Is your newer TBI motor skipping??...might want to read this.

[diesel4me]

My older brother ran into some trucks with TBI woes in the fleet he maintains recently..they have several 2002 and newer trucks with the 5.3 and 6.0 motors,and two of them started skipping recently..hooking up a computer to read the codes showed "cylinder misfires" on both trucks..

He checked fuel pressure,it was within specs..had spark at the plug in the "dead" cylinder,and the plug wire and coils checked out OK too!..so he assumed the injector was to blame--pulled it out,it was clogged with red dust--rust!..truck has about 60K on it!..

So he gets a new injector,installs it,and it runs perfectly again--for a few minutes anyway!--soon it is skipping again,and this time its another cylinder that is "missing"!..pulls that injector,it too is plugged solid with the same red rust dust!..

He assumed the fuel tank was either rusted ,or contaminated with bad fuel,so he pulls the tank out (bitch of a job!)--then finds as he pulls the sending unit out,that the tank is spotlessly clean,and NO rust in the tank!..--the fuel filter had no rust in it either,after cutting it in half to inspect it!..

So he moves on to the steel fuel lines,that run from the tank to the engine--and found a TON of rust growing INSIDE that steel line!--also,the fuel rail itself that goes on the injectors is rusting badly inside,and is clogged up with that red rusty dust!.. ..not something you'd expect to see on a 4 year old truck with low mileage!...

The local GM dealer parts counterman told him this is not all that uncommon!--but so far GM has no plans to replace the lines under a "silent recall" or warranty them,so its up to him to replace all the rusted lines,the fuel rail,and all 8 injectors,to the tune of 1200 bucks!..good thing the company owns the trucks..he assumes the other trucks with the same symptoms are suffering from the rusted line syndrome too.. lots of work ahead of him!..

Just thought some of you guys with TBI troubles might want to hear about this dilema...I think it sucks a vehicle that new would already be having this type of trouble,and if I had paid 20 grand for a new truck and it was having this trouble,I'd be really pissed!..WTF are they using for steel,recycled rust??...made in MEXICO is stamped on the original line,AND the new ones too,that will likely be junk in a few more years too!..whatever happened to GOOD quality??.....

 

[pauly383]

What is the cause of the rust ? The area you live in , or the fuel itself ?

 

[84zz4ss]

As a gm dealership tech I have seen a few of these. In my experience gm will not cover contamination under warranty. I have seen a customers insurance company pay for the repair. I question fuel quality..

 

[diesel4me]

Fuel??..

I'd say the lines themselves are the cause,probably made from recycled steel of poor quality,(and not galvanized on the inside??),more than anything..There would have been rust in the tank and fuel filter if fuel contamination was to blame,IMO...

I have seen many later model vehicles with rusted fuel rails the past couple of years here,and when I go to a junkyard to buy another one,more than one already had a pinhole rusted thru,after getting it all installed!--and I had to go strip another one..dealer gets outrageous money for a new one (if even available!),so used ones get installed here quite often..

They have quite a profitable raquet going here--first it was sending units that rotted out in 5 or less years,that often had the fuel pump integrated,so you had to replace everything to the tune of 500 bucks in many cases..now the entire fuel system seems to be made of "temporary" steel,that only lasts long enough to avoid being replaced under warranty.. ..the average Joe cant afford to dump 1500 bucks into a fairly new low milage truck!..

 

[84zz4ss]

Just to check some details. The lines into and out of the filter are metal lines. But the filter was clean? The fuel tank most of the time is poly. Should not rust. The fuel rails where the injectors plug in is also plastic. Should not rust. The system also has a steel return line to the tank so if the lines are the source of the rust it should also be present in the tank.

I agree that there is a problem. Is it fuel quality? Could it be water?

This is in no way meant to be offensive. But just another set of eyes looking at the problem.

 

[ryan22re]

When I would get one, they would have rust in the tank, and the rust would have usually damaged the fuel pump as well. Most times clog the injectors in that are at the ends of the rails i.e. Cyl's 1, 7, 2 and 8. Done two or three of them that way. Two covered by warranty, one not.

 

[diesel4me]

rusting away...

Yes,the tank was plastic--and clean as the day it left the factory, he said!..no rust in the filter either,just in that fuel line going to the motor,the fuel rail itself,and the injectors..he doesn't see any way the fuel could have done it..he is certain its just crappy steel,rotting away in record time!.. I wonder of "Oxogenated" gasoline causes more rust,seeing it has its own oxogen supply??.and ethanol mixed in with the gas will help "flush" out any contaminants too..I know many boaters here have had a nightmare with their fuel systems since this 10% ethanol gas was introduced last spring here..fiberglass tanks are freaking out,old rubber fuel lines are failing,causing fires,etc..

He's going to put a magnet on the fuel filter when he replaces everything,hoping if it goes get "rusty" gas somewhere down the line it will trap it in the filter,and not let it get any further than that..but this was not the cause of this dilema,it was an "inside job"..GM used cheap mexican made lines,and their customers will be the ones paying for the repairs evidently,in most cases..

 

[sweetk30]

we just had a 5.3 truck in shop. mis fires left bank. found sucked in intake gasket. replaced. still did it. customer/employe did own master tuneup. plug wires and filters. 1.5 hrs diagnostic time later found a busted up cat on left bank. banged on left exaust and rattled all the way down the line. unbolted manifold to down pipe and all problems went away.

but i have to seen rusted fuel rails and lines. and the filter was clean. others i have seen 95% pluged filter and still ran good.