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Discussion Starter · #1 ·
I've been having a lot of trouble with flat spots and hesitation with my 1.3L EFI on my 1.6L block. After many months of working on it (off and on), I have it running with no hesitation and the acceleration is great. RRich provided some really great help that ultimately solved the problem. By adjusting the throttle position sensor (TPS) counter clockwise - rich/more fuel direction (completely disregarding the book - which is for 1.3 EFI to 1.3 Block) it was possible to get rid of the hesistation.

The futher the TPS is turned in the counter clockwise direction, the more sensitive it becomes - the throttle response it magnified. It also becomes more sensitive to throttling back - it "senses" that you've let off the gas. When this happens, it cuts the fuel - the further counter clockwise the more dramatic the reponse to this as well - results in sudden decceleration. So, it is important to find that happy middle where the hesistation is gone but it doesn't jerk around because it begins to detect a let off when you are actually trying to hold the throttle steady.

The TPS also affects the idle speed. I set my idle up to approx. to approx. 900 instead of 800. This seems to have helped with the sensitivity associated with decceleration noted above.

My TPS does have a slight flat spot when measuring the resistance with a meter. Possibly worn out at that spot. However, it doesn't seem to affect it at the adjusted position - a new one may very well make things even better.

I haven't spent a lot of time trying to fine tune my setting but I have driven it for a week now and am very happy with the result.

Just wanted to pass this along for others that may be having problems or those who may be considering this set up.

Thanks again RRich for all your help. I really appreciate it.
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