Welp heres the scenario.New 392 Stock compression.When the engine starts it runs for a few minutes,gets to 158-175* then surges and stalls.When it stalls it stops very abruptly.On the 3rd attempt to start it it feels like the motor has a dead battery or maybe even hydro locked.I am baffeled.BTW ZERO codes At first I thought maybe my tuner forgot to scale my injectors and was filling the cylinder with fuel,so I put the stock injectors back in installed the 93 tune and bumped the idle.No help.I also replaced the battery and did a compression test.All 8 were at 185 ish. Now with 1 plug removed from each cylinder is spins over fine,no strain on the starter Im beginning to wonder if its the cam,maybe it bad?Ground wrong?And yes I am 100% sure it is installed right. Im open to all sugestions and appreciate any info.
Geezus Scott......so sorry you're having these issues. I'm not tech savvy, I'll leave that up to Cam, Ralph, Dave, etc. But I feel your pain. I know what it's like to have a car on the skids. I guess what I'm saying is if you need a shoulder to cry on, I'm here for ya, lol. Does that sound ghey?????? :blush:
Sounds like it's happening right when the PCM goes to cruise-idle mode? which is the first closed loop mode it gets to. maybe after the third try it's warmed up enough to go into that mode almost immediately? You have anything that monitors whether the PCM is in open or closed loop operation (both the DashHawk and DashDAQ will do that if you don't have a StarScan)? Might provide one clue anyway. It's the first closed loop mode, it's the first mode where the PCM runs a bunch of diagnostics, it's the first mode where the engine uses a variable idle speed strategy, etc. IGNITION SWITCH ON (ZERO RPM) MODE When the ignition switch activates the fuel injection system, the following actions occur: * The PCM monitors the engine coolant temperature sensor and throttle position sensor input. The PCM determines basic fuel injector pulse width from this input. * The PCM determines atmospheric air pressure from the MAP sensor input to modify injector pulse width. When the key is in the ON position and the engine is not running (zero rpm), the Auto Shutdown (ASD) and fuel pump relays de-energize after approximately 1 second. Therefore, battery voltage is not supplied to the fuel pump, ignition coil, fuel injectors and heated oxygen sensors. ENGINE START-UP MODE This is an OPEN LOOP mode. If the vehicle is in park or neutral (automatic transaxles) or the clutch pedal is depressed (manual transaxles) the ignition switch energizes the starter relay when the engine is not running. Thefollowing actions occur when the starter motor is engaged. * If the PCM receives the camshaft position sensor and crankshaft position sensor signals, it energizes the Auto Shutdown (ASD) relay and fuel pump relay. If the PCM does not receive both signals within approximately one second, it will not energize the ASD relay and fuel pump relay. The ASD and fuel pump relays supply battery voltage to the fuel pump, fuel injectors, ignition coil, (EGR solenoid and PCV heater if equipped) and heated oxygen sensors. * The PCM energizes the injectors (on the 69° degree falling edge) for a calculated pulse width until it determines crankshaft position from the camshaft position sensor and crankshaft position sensor signals. The PCM determines crankshaft position within 1 engine revolution. * After determining crankshaft position, the PCM begins energizing the injectors in sequence. It adjusts injector pulse width and controls injector synchronization by turning the individual ground paths to the injectors On and Off. * When the engine idles within ±64 RPM of its target RPM, the PCM compares current MAP sensor value with the atmospheric pressure value received during the Ignition Switch On (zero RPM) mode. Once the ASD and fuel pump relays have been energized, the PCM determines injector pulse width based on the following: * MAP * Engine RPM * Battery voltage * Engine coolant temperature * Inlet/Intake air temperature (IAT) * Throttle position * The number of engine revolutions since cranking was initiated During Start-up the PCM