my 454 rebuilt. I pulled it, stripped it, and dropped it off. I told them all stock components and specs. What I got back was flat top pistons and a different cam. I was cool with it not understanding the effects a cam change would have on the TBI. It was hell from that point on. Running super rich and not idling well. I went thru every sensor, purchased software, cables, and such. Nothing worked. I had a Eldelbrock 750 sitting on a shelf along with an extra HEI. Today I picked up a fuel pressure regulator and made the swap. Holy cow, the truck completely rocks now. Not running rich anymore and has tons of power. Idles real nice. I'm very happy with the results. All the TBI stuff will be sold!

cochino12 · 04-02-2012, 11:04 PM

Reading that doesn't make me want to keep mine any more haha, what did you end up with for cam?

AusTx68 · 04-02-2012, 11:27 PM

Well, to be honest I'm not sure. It's not aggressive but definitively not like the stock cam. This truck has been my secondary backup. Only used for hauling and parts runs. I did the rebuild for reliability without really considering the specs. Until now it wasn't much fun to drive. It certainly didn't feel like a 454. Does now

SCOTI · 04-03-2012, 12:33 AM

Quote:

Originally Posted by AusTx68

Well, to be honest I'm not sure. It's not aggressive but definitively not like the stock cam. This truck has been my secondary backup. Only used for hauling and parts runs. I did the rebuild for reliability without really considering the specs. Until now it wasn't much fun to drive. It certainly didn't feel like a 454. Does now

If @ all possible, could you try & find the cam info or p/n?

I also went w/flat-tops & a 'towing' cam. I'm concerned about going through something similar even though I got a custom chip that is 'calibrated' w/the engines specs from tbichips.com/Harris Performance.

Did you use the stock chip or??

ericjon262 · 04-03-2012, 01:03 AM

without a thorough tune, the cam is useless, throw an ebl flash on it and reprogram for the changes and it'll run like a top.

INSIDIOUS '86 · 04-03-2012, 02:13 AM

You did the right thing. Tbi is useless on anything performance.
Posted via Mobile Device

SCOTI · 04-03-2012, 08:41 AM

Quote:

Originally Posted by INSIDIOUS '86

You did the right thing. Tbi is useless on anything performance.
Posted via Mobile Device

Performance is subjective....

Since he's not building a race car or hi-perf motor (just a solid DD type w/improvements for efficiency), the OE TBI system should be able to be tuned for it.

RandyP · 04-03-2012, 08:57 AM

I'm close to going carb on my 87. Poor choice of crate engine has me in the spot. The cam and heads on the replacement engine just really does not work with the TBI, main issue is vacuum it seems. It'll run pretty good as long as you drive it every single day, but still has a slight idle issue once warmed up. Not quite bad enough of an issue to cause it to stall at lights, but enough to make you rest your foot on the gas pedal at a red light to give it just a little more RPM to be sure it does not die. And that's w/out the AC on, with the A/C on you have no choice but to two foot it at stops.

lurch115 · 04-03-2012, 03:31 PM

IMO the throttle body setups on this body style where the worst.

INSIDIOUS '86 · 04-03-2012, 04:26 PM

Quote:

Originally Posted by SCOTI

Performance is subjective....

Since he's not building a race car or hi-perf motor (just a solid DD type w/improvements for efficiency), the OE TBI system should be able to be tuned for it.

Should be able to yes. But a very limited range it seems for tbi
Posted via Mobile Device

04-02-2012, 11:01 PM	#1
AusTx68 Registered User Join Date: Nov 2008 Location: Italy Posts: 1,278	Gave up on my TBI and went Carb Long story short, I had my 454 rebuilt. I pulled it, stripped it, and dropped it off. I told them all stock components and specs. What I got back was flat top pistons and a different cam. I was cool with it not understanding the effects a cam change would have on the TBI. It was hell from that point on. Running super rich and not idling well. I went thru every sensor, purchased software, cables, and such. Nothing worked. I had a Eldelbrock 750 sitting on a shelf along with an extra HEI. Today I picked up a fuel pressure regulator and made the swap. Holy cow, the truck completely rocks now. Not running rich anymore and has tons of power. Idles real nice. I'm very happy with the results. All the TBI stuff will be sold! __________________ '68 C-10 SWB 383 Stroker (Sold 3/2/2013) '87 R2500 LWB 454 TBI converted to Carb Last edited by AusTx68; 04-02-2012 at 11:21 PM.

