No Power To Coil - 96' Caravan 3.3

van suddenly died and would not start. This van has a lot of miles,
160K, and recently was run with oil very low (2 qts, few weeks). I
thought that the timing chain broke but looking at the valves they
seam to be moving fine. This happened one day after replacing bad
compressor and tensioner that were making a lot of racket. We put
about 50 miles on the van and everything was running great and then it
died while on the interstate. We heard a little thunk as it died but
nothing very loud.

After testing, I found that it did not have any spark. I checked the
coil and found that it tested good. I checked to make sure there was
power to coil and I have not been able to detect anything (using light
buld circuit tester). I have no error codes when using the key method
except usual 12 & 55. I decided the cam or crank sensor might have
went. I replaced both and still no power to coil. Tested both and
fuel pump relay and ASD and both appear to be fine. The fuel pump
clicks on and develops pressure when the key is turned on. If I
unplug the cam and crank I immediatly get error codes 11 & 54.

I think I am down to the PCM but wanted to get someone's opinion on
this. Will power still be deliverd to the coil if the timing chain
has slipped? Also, is there anyway to test PCM with out having a
computer? What else will cause the PCM to shutdown power to coil?

Thank you,

Todd Isaacs

 

This has to be tested with a voltmeter, not a test light, and it must be
done while cranking the engine *using the ignition switch*. Was this
procedure followed?

You say you tested the ASD relay. It may be clicking, but the contacts may
have failed, so you need to check for continuity across terminals 87 and
30 with the relay energized. Also, check that you have power to the wire
that hits terminal 30 of the ASD relay -- if not, look for burned out
fusible links.

DS

 

Daniel,

I checked the coil source with a voltmeter and I used the test light while
cranking.

I also checked the ASD while it was energized (across 30 and 87) and
everything looks good. I still do not feel comfortable with the voltmeter
test on the coil supply. I think my volt would have a hard detecting the
quick pulse??. I did check the resistance on the primary and secondary side
of the coil and all checked out good. I checked the terminal voltage for
the ASD and got 12v with key on. I did get a slight fluctuation , at the
coil source , on the voltmeter when I started cranking but it went to zero
almost immediately.

I will test everything agian tomorrow.

Todd

 

I checked everything again and found plug going to ERG solenoid was broken.
I remember this is why my check engine light came on a while back. I
checked the coil driver circuit and found that b+ is giving 12V with key on
and cranking, so ASD should be good. I found that coil driver for cyl 3&6
are constantly ground while ignition on and during cranking. The other two
cylinder drivers are open with key on and intermittently ground while
cranking.

How do I find out why the coil driver for cyl 3&6 is constantly ground?

Todd

 

What you're describing is one of the symptoms that occurs
when the camshaft position sensor and the crankshaft
position sensor are out of synch.

The two most obvious causes would be (in no particular order)
Stretched timing chain.
Broken flexplate.

Easy enough to check with a dual trace labscope.*

 

Looks like I've went as far as I can go with testing because I do not have a
dual trace scope and I would not know how to do the test.

Thanks for the information,

Todd



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