Timing chain?

Rudy Technician Montebello, California Posted   Latest   Edited  
2001 Ford Explorer Sport Trac 4.0L (E) 5-spd (5R55E)
P0304 - Cylinder 4 Misfire Detected
P0305 - Cylinder 5 Misfire Detected
P0306 - Cylinder 6 Misfire Detected
P0175 - System Too Rich Bank 2
Lack of Power
Engine Rattle

I strongly suspect the vehicle has a timing chain issue,however Id like a little info on what Im seeing. Ive compared my wave form with the one we have here(thanks ATG) and on other sites and it looks the same. 

However I have these blips(sawtooth?) in my camshaft trace(red), and Id like to know if that is indicative of a chain issue,or maybe thats simply my equipment.

Stephen Technician
Gallatin, Tennessee
Stephen Default

I notice that the blips also appear in the yellow trace, as elevated pulses. I more suspect them to be some kind of bleedover from the ignition.

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Rudy Technician
Montebello, California
Rudy Default

Thanks Stephen.

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Jamey Owner/Technician
Ventura, California
Jamey Default

Hi Rudy, The one you posted looks good. Is this your problem car?

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Dmitriy Analyst
Toronto, Ontario
Dmitriy Default

Stephen is correct — both traces are affected. What do you use as a scope ground? And how healthy are ECM grounds relative to battery negative?

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Rudy Technician
Montebello, California
Rudy Resolution

Ok guys I was just checking things the easy way before getting too intrusive. I certainly didn't want to chase my tail on stray, ghost images. After Stephen posted his thoughts,I moved on to my next step, checked back pressure. 10+ psi at WOT. Safe to say I found my issue(although the engine still rattles like a mother) BTW my scope lead was attached to battery ground. Ive never had an image…

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Todd Mobile Technician
Morinville, Alberta
Todd Default

Those are coils methinks.

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Geoff Diagnostician
Lahaina, Hawaii
Geoff Default

2001 Ford with bad chains AND bad converters.....how did you get one of our customers cars Rudy? LOL - Happy Weekend Vato.

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Glen Owner/Technician
Arthur, Illinois
Glen Default

When a 4.0L SOHC stops "Rattling", only then is it cause for concern ;)

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Marlin Technician
Estacada, Oregon
Marlin Default

That is just a set of loads being turned on and off, coils or injectors. Seeing this type of impact is very common when the scope is set up to display fine detail.

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Bob Owner/Technician
East Longmeadow, Massachusetts
Bob Default

This would be a good one to look at fuel trim on. A clogged cat on one side will cause trim to be skewed in opposite directions bank to bank.

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Rudy Technician
Montebello, California
Rudy Default

Bob- Yes, Ive seen that quite often. In this case bank 2 was -25%(stft), however bank 1 was only slightly off at +7% to +10%. Ive seen similar readings when one bank is out of time.

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Doug Diagnostician
Petersburg, West Virginia
Doug Default

Agree with the other comments , just a turn on of another component . Sync from a coil would of probably verified. Suspect those are the events being seen .

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