[angelo]

Cars were using the 4.2 up through about 2005-2008, we are talking about more recent change in O2 sensors. The circuitry for reading the sensor changed so the tech inside the throttle body would need to match the sensor to work.

[1980 TA]

Just to be clear, the difference in the AFR is between the speedhut gauge in the dash and the handheld unit. Everything is new and supposed to be correct on the speedhut gauge. I'll chat with them and see what they think is the cause. The error in the gauge reading didn't help the carb get a fair shot as I was going too rich with every adjustment.

Fuel injection did well tonight as I took the car out to a meeting. Getting better every time. Pulls real nice to 4500 now under not quite full throttle.

No old car smell when driving into the garage. Being curious, I opened the gas cap as soon as I pulled into the garage and no sucking air sound. I am running a tanks ink vent high up on the core support "T'd" into the FCC and feeding the factory vent line. Only problem is at speeds over 45 or so, I get a very faint fuel smell inside the cab with the windows up and the vent on. I'm guessing some vapor is making it from under hood in through the air vent.

[Mace1971]

I don't think I'd vent the fuel system under the hood. Too many potential ignition sources.

[Yater]

Hi everyone,

Long time since I last posted in the forum.

Just saw this thread and thought I could update you. I think some folks out there were interested in the feasability to install such filters in Formulas...

I just installed the Fitech Go EFI 600 + Fuel Command Center in my 73 Firebird Formula.

No clearance issues with the Formula hood.
I searched for a long time for a suitable dropped air cleaner and made a few drawings and sketches myself with the dimensions of the TBI and the ones "estimated" for the air cleaner (being based in Europe, unfortunately I purchase most of the parts on a "half-blind" basis...). I went with a 16 in. cleaner with 1.75 in drop., 3 in tall filter.
It worked nicely ! everything fits under the cleaner, including the TBI and fittings withoug modifications, and the overall set-up clears nicely under the hood.

I installed a fuel pressure regulator before the FCC set at 3 psi and it helps with less pulse incoming into the FCC, I read somewhere that the fuel temperature entering the FCC should also be lower. I also modified the PWM of the FCC pump and set it as 40% as recommended.

I vented from the FCC, using the pre-existing venting tube till the gas tank, then I modded the gas cap as explained here:

http://www.chevelles.com/forums/45-c...em-solved.html

So far so good. In case this venting trick would not work well, I also have a VVR rollover vent valve from Tanks Inc. like the one Angelo used in his car (Angelo, I wrote in your modsandrodstv board to ask about this and I realized very late that you were very keen to respond. Thanks a lot!!).

Everything seems to be working fine so far. The shop is finalizing the fine-tuning but we went for a test drive last week and everything seemed to work very well. First impressions are that the car feels more responsive. I need some more driving for a better judgement. But overall satisfied so far.

Some pictures of the install....


Initial mock-up after I received the 16 in. air cleaner:








Air cleaner & filter (the filter is from Airaid) before installing the Fitech unit:



FCC set-up before installing the pressure regulator:





With the pressure regulator in place:



And the TBI unit installed...



Hope it helps for the Formula owners...

See you around !

[JLMounce]

Looks good! Not sure if you've fired this up yet or not, but I see you have a vacuum line to the front vacuum port. That port is specifically for boost reference and may cause issues with the unit in a normally aspirated setup. Funky idle, weird AFR readings etc.

It obviously can read vacuum as boosted engines aren't always in positive pressure, but if you find that the unit is running a little wonky, moving that vacuum hose and plugging that port may solve an issue.

[Yater]

Hi Jason,
Thank you for your comment.
Not sure to see what vacuum line / port you refer to. Are you talking about the FCC or the TBI ?
We did start the car and go for a 1st test drive and everything seemed to be OK.
Appreciate if you can further explain. Thanks!

Originally Posted by JLMounce

Looks good! Not sure if you've fired this up yet or not, but I see you have a vacuum line to the front vacuum port. That port is specifically for boost reference and may cause issues with the unit in a normally aspirated setup. Funky idle, weird AFR readings etc.

