Start but won't run

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MLF

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Hi,
I have a new engine in a 1983 CFI Transam. I have timed it, and it will turn over and run about 3 minutes then sputters and dies. It seems as though it has lost the spark but I don't know. Fuel pump is new.
Thanks,
MLF
 
Have you done a fuel pressure test?
Have you tested for spark?
How did you set the timing?
 
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I would start with a Fuel pressure test both at start and monitoring it until it stops running. Most FI systems use an increased fuel pressure to richen the mixture during cold start conditions, and back the fuel pressure off once a certain temp is reached by the engine.
So it could be a weak Fuel pump, clogged fuel filter, or less likely a bad temp sensor or wiring giving a false signal to the computer.
 
cammerjeff said:
I would start with a Fuel pressure test both at start and monitoring it until it stops running. Most FI systems use an increased fuel pressure to richen the mixture during cold start conditions, and back the fuel pressure off once a certain temp is reached by the engine.
So it could be a weak Fuel pump, clogged fuel filter, or less likely a bad temp sensor or wiring giving a false signal to the computer.
Click to expand...
Thank you. I am going to check fuel pressure today. Fuel pump is new,and filter seems to be clear. I'm going to check condensor also and ignition coil.

Thank you for your response!
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MLF said:
Thank you. I am going to check fuel pressure today. Fuel pump is new,and filter seems to be clear. I'm going to check condensor also and ignition coil.

Thank you for your response!
Click to expand...
A new fuel pump can fail.
What condenser?
You should have an HEI ignition with three components that can fail, module, pickup, and coil.
 
It has new module , new coil. Consistently kicks off at about 140 degrees at 3 minutes. No code.
Is it EGR or ECM?
 
That leaves the pickup as far as ignition but you haven't determined whether you have a fuel pressure problem or ignition problem.
You never answered the question about what condenser are you referring to in post 4?
 
melsg5 said:
Have you done a fuel pressure test?
Have you tested for spark?
How did you set the timing?
Click to expand...
Hello,
The fuel pressure before start is at 9 psi. At running, it maintains at 12psi and when it dies, the pressure is still at the 12 psi. My manual states that the pressure is 9-13 psi.
The appears to be spark, and timing light was used to set timing. The EGR valve was bad also and was replaced.
The spray pattern is good at the beginning, but after it dies and I try to restart, it is no longer a nice cone pattern, but a heavy droplet.
Thank you!
Melissa
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The capacitor/condenser is for radio static and can be temporarily removed.
Did the CFI system work correctly before the new engine?
Attach the timing light to any cylinder and see if the light stops flashing before the engine stops.
Does the spray pattern change prior to engine stopping?
 
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Yes, the spray pattern changes prior to the engine stopping. There appears to be spark before it dies, but I need to recheck. It actually stopped running 15 years ago, and I started 2 years ago working on getting it back running.
 
So the throttle bodies haven't been used in 15 years?
I can tell you if it was a carburetor it should have been opened and I would say the same for the throttle bodies.
Were the throttle bodies removed from the intake?
Have you checked for a vacuum leak that appears as the intake and throttle bodies warm up?
 
melsg5 said:
So the throttle bodies haven't been used in 15 years?
I can tell you if it was a carburetor it should have been opened and I would say the same for the throttle bodies.
Were the throttle bodies removed from the intake?
Have you checked for a vacuum leak that appears as the intake and throttle bodies warm up?
Click to expand...
I have not checked the vacuum during the warm up so I will check. The throttle bodies/ fuel injection system was rebuilt.
I appreciate your help so much!
Melissa
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Have you contacted the rebuilder of the CFI?
 
The initial timing was set with the electronic timing control disconnected and then it was reconnected?
 
Yes, the electronic control was discontinued prior to timing and then reconnected. It seems now that it is consistently flooding. I have rechecked all vacuum lines and have not found a problem. It now will only run a few seconds and the fuel is pouring in and not a nice spray pattern. When trying to clear flooding, no improvement. It did run long enough to put code 33 and 34. MAP changed, voltage checked to circuit and .2 oms. Does this mean faulty ECM? If so, does it have to be exact change as I have not been able to find exact match but one that is supposed to fit. Plan to re check every thing I have changed, check Park neutral switch, TPS sensor, recheck vacuum, check oil for fuel due to flooding and recheck o2 sensor.

Thank you for your assistance!
Melissa
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I would start researching CFI flooding. A number of issues show involving the coolant temperature sensor and O2 sensor.
The CFI rebuilder gave you nothing concerning flooding?
 
melsg5 said:
I would start researching CFI flooding. A number of issues show involving the coolant temperature sensor and O2 sensor.
The CFI rebuilder gave you nothing concerning flooding?
Click to expand...

Hello, again

I did replace all sensors and it still seems to be flooding. ECM sent in for repair . I'm wondering if I need to send throttle bodies in to a different place for evaluation as I am running out of ideas. Code still showing MAP sensor although I have replaced the sensor and all vacuum hose.
Thanks,
Melissa
 
No, I didn't use tape on sensor but did splice wire and repaired with shrink wrap.
I'm wondering if I may have inadequate spark plugs? I replaced engine from a 305 to 350 small block but I think the plugs are from the info for the 305..
 
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