Hey guys, i have a large engine surge when I turn on heat from zero to high. Everything is warmed up and had been running for a while too. No matter how many times I turn on the heat from completely off to high, the engine will violently surge with it showing up on all gauges in instrument panel. Any ideas?

 

Turn the heater on more slowly? Sorry I'm in a weird mood today.

It's like telling the doctor "it hurts when I do this." So his cure is "well then don't do that."

Anyway, what kind of surge? What is it running at with the heater off and what does it surge up to? Need more info

 

It is just a strong engine surge. There is a little bit more to it, after the surge the temperature gauge rises to nearly red (slowly) and then just drops to midway. By the way, the only reason for me testing the malfunction over and over is because I had recently purchased the toyota about a month ago, just trying to isolate the problem but I am unfamiliar with the cooling system of the engine--so I'm kind of in the dark here.

 

More info? Engine info may help others. I really can't contribute, I'll be honest. It's a slow day here at yotatech.. trying to keep this post alive toward the top of the list to help get a reply.

 

Not sure what the problem is; However I would look into the battery or a charging problem. I would think that the fan on high draws more current, charging system unable to keep up, so engine revs high to increase electrical output.
However, I could be completely wrong?

 

Sounds reasonable and plausible. There is a small electric fan instead of the factory fan--not sure but could be related. The more i write on here the more I realize I should be in the "newb" section.

 

OK how's this... Do you have a battery guage on your instrument panel? Sounds dumb but we still don't know what you're driving. What does it do when you turn the heater on? Your alternator could be dying and not producing enough juice so the engine automatically increases the RPM?

 

Its a 94 4runner--22re with 10,000 on rebuild, up to california emissions. Also has a sub and amp so there is a little more of a electrical draw. Been considering adding a capacitor or a stronger altternator.