It obviously can read vacuum as boosted engines aren't always in positive pressure, but if you find that the unit is running a little wonky, moving that vacuum hose and plugging that port may solve an issue.

[grivera]

Nice! Which intake is that and did it require the shim adapter?

[Yater]

It's an Edelbrock performer.
I think we used the supplied gasket, if that's what you refer to.

Originally Posted by grivera

Nice! Which intake is that and did it require the shim adapter?

[JLMounce]

Originally Posted by Yater

Hi Jason,
Thank you for your comment.
Not sure to see what vacuum line / port you refer to. Are you talking about the FCC or the TBI ?
We did start the car and go for a 1st test drive and everything seemed to be OK.
Appreciate if you can further explain. Thanks!

I was referring to the vacuum line attached to the front of the TBI unit itself. That line is what the ECU uses to reference boost pressure. The ECU then uses that to accommodate fueling and timing changes if so equipped.

I do not know if it's even connected to the vacuum system and if you have a vacuum accessory located off it (like a vacuum advance) it may not be functional as a result.

Some people that have had accessories hooked up here have shown driveability or other run issues. That certainly wouldn't always be the case however. If you're up and running well, you may not have anything to worry about there.

[Yater]

Thanks a lot Jason
I will have my shop checking this tomorrow. In principle they did the install following the instructions from Fitech but will double check!

Originally Posted by JLMounce

I was referring to the vacuum line attached to the front of the TBI unit itself. That line is what the ECU uses to reference boost pressure. The ECU then uses that to accommodate fueling and timing changes if so equipped.

I do not know if it's even connected to the vacuum system and if you have a vacuum accessory located off it (like a vacuum advance) it may not be functional as a result.

Some people that have had accessories hooked up here have shown driveability or other run issues. That certainly wouldn't always be the case however. If you're up and running well, you may not have anything to worry about there.

[JLMounce]

Originally Posted by Yater

Thanks a lot Jason
I will have my shop checking this tomorrow. In principle they did the install following the instructions from Fitech but will double check!

Yeah, therein lies the problem. The instructions do have a diagram of the ports, but nothing specific is discussed about that front port and what it does.

Their materials are getting better, but there's a lot to be desired in their write-ups.

http://fitechefi.com/fitech-uploads/...nsm12.9.15.pdf

Reference figure #4 on Page 4 of the pdf.

This is partially our fault as installers as well. Carb's have vacuum ports on the front, why wouldn't a TBI be the same thing?!? It's easy to just assume you can use that, but in this case, it's likely that whatever accessory you've got hooked up there likely is non-functional.

[Yater]

I can only agree.
Their base instructions lack of A LOT of the info that can be found on forums, etc.
The fact is you have the feeling that you may always have forgotten some update or .....
It shouldn't be such a huge effort for them to issue an updated "2.0" version of the manual integrating all the tips and tricks ...

So Jason, where do you think this tube should go if not in the current nipple ?

EDIT: looking at fig.4 you mentioned, should it go into the 3/16 nipple at the back instead ?

Originally Posted by JLMounce

Yeah, therein lies the problem. The instructions do have a diagram of the ports, but nothing specific is discussed about that front port and what it does.

Their materials are getting better, but there's a lot to be desired in their write-ups.

http://fitechefi.com/fitech-uploads/...nsm12.9.15.pdf

Reference figure #4 on Page 4 of the pdf.

This is partially our fault as installers as well. Carb's have vacuum ports on the front, why wouldn't a TBI be the same thing?!? It's easy to just assume you can use that, but in this case, it's likely that whatever accessory you've got hooked up there likely is non-functional.

[JLMounce]

Originally Posted by Yater

I can only agree.
Their base instructions lack of A LOT of the info that can be found on forums, etc.
The fact is you have the feeling that you may always have forgotten some update or .....
It shouldn't be such a huge effort for them to issue an updated "2.0" version of the manual integrating all the tips and tricks ...

So Jason, where do you think this tube should go if not in the current nipple ?

EDIT: looking at fig.4 you mentioned, should it go into the 3/16 nipple at the back instead ?

