How to balance/synchronize Crossfire Injection throttle bodies Part 2- balancing and adjustment.

[@LynxStarAuto]

This brought back memories man. I remember in tech school, in the early 00's, our teacher had a 82 Firebird with a 305, crossfire. And he showed us how to use a manometer on it.

[@giovannicofre4906]

Really appreciate that you took the time to put these videos together. Great instructions. Love Crossfire!

[@Joesmusclecargarage]

No problem 👍

[@LastFrontierGarage]

Love these videos man, I’ve got an ‘84 Vette and always had trouble finding the finer details regarding adjustment for Crossfire, thank you!

[@567musicman]

I am glad you posted this video explaing this procedure. I just recently purchased an '82 Collector's Edition corvette with the crossfire injection. I've only driven it from the dealership to home. It seems to run fine, good and responsive, idles well and has good power on the road. I WOULD like to check and syncronize the TBIs in the spring when I get it out of the garage. You stated in this video that a person can make a manometer fairly easily and inexpensively but didn't explain how to. Would you please, do a video showing in detail how to make a manometer? I would, as well as a lot of others would greatly appreciate it. Thank you, sir! Have a grea day and keep those informative videos coming!

[@Joesmusclecargarage]

Sure thing. I’ll make a video detailing how to make a cheap, but very accurate water manometer 👍

[@rickyj2013]

Thank you so much for sharing this information. I’ll be watching every video you post 👍🏼

[@cantonm3racer]

Thank you Very Much for explaining this!

[@Joesmusclecargarage]

No problem. Glad it helped. Let me know if there are any other how-to videos you would like to see.

[@zameul35]

Thanks so much for this video. I'm doing a frame off on my 82 Corvette and should have it painted this month so getting close to finishing and have been dreading this part since i have installed a higher pressure fuel pump and a Renegade intake manifold.

[@Joesmusclecargarage]

Hello Kensington, there is nothing to dread when it comes to balancing the TBs. It’s a simple 10 minute procedure. Regardless of what parts you have “changed”, the procedure is the same. What are you running for headers and exhaust? Cam? I would start with 13psi on the fuel pressure. Do your final tuning with the O2. Use a DVOM and aim for .850-.900mV at WOT. It’s all simple easy stuff. People unfortunately make it out to be much more than it really is.

[@zameul35]

@@Joesmusclecargarage The renegade and fuel pump is all. I wanted to keep as original as possible but with a little more power. Down the road i might cam it and put some heads on it.

[@Joesmusclecargarage]

Then balance the TBs and bump the FP to 13psi +/- .5psi

[@demoking1422]

Great video clear and informative Thanks

[@joshlara8237]

Ive always wanted a crossfire tbi camaro

[@Paragraph247]

As far as I understand the manual for my 82 Corvette („TBI Model 400, side 6C1-3 f.) it tells to adjust the rear tbi by screwing the „minimum air adjustment screw“, whereas the slave tbi (front) has to be adjusted by screwing the „idle balance screw“. This belongs to the separate adjustment of each tbi. Do you agree so far ? Next step, when connecting the hoses with both tbi units at the same time - what screw has to be used for adjustment then ? Sorry for the maybe dumb question, but I couldnt identify your voice within the engine sound. Thanks for your enthusiasm !

[@Joesmusclecargarage]

When you have both water manometer hoses connected to the throttle bodies, the balance screw between the throttle bodies is used for the final fine tuning.

[@Paragraph247]

@@Joesmusclecargarage Thanks. So for adjustment of each TBI alone for every single adjustment you have to use the other screw (minimum air adjustment screw) on the rear TBI ?

[@Joesmusclecargarage]

No. You use the adjustment screw on the rear TB when adjusting the minimum air/rear TB. The balance screw is used for adjusting the front TB.

[@Paragraph247]

@@Joesmusclecargarage So the math is: adjust rear TBI by screwing the screw at the same (rear) body (step1); adjust front TBI by screwing the adle adjustment screw between the bodies ( Step 2); final fine tuning by using the idle adjustment screw as mentioned in step 2 (Step 3).

