Enertia Posted May 29, 2004 Report Share Posted May 29, 2004 My 1988 engine is totally stock and I am using the stock injectors (no MPI) using staged setup which the haltech unit allows me to do. Â Small injectors at lower loads and big injectors at higher loads. The car runs great when I step on the gas slowly - yes, the power is there and more, but when I abruptly step on the gas it pops or backfires. Â I modified the ignition map and I was able to reduce this problem but I got to a point where any changes on the ignition map doesn't help or doesn't reduce this backfiring. Â Of course, I maybe doing something wrong so don't negate the idea that my ignition map is incorrect. Do you think its leaning out when I step on the gas hard? Â My problem with this idea is that I am using the stock injectors therefore it should work if I can figure the stock mapping. My biggest question is why is it backfiring? What are the possible root cause? Link to comment Share on other sites More sharing options...
Vanishing Point Posted May 29, 2004 Report Share Posted May 29, 2004 Try checking the TPS. I am not famialier with haltech but there should be some accelerator enrichment adjustment to give your engine an extra shot of fuel when you step on the gas. If the TPS is bad your haltech will not know the rate of change of the throttle and not enrichen the mixture enough. Tony Link to comment Share on other sites More sharing options...
Joel Posted June 1, 2004 Report Share Posted June 1, 2004 Your likely running to rich. Thats what it sounds like. Try increasing the fuel where the problem exists in the map substancially, and see if the problem gets worse (The same, but worse), and that'll give you a hint that its to rich and to lean it out. Check and make sure you don't have to high of a throttle pump setting. Joel Link to comment Share on other sites More sharing options...
Shelby Posted June 2, 2004 Report Share Posted June 2, 2004 Joel i may be wrong but i'd go with him being too lean, that pop is exactly what happens with a carb'd engine that has no excellerator pump, or a fuel inj engine with a bad tps,, even the stock quest switch'd from the small inj to the large inj when the throddle was move'd quickly more then doubleing the fuel for an instant there should be a seting for quick tps action on the ecu , or i sure hope so , some systems use a vacum signal to increase the fuel pressure at that moment to , (the loss of vacum causes the reg to increase the pressure 5-8 lbs ) all to elim this pop and lean spot when the throddle is snap'd open Link to comment Share on other sites More sharing options...
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