any LS3 guys here? tech question

[mjeff87]

Buddy of mine has a 20XX-something Suburban, LS3 engine.  He was driving it the other day and it crapped out on him and now is a crank-sputter-no start.  I'm trying to help him remotely but I'm not an LS guy.  He said it had about 1/4 tank of gas in it and he dumped a 5 gallon can of "old" gas in it the evening before it crapped the bed.  Not sure that has anything to do with it, but it's worth mentioning (read on).  After it died, he filled the tank with new gas and added a bottle of something (fuel system cleaner-ish), which didn't help.  He's convinced his fuel pump is shot, but he did confirm 54 psi with KOEO, which is spec.  It jumps to 58 when cranking also.

 

I'm thinking CPS, or something causing either the plugs or injectors to not fire (like a CPS, lol).  I've asked him to pull a plug to see if it's wet, which would tell if the injectors were firing, and also asked him if the tach needle was moving while cranking.  IIRC, if it doesn't move that's an indicator of a failed CPS.  I'm waiting on a reply for him on both of those questions.

 

Anyone have any other ideas?  He's about ready to order a new fuel pump, and I don't want to see him just throw (expensive and/or hard to replace) parts at it hoping to fix it.

 

edit:  I've also asked him what, if any, codes have been thrown.  Waiting on that info too and will update thread if needed.

 

Thanks

[Pete M]

it's quite possible that the bad gas is the issue and the only fix is to drain it all and start over.  had to do this just the other day with my lawn tractor.  

 

if he's reeeeeal lucky it might just still be residue crap gas in the hoses and he just needs to drain that out. 

[Smokeyyank]

If he's getting fuel pressure to the injectors it's not the pump. My wifes KJ just crapped the bed because the fuel pump went out. I can't hear it prime and I got 0 pressure at the schrader valve. Has he tried to start it in neutral? Possible neutral safety switch. Is he getting a spark? Last thing is does he have a key with the chip in it? I know sometimes if those go bad it won't let you start them. Like on the KJ. 

[mjeff87]

1 hour ago, Pete M said:

it's quite possible that the bad gas is the issue and the only fix is to drain it all and start over.  had to do this just the other day with my lawn tractor.  

 

if he's reeeeeal lucky it might just still be residue crap gas in the hoses and he just needs to drain that out. 

 

He said it was a can of crappy gas he had in the shed for his mowers and whatnot, from last year.  It's quite possible that it was more water than gas.  It's either that or a no spark condition.  I told him to fog the intake with a small amount of ether to see if it would pop off, which would rule out an ignition problem, at least.

 

 

11 minutes ago, Smokeyyank said:

If he's getting fuel pressure to the injectors it's not the pump. My wifes KJ just crapped the bed because the fuel pump went out. I can't hear it prime and I got 0 pressure at the schrader valve. Has he tried to start it in neutral? Possible neutral safety switch. Is he getting a spark? Last thing is does he have a key with the chip in it? I know sometimes if those go bad it won't let you start them. Like on the KJ. 

 

don't say that about a KJ.....I drive one and at times I can hear the pump whining like the old one in my MJ did just before it died, lol.  I'm NOT looking forward to replacing it, either via dropping the tank or going in from the top.  I've done the research, and both are not things I really want to do 

 

I don't think it's a NSS issue, but I'll ask him to try the neutral trick.  Ether test will confirm spark (if he actually does it), and I have no idea on the chip key.  It's been running fine up until a couple days ago and actually died on him while driving so I don't think that's the issue, but thanks for mentioning it as a possibility 

[Smokeyyank]

28 minutes ago, mjeff87 said:

don't say that about a KJ.....I drive one and at times I can hear the pump whining like the old one in my MJ did just before it died, lol.  I'm NOT looking forward to replacing it, either via dropping the tank or going in from the top.  I've done the research, and both are not things I really want to do

 

Yeah here random dying issue turned into a permanent one. I'm hoping I can take care of it from the top but will see what happens. Will probably fix it and get it ready to sell. She's pushing 175k on it and I'd rather not deal with a head gasket if it decides to go. 

 

Good luck on helping him out. Hopefully he actually tries to trouble shoot it and not fire the parts cannon. 

 

 

[mjeff87]

I don't have any drivability issues with mine (knocks on wood....), it's just every once in awhile the pump gets really loud.  It's an 02, with only 130k on it.  I figure if the head gaskets or valve seats (or keepers) were gonna fail, they would have done it by now.  Lol.

 

 

I'm shooting for 200k on it, which would be about 3 more years of driving it.

[Alexia]

I did the water in gas bit before.  Pressure was fine, but the external fuel filter was saturated with water along with a thin layer of water at the bottom of the tank that was difficult to see from looking inside.  It took pulling the tank and replacing the fuel filter to fix it.

[mjeff87]

Well, he's convinced that it's bad fuel (and I'm leaning in that direction as well), although he did not do any of the tests I suggested. 

 

He wants to cut a hole in the floor to access the pump, pull it out and insert a harbor freight hand-crank pump to suck the tank dry.  I quietly suggested he find a connector somewhere in the fuel supply line underneath (is there an inline filter on Suburbans?) or use the schrader valve on the fuel rail (take the core out), add a hose and jumper the fuel pump relay slot and let the in tank pump empty the tank.  But what do I know........lol.

 

I'll update with what he decides to do. 

[87Chief]

Saw this the other day... Send this to him if you think this might help..

