One last shot... Breaking up!

[turboj91]

Re: One last shot... Breaking up!

So when are you putting the new O2 sensor in ?

I think he did the O2 already and nothing changed? I have a saying "New only means no one used it before you" but to have a second O2 cause a problem at the same exact rpm ??? I have seen stranger things but...?? I thought O2 a while back, but he unplugs it and nothing changes - doesn't even throw a code??? There are many things that are not logical on this one.

 

[ghettosled]

Re: One last shot... Breaking up!

i kinda skipped around in this thread but i did not see anywhere that you tried disconnecting the wide band 02. Since it started around that time it would make sense to completely unplug it from all power sources. is it powered direct to the battery or somewhere like the firewall junction block?

i had one that caused some weird issues, and kicked datamaster offline anytime it was plugged in and started to warm up. A short or something in the 02 sensor could be more pronounced when it gets warm and starts screwing with your grounds.

 

[BoostedSUV]

Re: One last shot... Breaking up!

So when are you putting the new O2 sensor in ?

I will pick up a new one tomorrow from autozone. I wanted to try the grounds first before I threw another 60 bucks or so at it.

 

[BoostedSUV]

Wbo

Wbo

i kinda skipped around in this thread but i did not see anywhere that you tried disconnecting the wide band 02. Since it started around that time it would make sense to completely unplug it from all power sources. is it powered direct to the battery or somewhere like the firewall junction block?

i had one that caused some weird issues, and kicked datamaster offline anytime it was plugged in and started to warm up. A short or something in the 02 sensor could be more pronounced when it gets warm and starts screwing with your grounds.

Hey Mike, I appreciate you jumping on board this slowly sinking ship! I actually had this problem prior to the WBO2 install. I was getting a "lean" break up according to Datamaster so I put in the wideband as a second "opinion" to see if it's a false "lean" reading on the stock O2 but the WBO2 shows the same thing. This problem was always there since 2006 but it really popped up bad and showed it's face after I put in an Elec FP gauge in one friday night after driving the truck home from work. Could be a total coincidence but I can't make sense of it. Motor has been out 4 times since then and I've made a lot of changes along the way but i never could get this issue to "go away." It had good days and bad days but it was never gone...

Definitely gets worse when engine warms up, when I first start the truck it moves clean through the RPM range

 

[turbodig]

Re: One last shot... Breaking up!

I'm ohm testing grounds, should I be using the volts side of VOM to test them? The only ground I can get under .5ohms is the block.

I'm getting 16-19 volts at the junction block on the firewall near the FP relay with the truck running...

16-19 volts... with the ground where?

Try moving the ground probe around to different places and see if it changes.

The Diode trio in the alt could do things like this, as could the regulator. Is the wiring/connectors to the alternator ok?

EDIT - if you have a DVM that measures AC, you should be able to measure any ripple coming from the alt, if there is any.

You don't have an optima battery, by any chance?

 

[BoostedSUV]

Re: One last shot... Breaking up!

16-19 volts... with the ground where?

Try moving the ground probe around to different places and see if it changes.

The Diode trio in the alt could do things like this, as could the regulator. Is the wiring/connectors to the alternator ok?

EDIT - if you have a DVM that measures AC, you should be able to measure any ripple coming from the alt, if there is any.

You don't have an optima battery, by any chance?

I had the ground connected to the alt bracket and I also tried it with the ground to the battery. If I probe the alt and batt with ground to the same spots I get a steady 13.8. By bad alternator what do you mean? I get 13.8 out of it so it's not a lack of voltage, but it could be doing other weird things.

No optima battery any more, got tired of fighting with them. I just have a red top Duralast or something like that from Autozone.

 

[WyoSyclone]

Re: One last shot... Breaking up!

Where in the harness does the rpm get picked up? Cranking at 6300 rpm may be a clue to something.

The white wire coming out of the 2-pin connector at the coil is the feed to the tach.

I mentioned in one post way back about the pink wire in that 2-pin... it is the Ignition feed to the coil, and in turn, the ignition module.

If this ignition feed was bad (remember Don's bad ignition switch) it would affect the ignition module and could give the impression that the truck had a bad ignition module. This pink wire only feeds this circuit and nothing else.

Matt, I know this would be a pain the rear but you could try feeding that pink wire from an alternate source so that the ignition switch is bypassed.

 

[cloneman315]

Re: One last shot... Breaking up!

that volt thing is bothering me,try another alt.

 

[turbodig]

Re: One last shot... Breaking up!

I had the ground connected to the alt bracket and I also tried it with the ground to the battery. If I probe the alt and batt with ground to the same spots I get a steady 13.8. By bad alternator what do you mean? I get 13.8 out of it so it's not a lack of voltage, but it could be doing other weird things.

No optima battery any more, got tired of fighting with them. I just have a red top Duralast or something like that from Autozone.

Try putting the - probe of the DVM on the alt output, and the + on the firewall block. If you get anything for voltage between them, something is seriously messed up. If you do get voltage, disconnect the battery (both sides) and ohm check between the alternator output and the block. It should be very close to 0 ohms. (< 1)

Is it possible there's a fuseable link partially whacked someplace?

