Timing Belt Discussion

danielwd · Dec 27, 2010

I successfully changed out my clutch. On a 15 minute test drive, my upper radiator hose began to bulge and coolant was leaking out of the radiator on the driver's side. The truck was running really, really rough and was having much trouble accelerating, especially from 2nd to 3rd and almost impossible even to get the truck up to speed to change to 4th.

I decided to change out the thermostat (I thought this was causing the upper hose to swell), and since I am doing that, I figured I would change out the timing belt.

Curiously, when I observed my timing belt, in accordance to the existing timing belt marks (cam shaft sprocket mark to inner timing belt cover AND crackshaft pulley key mark at 12 o'clock positioning), the marks are about 2 1/2 teeth off. Could it be that my truck's timing is off causing the rough engine and lack of acceleration? Is it even possible that a timing belt skip a couple of teeth on its own? The timing belt tensioner seems in place and the belt is tight.

I have not removed the timing belt yet because of how curious I am about this. I guess I could be misreading the marks, but it seems pretty straightforward.

martin · Dec 27, 2010

First things first, it sounds like a blown head gasket, or worse. You need to do a compression test to confirm this. Second, If the cam timing is that far out I'm surprised it runs at all. good luck.

feellnfroggy · Dec 27, 2010

On a 2.3 with timing belt it can be two teeth off and run rough. However the teeth need to be perfectly lined up or 180* off, this is due to the fact that the cam turns twice to the cranks once. Its a matter of loosening the timing tension bolt and adjusting the belt one tooth at a time in either direction. Dont forget to remove the spout plug prior to doign any of this. And depending on mileage it would prolly be better to just get a new belt and start over from scratch.

danielwd · Dec 27, 2010

martin said:
First things first, it sounds like a blown head gasket, or worse. You need to do a compression test to confirm this. Second, If the cam timing is that far out I'm surprised it runs at all. good luck.

I am in the midst of doing a compression check now but am confused about a couple of things.

First, to disenable the plug wire coil packs, I guess you just unplug the electrical from each coil pack. I have the 1994 V4 2.3 and the coil packs are right by each other on the passenger side of the engine. The electical inputs are simple to see and simple to unplug.

Second, I think I am supposed to disable the fuel system to make sure it doesn't flow. I think just taking out the fuel pump relay fuse in the power distribution box should do this. Can anyone confirm this?

Third, there is always airflow and to check compression, I think it should be important that air cant leak out secondary places, like open spark plug compartments. So can anyone confirm that I need all 7 spark plugs in and tightened? Obviously the 8th spark plug compartment would hold the pressure gauge?

Finally, to check compression, I need to crank the truck with my one foot on the clutch and one on the gas pedal, probably all the way to the floor to open the throttle. Can anyone confirm that I would need to hit the gas pedal to the floor when attempting to crank?

Because I am in the middle of changing my timing belt and thermostat, my drive belt is off and the upper radiator hose, along with the thermostat housing, are disconnected. I'm thinking about at least reconnecting the thermostat housing and the upper radiator hose to ensure the coolant in the engine doesn't end up all over my garage wall when I crank the truck.

Any suggestions or answers to my questions would be greatly appreciated.

gwaii · Dec 28, 2010

i assume by drive belt you mean the one that drives the water pump and alternator,not the timing belt.

if this is off,you don't need to worry about the upper hose as the water pump won't be turning with the motor.

remove one plug from each of the cylinders before doing the compression test.you only want pressure in the one you're testing.this will ease the load on the starter.

it would be best to have the throttle open while cranking.

cranking and throttle can be done from inside the engine compartment....this would be easier than doing it from the cab.

feellnfroggy · Dec 28, 2010

what he said. a compression tester is best, but if you have to just stick your finger over the hole and turn it by hand (this only works to make sure you any compression at all, not specific measurements)

danielwd · Dec 28, 2010

gwaii said:
i assume by drive belt you mean the one that drives the water pump and alternator,not the timing belt.

if this is off,you don't need to worry about the upper hose as the water pump won't be turning with the motor.

remove one plug from each of the cylinders before doing the compression test.you only want pressure in the one you're testing.this will ease the load on the starter.

it would be best to have the throttle open while cranking.

cranking and throttle can be done from inside the engine compartment....this would be easier than doing it from the cab.

