83 720 no fire

[Kennyt]

When it is cold out like below 30° my truck will not have any fire out of the ignition coils. I have voltage at both coils with the switch on. But when turning engine over there is no spark out of either coil. I have changed the coils with the same result. Verified and changed ignition coil fuse also. Any and all help is greatly appreciated

[datzenmike]

Do you pump the gas pedal two or three times before trying to start the engine?

 

How are you checking for spark? If at the plug then possible the spark is jumping to ground in the distributor or even at the high tension wire on the coil to the - terminal.

 

Replacing the coils is an expensive way to eliminate the coils as the cause. For future reference it's rare for a coil to fail. It's almost infinitely rare for both to fail at the same time. That would indicate something common to both coils causing the problem.... such as bad battery voltage bad ground or the ignition module. Is the distributor well bolted down? Well grounded? All coil and distributor wire connections tight? Put your old coils back on they are better that anything you could buy today.

 

 

Try jumper cables and a boost from another vehicle. This would eliminate poor voltage from a dying/low battery.

[Kennyt]

I press the pedal once to set the choke. Weber 32/36. Inhave verified that the choke is in fact closed. I have a spark tester that i plug in between the coil and distributor. No spark when turning engine over

 

I tested the same way on my 85 and i got spark just none in the 83.

 

I had some extra known good coils from another truck i installed to check.

 

I replaced the ignition module back in the summer due to only one side firing. If the weather warms up it will start with no issues.

 

All connections are tight. I will boost battery from another vehicle to see if this helps.

[datzenmike]

Then you have a suspect ignition module. Unlikely it's a Nissan unit. Never seen one not fire from cold.

[Kennyt]

Well mike. I have learned something. I boosted it from my 85 let it sit for a couple minutes and boom. Fired right up. Inwould have never thiught of that. My thought is that if the battery has enough juice to turn the engine over that it would have enough to start the engine. Wow. Thanks mike. You are definitely the expert. Your thoughts on this?

[datzenmike]

The module should fire even if the battery is down a bit. Where did you get the module? Surely it's not a Nissan part?

 

Measure the battery voltage tomorrow when it's cold. Should be 12.7 fully charged even at 20F.

[Kennyt]

It is not a nissan part. I ordered it online. Cant remember where. I will check the voltage in the am. Thanks for the info