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einar944
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86 944 engine starts and then dies
Feb 7th, 2019 at 1:50am
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1986 944 normal, can start engine, runs about 2 to 3 seconds and dies.  Tested Air Flow Meter with known good one, tested ECU with known good one,  checked for vacuum leaks, had fuel injectors rebuilt and tested and still can't get the car running.  Any ideas on what else I can look into.
  
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Cambo
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Re: 86 944 engine starts and then dies
Reply #1 - Feb 7th, 2019 at 4:57am
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Will it stay running if you hold the throttle open?
  

87 944 N/A 5 speed
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einar944
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Re: 86 944 engine starts and then dies
Reply #2 - Feb 7th, 2019 at 4:12pm
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It does not stay running at full throttle.  Also, I did replace the fuel pump and fuel filter.  Cleaned the rail, and the gas tank.
  
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Dave W
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Re: 86 944 engine starts and then dies
Reply #3 - Feb 7th, 2019 at 4:52pm
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If it starts and runs at idle but dies as soon as you touch the gas pedal, then you probably forgot to connect the wires to the AFM.
  

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Cambo
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Re: 86 944 engine starts and then dies
Reply #4 - Feb 7th, 2019 at 5:11pm
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Is the J boot torn or ripped at all?
  

87 944 N/A 5 speed
06 Honda Element 4WD 5 speed (for sale)
14 Honda Accord Sport 6 speed
19 Ford F-150 ecoboost
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einar944
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Re: 86 944 engine starts and then dies
Reply #5 - Feb 7th, 2019 at 6:38pm
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J-boot is fine.  Tested all vacuum connections.  Wires are connected to the AFM.  If I disconnect the AFM connection the car will idle - poorly.  With connection to AFM in place turn key, immediate start and then it dies.
  
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Dave W
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Re: 86 944 engine starts and then dies
Reply #6 - Feb 8th, 2019 at 9:53pm
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next test: do the DME Relay jumper.  Or switch to your spare DME Relay.

if it runs with the jumper but not with the spare, then it is probably the speed sensor.  The DME cuts off fuel if it doesn't detect 200 rpm.

  

Dave - black 84 no longer exists. Sad 83 self destructed. All better now. Smiley
... Let's go hit some twisty roads! ...
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einar944
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Re: 86 944 engine starts and then dies
Reply #7 - Feb 9th, 2019 at 11:51pm
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I replaced both sensors, the speed sensor is new.  I just did the Alarm bypass and still have the same issue.  This is what is so perplexing.  I've gone through the list of possible issues, ran the tests and still have the same issue.  Thanks for all the suggestions.
  
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einar944
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Re: 86 944 engine starts and then dies
Reply #8 - Feb 9th, 2019 at 11:52pm
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Oh yes, used the jumper this morning and car woould not start.  DME relay is new.
  
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einar944
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Re: 86 944 engine starts and then dies
Reply #9 - Feb 9th, 2019 at 11:53pm
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and one more point I am getting tach bounce.
  
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Dave W
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Re: 86 944 engine starts and then dies
Reply #10 - Feb 11th, 2019 at 6:10pm
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ok, i vote for a clogged fuel filter or maybe junk in the tank.  Running for a short period is a symptom that only a small amount of gas is getting through the line.
  

Dave - black 84 no longer exists. Sad 83 self destructed. All better now. Smiley
... Let's go hit some twisty roads! ...
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Ky951
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Re: 86 944 engine starts and then dies
Reply #11 - Feb 11th, 2019 at 6:33pm
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When it starts and dies shortly afterward, I think about the clarks garage suggestion or too much fuel pressure.  Easy test...  From Clarks-Garage.com

"Disconnect one fuel injector connector and attempt to start car. If the car starts and runs, where it would not before, then the Fuel Pressure Regulator (FPR) is most likely bad and should be replaced. Bascially when the FPR fails causing the fuel rail pressure to go high, the injectors have too high a differential pressure across them, they draw too much current, and the injector driver shuts down. Disconnecting one injector wire reduces the injector current enough to allow the engine to start. Realize that the car will run very rough as it's running on three cylinders"
  
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einar944
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Re: 86 944 engine starts and then dies
Reply #12 - Feb 13th, 2019 at 7:39am
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Thanks for all the suggestions.  I cleaned the fuel tank, replaced the fuel pump and the fuel filter and blew out all the lines. 

I just did the FPR test again last night.  No change. 

I am going back the do more testing on the Air Flow Meter (AFM).

Pretty much been through all the testing  and replacing.
  
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Ky951
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Re: 86 944 engine starts and then dies
Reply #13 - Feb 13th, 2019 at 1:53pm
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Since you have been through everything, maybe it is time to go back to basics. 

Fuel, Timing and Spark

  • What have you done to test the fuel pressure so far? 
  • What have you done to make sure the vacuum is holding? 
  • Have you confirmed the timing is correct and you haven't skipped a tooth? 
  • Have you confirmed the rotor screw inside the distributor didn't back out and cause the rotor to loose it's place? 
  • Have you confirmed the plug wires are routed correctly from the distributor for the firing sequence (don't ask me why I ask this...  Embarrassed)
  • I think there are some noid tests for the injectors to make sure they are firing.
  
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einar944
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Re: 86 944 engine starts and then dies
Reply #14 - Feb 13th, 2019 at 4:12pm
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Sort of started doing that this morning.  Checking power going to AFM and DME coolant sensor.  I have verified the timing several times - just put new belts and pulleys on.  I am going to check the injector wiring, had injectors rebuilt and tested.  Need to get adapter to check the fuel pressure.  It is a good idea to check the plug wires are correct.  I have done the tests on the AFM, the speed senor and reference sensor and replaced them with new.

The really odd part is the car will start on a few turns, which is an indication there is some fuel and good spark and the timing is good.
  
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