[Diy_efi] Hesitation

[David Rowley]

I've put a couple of GM TBI units with a 1227747 ECM on 3 different vehicles (only 1 was a Chevy).  Even though all three motors looked similar on paper, they all had different fuel and spark needs.  The GM TBI has 2 different "accelerator pump" tables.  One is for differential MAP and the other is for Differential Throttle Position (as read from the TPS).  You will need to change and test these 2 tables to fix the hesitation problem.  The easiest way is to use software like Tunercat with a Pocket Programmer, or make friends with someone else who has these tools.
   
  Yes, the ECM gets hot.  Not to worry.
   
  Good Luck,
   
  

Scott Scott <scott_o_matic at yahoo.com> wrote:
  I just put a TBI setup from a 1991 Silverado onto a
1969 Mustang with a 302 (2bbl). It runs well, idles
smoothly, but I have a couple of issues. 

1?It has some hesitation on acceleration. Not when I
rev it in the garage, but when its in gear. Timing is
currently set at 10 degrees BTDC (base timing), I?m
thinking of adding a little more advance to it. Any
other ideas? It actually stalls out sometimes when I
try to make a fast getaway. 

2?I put the ECU under the dash. I reached in and put
my hand on the box after I had been driving a while,
and it was VERY hot to the touch. I almost couldn?t
hold on to it. Is this a normal operating condition
of the GM ECU? 

Any tips are appreciated! 


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