Suburban dilemma

[Fryer5]

Last year I bought an 08 suburban 2500 with 51,000 miles. Body in excellent condition. I planned on using this to tow my trailer and be an everyday driver for my wife for many years to come. It ran and drove with no noticeable problems at all. I changed all the fluids, difs, transmission flush, transfer case. Gm dealer didn’t recommend a radiator flush at that time.
Now onto the problems
1. The stupid thing has ghost in it. An electrical problem that randomly completely resets the computer. The clock will be reset. No error lights on the dash. Sometimes when this happens it will not start. Turn key, NOTHING, no click, no dim lights. NOTHJNG. wait 1!hour, starts right up. It has done this to me twice while driving, leaving me and my family stranded on the side of the interstate. Once while pulling the camper.
2. The rear end is making a horrid noise, probably the pinion bearing. This truck has the 3/4 Ton 8 luv axle, it has been properly serviced by the dealer, and yet has spun a pinnipn bearing? Very frustrating.

So, I guess the advise I am looking for is should I fix it and keep it? (No one has been able to find the “ghost” electrical problem despite several thousands of dollars in repairs)
Or do i send it on down the road and start looking for it’s replacement.
To be honest, I am really not in a good place to be looking for new suburbans financially.


To add to this, my wife of course is saying never again to this truck, and after this expierence I am not wanting to buy another used suburban.

All input appreciated

Fryer 5

Ps. I have always been a GM fan, and still am. My other two chevys serve my family great

[BenK]

Sorry, not up on all of the changes and apologize...yours has top post, so my comments out in the weeds...

But, interesting to me enough to look and found this one pointing to the OEM negative lead being an issue that causes total power loss

Check it out...might be your issue. Key is total power loss to reset. Nothing else can do that, that I can see. Cam sensor...nope, not over night as it has nothing to do with the power system, other than being a consumer of power

YouTube video on GM negative lead issue

[BurbMan]

Not sure about the 2008, but on the 01-06 with the 8.1L, you got 2 fuel tanks. The main tank is on the left side inside the frame rail, basically under the driver's seat, and the second is in the rear, under the cargo floor, above the spare tire holder. I'm not 100% certain how this system operates, but I can tell you what I know from taking it all apart in 2013 to replace the brake lines and fuel lines.

The fuel filler neck on the rear fender flows gas into the rear tank, and the rear tank is also connected to the main tank with a large gravity feed tube. Despite this, each tank has it's own electric fuel pump with sending gauge.

The main tank operates as expected, there are fuel, return, and evap lines connected and the pump runs whenever the ignition is on. The rear tank is configured similarly, with fuel and evap lines connected to the main tank. The pump in the rear tank doesn't run continuously, but is cycled by the PCM.

NOTE: The service manual only states the above, it doesn't say what conditions the PCM uses to turn the fuel pump on/off, it only states that you can test activate the pump with a scan tool.

Each pump sends its fuel level readings to the PCM which then uses an algorithm to combine the readings and determine where to display the dash fuel gauge.

So I'm not sure why there is a pump in the rear tank to pump fuel into the front tank when the rear tank sits higher than the front tank and there is a large gravity feed from one to the other. I've not heard of the rear pump causing a stall or no-start condition, but that doesn't mean it's not possible.

Servicable life on GM fuel pumps has proven to be about 100k miles....if you were inclined, you might consider changing both fuel pumps, if nothing else but to rule them out as a suspect.

[falconbrother]

I really would try and save that burb. They are great vehicles.

[Fryer5]

So my suburban doesn’t have side post battery terminals. It is a top post system, and I have replaced all the battery cables. I have cleaned and dielectric greased all battery connections. I cleaned and greased the main power fuse on the fire wall. I added an additional body ground cable. I removed, cleaned and greased the main power distribution block under the hood.
I am leaning towards the possibility of it being 3 possible contributing problems:
1. The rear end this should be an easy to diagnose and simple repair (at a shop). Not relevant to the electrical issues in any way.
2. The shut down while driving may be fuel pump related, unrelated to the failure to start problem. I have read there is a possibility of two fuel pumps on the high capacity tank (39 gallons). Both times it **** down the truck had be running for an extended period. The first time it shut down while driving it had been running for about 16 hours, and the second time about 7 hours.
3. The random failure to start and resetting of the radio clock??? I really have no idea. Now I am wondering if it is possible to have an intermittent short in the battery.

Hopefully a shop near me that comes highly recommended can diagnose and fix it. Until then, I am blessed to be able to surrvive while it sits parked in the driveway.

