TOPIC: TBI Testing and Information

Hello There

So yesterday i practiced my first groves on some tbi I got from a junk yard i got one of both castings filled in the IAC pathways with JB quick and rerouted them then did the groove with the large bit. I got a couple of questions i still have my original tbi that was on the truck so i can do that one right. I did install one of the TBIs and did reset the computer followed the steps

its running really low rpm so i adjusted the idle screw to about 900 rpm in park and it makeing a noise from the IAC pathway that sounds kinda like a rattle snake rattler at idle and when stopped in gear when i give it acceleration it goes away any idea what it might be?

I have a adapter that converts from 4 barrel to the 2 barrel tbi and a throttle spacer on it that has individual pathways for each bore on the tbi i capped off the pvc intake port and re routed it into the bottom of my air cleaner i also capped off my egr pathway because my intake has no egr the map censor and the vent to my fuel tank are the only vacuum lines hooked up to the tbi

Should i have set the idle before installing the groove?
If so should i have done the IAC pathway restriction first then installed the tbi to find correct idle then remove and do the groove?
Or am i still ok whit doing everything first then adjusting idle?

Thanks Joshua Padilla

I'm going to jump in before Tracy or Ron and suggest that 900rpm seems high for a hot idle to me...it was probably pretty close before you adjusted it. Maybe adjusting spark plug gap would've been a better thing to do at that time...
As far as the sound- it's rattling or hissing? Hiss is airflow, possibly a leak. Try spraying some carb clean at the IAC. If the idle changes, you should fix that problem first.

Before adjusting it i had to have my foot on the pedal a little just for it to start then when i would let of it would idle like at 400 rpm almost shutting off i have the spark plugs gaped to .050 i can gap them more and i did the leak check with brake clean it was all good no leaks the noise is coming from the inside where the air flows into the IAC itself, i put my figure in that little pathway and the noise got a little quieter just curious if this is normal for TBIs

Joshua Padilla

if it was a stumbling idle, (which it was - you cured it by giving it more air at the gas pedal) then it wasn't getting enough air. you needed to open up the IAC pathway (or find what the restriction was that was rattling) rather than increasing the idle by opening up the throttle plate's rest position.
Can you take the idle back to where it was, and then open up the IAC restriction (however you did that - make the hole bigger or add another hole to a restrictor plate) until it idles without stumbling?
once you've got it right, you can probably open up the plugs some more. and then re-address the idle. I think most engines 6 cyl and bigger can idle anywhere between 400-700 when air and spark is properly adjusted without affecting mileage adversely. if this is a v8 chevy, I drove a big old carb'd Suburban that Idled at just under 500.

Hi Josh. If I could see good pics of this TBI, the underside- then I can give opinion on your work. When you Groove something, it really helps to take and post pics of your work. Then we can all offer help, and it broadens the knowledge base too! I'm unsure about a rattle noise, but I would guess that IAC air is insufficent to support correct idle RPM. Since this was a replacement TBI you Grooved, it's also possible that it's idle speed screw was adjusted too far closed. Try touching the IAC at idle, see if ya feel vibration to match the rattle sound.

Another thing, Josh-- also best to start a new message when you post something new. We've had too many huge long message threads, makes it a bitch to find info down the road!! State year, make, engine size, in the title. Thanks!

Tracy G

Hey Joshua!

What you have there is fouled IAC Valves. You need to first try to clean them. Use a good solvent for carbon residues. That's the result of having the PCV gasses routed through the throttle assembly.

Nasty!

If cleaning them doesn't resolve the issue (the noise that sounds like dogs humping each other) then you're going to need to replace the valve(s). Likely, just go ahead and replace the valve to be sure it's corrected. Personally, I opt for the least labor-intensive and the valves are cheap so it's best to just replace them (time is your most valuable resource. Choose how to spend it wisely.)

Get rid of the spacer. The Groove functions best when you do NOT include a lot of other half-baked stuff that, although fine in principle, cannot compare to the results of a good Groove job.

WHen we get the new G-Force throttles online you'll want to just buy one of them. For now. take off everything that is not stock before continuing. You're wasting a lot of time and complicating the troubleshooting process.

It won't take long before you're a real pro!

Keep at it, my friend and remember as captain Taggart of Galaxy Quest says: "Never give up! NEVER surrender!"

Ron
Gadgetman

Oh, andread the instructions. I have no way of identifying your vehicle becuase you didn't put the yr, mk, model, engine in the topic. I wanna help, but have precious little time to go hunting.

I don't mean to be sharp, and I know that others have been doing the same poor way, and no one's been straightening them out, but the info is VITAL to successful troubleshooting....

Here are some pics of what i did

Also the vehicle im working on is my 1991 Chevy Suburban that has a 383 stroker that has vortec heads with a 4 barrel intake this is why i had to install an adapter for the TBI.

