No Start After Cold Snap

[Oblithian]

I generally keep my car in the garage in the winter. So far, it has only had the occasional struggle starting when left out in the cold. However, this last weekend it was down to -37C, and I was over at a friend's place now it's Tuesday, -10C, and it still wont start (cranks but no firing at all).

 

I have heated it well beyond what it should need to start (using several devices). with no luck. I have found the following, the pump still works, there is spark, it cranks just fine, and it won't start even when jumped. It runs and starts just fine above +5C (with no external heater).

 

There is a possibility the fuel lines have frozen but that seems unlikely, and I have no way to test compression, but I hear that is another possibility.

 

Does anyone have ideas or suggestions?

Edited December 15, 2016 by Oblithian

[NewZed]

What year car?  Is it fuel-injected or carb'ed?  Is it factory stock or modified?   Will it start with starting fluid?

[Miles]

Move to California.

[Oblithian]

I like the last suggestion. It is a 75 and it is fuel injected.

 

It almost started today. It seems like perhaps the thermotime may have flooded the engine when it was simply too cold the first day. Then I just didn't give it enough time and compounded the problem on the following days?

Edited December 15, 2016 by Oblithian

[NewZed]

Starting fluid.  Pop off a small vacuum line and squirt it directly in to the intake manifold.  At least you'll know if it will run once started.

[seattlejester]

You can pull a spark plug or all the spark plugs and crank it and see if gas comes out with the fuel pump relay pulled. Then if it is clear you can put the spark plugs back in and do as NewZed says and use some starter fluid to see if fuel is the problem. 

 

I am curious what the methods to "heat with several devices" entails. 

 

If it is ECM controlled then it might not be getting sufficient voltage especially during cranking in the cold. 

[Oblithian]

I will pull a couple of plugs to see. Then try starting fluid.

 

Unless the circuits have frozen in a way that interrupts conductivity or increases resistance, I am not sure how it could be receiving too low of voltage. The battery is fully charged and a jump did not help.

 

I took just about every device that makes heat and attempted to heat every key part of the car... which also included the key at one point, as the door lock was frozen).

[seattlejester]

The battery would be the concern. In the cold they output less due to the temperature essentially slowing down the chemical reaction that causes the voltage differential. During cranking the voltage also drops to about 9 volts or less which if the battery was undercharged and cold could drop to something like 7 volts which might not be enough to power the ECU.

 

However if you had a jump while cranking then this is unlikely the case.

[Chickenman]

I like the last suggestion. It is a 75 and it is fuel injected.

 

It almost started today. It seems like perhaps the thermotime may have flooded the engine when it was simply too cold the first day. Then I just didn't give it enough time and compounded the problem on the following days?

Common problem on Rotary cars. Can happen in Canada with piston engines as well. Try a set of fresh plugs. Wouldn't hurt to throw some Gas-line antifreeze in the tank as well.

 

When I used to ice race we would throw on a Block heater, then remove the Battery and plugs. The Battery would stay in the Hotel room with us and the plugs went on the Heat register. Even then it was difficult starting in -30 to -35C weather .

 

The factory 1975 and 1976 Trignition systems are pretty weak sauce as well. Not much better than points as far as ignition output. Consider upgrading to a Matchbox Dizzy or an aftermarket Ignition box like a Crane or MSD.

 

Cold fuel doesn't vaporize very easily and you need a high energy spark to light it off.  Cold fuel, fuel fouled plugs and a weak igntion system can = Frustration.

[Oblithian]

Hmmm. Would there be a modern HEI that is easy to install? By which I mean, only requires rewiring at the distributor/cool.

 

...Or I could just swap to injectors with better atomization.

Edited December 19, 2016 by Oblithian

[NewZed]

Search "GM HEI module 240Z" for one.  Or swap to the 280ZX distributor ("matchbox" in CM's post above).

 

This link covers much of your problem - http://www.fivestarmanufacturing.com/kat_s

[Oblithian]

Thanks! Anyway I just got it started. I pulled the plugs, blew the fuel out, cleaned the fouling, put them back in, disconnected the 7th injector and it started.

 

Your suggestions have all been quite helpful.

Edited December 20, 2016 by Oblithian