I spent fifty years working on GMC, Ford, and other makes as a mechanic, so I speak from experience, not that I am necessarily the sharpest knife in the drawer.
First, I am sixty seven, I have had nearly fifty years years of experience repairing numerous makes of vehicles including GMC, so that is out of the way. Yes, I am old but not ready for the pasture and my brain is working reasonably well.
The 1997 GMC torpedo fuel pumps like so many, are basically prone to failure (I wanted to use another definition about the fuel pump quality - however, I want to keep my comments civil).
Whether original equipment or aftermarket, it makes little or no difference with regard to part quality, basically, we have become China dependent. This isn't just my consensus, you can find hundreds, if not thousands of professional mechanic posts on the Internet about the continual failure of these fuel pumps. The average life span of these pumps is 2 - 4 years, assuming that you keep your gas tank at least 1/2 full, install a decent fuel filter and change it at no less than at 10,000 mile intervals.
There are differences in fuel filter quality/brands as well, many swell up so bad that they become restrictive and can affect fuel delivery placing additional strain on the pump. These fuel pumps also overheat and become toast easily if you run your tank below quarter, I would recommend that you keep your gas tank between quarter, and half full.
Contrary to popular belief, the majority, if not all these fuel pumps are manufactured overseas, China being the major resource. Do not be fooled when some tells you about original GM parts/equipment being better than aftermarket parts, GM has many of their parts manufactured in China. As long as the replacement parts are assembled in the U.S, they can be designated as original equipment, when in fact they were manufactured in China or some other third world country. So do not be fooled into believing that when you buy an aftermarket replacement part your getting a part of lesser quality. All they do is stamp their name or logo on the same part.
For example, I recently replaced a GM original equipment ignition control module on a GMC Sierra half ton four wheel drive 5.7 liter, while removing the defective control module it was stamped with the original "GM" Equipment Logo" on the front, when you turned it over, it was stamped "Singapore." So, once again, do not be fooled into believing that it was actually made in America and is any better or worse than an aftermarket replacement part.
You can pay $80.00 to $120.00 for an original equipment 1997 GMC fuel pump or you can pay $19.95 plus shipping for a fuel pump from Genesis Auto Parts that is no better or worse than the designated original equipment fuel pump, by the way they have an excellent reputation for automotive replacement parts. (I do not work or get paid any residuals from anyone for my recommendations).
About failing or failed in-tank GMC fuel pumps.
The fuel pumps on the 1997 GMC 5.7 and other years all have the same problem, the torpedo pumps generally fail within two to four years, regardless of whether you have a fuel pump strainer installed, keep the tank filled to capacity, and have a high quality fuel filter installed, basically, they're all the same. This is more of a problem now-a-days due to an economy which has made it difficult for families to keep the gas tank half to full.
I have read so many comments on this fuel pump issue over the years and most are way off base with regard to fuel pump diagnosis, but the most ridiculous of all is, that one must purchase an original equipment fuel pump because the others are junk or of lessor quality.
First of all, the majority of all these fuel pumps are now manufactured in China, the only difference being that they have their name or logo stamped on them "original whatever name" that is stamped on the pump means absolutely nothing. As long as the pump is assembled in the U.S. It can be identified as original equipment made in America, when in fact all the piece parts were manufactured in China, for all I know, they have found away around having to import the piece parts and are importing them already assembled, that what they call "trade agreements ". So, you can pay $80.00 to $120.00 for a fuel pump or, you can pay $19.95 plus shipping and handling from Genesis Auto Parts and get the same quality, (I do not work for anyone, I am retired).
Bottom line, I have replaced three of my own fuel pumps in eleven years on my GMC 5.7 and I have listened to hundreds if not thousands of complaints about GMC failed fuel pumps, you can find this information all over the Internet.
So what is "original GM equipment" anyway?
Here is one example, I have replaced ignition control modules on GMC's, when I was removing the original equipment defective devices, they were stamped "GM" on the front implying that they where original equipment made in America of the highest quality. When you remove the module, on the back of the device, it says "Singapore", I think Singapore is in China, do you?
Back to the pump issue.
The bottom line, you are going to have to live with this fuel pump aggravation and replace the pump numerous times over the life of your vehicle. I would suggest that you replace the fuel filter at intervals of no less than 10,000 miles, also be sure that you install a gas strainer on the pump when you replace it. These pumps overheat easily if you run your gas tank too low, never below quarter, I would suggest quarter, to half.
You also need to know how to perform a proper fuel pump test to determine if the fuel pump is beginning to fail or is actually dead. Spend $30.00 and get yourself a fuel pressure gauge, most come with adapters for both GM and Ford vehicles.
Here are the tests that you need to perform.
Be absolutely sure that you inspect your fuel filter for restrictions before performing the following tests. Some fuel filter brands are known to have filter elements that can actually swell and restrict flow. Be sure that your coolant temperature sensor has been checked and known to be in good working condition, that's the one that generally sits up front near the thermostat housing, it can also cause hard starts. Having verified the above we move on.
Perform the following tests when the vehicle is stone cold, let the vehicle sit overnight, then perform the tests. This is important because if the vehicle is warm, it may start, but when cold, it will not start.
1. If your vehicle starts hard, or when it is stone cold it fails to start at all or, requires numerous cranking attempts to get it started or, requires that you spray starting fluid or pour a few drops of gas into the throttle body, your pump is on the way out or gone.
The 1997 GMC Sierra vehicles have a fuel pressure port on the fuel line under the hood, it is a Schrader Valve port where you can attach the fuel pressure gauge. Now have someone sit in the vehicle and turn on the key (do no t crank the starter/engine), now observe the reading, it must read at least 60 - 65 PSI, if it reads "0" the pump has failed, if it reads below 60 PSI and does not drop to "0", you have a fuel pump issue that is in the beginning stages of failure. Assuming the fuel pressure test met the 60 - 65 PSI requirement, go to step two (2).
2. If the gauge does read 60 - 65 PSI, now have your friend crank the engine, read the result, if the gauge drops below 50 PSI but does not go to "0" when cranking (not running). Yes, while the engine is cranking your fuel pump is on its way out and will either cause hard starts or, not start at all without a priming assist with starting fluid or a few drops of gas poured into the throttle body. Anything below 50 PSI when cranking, you are going to have to replace the pump. Most fail to perform the cranking test and misdiagnose any fuel pump delivery problem.
Obviously, if the gauge reads "0", the pump has complete;ly failed. Yeah, I know checkT the fuse first.
Yes, there are other things that can cause hard starts or failure to start, however, 99% of the time the tests noted above will reveal either a good fuel pump or one that needs to be replaced, or one that has failed.
Hope this helps.
Monday, December 12th, 2011 AT 8:50 PM