Finding a short in your lb7 engine harness is sufficient in order to make any truck owner want to pull their hair out. If you're driving a 2001 to 2004 Chevy or Sierra along with the 6. 6L Duramax, you already know that these vehicles are absolute workhorses. They've got the power, they've got the classic appearance, and they don't have all the complicated emissions equipment that the newer trucks are bogged down with. But, since these trucks grow older, the electrical system starts to show its age, and the main engine wiring harness is usually usually the 1st thing to begin performing up.
It's not really the design flaw as much as this is a consequence of time and environment. Believe about what that will harness has to live through. It's sitting down right on top of a hot engine, vibrating for 100s of thousands associated with miles, and getting pelted with street salt, moisture, and oil. Eventually, the plastic looms obtain brittle, the insulating material on the wires cracks, and you're left with a truck that runs like garbage intended for no apparent cause.
The Infamous Rub Points
If you've invested whenever on the particular diesel forums, you've probably heard individuals talking about "rub points" on the particular lb7 engine harness . This is the most common reason for electric gremlins in these specific trucks. The particular way the harness was routed from your factory involves several sharp bends plus metal brackets that, over twenty many years, behave like a slow-motion saw against the wires.
The biggest culprit is normally right over the alternator bracket. There's great section of the harness that will sits there, plus even with the factory plastic loom, the vibration associated with the diesel engine eventually wears via. Once the real estate agent is exposed and touches that bracket, you're going to see some strange stuff. Your truck might suddenly go into limp setting, or you could easily get a "Reduced Engine Power" message for the dash that disappears the next time you start the truck.
An additional spot to check is near the particular FICM (Fuel Injection Control Module). The particular wiring there is certainly packed in tight, and the heat from your engine tends to cook the wires until they're simply because fragile as dried out spaghetti. If you're poking around within there, be mild. You might go in to fix 1 wire and finish up snapping three others simply by relocating the harness out of the method.
Dealing with the Dreaded Injector Rules
Probably the most frustrating parts in regards to a screwing up lb7 engine harness is that it often mimics the outward symptoms associated with failing injectors. We all know that will LB7 injectors are a sore place and an enormous job to substitute. Imagine spending a weekend and a few thousand dollars swapping out injectors, only to flame the truck upward and realize you still possess the exact same misfire or P0201-P0208 codes.
Occasionally, the issue isn't the injector itself but the transmission arriving at it. The particular harness carries the high-voltage signals through the FICM to the injectors. When the wiring is affected, the signal doesn't get through cleanly, or it pants in order to the block out. I've seen guys replace their entire fuel system when all they actually needed was to repair a few ins of wire or replace the harness connectors.
The good way to be able to test this is actually the "wiggle test. " While the truck will be idling (and in case it's safe to do so), carefully wiggle sections of the particular harness. If the particular engine's tone modifications or the misfire clears up regarding an additional, you've found your trouble area. It's a low-tech remedy, but it works remarkably well for finding those intermittent fractures.
Repairing compared to. Replacing
When your lb7 engine harness begins falling apart, you've got an option for making: do you try to plot it up, or even do you bite the particular bullet and buy a new one? There isn't an one-size-fits-all answer here, and it generally depends on how much patience you have and how much cash you want to spend.
Fixing the harness is definitely the budget-friendly route. If you've discovered a specific scrub point, you may cut out the bad section, solder in some fresh wire, and make use of some high-quality marine-grade heat shrink in order to seal cracks up. Do not use those inexpensive crimp connectors or simply wrap it in electric tape. Within an engine bay, those won't last per month. A person need a solid, weatherproof connection.
However, if the harness is falling apart in multiple locations, you're just enjoying a game associated with whack-a-mole. You fix one short today, and another 1 arises next 7 days. At that point, a full replacement is usually the only way to get your own reassurance back. Brand new OEM harnesses are getting harder in order to find and can be pretty pricey, but there are usually some solid automotive aftermarket options now that will are actually built a bit tougher compared to the originals, along with better heat protecting and improved redirecting.
What to Look for in the Replacement
If you choose to go for a new lb7 engine harness , don't just buy the cheapest one you find on a random auction site. You would like something that uses high-temperature cross-linked polyethylene (TXL) wire. This particular stuff is made to deal with the heat process of a diesel engine without getting brittle.
Furthermore, go through the connectors. The particular LB7 uses some pretty specific attaches for that FICM plus the sensors. The high-quality replacement harness will have connectors that click directly into place firmly. When the fit is free, you're just inviting moisture to get inside and rust the pins, which usually puts you right back to began with intermittent electric issues.
Several aftermarket harnesses furthermore come with "loomed-in" protection in the locations where the stock harness was known to rub. This particular is a massive plus because this means you won't have to DIY some extra cushioning having a piece of heater hose plus some zip ties—though honestly, that's nevertheless a pretty great trick for any LB7 owner in order to know.
Tips for the Swap
Swapping out an lb7 engine harness is not a fun job, yet it's straightforward if you take your time. My biggest piece of advice? Take photos of all things. Before you decide to unplug an individual thing, take 50 pictures from each possible angle. You believe you'll remember exactly where that one ground wire went, yet three hours later on, when you're elbow-deep within the engine bay, you won't.
Labeling is your own best friend. Make use of some masking record and a gun to label both sides of every single connection. It makes the reinstallation go so much faster. Also, keep an eyesight on the plastic clips that keep the harness to the engine. They're probably going to break the 2nd you touch them. Have some heavy-duty, high-temp zip ties on hand so you may secure the new harness properly. If you leave it sagging or even loose, it's just going to vibrate against the block and wear by means of again.
It's the great period to clean some misconception. While the harness is out, you'll have got access to parts of the engine you can't see. Clear off the crud, inspect vacuum lines, and look for any gas leaks around the filter head or the FICM.
Keeping Your Vehicle on the Road
At the end of the day, the lb7 engine harness is simply another maintenance item on an older truck. It's not mainly because exciting as the new turbo or a set associated with wheels, but it's what keeps the particular whole thing operating. These trucks can be capable of carrying out 500, 000 miles if you take care of the "bones, " and the wiring is a large part of that.
It's simple to get frustrated when your truck starts tossing codes and performing erratic, but don't give up upon it. Most of the time, these engines are mechanically sound—it's only the "nerves" (the wiring) that are frayed. Whether or not you spend the Saturday soldering within your driveway or even you drop the money on a brand-new harness, getting that electrical system categorized will make the vehicle think that new once again. You'll get much better throttle response, even more consistent idling, and, most importantly, a person won't be continuously worrying about whether or not you're going to make it for your destination without the tow truck.