Car will start up cold and idle for a few minutes 2-5 without hesitation. Then just suddenly stall out, die. It sometimes starts up again but not always. Usually it will die and can't restart, does crank fine.
Fuel pressure is there and spark is at the plugs but injector is not firing when it dies and trying to crank.
Injector works fine and I see nice spray pattern when cold.
Tach is unplugged although was working before I unplugged it (would move 200-400rpm while cranking)
I have replaced Distributor ICM Pickup coil Cap, Rotor, wires, plugs MAP TPS EGR O2
Seeing as how it's a whole lot more difficult to check fuel pressure on a duke as compared to a 2.8 V6... how are you testing the fuel pressure, and what is it?
i had an 84 that would do something similar, it wound up being the fuel pump relay on mine. i didnt see that you had mentioned that, try putting a new one in and see what you get, cheap and easy, if it works for you, even better. good luck
spark is at the plugs but injector is not firing when it dies and trying to crank.
There is spark and there is SPARK. When your engine stalls out, are you able to see a healthy spark from any/all of the spark plug leads that will jump a quarter inch gap?
Another question regarding ignition... When you timed the ignition, did you have the ALDL jumper installed?
[This message has been edited by Patrick (edited 06-30-2020).]
No stumble just dies. When this happens I pull the air filter cover off when cranking and now fuel coming out of injector but nice even spray when running.
I suspect you meant "no fuel".
If you were to spray ether (or trickle some gas) into the throttle-body while cranking at this point, would it start?
Haven't tried spraying fuel but I'm 99% sure it would start.
So next thing I tried was removing the center console to let the ecm have alittle more air circulation ( as I was thinking it was a heat issue). It started and never shut off idling happily for 10-15 min. I even tapped on the ecm several times to ensure all was good and no bad solder joints. Still ran. Now to continue to monitor tomorrow as I'm not sure if it was me removing the ecm and cleaning the contacts and unplugging and plugging in a few times that made the issue go away or indeed the heat.
Well I crossed my fingers and toes but it did not work unfortunately.
Started car yesterday and looks like was all well idling perfectly for a tad longer then normal and bang shut off. Urghh.
I'm trying a used ecm from wreckers today. Would an ecm from an '86se 2.5 4spd still work in a 2.5 auto to fire up the car and idle, without driving it?
Depends on what year car your engine has. Generally, yes it should. You say you have a distributor so you must have an 84-86.
Before it fails - key on engine off - does the check engine light come on? It should. After the key has been off for at least one min, then when you turn the key to on, does the fuel pump come on for two seconds and then turn off? It should. When you as shortly as possible bump the starter does the fuel pump come back on for two seconds and then turn off? It should.
When it is failing repeat the tests. If all are failing, look for issues with the ECM not getting power. The first place I would look is the ECM reset connector.
If an 84, I would make sure the wires on the starter are tight. The 84 feeds power to the ECM through the battery cable at the starter.
[This message has been edited by phonedawgz (edited 07-02-2020).]
I have an 84 and a few years ago, I had the exact same symptoms. Always started fine cold, but would die after it had been running for awhile. Replacing the ECM resolved my problem.
Try tapping the ECM w/ fingers trying to start after dying. Sometime may help but ECM is "dead" if that does help.
Common fail mode is parts inside of ECM w/ iffy solder joints, "bad" "transistors," and more that work when completely cold or stop working parked overnight. ECM/PCM parts can heat to Full Operating Temp in Seconds to a few Minutes regardless of weather but Cabin Temp can affect when Iffy ECM works or dies. (Parked in sun even on cool days can make Cabin Temp climb above 120°F.)
Most if not all EFI setups have "12v" w/ Key On and ECM/PCM Turns On Injection by Turning On a Driver "Transistor" on the Ground side on the Injection. In your case that the Blue wire from injector. All it takes to have problems is a very small crack in a solder joint to that "Transistor."
("Transistor" because includes MOSFET and others but exact type of Driver part is unimportant here.)
Best is Need a Noid light to test the "signal" to the injector.
option is back probe the injector plug w/ + probe to V-meter - probe to engine... Leave Injector plugged in. key on, engine not running after it Dies.. Does Red wire have "12v?" Yes, does Blue have "12v" too? Yes then Injector Coil likely good. Keep meter there and try starting the car. Meter should "go nuts" and display odd volts because ECM will "short out" the blue wire every time it turns on the injector "transistor."
If is ECM, Save The PROM/MEMCAL to move it to replacement ECM.
------------------ Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should. (Jurassic Park)
Thank you everyone for your inputs and suggestions.
Tried the used ecm from wreckers with 4spd from an 86 se 2.5. Son of a gun it started up and ran AND DID NOT SHUT OFF. Ran idling for over 10min.
Removed the prom from from my auto car and put it in the used ECM and repeated the process, started right up and ran idling for well over 15min AND DID NOT SHUT OFF.
Tomorrow I'm going to take it out on an actual drive and see what happens but this I believe has solved my issue.
Old ecm that was in the car did start the fuel pump for 2 sec with key on but would not start the fuel pump again for 2sec after bumping starter. New ECM did the 2sec fuel pump start both times so I was elated when that happened. Fired right up after the bump and has not died.
Well looks like all is ok thus far. Took car out for a drive and not one hiccup ran very smooth. The tcc was unplugged and tach was unplugged for its first test. Will plug in tcc next and give it a go and tach will be reconnected once I get the new replacement from Rodney. Didn't want those in the equation until i was sure new ECM was solving my issue.
Sor far so good. I will report back when all is hooked up and let everyone know the outcome.