[LVJJJ]

Suburban's forever. Love 'em. My "new" 94 developed a noise we thought was in the front 4wd pumpkin, but turned out it was worn bearings in the rear, got bearings and seals repaced $400, quiet now. Gears were fine, has only 142,000 on it. I'm not sure I'd buy a former governemtn vehicle, too many things coulda been done to it. Driver's of it woulda had no pride of ownership, who knows how and where the drove it.

[mich800]

If I am reading this correctly the OP is not really saying the ECM is resetting (how would they know that) but that there is an intermittent electrical loss long enough to reset the radio time. Ben's suggestion would support that.

[BurbMan]

I had to replace my rear gears at 100k miles, but not because they wore out...I had the truck in for an oil change and the grease monkey saw the leaky pinion gasket and decided that a few cranks on the nut ought to tighten it right up and would stop the leak. Well, it stopped the leak alright, and it only took 100 miles for the rear to start howling like crazy. Cost me a grand for new gears at an axle shop and I got the first shop to pay for it.

The 14-bolt fill floater in the 2500 burbs is what it used in 3500 trucks....it might be broken but it didn't just wear out. Entirely possible break in period was disregarded as was noted.

Regarding the electrical, if it is resetting the PCM then I would look for something major. Might be the circuit breaker they use in place of the fusible link these days. Agree there is probably stray aftermarket wiring that was improperly secured when lights and such were de-installed, and this is producing a random short somewhere.

I would think a GOOD auto electric shop would be able to trace this out for you, I wouldn't sell this one down the road just yet.

[BenK]

This aliment happens to any side post battery that has that lead, crush washer in the connection stack. Ok if left as is from the factory...but...once that connection is loosened and re-tightened...the crush washer will no longer have enough 'crush' to maintain a good connection

Links to threads from one of my forums...ditto solutions from another of my Boy Racer forums, but won't link them here


Note that there are some posts with sleezy stuff and part of why that forum died...freebie and out of pocket ran into better software needs...but not enough of the members pitched to help defer our costs


Andy has since stopped updating this site
Many of the links don't work, but many still do. We discussed many problems and solved most on this reference site to my old Suburban Forum. I'm "Ben" over there



BATTERIES & CHARGING SYSTEM
Sub page to the above site


Positive battery terminal modification
My first post on this GM battery side post discovery and solution. Year 2000, so my Suburban has 17 years with that modification and have NOT had a connection problem since... Hasn't died for unknown reasons (sure the fuel pump has left me stranded a few times and once with ignition module dying). No more mystery computer resets by itself, etc.


battery dies on '99 K2500 7.4L
One of many, many issues from the GM positive lead washer...a shame most didn't believe it back then and that continues to this day here...an approx $5 buck and 1 hour fix vs so many willing to toss their vehicle and spend tens of thousands on an other vehicle


POS Battery - Can someone outline the right steps to take care of it?
A good one representing this thread here


Need Help!!! Sub died!!!


Charging system troubles


how to replace the positive bat. cable


What Happens when they go bad


The INFamous Battery Problem!


How2 to jump start another vehicle without damaging your alternator
While at this...here is the best way to jump another's dead battery WITHOUT killing hour alternator. An another 'again' folks don't believe in this and then come back with a sad story of yet another dying or dead alternator...

[captnjack]

I forget the years or models/engines involved but the Suburban forums are full of stories about entire vehicle shutting down randomly. Including while driving. I don't remember anyone coming up with a conclusive answer either.

[falconbrother]

I think it would be real interesting to have a multimeter and test the circuits backwards when it shuts down like that.

[Fryer5]

I appreciate all the input.
Trying to find a decent mileage (around 100,000) non rusted 3/4 Ton suburban in Wisconsin right before winter is not a task I am looking forward too. Not impossible, but difficult. I have previously owned 2 suburbans:
An 06 that I bought new. Zero problems until a wreck at 160,000 miles totaled it
An 05 that had 100,00 on when I bought it, kept it until 229,000 miles and rear ending was making noise, decided based on mileage it was time to go. Only thing I did to it was a new rear end at 150,000 and a water pump.

I really like my suburbans. I really thought this one would last us for years, it was overkill on all accounts being a 3/4 Ton. The 1/2 tons I owned before always towed the trailer fine. The second one had the lighter duty rear end, which lead me down the 3/4 Ton path.

[Chrisatthebeach]

I wonder if there is a short in the circuit board of the ECM. When it gets hot it could randomly short out, then after you sit for an hour it cools down, the circuit closes back up and then it starts again. The fact that it randomly stops could be vibration at just the right time when it is heated up.

Do you know of someone with another similar model you could switch out with for testing purposes and rule that issue out?