maintains ignition timing at 9° BTDC. ENGINE WARM-UP MODE This is an OPEN LOOP mode. The following inputs are received by the PCM: * Manifold Absolute Pressure (MAP) * Crankshaft position (engine speed) * Engine coolant temperature * Inlet/Intake air temperature (IAT) * Camshaft position * Knock sensor * Throttle position * A/C switch status * Battery voltage * Vehicle speed * Speed control * O2 sensors The PCM adjusts injector pulse width and controls injector synchronization by turning the individual ground paths to the injectors On and Off. The PCM adjusts ignition timing and engine idle speed. Engine idle speed is adjusted through the idle air control motor. CRUISE OR IDLE MODE When the engine is at operating temperature this is a CLOSED LOOP mode. During cruising or idle the following inputs are received by the PCM: * Manifold absolute pressure * Crankshaft position (engine speed) * Inlet/Intake air temperature * Engine coolant temperature * Camshaft position * Knock sensor * Throttle position * Exhaust gas oxygen content (O2 sensors) * A/C switch status * Battery voltage * Vehicle speed The PCM adjusts injector pulse width and controls injector synchronization by turning the individual ground paths to the injectors On and Off. The PCM adjusts engine idle speed and ignition timing. The PCM adjusts the air/fuel ratio according to the oxygen content in the exhaust gas (measured by the upstream and downstream heated oxygen sensor). The PCM monitors for engine misfire. During active misfire and depending on the severity, the PCM either continuously illuminates or flashes the malfunction indicator lamp (Check Engine light on instrument panel). Also, the PCM stores an engine misfire DTC in memory, if 2nd trip with fault. The PCM performs several diagnostic routines. They include: * Oxygen sensor monitor * Downstream heated oxygen sensor diagnostics during open loop operation (except for shorted) * Fuel system monitor * EGR monitor (if equipped) * Purge system monitor * Catalyst efficiency monitor * All inputs monitored for proper voltage range, rationality. * All monitored components (refer to the Emission section for On-Board Diagnostics). The PCM compares the upstream and downstream heated oxygen sensor inputs to measure catalytic convertor efficiency. If the catalyst efficiency drops below the minimum acceptable percentage, the PCM stores a diagnostic trouble code in memory, after 2 trips. During certain idle conditions, the PCM may enter a variable idle speed strategy. During variable idle speed strategy the PCM adjusts engine speed based on the following inputs. * A/C status * Battery voltage * Battery temperature or Calculated Battery Temperature * Engine coolant temperature * Engine run time * Inlet/Intake air temperature * Vehicle mileage This temperature is about where the PCM starts monitoring/using the short term adaptives to update the long term adaptives. So it's using the value it started with in the long term adaptives in open loop. As soon as it goes closed loop it uses the short term adaptives and starts updating the long term adaptives. Short term can adjust 25%. Long term can adjust 25%. If short term is pegged one way or another you're going to get about a 25% fuel adjustment almost immediately and then the long terms will start to move and you could end up with a 50% adjustment (of course at that point it should throw a code). Long term is maintained over key cycles so if the long term was moving you might expect the problem to get worse on successive starts but if it just dies immediately when the short terms hit the long term might not even be getting adjusted. ... assuming the fuel adaptives have anything to do with causing the problem. FUEL CORRECTION or ADAPTIVE MEMORIES DESCRIPTION In Open Loop, the PCM changes pulse width without feedback from the O2 Sensors. Once the engine warms up to approximately 30 to 35° F, the PCM goes into closed loop Short Term Correction and utilizes feedback from the O2 Sensors. Closed loop Long Term Adaptive Memory is maintained above 170° to 190° F unless the PCM senses wide open throttle. At that time the PCM returns to Open Loop operation.
