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New timing chain set, but rotor won't turn when crank does.

H

hoddie

NAXJA Forum User
Location
Canada
Title says it all. I had a no-start in my '91 Cherokee and I went through all the usual suspects only to find that the rotor didn't turn when I turned the crankshaft. So, this would indicate a broken or slipped timing chain. Anyway, I tore it all down and replaced the set. All back together, turned it over and nothing again. Turned the crank and the rotor still isn't moving. I know the gears are good, I know the marks were lined up. What is going on?
I have read that my problems may be CPS related. Will this sensor shut down the engine if it can't read postion on start up? Could this also mean that my distributer shaft or gear is broken? Oil pump?
Any suggestions would be appreciated.
Thanks,
Hoddie.
 
hoddie said:
Title says it all. I had a no-start in my '91 Cherokee and I went through all the usual suspects only to find that the rotor didn't turn when I turned the crankshaft. So, this would indicate a broken or slipped timing chain. Anyway, I tore it all down and replaced the set. All back together, turned it over and nothing again. Turned the crank and the rotor still isn't moving. I know the gears are good, I know the marks were lined up. What is going on?
I have read that my problems may be CPS related. Will this sensor shut down the engine if it can't read postion on start up? Could this also mean that my distributer shaft or gear is broken? Oil pump?
Any suggestions would be appreciated.
Thanks,
Hoddie.
Click to expand...
The shaft is broken in your distributor?
 
The rotor is a mechanical piece, it should turn regardless of the CPS. The CPS only sends spark through the rotor.

Was the old chain broken? If the old chain was in one piece and still attached to the cogs (even loosely), the rotor should have turned. It sounds to me like you have either a broken distributor or a broken camshaft and the timing chain was a misdiagnosis. Pull the distributor out, if you can turn the gear on the bottom and the rotor turns with it, you've got a broken cam.

What preceded this problem? Any oil pressure issues or anything? If a cam bearing siezed, it could very well have sheared the camshaft in two.
 
"The rotor is a mechanical piece, it should turn regardless of the CPS. The CPS only sends spark through the rotor."
That is what I thought as well.
I will pull the distributer out and check it. No major oil issues, except for the huge amount of blowby. Would this cause a situation like this?
As for the other issue, could it be an electrical thing as well as a broken shaft? I don't even have a clicking when I turn the key over.
Also should mention that the steering column is loose too. Don't know if that would cuase a no start. It did cause the radio to turn off when it was in accessory position if the wheel was bumped.
 
Last edited:
hoddie said:
"The rotor is a mechanical piece, it should turn regardless of the CPS. The CPS only sends spark through the rotor."
That is what I thought as well.
I will pull the distributer out and check it. No major oil issues, except for the huge amount of blowby. Would this cause a situation like this?
As for the other issue, could it be an electrical thing as well as a broken shaft? I don't even have a clicking when I turn the key over.
Click to expand...
What other issue? Of course the rotor don't turn if the engine don't.
 
I can manually turn the engine with a socket, but I don't get any power up like you would if you turn the key to run. I do have a charged battery.
 
hoddie said:
I can manually turn the engine with a socket, but I don't get any power up like you would if you turn the key to run. I do have a charged battery.
Click to expand...
No click means you probley knocked the ground wire off your starter relay if it was ok before.

The black wire on the bottom right.
srelay.jpg


The red arrow is pointing at the Starter relay.

relayscopy.gif
 
hoddie said:
All back together, turned it over and nothing again. Turned the crank and the rotor still isn't moving. I know the gears are good, I know the marks were lined up. What is going on?
I have read that my problems may be CPS related. Will this sensor shut down the engine if it can't read postion on start up? Could this also mean that my distributer shaft or gear is broken? Oil pump?
Any suggestions would be appreciated.
Thanks,
Hoddie.
Click to expand...

You've either got a broken distributor shaft or severely worn distributor drive gear teeth. The latter is far more common so my money's on that. If the dizzy gear teeth don't mesh with the gear teeth on the cam, the dizzy won't turn. Another possibility is a cracked distributor base causing the dizzy to bounce off the cam.
Take off the dizzy cap and if you can easily turn the rotor manually through several degrees, or the shaft pops out when you apply upward traction to it, you'll need to remove the dizzy to investigate further.
If you find a broken dizzy shaft, there's a good chance that it will have also taken out the fork on the oil pump shaft as well.
 
Last edited:
Okay, so here is what I have now.
Pulled the valve cover off, I had to clean it out anyway, and checked the valve train. As I turned the crankshaft bolt the rockers went up and down. I made sure all the cylinders did. So no damage to the camshaft. Next thing to check was the distributor. I removed the hold down bolt and clamp. I had to really pull on the body to remove it from the block. Once I got it out, I checked the drive gear. There were 3 of the teeth sheared off. The cam was moving without any problems but the dist shaft was jammed. The teeth are in the oil pan now, I'll worry about them later. The bottom of the shaft was also twisted. The oil pump slot is good to go as well. No damage to the camshaft teeth either. So this was the problem all along. I wish I had pulled the dist myself instead of getting a professional to check it out. The timing gear set was the wrong problem. Well at least I know the gears are good to go now too.
Anyway, I was also found out that the camshaft sensor, which is located in the dist body, works with the crankshaft sensor to send the position of #1 piston at TDC. If the cam sensor looses the signal while it is running, the PCU will run off the last know signal. Once the engine stops, it will not start again until it can pick up another signal on initial turn over. Because my dist shaft was jammed, no signal, so no start.
It all seems so simple now
Well now I am off the find a new or new to me distributor.
The saga continues.....
Hoddie.
 
