Here's why I had to put in the new head/HG: http://www.4x4wire.com/forums/showf...p;amp;sb=5&o=186&fpart=1

I just fired up the engine after having installed a new head, and I can't get the engine to stop loping. No, not the kind when you've got a hot cam, but the kind that's telling you there's air in the cooling system. Thing is, I burped it, and I'm 99.9% sure there's no air in there. I have one of those T-fittings installed in the uppermost heater hose, and there's no bubbles coming out when I crack it open. The idle won't settle down either (high idle).

Radiator's full. I'm getting full heat in the cab. Timing is set with the jumper engaged. No codes being thrown.

My A/F ratio meter tells me it's in open loop, but when I step on the throttle it goes into closed loop.

Make sure your TPS is set up properly; root of all evil.

I tested it when I had the plenum off. It met the specs, and I didn't change it. I don't know why it would be a problem now. I won't entirely rule it out, though, if I can't figure this out.

I tried to find a sensor that I forgot to plug in. Haven't found any yet. Same with vacuum hoses.

I'm wondering if I should keep playing with the coolant system to see if I possibly didn't get all the air out. Before I fired it up I got the radiator full and left the cap off. Big mistake! It blew coolant everywhere. So, I capped it.

For some reason I can't remember how I did it in times past. I think I've always tried to leave the cap off if I could. I don't know if that makes a difference or not, but once again, I didn't see any bubbles coming out of the T-fitting when I cracked it open.

I wonder if there's something significant about the fact that the O2 sensor goes into closed loop only when I give it some throttle?

Interesting....hmmmm...stick the ol' jumper on there and see how it runs quick.

I take it the 02 sensor lead is intact as well.

When I jumpered it the loping would stop and the idle would kick down like it's supposed to. However, the idle was still high. This is one of EB's super duper heads with gigantic monstrous valves, so maybe I need to make some adjustments to get that idle down. <img src="/forums/images/graemlins/lol.gif" alt="" />

The coolant gushing out of the rad tells me you do infact have air in the system.

How much coolant did you put in? Whats the capacity?

While its running and hot, try burping it from various hoses like the upper and lower radiator hose. Loosen it until coolant pours out a bit.

Also, looping at idle but OK at speed indicates a vacuum leak. Sometimes it can be VERY difficult to find, especially a crack in a hose or intake tube. Get a can of ether or a propane torch and spray around the intake tube and all the vacuum lines, and see if the idle smooths out or increases. This indicates a vacuum leak.

Capacity? I'm not sure. But I did initially put in well over a gallon (you'd think I'd remember exactly, but the memory's not so good).

What I'll do is pull some of that coolant out of the radiator, and then I'll fire it back up with the cap off. When I did initially fire it up that first time, there was a tremendous amount of foam (bubbles), but by the time I put the cap on they had mostly subsided.

I thought about check for vacuum leaks like you suggested. I'll see what I can find.

I'm calling it a night for now. I'll resume this in the morning. I ran the engine with the radiator cap off, and I can't see how there can still be air in the system. I had the cap off the T-fitting when I started it up, and the coolant came gushing out. So, I closed it but left the radiator cap off.

I took a look at the TPS. It's fine. I did notice that when I turned it to where the engine wouldn't kick down (with timing jumper set) the lope went away, but the high idle remained. Also, when I unplugged the TPS it did the same thing. If the problem is in the cooling system, can applying throttle, unplugging TPS, etc. cause it to go away? I don't have a good enough understanding of these machines to answer that.

Haven't checked for vacuum leaks yet. Still, it has been my experience that a lopey idle has more to do with the cooling system than a vacuum leak. Whenever I've had vacuum leaks it has caused a high idle, but not lopey.

Only thing I can think of for the radiator is to make sure you've got the heat (not fan) turned on, so your coolant circulates thru the core.

BTW, I broke down and got one of these for about $30 at NAPA awhile back; it's a radiator funnel kit:



Now that we also are aware this is one of EB's heads, you might give this a read:
http://www.4x4wire.com/toyota/tech/cam_degreeing/

Might need to dial in the sweet spot.

When I had it running, I had the heat & fan turned on. I haven't taken it out on the road yet. I wonder if doing that will work it over hard enough to get things going.

It seems I've got two problems: Loping idle, high idle.