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Discussion Starter #1
ok so I'm having a problem here. i have a 96 bronco with a 302. when i go to start it 1st thing in the morning it starts perfectly fine. if i shut it off and start it back up within 10min it starts perfectly fine. but if i start it after it sits for at least 1hr it will either crank for about 5sec before starting or it will spit and sputter around 300 rpm for about a 2sec then it idles perfectly fine. But if you stand by the exhaust you can hear a very slight miss and you can barely feel it during light acceleration like it has a low RPM miss. Other than this it runs perfectly i have already replaced plugs, wires, cap, rotor, coil, IAC, TPS, MAF, egr valve and sensor, new OEM injectors, cleaned intake and throttle body the fuel pressure is right where its suppose to be and there aren't any vacuum leaks and compression is good. I'm sure I'm forgetting some things but i have replaced so much that i don't know what else it could be Maybe some bad plugs? any help would be appreciated
 

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yo,
try this, but get is scanned for Codes somewhere for free; ensure that they do Both KOEO and KOER tests
& w/eng @ normal op temp for KOER- IF possible

No Start & Start, but when Starting Runs & No DTCs in a 96 "...As far as the signals in/out for spark and fuel between the EEC-IV/V they are basicly the same. Yes I know there is a makeshift crankshaft positioner for mis-fire detection, but that is probably not the issue here. I looked some info on one of my Service cds to compare the EEC-IV and EEC-V signals. Both use the PIP, SPOUT and IDM signals. According to the manual the PCM uses the PIP signal to trigger the injectors. So I would suspect a possible missing PIP signal. I am not 100% clear what the IDM signal does. I did have one other thought around midnight last night: Both systems will shut off the injectors if the TPS signal indicates full throttle when in the Start mode. What if the OPs TPS was shorted? This would send the +5V reference signal directly through to the feedback signal. Easy check: disconnect the TPS, then try to start. Next I would start verifying the PIP and possibly the IDM signals are getting back to the PCM..." MIESK5 NOTE; from Ford EVTM; The Control Module (PCM) runs the pump{s} for one second when it receives an ignition- on signal. It also runs the pumps as long as it receives a PIP signal from the Hall-effect devices, it continues pump operation even after the key is released from START. If the PIP signals fall below 120RPM, the control module cuts off the signal to the fuel pump relay or the integrated relay control module. The pump will also run when the terminals of the fuel pump test connector are jumped. the Control module signals the pump when it receives a CRANK signal, and when the Control module gets PIP signals that the engine is running. the pump does not run if the PIP indicates the engine is not running even with ignition ON {except for that first one second}.
Source: by rla2005 (Randy) at FSB
 

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Thinking about this a little more, could it be temperature related?

I don't think that you have an IAT because you have a MAF, but you do have a ECT engine coolent temp sensor.

Is your coolent full?

Did you pull codes?
 

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Discussion Starter #5
my coolant is full just recently did a flush on it. It doesn't leak or anything. and i pulled codes a while ago and the only thing that came up was a bad egr valve which I've already replaced. Im starting to lean toward the fuel pressure regulator because thats one of the only things i haven't replaced plus if you pull the little vacuum hose off it smells like gas and after it sits for a while you can see just a tiny bit of liquid underneath the the vacuum hose. i never noticed it before cause its such a small amount. Could this be a cause? never had to deal with a regulator before
 
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