[@Paragraph247]

Would appreciate a final confirmation of that summary. Thanks.

[@steveo170]

Can’t tell you how fortunate and timely it was finding your videos. Everything you’ve demonstrated are tasks I will need as I refresh my ‘82 L83. I do have a couple of questions; Is there a replacement source for the factory sync screw? Mine has weld on the upper threads that don’t allow the full adjustment range. Would any carburetor repair shop be able to rebush the throttle body? Lastly, in your latest video as well as in an earlier one, you mentioned you’ve done some work on the factory intake manifold, maybe you could share lessons learned/dos/don’ts on that work. Thank you, looking forward to seeing more from you.

[@Joesmusclecargarage]

There are no factory replacements for the balance screw. The screw itself is an M5X0.5mm. You could use a standard screw of the appropriate/required length and use a jam nut, or drill and tap the arm on the TB for a more conventional M6 or 1/4” size. A competent carb shop can absolutely bush the TBs. I had mine bushed a couple of years ago. I can go into detail regarding manifold porting in a future video, or email me at [e-mail]

[@steveo170]

@@Joesmusclecargarage Thank for the info, haven't decided but will likely drill and tap for a 1/4-28 and use a jam nut. I'll email you on the intake manifold topic. Thank you for sharing your expertise.

[@cyrushenry1909]

Love the original hub caps. What size tyres are you running?

[@knightriderhelpjeanluc]

hello where can buy this system please? have you a link ? need to make same to my crossfire 83 thanks you ! actually motor stop after around 10 sec , i dont know why..

[@epicshoutouts4975]

I have a high idle. I changed vacuum lines and EGR valve and resealed the intake manifold car runs and smells better after that but still somewhat high idle when I push the gas it sounds like there is a hissing coming out the front throttle body also that front throttle body has a faster gas flow then the rear one. when i plug the hose coming into the break booster after like 15 seconds car stalls I ordered a couple IACVs have then any day now. what do you think my problem could be? is a carb sync what I would have to do?

[@Joesmusclecargarage]

A CFI doesn’t use carbs. They are single TBI units. I would start by synchronizing the throttle bodies and setting your minimum air.

[@epicshoutouts4975]

@@Joesmusclecargarage Oh ok thanks I'll give that a whirl.

[@kevinoman5829]

Hi, love the videos any chance you could do a video on how to hook-up a 700r4 to the crossfire?

[@Joesmusclecargarage]

Yes. The LU5 was factory equipped with a 700R4 in 1983, and the L83 used the 700 in 1982 and 1984. What exactly would you like to know?

[@danielkarlsson8083]

Hi Joe! Thank you for the great crossfire videos. Noticed that you never touched the minimum air/idle screw on the front tb. Any idea how to set it on a cf that previously was leaky and has been fiddled with a lot? I noticed you only used the balance screw to set the front tb.

[@Joesmusclecargarage]

You don’t touch the minimum air screw on the front TB to sync them. You set the rear TB, then the front using the balance screw. Once complete, you set the minimum air screw on the front TB to have a .005” gap between the tab on the linkage and the screw itself.

[@danielkarlsson8083]

@@Joesmusclecargarage Thank you for the reply and greetings from a cold Finland! :-) That adjustment sounds logical, will do it like that.

[@mikewalsh3281]

Yeah I like to have to question If I don't hook the battery every time I park my car do I have to do that every time Jack it up and go 35 miles an hour and then drive it

[@Joesmusclecargarage]

No. The IACs only need to be relearned when the engine is run while they are disconnected.

[@nicksvette]

Hi. First off thank you for the video. My question is, when you are done balancing the TBs and then proceed to use the rear idle stop screw to adjust the final idle speed, isn't that lowering the 6in setting? Whats the point of bringing the throttle bodies to 6in if the idle is too hight at 6? Is that just a base setting or is 6 required to run properly?

