Car hard to start with cooling fan running?

[70Uglybird]

I have a fan that is set to continue running after the car is shut off until it reaches 180 I believe. Car runs fairly hot so its going for awhile whenever I shut off the car. If I try to start it during this time it barely starts. Very choppy turn over then catches. If I let it sit for awhile it starts fairly easily. Hot starter is a possibility but I do have a RobMC starter, with a 0 gauge wire going to a quality battery in the trunk.

My first inclination is to wire the relay to a switch power source so it just turns off when the car turns off. But I"m worried that is masking a power problem. I'm going to look at installing a 3 wire powermaster alt 100amp and getting a bigger charging wire. But with the car off how much does the alt come into play? It takes it a while for the fan to come off so I'm pretty much stuck for a bit when I shut it down when out and about (PITA at say a gas station)

I'm looking at the mad electrical setup but don't quite understand it just yet. Maybe the book he sells would be a good first read...

I'm thinking the alternator is a no brainer but wondering is these are symptoms of a different problem?

[4mul8ion]

Just for clarification, are you saying that the car is hard to start when the car is hot and the cooling fan is running and is ok when the car is cooler and the fan is off? What is the current draw of the fan when it's running? Can you wire an interrupt switch to the fan relay so that you can hot start the car without having to wait?

[70Uglybird]

Exactly, let it sit all night starts right up. Drive it 3 miles, stop it let it sit for 5 minutes and it barely turns over, although its never not started. Frustrating thing is this is the same behavior it had with the old motor, old stock starter, autozone battery and stock battery cable. I have spent alot of money and have the some result!

The fan setup is the same as yours, 22amp running 30a to start. I just drove it 10 miles in traffic. Turned motor off, fan stays on, if I start it seconds after it starts right up. Then turn it off and a minute later rev rev rev rev slow than start.

I'm thinking now maybe its a combination of heat and the draw electrical system from the fan. Frustrating.

[Cobra 498]

Measure your battery voltage just before you try a restart and then with the starter engaged. 22 amps is a big draw with no alternator (engine off) and could pull the battery down if on very long. The starter will have a higher resistance when hot, even the good ones so that will take more voltage to operate at normal warmed up temps. Make the same measurements when cold and compare. Some of the gel cell batteries seem to have a little higher internal resistance and do not provide as much available amperage as other configurations, they also discharge a little faster. The battery voltage test will tell you a lot about the problem. I had a similar problem and added a manual switch to the fan as suggested earlier, I also changed battery brands.

[Thephranc]

Heat soaked starter. If you haven't already wrap the exhaust or use a starter blanket. I had the same issue until I did some heat controlling with header wrap and a starter blanket. And you might want to read this:

http://www.streetlegaltv.com/tech-stories/electronics-efi/top-ten-wiring-tips-with-ron-francis-wiring/

Might help.

[70Uglybird]

Good stuff. I think a manual switch and measuring is first up. I do like the remote selenoid and the making the big gauge wire running through the cabin only live during starting. But right now I'm just trying to get a few weeks of driving in before rains come!

[marolf101x]

Unless you have an electric water pump running the fan with the engine off doesn't accomplish much. The radiator will be cooled, and the water will move a bit due to different temps between the block and radiator.

However, the point of the cooling system is to cool the engine.

[71RS/SS396]

How big is your negative cable?
It needs to be just as big as your positive.
How much initial timing?
I agree with Brit, it's pointless to run the fan with the engine off

[70Uglybird]

Both are the same size the 0/1 battery relocation wiring kit from Painless. I'll have to confirm the timing.