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Todd M
Todd M,
Category: Chevy
Satisfied Customers: 1254
Experience:  Technician at Montgomery Motors
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I replace the timing chain on my 1997 Blazer 4.3 L but now

Customer Question

I replace the timing chain on my 1997 Blazer 4.3 L but now have no spark. What could cause that/
Submitted: 6 months ago.
Category: Chevy
Expert:  Todd M replied 6 months ago.

Hello. My name is ***** ***** I will be assisting you today. First, What have you checked? Have you checked any of the fuses?

Customer: replied 6 months ago.
fuses seem all ok. getting no fire at coil but truck ran before replacing timing chain
Customer: replied 6 months ago.
i am trying to get truck to run before putting it completely back together
Expert:  Todd M replied 6 months ago.

If you are not getting fire, you need to check the connections to the crankshaft sensor. This sensor not firing, or disconnected with cause a no spark issue. Also, this is a component that you have to come in contact with when doing the chain.

Expert:  Todd M replied 6 months ago.

Give me just a moment to review a few things.

Expert:  Todd M replied 6 months ago.

Also, are you sure you have the distributor timing right?

Expert:  Todd M replied 6 months ago.

Here, I am providing diagnosis information for the crank sensor. Give me just a moment.

Customer: replied 6 months ago.
the gears will go on one way.....in or 160 out the distributor is pointing to where the number 4 would fire. The gears behind the camshaft gear the bigger gear is at 12 oclock but find no mark on the smaller gear I put the ring for the crankshaft sensor back on and and put new timing chain cover on......but not permanent so that i could put the chankshaft sensor back on.
Expert:  Todd M replied 6 months ago.

I understand.

Expert:  Todd M replied 6 months ago.

Here is some information for the chain and sprockets, just in case. You need to test the crank sensor circuits and the distributor circuits to verify proper function so you will know exactly where you stand.

Customer: replied 6 months ago.
would it make a difference if the i haven't put the balancer back on yet?
or i think the crank spocket is all the way back but if it is a little forward would it affect the crankshaft sensor?
Expert:  Todd M replied 6 months ago.

I don't believe it would, the crank sensor doesn't read the balancer in this vehicle. Let me be sure.

Expert:  Todd M replied 6 months ago.

No, the balancer wouldn't cause this. I'm think that you may have damaged or not have the cranksensor connected properly. Also, you should check the connection to the ignition coil for power and ground also. Here is some ignition coil testing.

Customer: replied 6 months ago.
i ran out of daylight to do anything else today. I will try making sure everything is back as far as it will go tomorrow. I read online about resetting the crankshaft sensor had the battery unplugged so that should have reset it. I think my questions would be I am setting the timing to cylinder four correct? And if my crank and cam were out of time how would i determine it?
Expert:  Todd M replied 6 months ago.

You should have to cover all the way on also. This may effect the signal.

Customer: replied 6 months ago.
ok I just didn/t want to seal before i knew for sure it was to start.
Expert:  Todd M replied 6 months ago.

If you were out of time, the motor would be struggling to turn over because the actions are not moving properly. You should be setting the timing to number 1.

Expert:  Todd M replied 6 months ago.

When you have the distributor pointing at the 1 on the cap, the 1 cylinder should be a TDC.

Customer: replied 6 months ago.
are you sure because the manual is saying to set it to number four. On the enhanced ignition with the square cap the rotor is pointing at number one but when it fires it actually fires number four.
Expert:  Todd M replied 6 months ago.

One moment, please.

Customer: replied 6 months ago.
when number one fires it is actually pointing at four on the rotor
Expert:  Todd M replied 6 months ago.

If the timing is off, It would have to be internal(cam and crank shaft).

Customer: replied 6 months ago.
how can i determine that?
Expert:  Todd M replied 6 months ago.

When the rotor on the cap is point at 1, the number 1 cylinder should be at TDC.

Expert:  Todd M replied 6 months ago.

How can you determine if the timing is correct?

Customer: replied 6 months ago.
how the determine that the cam is on the right cycle
with the crank?
Expert:  Todd M replied 6 months ago.

As long as you have the timing marks correct you should be good. You will have to set the number 1 to TDC and verify that the timing marks are on the correct spots.

Customer: replied 6 months ago.
ok ill do that tomorrow thanks for the help
Expert:  Todd M replied 6 months ago.

Here are the locations of the timing marks just in case.

Expert:  Todd M replied 6 months ago.
If you require more information on this issue and/or are not satisfied, let me know, please, and I will attempt to assist you further on this. I hope this information points you in the right direction. If you have any further questions or concerns on this issue, feel free to ask. If you are satisfied, and have found this information helpful, a positive rating would be greatly appreciated. Thank you.A positive rating does not close the session. We will still be able to communicate and I will continue to assist you with this issue as needed.