New Fitech install, stuttering issue
And I appreciate the help 😉
Via the handheld, I confirmed that the basic engine settings are correct but I presume they weren't changed since I only wiped the learning?
I let it idle up to about 175 and took the attached screenshots
- Temp 176
- RPMS at 2700ish
- AFR 14.5ish
- AFR trim was bouncing between -1.8 and positive 1.8, 0 in the screenshot.
- IAC settled out at 66
Note that when I turned off the car, the radiator cap pressure release was dumping coolant. At 176 deg? Something seems amiss there.
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Look for a fault code. Are you running timing control?
I do not believe so, but how would I confirm this? I did search first, but I'm not coming up with much to figure this out. If it helps (and it may not) I have a Pertronix distributor.
Which pertronix distributor. That can be an issue. Also there is a section for fault codes. I believe you have an RPM noise issue. There is a pinned post for the fix. Wiring requirements section, blue wire sheilding.
"It's Blue"? I can get better info tomorrow and look up those fault codes. I found that post you referenced, thanks.
Note, just to reiterate, the car had been idling/running fine except for the initial stutter on takeoff. "Someone" adjusted the timing, it ran fine home. Next start it's all wonky, and been wonky since.
I (in my ignorance) would think if there was a wire-shielding issue, it would have been there from day one? But I'll defer to your expertise.
I'm open to getting a better distributor too, happy for suggestions. It needs new plugs and wires anyway, may as well give all that stuff some love.
Thanks again.
Rpm noise can be an intermittent problem. But still a problem. Very common issue. Adjusting timing can raise idle a bit, but not like that. You had zero fuel trim. That means the Fitech is in open loop. It is not adjusting and not learning. I am leaning towards the blue wire issue and then maybe the distributor. Need the model number.
So, I tracked down the over-idle issue. It comes down to complete user error\dumbassery and nothing to do with the EFI: When I pulled off the air cleaner to connect the handheld unit for the first time, I noticed the throttle cable was unsupported connecting to the throttle body (and in hindsight I remember the mechanic telling me this, but I had forgot): "that looked odd", so I reconnected it to the stock bracket. But... this put a very slight bend in the line. Enough so when I pressed on the gas for first start, it never returned to neutral, and just stayed depressed. After troubleshooting every step that had occurred since things went wrong, I'd realized I'd done this. Disconnected that clamp this morning, and it's back to a normal idle. WHEW.
I'll have some time later to get you those numbers again, at a correct idle. Do you think I should do another learning reset again before that based on the weird state it was in?
It should be ok. Just start from step 1 again and verify everything within range. I would get your idle right, check the timing and then go through the few steps. After that let it learn and run a 30 second data log at idle. Post it here. You will need to use Dropbox.
I'm going to presume the timing is right having it just been done. I let it warm up from idle, then took it for a drive, took pics before and after which are attached and labeled. Looks like in all cases, the IAC slightly too high (above 10): Presumably at this point I should go through the manual screw twisting steps to get that in spec? Then do the data log? When you say, 'let it learn' that means... idle it above 170c?
I checked the fault codes, there were only two : One was for a fan relay. I checked, and the mechanic had the 'electric fan' set on, so I disabled it. The other one was P000, which checking online seems like fine, it tells you it went full cycle with no faults (you probably know this).
And after all this, it's worth noting that weird stutter is still present, and just driving it around the neighborhood it would do a random weird stutter from time to time, but again, usually only during slow acceleration. However, I feel good that none of my previous dumbassery made anything worse.
As ever, thanks for your help.
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Yes, adjust your IAC steps a little more. Yes, the learn process happens above 170 degrees. It starts with some idle time, then some light driving. Doing good.
At this point, i am leaning towards a vacuum or exhaust leak causing the stumble. It will be a small leak. We can learn more with a data log of the stumble. The data log will also show us how well it is learning.
We are making progress!!!! When this is done, I hope you will be answering questions for guys on this site....