ee23

So I purchased my 1990 SR5 V6 4runner about a week ago. Been stoked ever since just being able to wrench on it. It wasn't running when I bought it, had it towed, i knew the fuel pump was gone.

The runner has been sitting for some 4 odd years, periodically started but never really driven. PO informed me that one day he went to start it up and it wouldn't fire. So he put it up for sale.

I installed a new fuel pump, plugs, cap and rotor. Im getting spark to the coil, havent tested spark to the plugs yet. And im getting fuel to the cylinder, spark plugs have fresh fuel on them when I pull them.

My next step is to rent a compression tester, but before I do I would like some input.

What would it sound like if the timing belt had snapped, when I am turning over the engine? It sounds like there isn't much compression and its turning pretty easily. Could a belt snap from sitting? Is it possible for the coil to send spark with a snapped timing belt?

THANKS!

drmix

How many miles are on it? Is it the factory timing belt?

ee23

It has 215K. I dont know if the belt is factory but the PO never replaced it. I am watching and listening to cold start videos on Youtube and the cranking on the healthy 3VZE's sound like they have much more compression. Should I just pull the timing cover and inspect for a slipped or snapped belt?

yotaman85

A compression test would be first on my list. In fact I compression check all motors before I buy a vehicle.

ee23

ok i will do that. If its the belt would some cylinders be fine, and others way low?

yotaman85

if it was the cam belt the motor would have a hard time turning over. if its spinning freely i doubt its the belt.

ee23

anyone else have some input? does this not sound like a timing belt issue?

oldblue

two really quick ways to see if the belt broke. take off your oil cap, look down in there, have someone crank the truck and see if some ˟˟˟˟ down there moves. or you can take the distributor cap off, have someone crank the truck, and if the rotor ain't spinning the belt more than likely broke. then the obvious next step would be to take off one of the upper timing covers and poke around at the belt.

ee23

oldblue thanks for the tips, I am gonna go try that. I just tested 3 cylinders (2 on left bank, 1 on right), until my battery ran outta juice. And netted a big 0 on the compression test. At this im crossing my fingers that its just the belt. But to have 0 compression over both sides its more than likely the belt, sounds like im leaving some valves wide open.

ee23

I just cranked the motor and the rotor is spinning. I dont have an extra hand at the moment to see if the valve train is moving through the oil cap. But if the rotor is moving then the timing belt is functioning?

oldblue

if the belt broke the compression readings are gonna be stupid low.

ee23

thats what I figured. 0 seems pretty stupid to me. This thing is turning into more work than I was hoping. Might as well do the water pump now too.

BLKNBLU

iTrader: (1)

If it turns out to be the timing belt, I have some parts for sale over in the Marketplace under Engines-Transmissions. Everthing but the water pump and a nice Aisin can be had from Rock Auto for $50-ish. Good luck.

Water pump
http://www.rockauto.com/catalog/x,ca...,parttype,2208
My ad
https://www.yotatech.com/forums/f107...-parts-249106/

ee23

ok so I pulled the timing cover off. The timing belt is intact, and when I hand turn the engine from the crankshaft the cams are moving. So I dont think this is my problem. I plugged the compression tester into a 4th cylinder and still got a 0 reading by hand turning. It feels as though there is only compression on one cylinder when I am turning it over.

The timing belt and the cam pulleys are all muddy brown, like greasy rust. There is also some corrosion around the water pump. What would cause this?

Thanks guys...

82shorty

id pull the valve covers off and have a closer look sounds like you have a stuck valve or two, very probable if it hasnt been really run in a while

James Woods

iTrader: (1)

So did you look at the belt around the crank, usually when I see timing belts that have gone bad, it is that the teeth get stripped off and usually the most missing teeth are down around the crank. Every time I have opened one of these motors where the belt is stripped there is dust all over everything and if there is a small leak somewhere that would explain your "greasy rust"

ee23

I have rolled the belt around a few times, I haven't seen any missing teeth or cracks in it. Looks to be in decent shape. I haven't pulled off the lower timing cover just yet.

I just pulled the right valve cover off, The lifters were all moving correctly however I cannot see the valves with the valve cover off since its an overhead cam...

Whats the likelihood of the belt jumping a few teeth causing my 0 compression? Would this be normal if it sat for a long time and periodically turned over? Could I determine this by lining up the timing marks?

James Woods

iTrader: (1)

You can determine from lining up all the marks, it could have lost tension from just sitting and then jumped time when cranked over, long shot but it could have.

ee23

OK just checked the timing marks and wow. With the crank at 0 the cam pulleys were at about ~315* (roughly 45* to the left of where they should be). Im guessing this means im in need of replacing the timing belt, and getting the timing set right. Im in a state of relief now I have identified the problem...lol

DeathCougar

iTrader: (23)

You still should have had some (albeit terrible) compression readings. Not zero.

Im banking on stuck valves. However, get the timing set right, then check compression again. If still at zero, you don't have a belt issue.