I'll bet you don't have any oil pressure when you crank the engine, either.

Remove the oil filler cap and watch the valves when someone cranks the engine over BRIEFLY. If the valves move, the camshaft is turning. (I assume you installed the Woodruff key that locks the cam sprocket to the camshaft, but one never knows. And the key could have sheared off, in which case the cam wouldn't turn.)

Assuming the cam is turning, then as already noted your problem is either that the cam gear that drives the distributor is worn down, or the distributor drive gear is worn down, or the pin that holds the drive gear on the distributor shaft has sheared off and the gear is free-wheeling.

Simple test -- remove distributor cap, grab rotor, see if you can turn it by hand. If the drive gears are intact, you should NOT be able to turn the engine over by grabbing the distributor rotor.
 
hoddie said:
Okay, so here is what I have now.
Pulled the valve cover off, I had to clean it out anyway, and checked the valve train. As I turned the crankshaft bolt the rockers went up and down. I made sure all the cylinders did. So no damage to the camshaft. Next thing to check was the distributor. I removed the hold down bolt and clamp. I had to really pull on the body to remove it from the block. Once I got it out, I checked the drive gear. There were 3 of the teeth sheared off. The cam was moving without any problems but the dist shaft was jammed. The teeth are in the oil pan now, I'll worry about them later. The bottom of the shaft was also twisted. The oil pump slot is good to go as well. No damage to the camshaft teeth either. So this was the problem all along. I wish I had pulled the dist myself instead of getting a professional to check it out. The timing gear set was the wrong problem. Well at least I know the gears are good to go now too.
Anyway, I was also found out that the camshaft sensor, which is located in the dist body, works with the crankshaft sensor to send the position of #1 piston at TDC. If the cam sensor looses the signal while it is running, the PCU will run off the last know signal. Once the engine stops, it will not start again until it can pick up another signal on initial turn over. Because my dist shaft was jammed, no signal, so no start.
It all seems so simple now
Well now I am off the find a new or new to me distributor.
The saga continues.....
Hoddie.
Click to expand...
Next time come here first. We don't make commission on parts.
 
hoddie said:
Next thing to check was the distributor. I removed the hold down bolt and clamp. I had to really pull on the body to remove it from the block. Once I got it out, I checked the drive gear. There were 3 of the teeth sheared off. The cam was moving without any problems but the dist shaft was jammed. The teeth are in the oil pan now, I'll worry about them later. The bottom of the shaft was also twisted.
Click to expand...

So my money was in the right place. :D
 
Hoddie now that you got a new dist pull the battery and have it tested and charged lets make sure it's good first then we will try and find why it don't crank. I'm pretty sure you have a wire off some where, non of your sensors can cause no crank.
One place to look is where the wires cross under the radiator I know you must have been in there if you changed the timing chain.
 
Okay I have a new battery (old one was covered by warranty). I hooked it all up again, now it turns over but still won't start. I checked it all out again. I have fuel at the rail and I know I have a good battery. So, I checked for spark. Nothing at the plugs, which are all new as well. Moving back to the coil, I found no spark there either. I measured volts coming into the coil and got about 10-11 volts. I think my coil is bad. Does this sound right?
Hoddie.
 
hoddie said:
Okay I have a new battery (old one was covered by warranty). I hooked it all up again, now it turns over but still won't start. I checked it all out again. I have fuel at the rail and I know I have a good battery. So, I checked for spark. Nothing at the plugs, which are all new as well. Moving back to the coil, I found no spark there either. I measured volts coming into the coil and got about 10-11 volts. I think my coil is bad. Does this sound right?
Hoddie.
Click to expand...
Thats good when cranking, Now the single wire is the trigger and it should pulse at 5 volts.
You should have a plug with three wires and a plug with one wire the one wire triggers the spark.
 
Before you buy a coil, have you tested the CPS output? I only have the test procedure for the Renix system, yours is different, but there is a simple test you should run to ensure that the CPS is sending a signal to the distributor.
 
Alright, checked the dist again and it is lined up right. Timing mark on dampner and #1 plug in dist line up. So gears are lined up. Now, I have replaced the cap and rotor. Last thing I checked was the coil output. Nothing at the business end. Voltage going in, none coming out. I put a new coil in and bam, huge blue spark at the cap now. Unfortunately, still no start. There was however some smoke rising from behind the valve cover while I was cranking it with my remote start. It looks like the only wiring down that way is the crank position sensor. I looked but it didn't look like the wires were burnt. Is there anything else that I could be missing? I think I am back to the crank sensor.
On the plus side, I did take my steering wheel apart and fix the loose torx nuts. At least I ended on a positive note.
Hoddie.
 
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