PDA

View Full Version : Rust inside Distributor


shunra
08-16-2010, 05:07 PM
Changed the distributor cap and rotor the other day and noticed quite a bit of rust and corrosion inside the distributor. Will this effect the module that is inside the distributor? Does anyone know what that module does or how to test it? I am thinking it might be some kind of cam position sensor.

Still can't get this thing to run right.

Hoosier Bob
08-17-2010, 12:05 AM
You have a distributor and a Cam Positon Sensor? Corrosion can happen in a distributor. I think your cam position sensor is ok.Changed the distributor cap and rotor the other day and noticed quite a bit of rust and corrosion inside the distributor. Will this effect the module that is inside the distributor? Does anyone know what that module does or how to test it? It is on a 2002 x-Star with the TBI 310hp engine. I am thinking it might be some kind of cam position sensor.

Still can't get this thing to run right.

shunra
08-17-2010, 12:38 AM
You have a distributor and a Cam Positon Sensor? Corrosion can happen in a distributor. I think your cam position sensor is ok.

Thanks for the reply HB. I don't really know what the module in my dist is for. There is some kind of Electrical module screwed down in there with two wires coming out of it. I thought it might have something to do with the timing adva
nce I have no idea how to verify that it is working properly.

Hoosier Bob
08-17-2010, 12:41 AM
What is your boat doing? Replace the cap and rotor. Boat runs great for awhile then? What are the symptoms. Thanks!;)Thanks for the reply HB. I don't really know what the module in my dist is for. There is some kind of Electrical module screwed down in there with two wires coming out of it. I thought it might have something to do with the timing adva
nce I have no idea how to verify that it is working properly.

shunra
08-17-2010, 01:01 AM
The boat has not been developing power like it should be. Slow out of the hole and will only go 35mph on the top end. It is also drinking gas.

I have a little more information now. I just got in from putting the timing light on it. It seemed to be way out of time. It appeared to be about 10 degrees AFTER top dead center. So about 20 degrees out of time. However I am not 100% sure on one thing. It is kinda hard to explain but my boat has the markings on the harmonic balancer that go from TDC to 60 degrees. There is a pointer on the timer cover case to line the number up to but that pointer is not straight up and down at 12 o'clock on the case. It is part way around to the side more like 1 or 2 o'clock when looking towards the crank pully.

I was not sure if I was suppoed to line up the 10 degree mark to the pointer, or if the pointer already represents 10 degrees BTDC. Long story short I have it set now so the 10 degree mark on the harmonic balancer is ligned up with the pointer. It seems to idle better but if this is right then it means my motor was approximately 20 degrees retarded on the timing. What could cause this? It seems like a lot to me.

Hoosier Bob
08-17-2010, 01:08 AM
First off stop messing around for a bit. Your boat is controlled by a computer as it is much newer than mine. Someone here can help and will shortly. If you set the base timing without bypassing the computer it will return to the position it feels is correct. if you do not have the proper equipment or knowledge you may not be able to time your boat. Rare for and electronic ignition, Control Module engine to change timing for no reason. Keep posting and bumping thread. List all changes and conditions that may factor in to your situation. Crap gas at a new lake? Changed timing, etc. Be specific. Good people here with much more info than I.The boat has not been developing power like it should be. Slow out of the hole and will only go 35mph on the top end. It is also drinking gas.

I have a little more information now. I just got in from putting the timing light on it. It seemed to be way out of time. It appeared to be about 10 degrees AFTER top dead center. So about 20 degrees out of time. However I am not 100% sure on one thing. It is kinda hard to explain but my boat has the markings on the harmonic balancer that go from TDC to 60 degrees. There is a pointer on the timer cover case to line the number up to but that pointer is not straight up and down at 12 o'clock on the case. It is part way around to the side more like 1 or 2 o'clock when looking towards the crank pully.

I was not sure if I was suppoed to line up the 10 degree mark to the pointer, or if the pointer already represents 10 degrees BTDC. Long story short I have it set now so the 10 degree mark on the harmonic balancer is ligned up with the pointer. It seems to idle better but if this is right then it means my motor was approximately 20 degrees retarded on the timing. What could cause this? It seems like a lot to me.

shunra
08-17-2010, 01:15 AM
Cool HB. Thanks for the input. I did bypass the computer as described on here somewhere. I'll wait and see what comes up.

