Toyorain

Long time lurker.. have done a load of reading but i have ti say I'm stumped.

My truck starts up fine cold, will run fine if it starts, idles fine. Re starts fine if within 30min of parking it. Any longer than that and it becomes progressively harder to start until at about one hour it will just crank without firing. If i come back 8+ hours later itll start.
I can smell fuel at the exhaust when this happens so I'm assuming it's getting plenty. This problem has gotten progressively worse/more consistent in the last month. This is my daily driver.

Cleaned the throttle body and adjusted the tps 3 months ago. Installed new timing chain/guide kit 8months ago. Radiator started leaning so replaces that last week. Interesting (possibly?) related problem.. for some reason the cooling system would rather push coolant past the cap then into the over flow res. I've been focusing on getting it running however because I start a new job Monday and need it.

Info

1990 toyota 4x4 pickup. 215000mi.
New radiator/cap/hoses
New alternator
New timing kit @195k
Adjusted tps/cleaned throttle body.
New o2 sensor (down by the cat) @200kish

There is an exhaust leak after the o2 sensor. Need a new lead gasket.. but other than that exhaust is solid.

RAD4Runner

Hoping it's not HG but need to look into that. Bad HG could send some coolant into one of more cylinder(s).

Try starting and running with radiator cap off. Splashing more than splashing from vibration or from water pump circulation or expanding coolant would mean bad HG. Neck of radiator on our Civic flew off from the pressure once.
Also make sure all your temp senders AND mounting threads are cleaned down to bare, shiny metal.

Toyorain

Supposedly the hg was done by a mechanic at 150k before I got it. I will next time it starts up. No other sign of it being the head gasket though. Runs good, no water in oil. No white smoke.

any ideas why it would push coolant out of the cap instead of into the over flow tank? The tank is one with an air vent in the cap and vertical rubber hose down stem. I've blown air through it so I know it doesn't leak/isn't plugged

RAD4Runner

Poorly fitting cap and radiator or bad cap could do that. A good cap should only send overflow to the overflow tank

Toyorain

So it's an aftermarket aluminum/plastic tank radiator from autozone. They didn't sell it to me with a cap so the goofball and Napa gave me one that looked like it fit. It was rated at 16lb, which I believe I need 13lb for my system. I went back to autozone and they couldn't figure out what cap fit but found one that looked similar to the one Napa gave me but with the correct psi.

thing is, I tried replacing the cap first before removing the old leaking radiator (may not have even been leaking now that I think about it) and it did the same thing with the correct cap.

(so, the original radiator with the correct new cap had the same problem.)

Toyorain

My personal hypothesis is something is not responding to temperature correctly and thinking the engine is hot when it's cold and vice versa. It's weird how consistant the symptom of not starting after sitting for 45 minutes is. It could maybe be related to the cooling system issue. Could there be something wrong with the overflow tank other than the cap? Seriously puzzles me

RAD4Runner

Quite possible. In order to accurately measure temperature and send out correct signal, the temp senders need to be cleaned at least once every 27 years
I did mine after 30 years - LOL! (here)

Toyorain

haha agreed. I have an idea that my two problems are related. There is obviously something weird going on causing the radiator to pull from but not add to the expansion tank. It forces coolant out the cap while it warms up, sucks some out of the over flow. Cools off, coolant doesn't go back to the overflow tank. Repeat the next day. So I guess my biggest clue is that, and I'm wondering if it is causing a sensor to not cool off enough, or something stays open or closes too quickly so the engine floods when I try to start it "warm"..

like wtf. The over flow hose and cap are fine.. and the cap has an air vent in it. And it's obviously pulling from the overflow tank. But why won't it go back in???

RAD4Runner

That's an oddball cap. Wouldn't OEM fit?

Toyorain

sorry, should have specified overflow tank cap. It has that little downward pointing hose on the opposite side of the line that goes to the radiator. I'm assuming to let air in/out.

I don't think the problem is the radiator/radiator cap/ or over flow tank unless there is more to the expansion tank then I can see.

I did read this. Might be a good clue but doesn't explain my warm start issue.. or does it?...

QUOTE=hcole;51049090]Drew 303, When I said coolant comes out of the cap that is what I meant. The coolant overwhelms the small 1/4" line going to the overflow bottle and spills out over the whole engine. The upper hose swells up and gets hard just before it blows and then the thermostat opens and then all is well. After this event occurs about 3 times you are low on coolant and then you have overheating problems. I also agree that the hole you drill should be no more than 1/8" big. I have stood over the engine and watched this happen.[/QUOTE]

Toyorain

Replaced the battery today, trying to get it to fail to start again to rule that out. Old one was corroded and nasty but only 2years old

wyoming9

iTrader: (1)

After it sits what do your spark plugs look like??

Leaky injectors fouling the plugs so they don`t fire

Getting any fuel in the oil??

Trucks sits for 8 hours plugs are dry it starts

RAD4Runner

possibility, too. Includes CSI. FSM has soecs for how much leakage is allowed. Amount that drips over a period of time.

Toyorain

Well guys, replacing the battery seems to have fixed it. Back to turning over 3 times and firjng every time. Still have the weird coolant coming out of cap occasionally but no more start issue

scope103

Borescope? Let us know how you do that. The injectors don't go into the cylinder, but the lower intake manifold.

XX [responding to wrong thread -- ignore. Sorry]

old87yota

I think you are replying to the wrong thread.