 

https://www.youtube.com/watch?v=E51wuf3xCm4

[Pete M]

why the hell would he not use the pump to drain the tank? 

[mjeff87]

1 hour ago, 87Chief said:

Saw this the other day... Send this to him if you think this might help..

 

https://www.youtube.com/watch?v=E51wuf3xCm4

 

 

LOL, I think you linked the wrong video.......I watched all 12 minutes of that.  It's the NEXT video (part 2) that shows the fix, which was the CPS, like what I'm thinking, but he didn't do any of the diagnostic tests I told him to do to try and figure it out.  He's convinced that it's fuel related, which it very well may be, but he needs to troubleshoot it first before tearing into it......

7 minutes ago, Pete M said:

why the hell would he not use the pump to drain the tank? 

 

 

You'd have to know him and his personality to understand it.  See above about troubleshooting, or lack thereof......he's very, let's say, impetuous.

 

He says there's about 18 gallons in the tank now, which I admit is alot of gas to drain.  I think he's just looking for the fastest way to get the fuel out of the tank.  Fastest doesn't equate to smartest, or most logical, in his mind.  LOL.

 

[mjeff87]

He also said it did have stored codes for O2 sensors and multiple misfire, but no CPS code.  So.....I dunno.  If he'd do the diagnostics like I told him to he wouldn't be playing the "guess this is the problem, let's replace THAT" game.  Oh well, I can only do so much.

 

The big thing is, he scored a replacement 5.3 awhile back and sent it to a machine shop for a full bottom end and head(s) rework.  It's ready for him to pick up so he can bring it back to his place and put a whole bunch of new peripheral long block stuff on it and swap it in.  I know already I'm going to be intimately involved (read: probably doing most of the work) when swap-time comes, and I'm dreading it.  

 

He doesn't want to take the time to fix the current problem on the old engine with the new one almost ready to go in.

[Pete M]

yeah... he's going to want to fix that issue first... 

[87Chief]

3 hours ago, mjeff87 said:

 

 

LOL, I think you linked the wrong video.......I watched all 12 minutes of that.  It's the NEXT video (part 2) that shows the fix, which was the CPS, like what I'm thinking, but he didn't do any of the diagnostic tests I told him to do to try and figure it out.  He's convinced that it's fuel related, which it very well may be, but he needs to troubleshoot it first before tearing into it......

 

 

 

 

Sorry about that! 

[mjeff87]

Just a quick follow up on this.....he's still at it.  Hasn't done any of the diagnostic testing suggested, but went and got a new CPS anyway and installed it yesterday.  That did nothing to fix it.  Then he texts me saying he "flushed out" the metal can the gas he put in was stored in and "clumps of sludge" came out.  He never said that gas was THAT bad......

 

I've got a feeling the (in-tank) filter is hosed at this point, but he claims he is still getting 54 psi at the rail (jumps to 58 when cranking).  A small part of me still thinks it's an ignition problem, but if it walks like a duck, then you know the rest.

 

I'll probably end up driving up there this weekend when I don't have any time to and help him get it sorted out finally.

[Smokeyyank]

[mjeff87]

^^^LOL, yup.

 

I think he's also mistaken when he's telling me the fuel filter is in-tank with the pump.  All of the interneting I've done today (while I'm here hard at work) is showing the filters were inline on the driverside framerail up to 2006.  IIRC, his 'burb is either an 03 or 04.  I would be totally not shocked if he was wrong on that.  It could be just as simple as swapping in a new $10 filter.  Or not.

[mjeff87]

Hallelujah.....it's not fixed yet, but at least he's doing diagnostics.  Says it will run for about 5-10 seconds on a shot of ether.  That little fact would have saved him the $30 or whatever he paid (proabably more, it was an AC Delco part) for the new CPS.  And, I've got him good with the idea of draining the tank via the fuel pump.  Hopefully that won't clog up the filter, which is still undecided as to in-tank or stand alone on the frame rail somewhere.

[Pete M]

fuel tank should have a sock in it.  that might be what he's thinking of.   But there will also be a fuel filter somewhere in a location that can be changed on a regular basis. 

[mjeff87]

There is a definite cutoff on the external filter......I think it's 2006 per everything I'm seeing on the internets.  After 2005 the filter is integrated into the pump assembly and is non-serviceable.  I've asked him 3X now what year his is, he's not answering the question.  Frustrating to say the least.

 

On a side note, I put a new valve cover gasket on the 2.0L in the Focus over the weekend.  I'd been getitng a faint "burning oil" smell after running on the interstate lately and it's been bugging me, especially now with nice weather and the windows down (A/C isn't working in it currently, but I'm not in any rush to diagnose the problem).  $45 and a gasket later, no more smell 

[Pete M]

so I can't replace the fuel filter?  just one more reason why modern cars suck to work on.  

[mjeff87]

Well, it took him a month but he finally just fixed it.  It ended up being the bad gas (if you can even call it that.....) he dumped in the tank.  He cut an access panel above the tank and pulled the pump and internal filter, replaced it with a whole new unit.

 

He sent me a pic of the inside of the (poly, not metal) tank.  Un-freaking-believable......

 

 

[Pete M]

the words escape me...

[mjeff87]

Yeah, for the want of trying to use up about $15 worth of old gas, it ended up costing him about $200 for a new pump/filter, a locking ring tool to get the pump swapped out, and 2 new O2 sensors.

[Pete M]

ouch...