305 TPI won't start when hot.
 

1986 305 tpi transplant in a 58 Apache. 700r4 trans.

01227165 AMU ECM

Had trouble when first installed with stalling after about 10 minutes.

Installed new pickup coil, new ICM, new coil and pressure regulator and she now starts on the button and runs forever without cutting out.

However.... She will not re- start once up to temperature, unless it's left for about an hour to cool.

Good spark on the plugs.
12 v on the injectors and 15 Ohms.
12v on ECM connector terminals D15 and D16 (injector returns to ECM)
Terminal B5 on the ECM connector shows 0.13 volts with ignition on and increases to 1.2 volts when cranking.

Tried disconnecting one at a time the coolant temp sensor, TPS and cold start injector but still no start.

Fuel pressure 42psi constant.

Only thing left is ECM or PROM? Unless I am missing something silly?

Checked all wiring and no obvious faults/ shorts.

DOES ANTONE HAVE A MAGIC WANT... PLEASE HELP!

Re: 305 TPI won't start when hot.
 

Will it fire if you prime it with carb cleaner or something?

Re: 305 TPI won't start when hot.
 

Haven't tried it but seems no fuel getting to the plugs. Not at home till tomorrow so will try and let you know the outcome.

Re: 305 TPI won't start when hot.
 

Hi there Mjdavis68

Run her up to temperature and turned her off with the key. Would not fire at all when I tried to start.
Gave a squirt of starter fluid down the plenum and she fired 5 or 6 times then started.

Did the same again and exactly the same.. Would not start. Squirt of starter, fired 5 or 6 times then started.

Any ideas please?

Re: 305 TPI won't start when hot.
 

Did you ohm the injectors when hot?

Re: 305 TPI won't start when hot.
 

:yup:

i had the same issue on my 91Z28 vert last year (only 7K miles on it!) i had 3-4 bad injectors when it was hot...

replaced all the injectors and it runs again like new

Re: 305 TPI won't start when hot.
 

The stock injectors are extremely prone to coil failure. More often than not they fail when they are hot.

Re: 305 TPI won't start when hot.
 

All 8 injectors are 15 Ohm when hot and when cold, but the 9th cold start injector shows only 3 Ohm

Is this correct?

Re: 305 TPI won't start when hot.
 

Tried the dizzy out of my 89 Corvette on the engine today and same problem, so can dismiss issues with the distributor from now.

All wiring to and from the distributor looks fine.

Checked all voltages back to the ECM and everything is as it should be except terminals b1 and c16 are only showing 12 volts when the engine is running. Thought they should both be 12 volts with the key in the on position?

Could this be the issue?

Someone please help.. I am now tearing my hair out... What's left of it!

Re: 305 TPI won't start when hot.
 

Have done a voltage test on pins 15and 16 with the injectors unplugged and it shows a nil reading so nothing shorted to live, so have come to the conclusion the ECM is at fault. Have bought another so will have it in about 2 weeks...

Thanks to you all for your input. I will let you know if it works!