FITech Fuel Injection Hesitation

[BobinHSV]

I have been running a FiTech for over 2 years om my '87 El Camino Almost every problem reported on the FiTech is related to improper installation/setup or fuel system. I run a Buick Roadmaster SW fuel tank with the proper GM fuel pump/sender unit. I have an external 30 micron filter before the FiTech unit and a proper return/vent system for the tank. I can let the ElCo sit for 3 months and react through the window, turn ignition on, wait for pump to stop with full pressure, then turn key to start and the car starts instantly. I spent quite a bit of time understanding the set up of the unit, and have had no problems at all. The person installing needs to understand the fundamentals of FI Systems, and be patient enough to read the instructions and follow them.

 

[jjmacswt]

I appreciated the advice.

The ultimate solution was to adjust the TBI butterflies to just barely cracked open. It took about 10 tries before this worked to eliminate the hesitation from idle to acceleration. Next, I lowered the AFR to 13, thus slightly enriching the fuel delivery and suspect I may drop it to 12-12.5 if needed. The car now runs great.

I credit Kenny, with Hyperfuel Systems tech department for ultimately providing the solution. I didn't purchase my EFI system from them and he still offered the assistance I never could acquire from Fitech.

Again, thank you all for the help as I'm not much of a mechanic.

 

[pontiacgp]

I appreciated the advice.

The ultimate solution was to adjust the TBI butterflies to just barely cracked open. It took about 10 tries before this worked to eliminate the hesitation from idle to acceleration. Next, I lowered the AFR to 13, thus slightly enriching the fuel delivery and suspect I may drop it to 12-12.5 if needed. The car now runs great.

I credit Kenny, with Hyperfuel Systems tech department for ultimately providing the solution. I didn't purchase my EFI system from them and he still offered the assistance I never could acquire from Fitech.

Again, thank you all for the help as I'm not much of a mechanic.

you're a better listener than alot of mechanics so keep at it and you'll learn lots......🙂

 

[CopperNick]

Great Solution that raises some more questions. First, when you tweaked the butterfly adjustment down to the absolute minimum, did you have to visit the idle speed on the monitor and bump it any to compensate? Second, where on the unit did you go to make that adjustment? Third, my own AFR is at about 12.7 or so with the engine warm. If the hand-held does show it at around 13-ish, it is usually a case of it being a cold engine on initial start. As the mill warms up, the AFR automatically leans itself out to the correct ratio. Fourth, your motor being a 350, the settings that give you the best responses may prove to be different for larger or smaller motors or built motors as opposed to stock or crate mills. Fifth, still looking seriously at my own fuel system as being THE culprit as fuel starvation displays a lot of the symptoms that I am experiencing and the 1st edition FI-TEch booster pump never did strike me as being the proper solution to begin with. (I hate budgets) As for my solution, Holley makes an electric pump in-tank pump that only requires a single hole to install; no ring of smaller holes and a mounting plate and additional drilling. It also comes with a dedicated return circuit that will allow me to decommission what FI-Tech originally suggested which was to repurpose the vent plumbing because the factory in tank pickup wasn't suitable according to them. The big hassle will be to drain and dry out the tank so that it can be drilled safely. May take using another new tank to accomplish that. Bummer.
And of course, Murphy has to stick his nose in; i.e. "when you have a budget, you don't have the time." Plus the forecast is for another 10 inches of white crap to descend upon us. "For what we are about to receive, we thank Thee."

 

[jjmacswt]

1. I was able to tweak the idle speed with the butterfly adjustment and I didn't touch the idle adjustment.
2. On the passenger side, fire wall side on the corner of the TBI is where I adjusted the butterflies. You'll need a small phillips head.
3. I had the car warmed up and was driving when adjusting the AFR.
4. Beyond my skill set
5. Some of the other recommendations that Hyper Fuel Systems provided included directly wiring the Command Center 2 to the battery. He also recommended gunning the engine making sure the fuel pressure gauge is maintaining 43 psi, which is what my TBI requires. The command centers are set for 56 psi but will adjust as needed and mine seems to be following suit.

If you haven't made a commitment to one solution or another, I'd recommend calling Hyper Fuel Systems and speaking with Kenny. Remember, I'm not a mechanic.

 

[Clone TIE Pilot]

1. I was able to tweak the idle speed with the butterfly adjustment and I didn't touch the idle adjustment.
2. On the passenger side, fire wall side on the corner of the TBI is where I adjusted the butterflies. You'll need a small phillips head.
3. I had the car warmed up and was driving when adjusting the AFR.
4. Beyond my skill set
5. Some of the other recommendations that Hyper Fuel Systems provided included directly wiring the Command Center 2 to the battery. He also recommended gunning the engine making sure the fuel pressure gauge is maintaining 43 psi, which is what my TBI requires. The command centers are set for 56 psi but will adjust as needed and mine seems to be following suit.

If you haven't made a commitment to one solution or another, I'd recommend calling Hyper Fuel Systems and speaking with Kenny. Remember, I'm not a mechanic.

Not sure about TBI, but with carbs the idle throttle valve opening angle is influenced by the ignition base timing. The more advanced the base timing is set, the further closed you can have the throttle blades at idle.

 

[Tony1968]

Yah, I was hoping these standalone TBI's would be better than they are. What is the point of them if they run like this and gain 0 mpg over a properly tuned carb? Even guys who like the swap have said 0 mpg gained. Isn't that the point of EFI, better mileage and drivability? I saw an AMC 6 build because FItech was their sponser, clearly the issue was their intake modification. Funny when they put on a 750 carb on, the 6 made the power they wanted, which wasn't much to begin with 242 hp, the FItech definitely could not learn fast enough on the dyno, didn't break 200 hp. Too bad, I had hope for these EFI setups, just shows, you get what you pay for.

The great Warren Johnson once spoke about fuel injection vs. Carburetors.
He said that a properly tuned carb will make more power than injection and I still believe him. The low pressure below the plates atomized fuel (and cools it) way better than efi. The only way efi will get better mileage is if the carb setup being compared to is not tuned perfectly. Efi is better for weather changes and elevation etc. But that is about it... jmho

 

[olds307 and 403]

Of course just talking these simple EFI, modern sequential and or direct injection is EFI is way ahead of carburetors. Also timing that can adjust to conditions is big advantage and should be absolutely used or there is little point to using these TBI set ups.

 

[Supercharged111]

The great Warren Johnson once spoke about fuel injection vs. Carburetors.
He said that a properly tuned carb will make more power than injection and I still believe him. The low pressure below the plates atomized fuel (and cools it) way better than efi. The only way efi will get better mileage is if the carb setup being compared to is not tuned perfectly. Efi is better for weather changes and elevation etc. But that is about it... jmho

There is also something to be said about the throttle response when everything is mechanical as well. I still prefer EFI in most all cases, but I am keeping this Monte carbed as it's a skill I want to stay in touch with.

 

[pontiacgp]

The great Warren Johnson once spoke about fuel injection vs. Carburetors.
He said that a properly tuned carb will make more power than injection and I still believe him. The low pressure below the plates atomized fuel (and cools it) way better than efi. The only way efi will get better mileage is if the carb setup being compared to is not tuned perfectly. Efi is better for weather changes and elevation etc. But that is about it... jmho

and weather changes all the time.....