New Fitech install, stuttering issue
Recently had a Fitech EFI 400 + fuel command center installed on my 68 Ford Country Sedan, 390 FE, + new Edelbrock intake. I had the work done for me by a local shop since I simply don't have the space. FYI, this is the first time the shop had done this type of work, but they're very familiar with old cars.
Been driving it for a few days now, and I'm noticing a stutter when I give it gas. It's most noticeable from idle, but it really can happen at any speed. Imagine you're in a parking lot, just giving it a little bit of gas to start rolling, and it'll briefly stutter. Very consistent. Same thing happens if at speed you aren't giving it much gas, then roll on a bit more, it'll stutter. Once it's going it seems to be pretty happy. At one point getting up to highway speed it briefly cut out entirely.
After a bit of research, I realized that there is no vacuum from the line going from the back of the EFI to the distributor. Could that be part of the issue?
This is all new to me, but I'm a good learner : If someone can start pointing me in the right direction I'd appreciate it. Want to learn what I can about this before I bring it back into the shop on Tuesday.
thanks
Distributor vacuum not an issue...
I can help, but need to start with the basics. Are you familiar with the handheld? Specifically the dashboard menu.
Step 1 warm engine to operating temperature. Verify coolant temp on handheld is above 170 and nearly the same as your gauge. Within 10 degrees. If not above 170, stop there. Unit will not tune unless reading 170 or above.
Step 2 monitor your IAC steps. Should be fluctuating around 5, or 2 to 8 variance. If not stop there. Adjustments can be made.
Step 3 if both temp and IAC steps are good, then take a pic of your AFR and AFR trim values. Post back here.
Thanks for the feedback : I've not used the handheld yet since the shop did all the work, but it's time to get familiar with it 🙂 I'll give all your suggestions a shot and report back.
So, the plot thickens: I hooked up the handheld unit and fired it back up: It's suddenly idling at 2500 rpm, never done that before.
However, I have a suspicion I know what's going on: While troubleshooting this with some guys, they felt the timing was off , and one of them adjusted it (they set it 'back to factory', they felt it wasn't). It drove home fine (no different than before, still with the stutter), and it has sat for two days. Firing it up the first time since it is acting wacky. Could adjusting the timing on this thing cause the issue?
I presume at this point I should just reset the whole system and do the first time calibration from scratch? I'll start looking into how to do that unless I hear a reply back in the meantime.
So along those lines, I found this faq:
I presume I need to do: "Resetting to a stock calibration". But do I also need to "Reset Learn" after than, or does it take care of it? Or do I just need to 'Reset Learn' and leave my current config?
But for the life of me I can't find any sort of set of instructions for how to configure this the first time, the data seems to be spread all over the place. For example, I have the paper Quick Start Guide, but it talks nothing about setting my IAC steps.
Anyway, I really don't want to screw this up and leaved it bricked in my driveway (well, already it's idling too fast to drive), so I'll take any suggestions I can get, thanks.
I did the learning reset: That got the idle RPM's to drop to around 1500, and IAC was sitting at zero. I read that if you adjust your timing (which happened) you need to reset your IAC. So I began that process based on the above linked doc, running around 150-170 deg. However, that didn't fix it, in fact things got worse: Since my IAC values were low (0), I started turning that screw counter clockwise half turn at a time and testing (making sure my TPS was zero between each attempt per the docs). It slowly started bumping from 0-5, but still mostly zero, however my RPM's are getting higher after each test. In fact, it seems like each time I stop\start the car, the idle RPMs get higher. I've left it back idling around 2800, higher than when I started this whole process.
Going to stop working until I get some advice, thanks.
Please reread my post from earlier. Particularly step 1.
So, I should just let it idle at 2800 rpm until it hits 170? I'm guessing your answer is going to be yes, but I wanted to confirm this. Thanks.
No, but up to you. Relax a bit. Here to help.
Verify your inital settings are still correct.