[@Joesmusclecargarage]

Setting each TB to pull 6in/h2o ensures they are balanced. What vacuum the TBs pull at base idle is irrelevant.

[@C-64]

I am curious, when a single line of the mono meter is connected, why doesn’t it get sucked all the way like a straw? Do you have to cover the other end of the manometer?

[@Joesmusclecargarage]

@@C-64 Because it is a very small amount of vacuum. Water is heavy. The vacuum won’t overcome the weight of the water. The other end stays open, otherwise you won’t get a reading.

[@randy3536]

Hello. I have an 82 Corvette. Hooked up the gauge and rear TBI was pulling 2 in. Turned screw to get to 6in. Switched to front TBI it was pulling abt 4in , adj that with the balance screw to 6in. Hooked gauge to both and balanced together. But when i try to turn the idol down , the rear TBI pulls 4 in and the whole balance is off again. What am i missing here ? And when i re-started the car after connecting wires & unblocking idol air , it did not idle at like 3000 but rather around 1100. Thanks

[@Joesmusclecargarage]

Your throttle bodies more than likely need to be bushed. The steel shafts wear the bores of the aluminum throttle bodies and cause the adjustment to vary, or not stay stable. As far as the idle being only at 1100, I have no idea. What was it after you relearned the IACs?

[@randy3536]

@@Joesmusclecargarage I fixed the broken screw on the TPS and set at .525. Timing I set at 8 BTDC. But with the balancing the best I can get is 4 in for both and that lets it idle abt 850 in park ( still a bit high ) Maybe a vac leak ? I think your right on with the bushing issue. Car has 115,000 miles and if i move , shake , ect any of the " bracketry " it changes the water gauge & idle. Thank you for posting videos they are very helpful with this CFI motor.

[@Joesmusclecargarage]

You’re off to a good start. You can get a 3/8” bushing and reamer kit for about $35 on amazon. The kit comes with a total of 8 bushings as well as the correct reamer. 3/8 is the standard throttle shaft diameter, and works on most carbs and GM throttle bodies.

[@randy3536]

@@Joesmusclecargarage Ok , i see that kit , will get it. While its apart , who would you recommend for the most complete rebuild kit for the rest of the TBI unit ? I will put a new top manifold gasket on also. Drove the car today and the idol goes up alot 1200 when you let off to try and stop. Going above 30 mph & back to idol made no difference. Prob lot of extra air getting in and the leaking shaft wear. issue. Thanks

[@johnF56]

Who would you recommend to re-bush the throttle shafts.

[@Joesmusclecargarage]

Any carb shop, or you can buy the kit that comes with a reamer off amazon for $38. It’s an easy job, and comes with a total of ten 3/8 bushings.

[@mikelaws8992]

Joe I put new idle control motors on my 82 but the only ones I could find were made in China is that OK? It will still stall wind slowing down sometimes

[@Joesmusclecargarage]

I haven’t had any luck with the chinese IACs. I have run the Standard AC2s with good luck. They’re a little pricey, but those cheap aftermarket parts are cheap for a reason.

[@scotthughes5552]

Where can I get a manometer like yours. The ones I found don't go over 4 pounds of vacuum height.

[@Joesmusclecargarage]

I think Grainger sells the slack tube manometers, or you can make one for about $6. I have a digital manometer as well, but I prefer the slack tube.

[@domscargarage8837]

Where i can buy this water manometer? I have 3 crossfire trans am, and i Need it to adjust and Sync

[@Joesmusclecargarage]

I would be willing to sell my original 1982 manometer. I’m done with CFI cars, and I sold my 83 over 18 months ago.

[@richeatongolf]

What did you use to remove those factories caps. I don’t want to damage the screws to adjust the idling

[@Joesmusclecargarage]

A small punch.

[@justinparden2]

Thank you for the video. I have a question on my rear throttle bottle the adjustment screw seems to be blocked off. Curious if you ran across that before.