Thanks for the info about the water pump motor not turning with the engine if the drive belt is off, which it is. I didn't even think about that.

When you say, "remove one plug from each cylinder before doing the compression", then you are implying that all spark plugs should be out (to ease the load on the starter), except for the one opposite the plug you are using the compression pump tester in. So, to recap, if I want to test cylinder #1, then all the spark plugs should be removed, then since there are two spark plugs for each cylinder, I need to place the compression tester in the number one plug compartment and a spark plug in the other number one plug compartment?

And I still am not sure I have the part right about eliminating fuel flow - I am thinking about just removing the fuse named "fuel pump relay" in the power distribution box to disenable fuel flow? Would this work?

Obviously to eliminate spark, I just unplug the electical plugs from the coil packs.

Do I have it right?

Thanks!

BRUTUS_T_HOG · Dec 28, 2010

danielwd said:
I am in the midst of doing a compression check now but am confused about a couple of things.

First, to disenable the plug wire coil packs, I guess you just unplug the electrical from each coil pack. I have the 1994 V4 2.3 and the coil packs are right by each other on the passenger side of the engine. The electical inputs are simple to see and simple to unplug.

Second, I think I am supposed to disable the fuel system to make sure it doesn't flow. I think just taking out the fuel pump relay fuse in the power distribution box should do this. Can anyone confirm this?

yes this will work

Third, there is always airflow and to check compression, I think it should be important that air cant leak out secondary places, like open spark plug compartments. So can anyone confirm that I need all 7 spark plugs in and tightened? Obviously the 8th spark plug compartment would hold the pressure gauge?

remove all plugs on the exhaust side of the engine(do not remove the intake side), this allows the engine to crank easier.. each cylinder is individual to the others and don't affect each other

Finally, to check compression, I need to crank the truck with my one foot on the clutch and one on the gas pedal, probably all the way to the floor to open the throttle. Can anyone confirm that I would need to hit the gas pedal to the floor when attempting to crank?

pedal to the floor, crank until you get 5 puffs on the gauge

Because I am in the middle of changing my timing belt and thermostat, my drive belt is off and the upper radiator hose, along with the thermostat housing, are disconnected. I'm thinking about at least reconnecting the thermostat housing and the upper radiator hose to ensure the coolant in the engine doesn't end up all over my garage wall when I crank the truck.

if you drained all the coolant out it won't matter. there is no belt to run the water pump anyway

Any suggestions or answers to my questions would be greatly appreciated.

i recommend replacing the timing belt and make sure you get the timing gears lined up to the right marks.. the cam and aux gears have different marks.. yet have BOTH on their pulleys. the correct mark is on the rear timing cover. also check the tensioner pulley/bearing for slop or rough sounding bearings and replace as needed

gwaii · Dec 28, 2010

danielwd said:
Thanks for the info about the water pump motor not turning with the engine if the drive belt is off, which it is. I didn't even think about that.

When you say, "remove one plug from each cylinder before doing the compression", then you are implying that all spark plugs should be out (to ease the load on the starter), except for the one opposite the plug you are using the compression pump tester in. So, to recap, if I want to test cylinder #1, then all the spark plugs should be removed, then since there are two spark plugs for each cylinder, I need to place the compression tester in the number one plug compartment and a spark plug in the other number one plug compartment?

And I still am not sure I have the part right about eliminating fuel flow - I am thinking about just removing the fuse named "fuel pump relay" in the power distribution box to disenable fuel flow? Would this work?

Obviously to eliminate spark, I just unplug the electical plugs from the coil packs.

Do I have it right?

Thanks!

removing the fuse will disable the fuel pump.if you want to be extra sure,remove the relay as well.

you are right about the coils....unplugging them will disable the spark.

as for the spark plugs,you have two in each cylinder.theres an exhaust side and intake side.only one of these needs to be removed from each cylinder.brutus says to only remove the exhaust side,though i don't see what difference it would make,outside of accessibility.

removing one plug from each will release pressure in the cylinders not being tested,removing both will do the same but is not really necessary.

danielwd · Dec 29, 2010

BRUTUS_T_HOG said:
i recommend replacing the timing belt and make sure you get the timing gears lined up to the right marks.. the cam and aux gears have different marks.. yet have BOTH on their pulleys. the correct mark is on the rear timing cover. also check the tensioner pulley/bearing for slop or rough sounding bearings and replace as needed

Thanks for the info. I have noticed the marks on the pulleys, although, for the crankshaft pulley, Haynes requires the key mark on the crankshaft pulley to be at 12 o'clock, which I think automatically puts the etched straight line on the crankshaft pulley as equal to the "TC" on the outer timing belt cover. I am just going to pay attention to the 12 o'clock mark for the key mark, and the etched mark on the crankshaft pulley should logically take care of itself.

