dodger65 Posted February 12, 2006 Report Posted February 12, 2006 here is the problem that has me tearing what's left of my hair out right now... 93 olds cutlass supreme 3.4 dohc vin x starts cold ok, but no throttle response (falls on its nose) until warm (or closed loop) once it's been started once, the pedal has to be to the floor (or very close) to start it--still stalls on throttle application once warm, throttle response is normal, but if it is shut off, won't restart unless floored... if map is unhooked--seems to run fine... map sends back 4.7v at the computer w/ the engine off seems to respond to vacuum changes... checked ecm grounds-ok... no codes, darn near every sensor in it has been changed before reaching me (including the map and the computer-my dad's a big parts changer... ) fuel pressure ok, rebuilt engine, no apparent vacuum leaks.... new plugs, wires, etc. checked the injectors for leaks, resistance, and flow (plugged or not) won't have access to a scan tool for a couple of days at least... kinda hoping that w/ the knowledge most of you seem to have, you might have a better understanding of what's happening than i.... thanks in advance, dodger Quote
95oldsVan Posted February 13, 2006 Report Posted February 13, 2006 My first thought is the TPS switch..check that for proper voltage and operation.Also be sure your TB blade(s) isnt getting stuck.Ensure the cable and linkages move freely. Hows the fuel pressure with the car On but not running and then the car running?What are their readings? Most cars,flooring the gas pedal puts the TPS in clear flood more which bypasses the injector signals to aid in starting the car if theres too much gas usually reuslting from a leaking injector(s).At least thats how I remember it explained. Try these outs and see what happens. Quote
dodger65 Posted February 13, 2006 Author Report Posted February 13, 2006 the tps is new. it has the proper 5v ref. voltage at the connector. tb seems ok... the fuel pressure is about 42psi key off and about 40 psi when running... one thing i did notice tonight, though is that after it gets warm and it's shut off, you can hear an injector leaking slightly. slightly being you can hear it, but it doesn't seem to affect the pressure... which is also frustrating, b/c i just had the plenum off and none of the injectors were leaking a week ago... but would that small a leak affect it that much, do ya think? Quote
95oldsVan Posted February 13, 2006 Report Posted February 13, 2006 the tps is new. it has the proper 5v ref. voltage at the connector. tb seems ok... the fuel pressure is about 42psi key off and about 40 psi when running... one thing i did notice tonight, though is that after it gets warm and it's shut off, you can hear an injector leaking slightly. slightly being you can hear it, but it doesn't seem to affect the pressure... which is also frustrating, b/c i just had the plenum off and none of the injectors were leaking a week ago... but would that small a leak affect it that much, do ya think? Your Tps has 5 volts..was that a WOT voltage test? Whats the voltage when its closed,and then slowly open it up?If you had 5 volts with it closed,somethings wrong there. Most TPS wont show 5 volts on the test.Youll see 4.0 and up volts during a hand test of cranking the TB WOT.A scanner is better..you can see the TPS voltage without the car running and then see it as you crack the throttle open and close. Also,if your hearing a injector leakage,best thing you can do is raise the rail and see if any droplets form on an injector tip.If so,you have a leak. Check the plugs to see if theyre gapped right and not wet from raw fuel leaking in there. Thats the only thing I can think of as of now. Quote
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