Hoosier Bob
08-17-2010, 01:20 AM
I will bump if the sissy's don't show!:D A good tip maybe to add info on engine and hours. Just saying.Cool HB. Thanks for the input. I did bypass the computer as described on here somewhere. I'll wait and see what comes up.

JimN
08-17-2010, 06:00 AM
I will bump if the sissy's don't show!:D A good tip maybe to add info on engine and hours. Just saying.

Hey weenie- he wrote "It is on a 2002 x-Star with the TBI 310hp engine" in the first post.

If it has a distributor, I don't think it has a cam position sensor and I'm not sure this motor's ignition system is that sophisticated.

JimN
08-17-2010, 06:09 AM
Changed the distributor cap and rotor the other day and noticed quite a bit of rust and corrosion inside the distributor. Will this effect the module that is inside the distributor? Does anyone know what that module does or how to test it? It is on a 2002 x-Star with the TBI 310hp engine. I am thinking it might be some kind of cam position sensor.

Still can't get this thing to run right.

The module is sealed but moisture could affect the quality of the ground. If you have the GM distributor like the one in mid-1980s cars and trucks (has a flat side with two plugs/harnesses), the IC (Ignition Control) module sends tach info to the ECM. The ECM doesn't know the base timing advance- it just works on the assumption that it was set to 10BTDC before it will be run. The timing is then advanced or retarded, based on acceleration, deceleration and RPM. It uses the connection to the distributor base as its ground, but it also has a separate black ground wire and a tan bypass wire. If the ground isn't good, it can use the tan wire as a substitute ground, so I could disconnect the battery before removing the IC module in order to check and clean the ground. It uses the mating surfaces of the distributor base and IC module- scuff it with emery cloth or a Scotch Brite pad, blow out any dust (compressor or air can for cleaning a computer keyboard- watch your eyes and don't inhale the dust) and re-install the module.

shunra
08-17-2010, 05:40 PM
Thanks for the reply. Here are a few pictures I pulled off the net that look like my distributor:

1st pick is what it looks like from the ouside. 2nd pick is what it looks like with the cap and rotor off. 3rd pic is what the module inside looks like.

shunra
08-17-2010, 05:45 PM
I will clean the mating surface to ensure I have a good ground.

Do you think 15-20 degrees is too much for the base timing to have drifted on its own? The engine has 540hrs on it and I haven't had it timed since I bought it with 300hrs on it. I am wondering if it indicates something else is wrong. How much do you think the timing would be out if the distributor jumped a cog?

JimN
08-17-2010, 05:52 PM
Thanks for the reply. Here are a few pictures I pulled off the net that look like my distributor:

1st pick is what it looks like from the ouside. 2nd pick is what it looks like with the cap and rotor off. 3rd pic is what the module inside looks like.

I kind of doubt the IC module is bad, but it does happen. However, if you remove the metal cover, you'll see a pickup coil and a piece that's not far from it, on the shaft. If the pickup coil is bad, it may run poorly all the time, or it may be intermittent- this will only affect the spark, not the injector firing. If you use a multi-meter to check the output, without piercing the wire's insulation, you'll need to use a stick pin or a T-pin (available from craft stores) to insert it past the silicon rubber seal around the wires on the plug. You'll need to insert one on the purple/white wire and one on the black/red wire- you need to set the meter to DC Volts and look for 1-2 V as it cranks or runs. Bend the pins away from each other so they can't touch.

If you see significantly less than 1-2VDC, you'll need to check the pickup coil. The pickup coil connects to the two pins on the IC module that are on the opposite side from the two main plugs.

JimN
08-17-2010, 05:57 PM
I will clean the mating surface to ensure I have a good ground.

Do you think 15-20 degrees is too much for the base timing to have drifted on its own? The engine has 540hrs on it and I haven't had it timed since I bought it with 300hrs on it. I am wondering if it indicates something else is wrong. How much do you think the timing would be out if the distributor jumped a cog?

The only time I have seen base timing change is when the distributor hold-down is loose. If that's tight, it can't drift unless it's told to. Re-set it at 10BTDC in diagnostic mode and see how it runs.

The distributor can't jump 15 unless something is physically broken or loose. If it remains at whatever it's set to, the pin is OK and the teeth are OK. I would say that it's likely the hold-down wasn't tightened fully. IIRC, the gear has 12-15 teeth and that would mean a minimum of 20 change if it skipped a tooth, or 30 if it has 12 teeth. Pretty unlikely, IMO.

