Okay, I've decided to rebuild the TBI on my 170,000 mile 88 Camaro 305. It has a stiff throttle pedal, high floating idle, and likes to drive itself like cruise control is always active. I checked the return springs, cleaned what I could, and noticed play in the throttle shaft combined with a squeak when I open the throttle blades by hand. It looks like the blades are sticking to the bore. Now, instead of having the stock unit sent off and get rebushed and all that jazz, I was thinking about just getting one of the Turbo City 46mm TBs, have them clean my injectors, then install a new TPS and IAC, and call it a day. My question: will the stock tune be okay with this? I know the speed density tunes can be rather finicky, so I don't want to throw everything off by adding more airflow.

i have a similar one and it has only run better. then again i have an adjustable fuel pressure regulator. of course though, a tune helps.

I just want to get the car running right for now. I figure going this route will get me new bushings, new return springs, and a cleaned unit.

I already ordered a rebuild kit from cfm-tech, so I'll have all the gaskets and everything.

I'm going to get a smoke can and check for vacuum leaks today and replace as needed.

DC Trumpet on this site offers a rebuild on TB units I recall. I would check with him.

Adding a larger TB unit may not be a good idea. It may affect drivability. the CL feedback from 02 sensor should keep the A/F OK during cruise in closed loop BUT your AE (aka pumpshot) will likely be off and the WOT aka PE also will be off as ECU cannot compensate sufficiently for the added airflow in AE and PE(no 02 feedback). Lean condition may result in both. Also during operation with coolant cold <160deg (open loop) the A/F may be lean affecting operation. Another factor to consider is larger changes will occur in manifold VAC with same pedal(TPS) movement. Swings in manifold VAC will hinder drivability. If you mod engine and need more CFM that is another story.

I tried to run my 46mm Xtremefi Unit a few years ago on the stock tune and it sucked. I lost a good bit of down low grunt. If you can tune it in it won't be as much of a factor.

You can sent your TB to turbocity and have it bored and everithing, get a quote. At least you are sure to get the exact TB for your application.

Definitely check with DCTrumpet too.

If it won't run nice you can always get a TB from the JY for free, and keep the 46mm one for when you start tuning.

Thanks for the input guys.

I'm just going to stick with the TB I have for now. I'm waiting on the rebuild kit to come in from CFM-Tech. The car is idling at about 2500 RPMs due to the TB-to-manifold gasket being non-existant. I'll give it a thorough cleaning before I put her back on with an open element cleaner. Got a new IAC and TPS ready to go, as well.

Let me know if you need any help.

Good luck with your project!

Thanks.

Changed the gasket and now she idles at around 1200-1000. The bushings on the unit itself are worn, and I think the blades are sticking in the bores since the pedal is very hard to press.

Unfortunately, this has been put on hold because the car just pissed a tank of gas in a parking lot, so I'm in the midst of pulling the tank and seeing what the Hell went on there.

If your pulling your tank I'd advise you to install a higher flow fuel pump while you have the opportunity.