[@Joesmusclecargarage]

Of course. They were capped at the factory. That basically means they TBs have never been adjusted. You can puncture the cap with a small pointed punch or an awl, and pry it out. If the cap is still there, I’m assuming your balance screw is still welded.

[@justinparden2]

Thank you. It is still welded. One last question I’m currently rebuilding the injectors and I notice the fuel regulator bladder I pulled out has some sort of swivel piece. The one I ordered does not. Did I order the wrong part.

[@Joesmusclecargarage]

@@justinparden2 I’m not sure what you mean by “swivel piece”. All the regulator consists of is the diaphragm and the spring.

[@richeatongolf]

Can you do vid with a digital monometer pleaseeeeeee

[@Joesmusclecargarage]

Next time I check/adjust my TBs, I’ll use the digital manometer. The process for the digital manometer is identical to the water manometer. Pull each TB to 6 in/H2O, then zero them against each other.

[@DM-fs9zg]

What about the idle stop screw on the front tbi, does it ever come into play, should it be backed off, someone has drilled mine out and I'm assuming it's been adjusted at some point.

[@Joesmusclecargarage]

The screw on the front throttle body (slave) doesn’t get touched. Your minimum air and TB sync procedure is done strictly with the balance screw, and the screw on the rear (master) throttle body. Somebody at some point had absolutely no clue what they were doing, and messed with it. It needs to be backed out so the butterfly is completely closed before you start the synchronization procedure.

[@DM-fs9zg]

@@Joesmusclecargarage yeah, whoever did it had the front drilled and the rear was still plugged lol, the sync screwed appeared to me as only affecting the TV cable, I know you know, I haven't attempted it yet, I rebuilt my tbi's last month and just got a water manometer. I really appreciate your time.

[@Joesmusclecargarage]

@@DM-fs9zg Anytime. Hope it all works out for you. Feel free to ask any questions you might have

[@CallforthePriest]

Joe, if you used a digital manometer to do this, what number would you be looking for on that?

[@Joesmusclecargarage]

6” on each TB, then 0” when doing the final balance.

[@garytilley8816]

Great information

[@marthacook384]

Hey Joe, Great videos mister!! I’ve got a 82 Vette CE. Just got done syncing the TB’s & had a couple of things go a little differently. Rear TB did pretty much what yours did. My TB’s have a phillips head adjustment screw. The front TB did pretty much what yours did - but when I hooked both TB’s to the monometer the rear TB went about 3” below 0” & the front TB went about 3” above 0”. I adjusted them to 0” & adjusted the idle & it seemed to be fine. When I hooked all the air sensors back up to the TB’s & put the air filter stuff back on & fired it up - it did not rev high it was like it was when I got done adjusting it. Do you think I did something wrong? Hey man - Thanks for all the great videos! Bryk

[@Joesmusclecargarage]

I don’t think you did anything wrong. I’ve had that happen when I was running the stock 6026 ECM. Most of the time they’ll idle super high until it relearns the idle, but sometimes you fire it up and it idles right where it’s supposed to. I’d just drive it and keep an eye on it. As long as it idles where you want it to, call it good to go 👍

[@marthacook384]

@@Joesmusclecargarage Thanks Joe!!

[@xtransam9970]

Thank you.

[@chriswilliams5.3]

I recently purchased a 82 crossfire TeaTop Firebird factory AC car and I’m having issues getting it to stay running i need some experienced help

[@Joesmusclecargarage]

Very cool car! 👍 You came to the right place. What kind of issues are you having?

