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84 duke will not stay running by thecage
Started on: 06-30-2020 02:08 PM
Replies: 19 (144 views)
Last post by: thecage on 07-03-2020 11:49 PM
thecage
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Report this Post06-30-2020 02:08 PM Click Here to See the Profile for thecageClick Here to Email thecageSend a Private Message to thecageEdit/Delete MessageReply w/QuoteDirect Link to This Post
Ok what should I be looking at or testing next.

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

Only thing left is coolant sensor or ECM.

Help!!!!
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Report this Post06-30-2020 02:40 PM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundEdit/Delete MessageReply w/QuoteDirect Link to This Post
Any ECM codes being set?
http://www.fiero.nl/cgi-bin/main.cgi?ECMCodes

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thecage
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Report this Post06-30-2020 02:49 PM Click Here to See the Profile for thecageClick Here to Email thecageSend a Private Message to thecageEdit/Delete MessageReply w/QuoteDirect Link to This Post
No codes, only the usual 12.
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Patrick
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Report this Post06-30-2020 03:44 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by thecage:

Fuel pressure is there


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?
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thecage
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Report this Post06-30-2020 05:11 PM Click Here to See the Profile for thecageClick Here to Email thecageSend a Private Message to thecageEdit/Delete MessageReply w/QuoteDirect Link to This Post
Using an Actron brass t-adapter in front of the fuel filter. Filter is brand new. Reads a steady 11-12psi even when engine dies.
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vette7584
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Report this Post06-30-2020 05:25 PM Click Here to See the Profile for vette7584Click Here to Email vette7584Send a Private Message to vette7584Edit/Delete MessageReply w/QuoteDirect Link to This Post
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
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thecage
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Report this Post06-30-2020 05:34 PM Click Here to See the Profile for thecageClick Here to Email thecageSend a Private Message to thecageEdit/Delete MessageReply w/QuoteDirect Link to This Post
Didn't change the fuel pump relay but swapped it with the AC one next to it. Same results.
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Patrick
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Report this Post06-30-2020 06:08 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by thecage:

Using an Actron brass t-adapter in front of the fuel filter. Filter is brand new. Reads a steady 11-12psi even when engine dies.


Okay, excellent. Not many people have/use that adapter.
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Patrick
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Report this Post06-30-2020 06:14 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by thecage:

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).]

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thecage
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Report this Post06-30-2020 07:15 PM Click Here to See the Profile for thecageClick Here to Email thecageSend a Private Message to thecageEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yes SPARK at all cylinders. Yes when I timed the engine it was with the AB shorted. 8.5deg

Like I said in my first post. Car starts when cold and runs perfect for 2-5 minutes before it stalls out. 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.

So weird
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fierosound
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Report this Post06-30-2020 07:20 PM Click Here to See the Profile for fierosoundClick Here to visit fierosound's HomePageClick Here to Email fierosoundSend a Private Message to fierosoundEdit/Delete MessageReply w/QuoteDirect Link to This Post
Intermittents and ECM test...

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Patrick
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Report this Post06-30-2020 07:47 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by thecage:

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?
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thecage
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Report this Post06-30-2020 09:43 PM Click Here to See the Profile for thecageClick Here to Email thecageSend a Private Message to thecageEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yes I meant - no fuel.

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.

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Report this Post06-30-2020 11:12 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by thecage:

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...


Unplugging and re-connecting an ICM is often enough to resolve ignition issues... so who knows, eh? Cross your fingers!

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thecage
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Report this Post07-02-2020 08:53 AM Click Here to See the Profile for thecageClick Here to Email thecageSend a Private Message to thecageEdit/Delete MessageReply w/QuoteDirect Link to This Post
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?

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Report this Post07-02-2020 11:04 AM Click Here to See the Profile for phonedawgzClick Here to visit phonedawgz's HomePageClick Here to Email phonedawgzSend a Private Message to phonedawgzEdit/Delete MessageReply w/QuoteDirect Link to This Post
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).]

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Report this Post07-02-2020 12:44 PM Click Here to See the Profile for edfieroClick Here to Email edfieroSend a Private Message to edfieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
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.

Good luck getting to the bottom of this.
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Report this Post07-02-2020 01:17 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
No Injector output is often a "dead" ECM.

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.

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thecage
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Report this Post07-02-2020 09:23 PM Click Here to See the Profile for thecageClick Here to Email thecageSend a Private Message to thecageEdit/Delete MessageReply w/QuoteDirect Link to This Post
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.

Will post tomorrow after my drive.
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thecage
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Report this Post07-03-2020 11:49 PM Click Here to See the Profile for thecageClick Here to Email thecageSend a Private Message to thecageEdit/Delete MessageReply w/QuoteDirect Link to This Post
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.

Hope this helps others in solving issues.
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