I have a 2002, the only electrical issue ever was the ABS module stuck killing the battery, was looking for a replacement on E-bay and found some guys in TN that rebuild them and shipped it to them for a rebuild with lifetime warranty for under 40 bucks, that was back in 2010 and it still works fine today.

I also had the pinion bearings in the rear axle go out as well, I pulled a heavy travel trailer at 500 miles for a 700 mile round trip, it started making noise at just under 36000 miles and was covered under warranty.

[BenK]

Here is the image of the modifications to my Suburban's positive battery post. Just replaced the battery last week and think it is the 4th battery, plus the OEM, so makes five batteries. Two were unnecessary, as it took cracking two batteries to figure out what the heck was going on...

An easy and of little cost to solve a major problem that will drive mechanics nuts...until they finally cut apart the OEM molded plastic surround. NOTE...this has to be done to both OEM cable lug ends...look closely and you will see that both of mine has the molded plastic surround cutaway (can't remember which one had the lead washer in it)

Ask if anyone does this, to take pictures of that lead washer so that I can save it to my files...thanks!

All of the OP's symptoms says to me, that the problem is that lead washer in the OEM plastic surround of the positive cable lug. Mine behaved exactly that way...dying in the middle of the freeway, mystery resets of the computer, appeared to be dead...but wiggling the positive cables had it finally start, etc, etc

Cheaper than buying another vehicle and if this doesn't solve, then proof that the problem(s) are elsewhere...not much to lose in trying this fix

Can't remember the thread, bolt dia or length, but easy enough to figure out.

Finger tighten the bolt, after installing the jam nut and the stack of lugs (mine has an alarm lug in the stack). Back off a half of a turn. Then, while holding the bolt head with a wrench, tighten the jam nut down to secure the stack against the battery connection land.




mysub mysuburban GMbattery batterypost GMBattPost

BenK wrote:
Ah...the good old BAD GM battery side post issue...if GM still has side post batteries in your year Suburban...

There is a one time use, lead, crush washer in the stack of stuff on the positive side post

One time usage, as once it is used and crushes to provide the proper contact pressure...it will "NO LONGER" provide proper contact pressure if reused.

Not many believed that on my old Suburban/SUV forum, but those that actually cut apart their positive lead lug end plastic...they found that crush washer

What happens is that the next time the positive post bolt is tightened...there is NOT enough lead washer thickness left to provide proper contact pressure...so everyone...me include till discovered this...cranked the bolt down a bit harder...

what then happens is that the bolt pokes into the battery case and cracks it. Just a bit, or lots if cranked hard enough

That then setups this failure mode:

• Acid leaks out ever so slightly and slowly
• That then corrodes the contact stack of lugs
• That then has the acid wick down the Positive Cable
• That some times corrodes the starter electrical post and sometimes the solenoid
• That then has the positive connection at the battery become intermittent
• That then cause all kinds of gremlins that is almost impossible to diagnosis
• That then load dumps the alternator numerous times to kill the alternator diodes

One of the question I ask is how many times have you had your alternator go bad...also if you have ever jump started another vehicle with your vehicle's engine still running...these two things kills many alternators

This become a vicious cycle chasing ever failing components seemingly associated

Solution is to either switch to top terminals, but few have the room between the hood metal and positive post

Bests solution is to toss that lead washer and replace the custom GM bolt with either a regular bolt of the right thread and LENGTH. That also is long enough to poke out to have a second jam nut between the bolt hex head and the stack of cable lugs. Gotta also have a brass/copper washer interface with the lead connection land on the battery. As that landing sits below the plastic case area

You can keep that stupid lead crush washer with the below image solutions...but was so PO'd that tossing it was the best for my mood at that time...

Not able to take a picture of mine, but found these pictures of what you can buy. I'll take a picture later and post back, but for now here are the pics found on line...such a common gremlin...

[anw7405]

I don't see, or maybe I missed it, how heavy your trailer is and amount of people/ cargo?

This is just my opinion and I'm a chevy guy too. I owned a 2007 denali as my last tow rig and absolutely hated that thing. Constantly in and out of the shop and literally falling apart. I wont go into all the details but it had electrical issues as well.

So.....if you need a 3/4 ton suburban still I would go back one body style. I have owned 2 2000-2006 suburbans, both with way more miles and abuse on them than the 2007, and they are great vehicles. Tires and batteries is all I worry about. I currently have an 05 3/4 ton burb with the 8.1. Hands down the very best truck I have ever owned. Just my 2 cents.

[winger999]

This may sound crazy, but I was just talking to a coworker this morning who has a 2010 Suburban that was making a similar noise to yours. He figured a problem of some kind in the rear end. A local mechanic looked at it with him, and it turned out to be a rusted parking brake that he had never used.