Tech Thread Only?

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Re: Tech Thread Only?

smogtech831
A shorted ignition coil. I assume an inductive  amp probe was used to measure the current. The vehicle needs  a new distributor.
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Re: Tech Thread Only?

scanner
smogtech831 wrote
A shorted ignition coil.
Winner!  

I assume an inductive  amp probe was used to measure the current.
Yes, absolutely correct.   I used a Vantage Pro along with a CA60 current probe.  The probe was placed on the black/yellow feed wire entering the distributor.    

The vehicle needs  a new distributor.
That is what I replaced.  Most times when the coil goes out, the module gets spanked, and will eventually fail shortly (weeks or months) after replacing just the coil.   I did give the consumer the option to replace only the coil.  The secondary most likely was shorted, which was reflected in the primary by the lack of counter EMF.    I also swapped out the worn out conventional spark plugs with iridium replacements.  

Congratulations, you are added to the list of excluded first responders.  
Why make it simple, when it will work equally as well complicated.
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Re: Tech Thread Only?

none
scanner wrote
 

Congratulations, you are added to the list of excluded first responders.  
Can I be added back to the list of people who can respond because I have got to tell you, if you and smogtech hadn't explained it I would still be looking at that pattern wondering what I was looking at. I've never used an amp test to tell if the coil was bad but it seems to work well and fast.

TOM
People are usually shocked when they find out I'm not a very good electrician.
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Re: Tech Thread Only?

Best Answer I Can Give
 Scanner, one of the first guys I would ask. But were you total fair?
 Didn't run. Well did you check for fuel first. Where were you hooked to. But that would have given it away.
Were we looking at a Fuel pump? A Coil?
You could clearly see it ramp up and then die.
tired, and just not the tired that sleep can fix.
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scanner
In reply to this post by none
none wrote
Can I be added back to the list of people who can respond because I have got to tell you, if you and smogtech hadn't explained it I would still be looking at that pattern wondering what I was looking at.
Okay, I guess I'll not exclude anyone, but you guys usually get it right away, and I would like to see more participation.  

I've never used an amp test to tell if the coil was bad but it seems to work well and fast.
I've been using a current probe since the late 90's.  My first set up was a Fluke Y8100 along with a Sun LS2000 scope.  It was an eye opener when I first saw it being used.   I found bad fuel pumps, coils, and injectors quickly.  
Why make it simple, when it will work equally as well complicated.
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Re: Tech Thread Only?

scanner
In reply to this post by Best Answer I Can Give
Best Answer I Can Give wrote
Scanner, one of the first guys I would ask. But were you total fair?
I suppose not, but that's all the data I collected before making the call.  It was enough for smogtech831
 to describe exactly what was wrong and what I replaced.  

 Didn't run. Well did you check for fuel first.
I did the check based on where the tow truck dropped the CRV.   My first inclination would be to shove the sniffer up the tail pipe and check for hydrocarbons.    Had I done that, it would have measured enough to start the car, thereby verifying the fuel pump, injectors, and rpm input.   The CRV was too far away from the EIS, and I didn't feel like pushing it.   So I checked for current first since it takes a second to hook up the probe around the wire and I got lucky.  

Where were you hooked to. But that would have given it away.
That would have given everything away.

Were we looking at a Fuel pump? A Coil?
You can see the initial coil current ramp go straight up, indicating a shorted winding in the coil.  If it were sloped from the beginning, I would have had to do more investigating.  

You could clearly see it ramp up and then die.
That's not dying, it the ICM firing the coil.  That is the normal coil charge duration.  

Why make it simple, when it will work equally as well complicated.
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Re: Tech Thread Only?

Best Answer I Can Give
 Thanks. Like you said, "Well I hooked to the coil and got this." Yes that would have given it away. Thanks again.
tired, and just not the tired that sleep can fix.
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none
In reply to this post by scanner
I think it was all fair and fun to try to figure out what I was looking at and as you said, SMOGTECH nailed it with the information you provided.
People are usually shocked when they find out I'm not a very good electrician.
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Re: Tech Thread Only?

Best Answer I Can Give
 Hey I will take all those I can. I LEARNED something.
tired, and just not the tired that sleep can fix.
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Re: Tech Thread Only?

scanner
In reply to this post by smgmn
Here's a 2003 GMC Yukon.  It's got a P0446.  If you look online, you'll see a bunch of different definitions/descriptions of the code.  

About 2 weeks ago, I tested it, and I didn't see anything wrong with the system.   I cleared the code, and told them to come back when the light turned back on again.  This time I saw this before performing a purge and seal.



I did a Hail Mary based on that scan and fixed it.  Comments.
Why make it simple, when it will work equally as well complicated.
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Re: Tech Thread Only?

none
Pressure sensor readings are all over the place with no switching of the vent or purge.
People are usually shocked when they find out I'm not a very good electrician.
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scanner
none wrote
Pressure sensor readings are all over the place with no switching of the vent or purge.
I changed the part, and here's the fix scan.   You can see the purge and seal, and that it holds vacuum, indicating that the system is working properly.



