UNDIAGNOSABLE! HELP!!

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03-06-2014, 12:03 PM

#11

hootie_john

2nd Gear Member

Join Date: Oct 2012

Location: TN

Posts: 263

Quote:

Originally Posted by jz78817

Huh, learned something new.

I'm guessing that if the alternator rectifiers are popped, the alternator dumps enough electrical noise to interfere with the cam sensor signal?

I'm not sure of the exact cause for the cam failure codes. It may be the weak/incorrect voltage or noise like you mentioned.

03-07-2014, 08:07 PM

#12

thecardoc

Join Date: Jun 2008

Posts: 1

Quote:

Originally Posted by chwithad

Approximately 1.5 years after I purchased it, everything went downhill. Started (and continues to have) MIL P0345 and P0349. Yeah yeah yeah, I've heard ALL of it about the alternators being bad. Replaced mine over 4 TIMES! Every shop I've taken it to straight out say they don't know what the problem is.
I'm tired of paying $800 for emissions waivers. I pray that there is someone on here reading this that has ANY advice/information. Thanks in advance for all and any help!

We have found loose timing chains to be a very common cause for those codes. There are two tests that we do to prove it before teardown. One is to use the digital oscilloscope to record the cam and crank sensor waveforms, and the other is to use the pressure transducer and get the running compression waveform and see if the cams are really in time or not.

While charging system noise can cause the codes, that is an easy test to prove/disproven simply by disconnecting the alternator and if the problem goes away, then the scope can be used to verify how much AC ripple is occurring on the charging system voltage.

Find a tech that has a PICO scope and can do the compression testing with it (WPS500) and he/.she will be able to prove what is going on.

03-10-2014, 01:11 PM

#13

chwithad

1st Gear Member

Thread Starter

Join Date: Jan 2009

Location: Northern Virginia

Posts: 53

There's a guy I know who works at the A.S.E. headquarters here in town. Approx. 3 years ago, him and his buddies from work came over with TONS of test equipment and tested nearly EVERYTHING under the hood. He emailed me the waveforms and I'll try to dig that up and post it up here. Hopefully someone is knowledgable to understand the results compared to what is normal.