[@chriswilliams5.3]

@@Joesmusclecargarage I got the car to start and fire realize I had a fuel pump problem so trace down some broken wires fix them now the fuel pump seems like it’s running too much fuel

[@chriswilliams5.3]

I can get it running but I have to unplug the wire for the fuel pump to get it to fire and plug it in intermittently to get it to stay running

[@Joesmusclecargarage]

@@chriswilliams5.3 First you need to verify fuel pressure when the car is running. This is done by placing a gauge on the fuel line connecting the two throttle bodies. Make 100% sure you have no vacuum leaks, especially the vacuum line running to your MAP sensor in the drivers side rear corner of the engine compartment. Make sure all of the bolts on the top plenum are tight. You can check for vacuum leaks by spraying carb cleaner around the manifold, plenum plate, and vacuum lines. If you have an active vacuum leak, your engine speed will change. Your TPS should read .54v at idle, and have a clean, unbroken sweep when the throttle linkage is moved. Also, once the car is running, check the base timing. It should be between 6-10 degrees BTDC. Remove and clean the IACs as well. All of these things are standard MAP based EFI things to check. That should get you started.

[@chriswilliams5.3]

@@Joesmusclecargarage it worked it was the vacuum line to the map that was bad I saw it was old and rotten but I didn’t think it would matter now I have to figure out why the pop up lights don’t work but the lights still working

[@benfong4650]

What is the size and length of the hose? Thanks.

[@Joesmusclecargarage]

3/16 clear tubing. About 10-12’ should be plenty if you’re making your own.

[@xtransam9970]

Whare can a buy the water manometer?

[@Joesmusclecargarage]

They’re all over the place online.

[@xtransam9970]

@@Joesmusclecargarage thank you, for your hard work in fixing the issues with the crossfire injection, the next question, what about high performance?

[@Joesmusclecargarage]

@@xtransam9970 A lot can be done in terms of performance gains. The basics would be bumping the fuel pressure and timing, and porting the base. You can go beyond that by going with a full exhaust system, which on a thirdgen can knock off over a second in the quarter. You can do a cam swap, torque converter, etc. There are Crossfire cars running deep 12s, and are as reliable as one that is bone stock. It’s all a matter of how fast you want to go, and how much you want to spend.

[@TFD1982]

Sounds good👍🏼

[@TFD1982]

@@Joesmusclecargarage it’s a compliment I’m not trying to be rude here

[@Joesmusclecargarage]

I know it’s a compliment.

[@daniellethomas6776]

Where did you get water meter from ?

[@Joesmusclecargarage]

I got mine from a dealership I worked at 20 years ago. You can get them on Amazon.

[@daniellethomas6776]

@@Joesmusclecargarage will it look like this or no I looked a little and they don't look anything like this :(

[@daniellethomas6776]

The one I do see only has 1 hose and basically 1 colored water gage measure

[@daniellethomas6776]

Its basically a tube with measurements , with 1 single hose?

[@Joesmusclecargarage]

@@daniellethomas6776 www.amazon.com/Dwyer-Roll-Up-Manometer-Pressure-18-0-18/dp/B009PAQARI/ref=asc_df_B009PAQARI/?tag=hyprod-20&linkCode=df0&hvadid=312432452293&hvpos=&hvnetw=g&hvrand=5066359453092574712&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=1013462&hvtargid=pla-624265933407&psc=1

[@johng.5473]

What is that tool called? How do you make it?

[@johng.5473]

Nm I saw the other vid

[@Joesmusclecargarage]

As I stated in the video; it’s a water manometer.

[@scooch3500]

What if my speedometer doesn't work?

[@Joesmusclecargarage]

Then you need to fix it. The ECM needs to see a signal from the VSS in order to relearn the IACs.

[@chrisWilliams-bz7lk]

How much does that tool cost?

[@Joesmusclecargarage]

You can pick one up for $60-70, or you can make one for less than $5.

[@crazyivancrazyivan8879]

on my 1982 collector edition there is no screw there to adjust anything its a blank spot unless im missing something youre moving so fast i dont see what youre fooling with lol also my valve screw seems to be welded so it cant move ,,, blah this thing is hard to start because its dumping way to much fuel but after u do get it running it runs fine ,, just have to get it started

[@Joesmusclecargarage]

Drill the knockout plug and remove it to expose the screw.

[@cyrushenry1909]

Unreal. My balance screw is still welded...