So what is the component that I replaced?  
Why make it simple, when it will work equally as well complicated.
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Re: Tech Thread Only?

D Rochells 150861
I swear it's almost always the the FTPS on GM. 7 out of 10 GM EVAP fixes last year were fuel tank pressure sensors, 1 was corroded harness connector, 1 was rusty tank and 1 was probably FTPS but it was new enough I kicked it to the dealer.
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D wrote
I swear it's almost always the the FTPS on GM. 7 out of 10 GM EVAP fixes last year were fuel tank pressure sensors
Good job, D!

It was the Fuel Tank Pressure (FTP) sensor.  


Why make it simple, when it will work equally as well complicated.
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Re: Tech Thread Only?

D Rochells 150861
Not gonna lie, I threw that part.
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D wrote
Not gonna lie, I threw that part.
That's what I did.   As everyone knows, most manufactures use vacuum to test the EVAP system.   In the first scan, a LOT of positive pressure is being measured, and going away.  If I took the cap off it would have done the same.  
Why make it simple, when it will work equally as well complicated.
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Best Answer I Can Give
 I have know idea how many shops and people that don't get it. But I replaced the part, it should work.
The part that tells you the part is bad, That's the true bad part.
 How many don't understand. power supply, computer, wire to part, part, wire back, computer ground. Any one of those could be bad.
tired, and just not the tired that sleep can fix.
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Re: Tech Thread Only?

D Rochells 150861
That corroded one, Buick Rendezvous. I wrote him up for diag, was off the next few days. I came back and my boss had changed the vent solenoid, and something else a TSB recommended. Code came back. I lowered the tank a bit, commanded the vent. No noise, hooked power probe to signal wire, no power. Unplugged silly harness junction at the frame. Pins had corroded and no contact. I know my boss can diagnose, but for some guys when they are working alone its easier to just go with what it probably is.
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Re: Tech Thread Only?

scanner
D wrote
That corroded one, Buick Rendezvous. I wrote him up for diag, was off the next few days. I came back and my boss had changed the vent solenoid, and something else a TSB recommended. Code came back. I lowered the tank a bit, commanded the vent. No noise, hooked power probe to signal wire, no power. Unplugged silly harness junction at the frame. Pins had corroded and no contact. I know my boss can diagnose, but for some guys when they are working alone its easier to just go with what it probably is.
If the part is accessible, I would try to test the component.    The FTP sensor on the Yukon is on top of the fuel tank on top of the fuel module.    I dropped the tank about 4" and had just enough room to sneak the part out and back in.   There was no way I was going to test the FTP sensor on the vehicle, so I just swapped it out.    Looking at the scandata after the repair,  I knew I had it fixed.  
Why make it simple, when it will work equally as well complicated.
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Re: Tech Thread Only?

scanner
In reply to this post by smgmn
When running a monitor, it's best to look up the enable criteria, or look up the code criteria for the component you're trying to complete.  Doing a generic drive cycle for a manufacturer works many times, but there are always exceptions.    

I always thought that Chrysler products would run the oxygen heater monitor after shutting down the vehicle, letting the coolant temp drop, and then turning the vehicle back on.  

http://rlescalambre.com/public/01-Chrysler.htm 

I had a 1996 Dodge Van w/5.2L that had run hundreds of miles, but couldn't get any non-continuous monitors to run.   They came to me in May, but didn't want to pay me to run the monitors.   Last week, they came in and I upped the estimate to 2 hours.   They balked at first, but apparently someone had convinced them to install a rebuilt ECM and a rear oxygen sensor with no change.  

I poked around the ECM, and found out that the other shop just threw the ECM into the Van.  The VIN was FFFFFFFF.     I wrote the VIN into the ECM.   I have no idea if that had any impact on the monitors, but why take a chance?  

While the consumer was waiting for his ride, I completed the Cat monitor first.    I had to drive the vehicle at least another 2 miles before I would shut it off, and try to run the O2 sensor heater monitor.   It didn't run.  I tried again, and it didn't run.   I finally looked up in Alldata the enable criteria for the O2 sensor heater monitor, and SOB, it runs after a cold soak, and at idle.   I texted the consumer and told him I'll need to hold the vehicle overnight to determine whether the enable criteria is being met.  

The next morning I saw this.



I'm watching the brand new Bosch sensor the other shop installed, not working at first, but eventually you can see the heater work.   I hate Bosch sensors, I've been burned a couple of time, I'll never use them unless it's OEM.    Surprisingly, the O2 sensor heater monitor ran.   BTW, I recorded the temps in Fº and not Cº, I don't know what happened there.   There were only 3 non-continuous monitors, so I was good to go.  

The take away?  If your generic drive cycle doesn't work, look up the enable criteria for your specific vehicle.   It'll save you a lot of time when you do a little research.  


 



Why make it simple, when it will work equally as well complicated.
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