CantRepeat
08-17-2010, 06:24 PM
The module is sealed but moisture could affect the quality of the ground. If you have the GM distributor like the one in mid-1980s cars and trucks (has a flat side with two plugs/harnesses), the IC (Ignition Control) module sends tach info to the ECM. The ECM doesn't know the base timing advance- it just works on the assumption that it was set to 10BTDC before it will be run. The timing is then advanced or retarded, based on acceleration, deceleration and RPM. It uses the connection to the distributor base as its ground, but it also has a separate black ground wire and a tan bypass wire. If the ground isn't good, it can use the tan wire as a substitute ground, so I could disconnect the battery before removing the IC module in order to check and clean the ground. It uses the mating surfaces of the distributor base and IC module- scuff it with emery cloth or a Scotch Brite pad, blow out any dust (compressor or air can for cleaning a computer keyboard- watch your eyes and don't inhale the dust) and re-install the module.


Jim should there be some clear grease the module? I thought had something to do with heat.

Hoosier Bob
08-17-2010, 06:42 PM
I was being nice Jimmy! Otherwise we may have been discussing rust on the coil packs! :DHey weenie- he wrote "It is on a 2002 x-Star with the TBI 310hp engine" in the first post.

If it has a distributor, I don't think it has a cam position sensor and I'm not sure this motor's ignition system is that sophisticated.

thatsmrmastercraft
08-17-2010, 07:03 PM
Dielectric grease is good for virtually all electrical connections in marine (and automotive) applications.

shunra
08-17-2010, 08:13 PM
The only time I have seen base timing change is when the distributor hold-down is loose. If that's tight, it can't drift unless it's told to. Re-set it at 10BTDC in diagnostic mode and see how it runs.

The distributor can't jump 15 unless something is physically broken or loose. If it remains at whatever it's set to, the pin is OK and the teeth are OK. I would say that it's likely the hold-down wasn't tightened fully. IIRC, the gear has 12-15 teeth and that would mean a minimum of 20 change if it skipped a tooth, or 30 if it has 12 teeth. Pretty unlikely, IMO.

The hold down was definately tight. It took quite a bit of loosening to get it to the point where I could adjust it. Before I adjusted the timing the distributor was basically "square" to the engine. Now it is skewed. I guess it would be by about 20 degrees :D

I thought the base timing could drift a bit with wear/streatch in the timing chain, but I have no idea how much a guy would expect to see after 540hrs. 15-20 degrees seems like a lot.

Hoosier Bob
08-17-2010, 10:08 PM
If you have wear in the timing chain it will bounce and not be a solid consistant timing mark. FYI. However if it is bouncing betwen 10 and 20 you may be correct!The hold down was definately tight. It took quite a bit of loosening to get it to the point where I could adjust it. Before I adjusted the timing the distributor was basically "square" to the engine. Now it is skewed. I guess it would be by about 20 degrees :D

I thought the base timing could drift a bit with wear/streatch in the timing chain, but I have no idea how much a guy would expect to see after 540hrs. 15-20 degrees seems like a lot.

JimN
08-17-2010, 10:33 PM
I was being nice Jimmy! Otherwise we may have been discussing rust on the coil packs! :D

Hey, you're the one who started calling people 'sissies'.

JimN
08-17-2010, 10:34 PM
The hold down was definately tight. It took quite a bit of loosening to get it to the point where I could adjust it. Before I adjusted the timing the distributor was basically "square" to the engine. Now it is skewed. I guess it would be by about 20 degrees :D

I thought the base timing could drift a bit with wear/streatch in the timing chain, but I have no idea how much a guy would expect to see after 540hrs. 15-20 degrees seems like a lot.

You'd have to beat the snot out of it to stretch the timing chain in 540 hours of use.

Hoosier Bob
08-17-2010, 10:35 PM
Hey Jimney!You'd have to beat the snot out of it to stretch the timing chain in 540 hours of use.

shunra
08-18-2010, 01:08 AM
No the timing mark is not bouncing. I guess it is a bit of a mystery.

oldairboater
08-18-2010, 11:40 AM
Old trick to check slack in timing chain is to move crank back wards till rotor moves then turn crank fowards and wait for movement of rotor. I know of guys who could predict wear fairly accurately doing that. Myself if it moved almost immediately it was good to go. That was with Ford engines---never owned a gmc product long enough to stretch a chain.

Hoosier Bob
08-18-2010, 09:13 PM
Is that how you spell it? Maybe I should switch to ********!:DHey, you're the one who started calling people 'sissies'.