 

[WyoSyclone]

Re: One last shot... Breaking up!

that volt thing is bothering me,try another alt.

Yup, me too....

Also, on 3 out of the 5 logs it's throwing a Code42 (EST)... of course this points to a voltage issue as well. One log shows battery (ECM) voltage momentarily dropping to .2 volts... in my experience this can only be an intermittent on a wire, or plates momentarily shorting out in the battery.

It's easy to take the alternator out and take it down to a NAPA to be tested.... get a battery out of another car and put it in for a test.....

:screwy::banghead:

 

[BoostedSUV]

Re: One last shot... Breaking up!

I've been tracing the schematics of the pink wire from the ECM side and it feeds the coil, ign module, and also goes through the overboost cut relay. I have that pink wire cut on the ECM side and going through a relay for the ECM voltage fix. The relay is fed off of the junction block on fire wall then back to ECM. If I understand correctly I bypassed the ignition switch feed to the ECM. I will have to follow schemetics and see if the coil is still fed from the ignition switch. I believe it still is and I just changed the feed to the ECM. I'm going to have to through schematics on fuse panel side and figure out where a good spot to bypass the ignition with hacking up my wire harness too bad. I'm going to have to put a battery feed to it correct? Anything switched would be through the ignition switch and wouldn't accomplish anything...

 

[WyoSyclone]

Re: One last shot... Breaking up!

I'm going to have to through schematics on fuse panel side and figure out where a good spot to bypass the ignition with hacking up my wire harness too bad. I'm going to have to put a battery feed to it correct? Anything switched would be through the ignition switch and wouldn't accomplish anything...

You could just do it right at the coil... there's about a 2 inch section of wire that is easy to get to.... I try to stay away from modifying anything close to the fuse panel.

I'd sure do the alternator test, and swap batteries first.... and do Dig's test between the alternator and power junction block.... I think we're all getting this narrowed down.

 

[turbodig]

Re: One last shot... Breaking up!

You could just do it right at the coil... there's about a 2 inch section of wire that is easy to get to.... I try to stay away from modifying anything close to the fuse panel.

I'd sure do the alternator test, and swap batteries first.... and do Dig's test between the alternator and power junction block.... I think we're all getting this narrowed down.

It kinda makes me wonder - is there some ghost wiring from past alarms in there?

A local had a second alarm that he found in the center console... somebody had installed one on top of the other.

At least you've found a problem... that's progress!

 

[BoostedSUV]

Re: One last shot... Breaking up!

Dig I will try your ALT test tonight and see what happens.

The battery is a little over a year old and this problem is 3 years old. When I changed the battery I had AutoZone test the alt and they said "it was fine". The voltage out put from is good but I guess it could be back feeding through the ground? When I was probing around testing voltage last night I put the pos side of the test lead to the ALT case and I was getting a reading varrying with rpm at the case but not at the block...

 

[BoostedSUV]

Re: One last shot... Breaking up!

If I disconnect the the plug at the ALT and run the truck will that disable the ALTs output? This way I can run the truck off the battery only and see if that does anything? Just a thought, or will the alt still backfeed regardless since its still spinning?

 

[BoostedSUV]

Re: One last shot... Breaking up!

Rob the .2 voltage drop you are seeing is most likely the Elec fan kicking on. Also the code 42 you see is stored in the system as I did not have a CE light during those logs. I hope we're narrowing it down!

 

[WyoSyclone]

Re: One last shot... Breaking up!

Rob the .2 voltage drop you are seeing is most likely the Elec fan kicking on. Also the code 42 you see is stored in the system as I did not have a CE light during those logs. I hope we're narrowing it down!

It's not a .2 drop.... it actually goes down to .2 while the truck is running. I'd disconnect the battery and alternator completely and then start checking each power/ground wire.. this can't be the entire problem because your logs show 13.8 while the breakup problem happens, but this should be checked anyway.

 

[WyoSyclone]

Re: One last shot... Breaking up!

If I disconnect the the plug at the ALT and run the truck will that disable the ALTs output? This way I can run the truck off the battery only and see if that does anything? Just a thought, or will the alt still backfeed regardless since its still spinning?

Yup, that would work as a quick test.

 

[BoostedSUV]

Re: One last shot... Breaking up!

Should I hold off on getting an O2 sensor for now?

 

[SloGN]

Re: One last shot... Breaking up!

Yup, me too....

Also, on 3 out of the 5 logs it's throwing a Code42 (EST)... of course this points to a voltage issue as well. One log shows battery (ECM) voltage momentarily dropping to .2 volts... in my experience this can only be an intermittent on a wire, or plates momentarily shorting out in the battery.

It's easy to take the alternator out and take it down to a NAPA to be tested.... get a battery out of another car and put it in for a test.....

:screwy::banghead:

i have seen this issue on the GN's where the motor mounts get weak and the motor flexes enough to short out the main battery cable on the exhaust manifolds. So it could be very possible that the main wiring at the starter or the fuseable links could have some issues.