Yeah, without knowing what that line is hooked to I couldn't really say. Based off the picture I would assume that's likely to the vacuum modulator on a transmission. If that's the case, use the 3/16" vacuum fitting on the back of the TBI on the right side. This will be manifold vaccum. If it's a vacuum advance and you want it on ported vacuum use the fitting on the left that is angled up.

Sometimes you have to play with that a bit. If you're running with a standard distributor and using a vacuum advance, some cars like manifold vacuum instead and you may need to cap the ported vacuum fitting and run a t from a line on the manifold vacuum port.

[Yater]

Ok. Will try to check all that.
I'm running an HEI
Thanks again!

[JLMounce]

Originally Posted by Yater

Ok. Will try to check all that.
I'm running an HEI
Thanks again!

Ya know, I saw that and didn't put two and two together. I'd run the vacuum can off the ported vacuum source to begin with. That's the way I have mine run and it works very well. I have my vacuum modulate for the TH400 off the manifold vacuum port.

[Yater]

[QUOTE=JLMounce;5717645. I'd run the vacuum can off the ported vacuum source to begin with. [/QUOTE]

Ok now I'm sorry but I'm lost .... :-)))
Not your fault but the fact that I'm not a native English speaker ...
If you wouldn't mind rephrasing with some sort of "tube doing function xxx connecting into nipple yyy".... Don't bother otherwise , I'll get it sorted with my shop, the guy is quite competent with EFI after playing with a few megasquirts...

[JLMounce]

Not to worry. I would run your vacuum advance canister on your HEI to the 3/16" nipple on the driver side of the TBI. This is the one that points upwards a bit. If you have an automatic transmission with a vacuum modulator, run that line to the 3/16" nipple on the passenger side of the TBI. Your PCV should run to one of the larger nipples and your brake booster to the other large nipple.

[Yater]

Great, much better!
Thanks for the recommendation, will try to check all that during the week.

Originally Posted by JLMounce

Not to worry. I would run your vacuum advance canister on your HEI to the 3/16" nipple on the driver side of the TBI. This is the one that points upwards a bit. If you have an automatic transmission with a vacuum modulator, run that line to the 3/16" nipple on the passenger side of the TBI. Your PCV should run to one of the larger nipples and your brake booster to the other large nipple.

[1980 TA]

I modded my gas cap in a very similar way to the link and plugged the tanks inc vent under the hood. No more gas smell inside the cabin. No gas smell in the garage either. I have charcoal screens for my air filter at home and I will play with fitting a charcoal filter inside the cap. I can get a whole lot of cap filters from the one sheet, even if I have to replace them with every oil change. I'm not too worried about leakage under acceleration with all of the baffles inside the filler neck. I filled up today and gave it a good run in first gear from a rolling stop and then checked the inside of the cap and it was dry.

The first gear run was fun. It lit the tires from a roll at 20 mph and pulled great to redline. Eased the shift into second gear and then eased it to the floor and it pulled to about 4700 rpm's and seemed to nose over so it still has some learning to do. Getting better with every drive.

That's the nicest thing about the unit so far. The car is enjoyable to drive. It is so much quieter now with respect to exhaust note and engine noise. It's also running much cooler as the heat through the floor boards would get uncomfortable after about 30 minutes of driving. I'm sure my carb tuning could have been better but this is so much easier.

I have driven the car more in the last few days than the proceeding month or so. It's just fun to take to town for any reason.

In 5th at 65 mph its pulling 19 + inches of vacuum. I thought for a RAIV cam that was more than respectable. Pulls 13 inches at idle now.

My throttle body does not have the nipple on the front of the unit but I did not buy one capable of using with boost so that may be the difference.

[Yater]

Originally Posted by 1980 TA

I modded my gas cap in a very similar way to the link and plugged the tanks inc vent under the hood. No more gas smell inside the cabin. No gas smell in the garage either.

Hi,
I'm interested in case you can find some time and take a picture of how you installed the rollover vent valve.

Hi Angelo, I'd you're reading this, same question for you since I didn't truly get to "visualize" from your explanation in your board.

Thanks a lot!