04-02-2012, 11:04 PM	#2
cochino12 It followed me home? Join Date: Mar 2003 Location: Yup Posts: 5,751	Re: Gave up on my TBI and went Carb Reading that doesn't make me want to keep mine any more haha, what did you end up with for cam? __________________ Adam That's why they call it a shortcut Kyle, if it was easy it would just be the way. 86 c-10 SWB 85 CCSB 90 GMC K30 Crew SRW 1985 C30 Dually

04-02-2012, 11:27 PM	#3
AusTx68 Registered User Join Date: Nov 2008 Location: Italy Posts: 1,278	Re: Gave up on my TBI and went Carb Well, to be honest I'm not sure. It's not aggressive but definitively not like the stock cam. This truck has been my secondary backup. Only used for hauling and parts runs. I did the rebuild for reliability without really considering the specs. Until now it wasn't much fun to drive. It certainly didn't feel like a 454. Does now __________________ '68 C-10 SWB 383 Stroker (Sold 3/2/2013) '87 R2500 LWB 454 TBI converted to Carb

04-03-2012, 01:03 AM	#5
ericjon262 Registered User Join Date: Mar 2007 Location: Displaced Floridian/Bremerton, Wa Posts: 281	Re: Gave up on my TBI and went Carb without a thorough tune, the cam is useless, throw an ebl flash on it and reprogram for the changes and it'll run like a top. __________________ '06 2500 HD 4x4. manual transfer case, crank windows. '88 V10 Suburban 4x4,"The Pig Rig" L05, 700r4, NP208, 4x4 beater camper fun truck project. My trucks don't leak oil, they mark their territory.

04-03-2012, 02:13 AM	#6
INSIDIOUS '86 Registered User Join Date: Jul 2009 Location: washington Posts: 4,178	Re: Gave up on my TBI and went Carb You did the right thing. Tbi is useless on anything performance. Posted via Mobile Device __________________ 377 sbc thumpr cam autogear m23 muncie 3:73 Detroit trutrac 3''spintech prostreet mufflers xpipe 1 3/4 headers build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217 Iroc gauge threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=554511

04-03-2012, 08:57 AM	#8
RandyP Getting Old; Going Broke Join Date: Apr 2010 Location: Owasso OK Posts: 2,764	Re: Gave up on my TBI and went Carb I'm close to going carb on my 87. Poor choice of crate engine has me in the spot. The cam and heads on the replacement engine just really does not work with the TBI, main issue is vacuum it seems. It'll run pretty good as long as you drive it every single day, but still has a slight idle issue once warmed up. Not quite bad enough of an issue to cause it to stall at lights, but enough to make you rest your foot on the gas pedal at a red light to give it just a little more RPM to be sure it does not die. And that's w/out the AC on, with the A/C on you have no choice but to two foot it at stops. __________________ *Why is every used 350 sbc out of a corvette?* There's only two things that excite a man, expensive toys and real expensive toys. *VEGETARIAN: That's an old Indian word meaning "I don't hunt so good."* When the going gets tough, switch to power tools.

04-03-2012, 03:31 PM	#9
lurch115 Registered User Join Date: Oct 2006 Location: iowa Posts: 722	Re: Gave up on my TBI and went Carb IMO the throttle body setups on this body style where the worst. __________________ "Horsepower is how fast you hit the wall, torque is how far you carry the wall with you." '84 chevy half ton short box 2wd, 67,000 actual miles '03 chevy 1500 HD crew cab 4x4 standard box, 6.0L



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