I managed to pin down the backfire issue, it seems to have to do with getting out of idle mode at speed - thus, it should be gone once I get my VSS.
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I managed to pin down the backfire issue, it seems to have to do with getting out of idle mode at speed - thus, it should be gone once I get my VSS.
Dr. In my early days (Late 70's early 80's) I heard some news about Ford V-8 fan blades breaking. The Tech next to me at the Olds Dealership explained a co-worker at his last job looked up after an engine rev with a blade sticking out of his forehead. Check for cracks on the Ford belt driven fan blades. If you live in cold climate leave the Thermac enabled. In the summer, disconnect the vac to it. I would run a cold air tube off the air flt to the front. The heat under hood is pretty high. Use a Thermocouple to measure it. (GM target Thermac Carb Air clnr temps are 140 to 150 deg F)
Getting there with the fuel table...
http://pic.armedcats.net/d/dr/dr_gri...27/blm_new.png
I think from here on it makes no sense to continue tuning until I get the VSS.
VSS is in, hesitation/backfire at slightly above idle RPM stays. Broadband O2 sensor shows her massively leaning out (consistent with backfiring).
I fear that due to the idle speed being "only" 650 on my Ford I am below the RPM level where the 7747 supports AE. Or is that a bullshit theory? As always, I am grateful for suggestions.
Finally took the plunge and registered TunerPro. It has been a reliable asset during the last year of tuning, it was about time.
I find that hard to believe. AE should work as the throttle is opened, no matter what the rpm is.
When does this backfire occur - at throttle tip-in or something else?
See here - I tracked it down, finally.Quote:
Originally Posted by lionelhutz
That's not exactly right...Quote:
Originally Posted by lionelhutz
There are tables (in most codes) that will allow for adjustments to AE based on RPM, and sometimes other parameters, so it's possible that AE needs to be adjusted when other changes are made. It's also possible to disable, intentionally or otherwise AE under certain conditions.
Engine has developed a tendency to sometimes misfire massively - first time it occured, she hardly came out of idle, had no pull at all, after a longer full-throttle stint. I was on my way to change the plugs then anyways and with new plugs, the issue was gone. So I figured - good timing in renewing the plugs.
Now it returned - several cylinders cut out in idle while sitting at a red light. This times, they returned to working order a few seconds later, though.
Got fuel. Compression's good. Plugs are new, plug wires are new. Thus, I ordered a new 7-pin module. It's either that or the coil.
Of course you can tune it. I was responding to the theory about the 7747 ECM not supporting AE at low rpms, as in it simply isn't there and hence can't be tuned.Quote:
Originally Posted by Six_Shooter
Pictures! :)
http://pic.armedcats.net/d/dr/dr_gri...506_130226.jpg
http://pic.armedcats.net/d/dr/dr_gri...506_191403.jpg
http://pic.armedcats.net/d/dr/dr_gri...507_194319.jpg
http://pic.armedcats.net/d/dr/dr_gri...507_180149.jpg
And times (slow ones)!
http://pic.armedcats.net/d/dr/dr_gri...507_201429.jpg
Have you perchance tuned out the issue you were having since going racing? That jalopnik article is pretty cool! :D