What's the cam spec? Are you beginning from a cold start up? How long have you been trying to get it to run? First time? Try letting it cool down completely and try again...some times the adaptives take a while to get the a/f correct on idle...it has taken me 3 COLD starts to get HAL to pick it up and idle right. Try another cold crank, then once it gets to idling correctly in park with a/c off, tunr on the a/c...it will surge and make an adjustment for that load requirement...turn a/c off and on a few times and listen for the adjustment. Once it learns that...turn a/c off and put it in Reverse...it will surge some and make adjustment for that load...do it a few times...then do same thing with a/c on...then do P to R several time with a/c on and a/c off...teach it to idle in different load ranges...turn steering wheel while in reverse and a/c on...you are applying load to the engine with power steering pump and a/c plus being in gear...many many variables it has to learn to become 100% reliable. Man thing is begin from a COLD start. Another thing to check is upstream O2's and MAP connections, make sure all connections are good and they are functioning correctly...most important sensors to fueling.
Thanks for the suggestions,Other have pointed to what Dave suggested.Dookie if it were one of the things you suggested wouldnt I get a code?I have zero codes.Also I have had the car started 15 -20 times already. And Dave why the hard start on the 3rd try.
I had a loose spade inside a upstream O2 connector that gave me FITS for a couple of weeks...the proverbial "loose wire" never threw a code. It would crank and idle on cold start and once it would go closed loop...it would surge, spit and sputter then die, and wouldn't crank again...it would turn over and fire up, but no idle at all....let sit till another cold start and try again...same shit. I fought it for weeks...called every "Hemi expert" i knew and tried all suggestions. Nothing worked...I even got some new O2 extensions and tried that... How I solved it: Figured out what pin #'s at PCM went to upstream O2's, then began at the first connector on first sensor and pinged it with a volt meter all the way to the PCM...when a circuit didn't make connection (ping) I investigated it thoroughly and found ONE spade in the back of the first connector coming from the harness (the male) not pushed in and fully seated...it wasn't making connection inside the connector...I pushed the spade in all the way, connected it all back up and it fired right up and ran like a sewing machine....True story Do you have a way of monitoring O2's?
Damn, Scott. i was just wondering how things where going. I wish I could help because I know how frustrated you are. I hope you get her going soon. I wanna race ya!!
Those symptoms are exactly like I had with the above O2 sensor connector issue...the motor would die so sudden, the belt would slip and I would get a *CHIRP*...It sounded horrible...then when I would go to crank it over it would be very difficult to get it to spin over fast enough for a restart...I would have to wait till it cooled to try again. ping your O2's and rule it out.
You know Scott, my car has some of those symtoms. The old PCM will start and idle perfect and you can put it in drive and it will idle around. There is no throttle response at all. The new stock PCM doesn't want to start. If it does it dies right away, and then won't start. Of course my car needs quite a bit of tune. Acts if the battery is dead. I know at SpringFest my car threw about a million codes, which was cleared. Cam said the old PCM was toast. Diablo has had my Predator since June 12th, so we haven't been able to do anything with it yet. Still have to check the K1 oil pump issue, and the intake is coming off for porting and enlargement for the 90MM. I just wonder if we're having some kind of parallel experience.
Pop the hood and see if the PCM smells like burnt toast :rofl2: :sorry:sorry, that just wasn't right. Lord please forgive me :sorry:
Wow That was wrong in so many waysoh:..lol But know it smells nothing like Hals.I would know as i was first on the scene the following morning after his shitty mishap.. On that note.Thanks for the info fellas and Kyle I will check on the 02s
wow..... i was just sitting here thinking to myself i need to call my buddy and see how things are....... i guess i got the answer! scotty - expect a call........ btw - kyle..... i remember when you went through your issues with the car not running and was blown away at it being such a simple fix as a prong in the wireharness to the O2 sensors!!! scotty, with all the wrenches turned and all the stuff replaced or taken apart, you never know!!!!
Pull the plugs off the PCM. Look at each and every prong. You will know if one or two are bent, it will be very obvious. Shit, call me.
Ill call you later bud,But I need to test the circuitry from the PCM to the 02 plugs according to Kyle.Just looking at them on the PCM side wont help I dont think.Not to mention I have not touched my PCM sense the day I removed my B&G..
I will try that tomorrow.Its raining.Here some video I just took.. BTW Just got my first code. 300 Random misfire..