By the way, the "auxillary" sprocket, what does it do? Does it drive the oil pump. I have to admit, I am kind of ignoring the mark on this auxillary sprocket because it shouldn't matter where the oil pump sprocket is lined up - it will still drive the oil pump.

danielwd · Dec 29, 2010

gwaii said:
removing the fuse will disable the fuel pump.if you want to be extra sure,remove the relay as well.

you are right about the coils....unplugging them will disable the spark.

as for the spark plugs,you have two in each cylinder.theres an exhaust side and intake side.only one of these needs to be removed from each cylinder.brutus says to only remove the exhaust side,though i don't see what difference it would make,outside of accessibility.

removing one plug from each will release pressure in the cylinders not being tested,removing both will do the same but is not really necessary.

Thanks for the info and the clearly indicated directions. I agree that the exhaust side is much easier to access! I will probably leave those off and tighted the intake side plugs.

One more thing! I still dont get how "to block the throttle open"? When I read this, I think of just pushing down on the gas pedal all the way, while hitting the clutch all the way down, in order to get that crankshaft to move (so I can get a compression reading). Will this work?

I will report my findings tomorrow.

BRUTUS_T_HOG · Dec 29, 2010

danielwd said:
Thanks for the info and the clearly indicated directions. I agree that the exhaust side is much easier to access! I will probably leave those off and tighted the intake side plugs.

One more thing! I still dont get how "to block the throttle open"? When I read this, I think of just pushing down on the gas pedal all the way, while hitting the clutch all the way down, in order to get that crankshaft to move (so I can get a compression reading). Will this work?

I will report my findings tomorrow.

yes holding the gas pedal works. and DO NOT ignore the auxiliary sprocket. it drives the oil pump AND provides the cam sensor with the correct signal. getting it out of time will make the engine run bad or not at all.

danielwd · Dec 29, 2010

BRUTUS_T_HOG said:
yes holding the gas pedal works. and DO NOT ignore the auxiliary sprocket. it drives the oil pump AND provides the cam sensor with the correct signal. getting it out of time will make the engine run bad or not at all.

Crap! I'm glad you chimed in. This makes me even more confused though because of the current state of my timing belt. I am so perplexed, I have stripped the truck, but I still have not taken off the timing belt because of the fact I am so curious. When I line up the crankshaft pulley keyway at 12 o'clock, the cam sproket is is about 2 and 1/2 teeth off from the mark shown on the inner timing belt cover.

Then there's always the auxillary sprocket, well just CRAP! It is way off of what Haynes is showing to be aligned.

How in the freakin' world was my truck even running? I think it is time for me to post pictures, if I'm allowed. I am not sure what the limitations are to adding pics here, but I think it's time I showed ya'll what I'm talking about.

BRUTUS_T_HOG · Dec 29, 2010

yes show pictures. i don't remember lining the keyway up for the crankshaft, i remember there being a dot on the sprocket that lines up with an arrow on the block. only visible after removing the crankshaft pulley. lining the pully mark up to the TDC mark on the timing cover should be correct also though.

either way if the cam timing has skipped you'll need to replace the belt and check the tensioner bearing.

i've had a camshaft seize up from lack of oil pressure and it stripped the teeth off a brand new timing belt before

danielwd · Dec 29, 2010

http://s562.photobucket.com/albums/ss65/danielwd1/album2/

I hope the above link works. I think I know what I am doing wrong. I am using that little circle on the crankshaft pulley to judge the "keyway" that Haynes says to line up at 12 o'clock.

Brutus, you made it clear to me that I probably cannot see the mark to line up the crankshaft sprocket until I take of the crankshaft pulley.

I was just afraid to take anything else apart because it looked wrong. I bet after I take that crankshaft pulley off, it will all make sense.

Other than maybe one thing. The auxillary sprocket doesn't look anywhere near correct, and there is no mark on the inner or outer timing belt covers, at least that I can see. Any ideas on that one?

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