• You've done some fine work here, Mr. Padilla!
• I see you also altered the shape of the plates.
• WAY TO GO!!!!
• Ron

G-Force throttles what is that?

• A topic for a WHOLE new discussion! A G-Force Throttle is the next generation of The Groove. I have developed a method whereby I can bring a core into my shop and completely re-cast the internals, building the technology into the part.
• This means that I will be making the throttle body fit the technology where The Gadgetman Groove is making the throttle body fit the tech. Small difference in words, HUGE difference in potential! (prototyping is currently underway)
• I expect to see far superior performance values from the G-Force in all respects.
• Of course, the proof (as they say) is in the pudding. But if my math serves (and I'm pretty good at that) then multiplying mileage will be limited only to what the ECU can accept.
• The G-Force Throttle is/will be the hottest automotive part to ever come off an assembly line.
  Ron.
[/b]

Here are more pics

Thanks Joshua Padilla


























(THANKS FOR ADDING THE PICS!)
Ron

Padilla wrote: G-Force throttles what is that?

All I'm going to say for now is that they are what Ron has been off working on, and continues to develop. He may be more forthcoming, but I don't think he's quite ready to let the cat out of the bag just yet.

Padilla wrote: Here are some pics of what i did

Also the vehicle im working on is my 1991 Chevy Suburban that has a 383 stroker that has vortec heads with a 4 barrel intake this is why i had to install an adapter for the TBI.

In my experience, I have found not one single part that doesn't take away from the benefits of The Groove. In the case of spacers or adapters (four- to two-barrel for instance) they have a negative effect on the delivery of the wave form created (amplified) by the Gadgetman Groove.

That's not to say it's impossible, but it does make it more likely your spacer reduces the gains.

You need to start thinking about the turbulence The Groove creates. It is a very particular wave-form, and will be affected by ANYTHING placed in the airstream.

Of course, if I could see the spacer itself I could tell more, especially when the specs (diameter and the like) of the spacer installation are known to me.

Now, I'm going to insert your pics so they load with the message. Feel free to edit your post and put notes on each picture should it be needed to emphasize the value of the pic.

Great work, though! Keep doing what you're doing-and keep getting what your getting...

BETTER!

Ron

G-Force throttles what is that?

Nice work there, Josh! You're doing and thinking as a real Gadgetman does. Thanks for the pics! On the idle RPM issue, you can leave the TBI bolted in place, just pull and try cleaning the IAC valve if ya didn't do that. If that IAC still rattles, swap out for another one. Is the IAC electrical plug/wiring OK? Guessing here- the ECU might have been cycling the IAC valve full open/closed trying to get air?

So, I'd first try cleaning or replacing the IAC Valve. If rattle stops, and RPM issue is fixed, all good. Cold start fast idle initial RPM's ought to be about 1500, coming down to 750-900 for hot engine. It should work smoothly on it's own. And it should not need base idle speed screw turned in to crack the throttle blades very much at all. Once you know the IAC valve is OK, if it's hard to maintain idle RPM's, THEN you could go back and open the epoxy air channel some, carefully. Look in the Index for previous examples of this. Have to find a balance between restricting IAC airflow, and maintaining enough to support idle RPM in all conditions. Ron's had the very best TBI results of all.

Also- the Power System mods- spark plug gaps, PCV re-route, even using RVS products, all add to engine smooth operation and driveability in all conditions. These will also improve idle quality/stability!

IF you do the same Groove process on another TBI, try cutting the epoxy dams down some to make placing the epoxy easier. To save both epoxy material used, and laborious sanding. I make epoxy dams from clear box tape, folded over to put sticky sides together. Then fix in place w/ another piece of tape. Quick, cheap and easy. Good looking Grooves, and I like how ya shaved the butterfly screws down. A detail point is to carefully sand down the Groove edges w/ very fine grit sandpaper, remove any raised burr edges.

Once the idle RPM is fixed, I can judge a Groove job, two ways. First, is during/after the relearn drive, do I feel increased off-idle torque. Second, I sniff the tailpipe before/after the Groove is installed. Increased off-idle and mid-range power, and cleaner tailpipe smell, indicate a successful Groove!

Adding the other Power System mods just improves results. I'd like to see your PCV re-route too!

Pics of the intake spacer will give more answers. A shot of the intake plenum w/ no spacer or gaskets in place would be good also, just to see what the combination is like. A wide shot to show the overall intake man. design/type would be good too.

you're doing GREAT, on the way to success, Joshua!

Tracy G

Hello I'm interested in doing all suggested mods on my 1994 K1500 Chevy Silverado TBI System. The Gadget guru's in Louisiana listed in Denham Springs and Mandeville are un available now. any others near Lafayette Louisiana? I may have a TBI base I can mod after joining up!