1990 4runner might have broken timing belt?
#21
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I sure hope not. I wanna be driving this thing soon, I have never driven a 4runner!! I would also like to free up some garage space I can barely move in there lol.
#22
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However if it does have stuck valves...how do I repair them? Im guessing I have to remove the heads, but will this be a job for a machine shop? THANKS SO MUCH GUYS
#23
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You have to check compression with all plugs out, the throttle body fully open and not by hand.
You must use the starter and let it turn over 5-6 times quickly.
Start with the simple stuff. Spark, fuel, air.
You must use the starter and let it turn over 5-6 times quickly.
Start with the simple stuff. Spark, fuel, air.
#24
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I tested the first 4 cylinders with all the plugs out and at WOT, using the starter via battery (until it died). The engines turns too easily, so I knew there was a compression issue when I bought the thing. I knew there was something really wrong after compression testing cylinders on both banks and not getting any. 45* out of timing is a lot.
I am curious about this though...the guy said it ran fine when he stopped driving it. He periodically started it over 4 years. The battery died eventually, he threw in a big deep cycle boat battery that has a lot more juice and CCA's im assuming. He tried starting it with this battery and no go, and he said it sounded like less compression. Could the extra juice from this deep cycle + the motor sitting for a long time cause an old timing belt to slip -45*?
I am curious about this though...the guy said it ran fine when he stopped driving it. He periodically started it over 4 years. The battery died eventually, he threw in a big deep cycle boat battery that has a lot more juice and CCA's im assuming. He tried starting it with this battery and no go, and he said it sounded like less compression. Could the extra juice from this deep cycle + the motor sitting for a long time cause an old timing belt to slip -45*?
#26
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If you're trying to read compression by turning it over by hand, 0 is about the best you'll get. You need the speed of the starter, and have to keep the throttle open wide for anywhere near accurate results, and you should pull the spark plugs from all the cylinders too.
Call me a little wierd but if it sat for 4 years, I'm going to guess the gasoline in the tank is 4 years old, right? That, by itself, may be enough to keep the engine from starting.... just a thought.
Call me a little wierd but if it sat for 4 years, I'm going to guess the gasoline in the tank is 4 years old, right? That, by itself, may be enough to keep the engine from starting.... just a thought.
#27
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So my old dad had a 78 f150, very different, I know, but had sat far too long. Fired it up with 5 yr old gas in it and shellacced #1,3,6 intake valves enough to bend the pushrods into pretzels. Still ran, but not well. So old gas may have stuck some valves open...
#28
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I did a compression test on 3 different cylinders using the starter, all plugs out and at WOT when I initially compression tested it. After getting 3 readings of 0psi, I knew something was wrong with the timing belt. One cylinder has compression, 5 dont.
It has fresh gas, fuel pressure, spark.
I pulled the timing cover and the belt is toast, and had obviously slipped. The water pump had corroded and the seals started to leak, and there is corrosion and nasty rusty coolant all over the belt. This probably deteriorated it very quickly.
My money is on when the battery had died, and he threw in a big deep cycle it caused the belt to jump quite a few teeth after it had rotted away. Good thing these motors are non-interface! I got a new belt, and water pump. Just gotta pop off this crank pulley nut and ill be in.
I am a little worried about a HG? I dont have any symptoms of oil and coolant mixing, however with the cooling system this rusty could that weaken the head gasket or eat it away?
Thanks Guys
It has fresh gas, fuel pressure, spark.
I pulled the timing cover and the belt is toast, and had obviously slipped. The water pump had corroded and the seals started to leak, and there is corrosion and nasty rusty coolant all over the belt. This probably deteriorated it very quickly.
My money is on when the battery had died, and he threw in a big deep cycle it caused the belt to jump quite a few teeth after it had rotted away. Good thing these motors are non-interface! I got a new belt, and water pump. Just gotta pop off this crank pulley nut and ill be in.
I am a little worried about a HG? I dont have any symptoms of oil and coolant mixing, however with the cooling system this rusty could that weaken the head gasket or eat it away?
Thanks Guys
#30
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You said you got a compression reading on one of the cylinders? What is the reading?
One thing to check if you think you are getting false readings on the ole compression checker is the shrader valve in the end. If it is missing, not tight, or just plain faulty than the gauge will not hold the pressure to show you your reading... Just my experience!
Good luck with the project. I have my 3.0 tore down right now too for some major tlc. FUN TIMES!!!!
One thing to check if you think you are getting false readings on the ole compression checker is the shrader valve in the end. If it is missing, not tight, or just plain faulty than the gauge will not hold the pressure to show you your reading... Just my experience!
Good luck with the project. I have my 3.0 tore down right now too for some major tlc. FUN TIMES!!!!
#31
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Thread Starter
Well to conclude this thread, I got the rig started at about 3:30am this morning. I got just enough stuff back on it to fire it up, and it boy did it fire right up. Im a stoked owner of a 2nd gen 4runner all thanks to this forum. Thanks for all the input guys it's much appreciated. Turns out that it was just a slipped timing belt, no stuck valves thank god.
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