Fuel Pump Going Out?
 

Hi everyone, quick comment/question... I have a 98 Blazer 4x4, 4.3l... I have never owned a vehicle before that I had to replace the fuel pump so I have no real idea what the warning signs are? Do they just suddenly stop working or does it vary? I noticed 2 days ago it began to kinda misfire, tach would move down while at idle but seemed fine while driving... Today though it wanted to cut out even while driving... I am hoping I just need a complete tune up since it has been about 2 years since the last one was done on it... I am no where close to the mechanic most of you guys are so I have a local shop do almost all of my upkeep on our vehicles. Any thoughts would be greatly appreciated, especially before I start throwing money into this thing :)

The best way to check the fuel pump is to have a fuel pressure leak down test done. It may not be the pump, it could also be the regulator/spider unit under the plenum. The test will show if this is the issue also.

Yep, check the fuel pressure.

I've had lots of experience with bad fuel pumps. In my experiences, they don't just quit completely. You'll notice a distinct lack of power. Heavy acceleration, or steep hills is where I've noticed it. Often I'll get a flashing check engine light, indicating misfire.

Thing is, the truck really dosen't lack power at all... The other thing is the yellow service engine light stays on constantly, but it has been on since the day I bought it which was a little better than 3 years ago! I had it checked out way back then and it could be a ton of different things lol... It has always ran just fine so I never messed with it. I must be near a record for a light that won't burn out :)

Do you remember what the codes are? Might be helpful to get those pulled, give us something to go off of

Ok, just went through every receipt and record I keep in the glove box and realized I never did a "complete tune up" on it... I only changed the plugs and wires! I am going to buy the whole package this time and see if that is my problem :) Can't do it until this weekend though but I will report back with an update, thanks for the replies!

There's not much besides plugs and wires. Guess you still could do rotor, dist cap and fuel filter

Mine was really weird when it went. She got reluctant to start for a bit but then ran pretty much fine once started. Then she flat refused to start on me in the driveway one day, so I added ~2 gal of fuel from a jerry can since my fuel sending unit (part of the fuel pump assembly) had been out for years so I figured I had inadvertently run out of gas. I chalked it up to stupidity, reminded myself to keep an closer eye on the trip mileage and didn't think much more of it. Ran and started for a few more days thereafter.

A week or so later she left me stuck in the grocery store parking lot; she had run fine all the way there but didn't want to leave. I put ~3 gallons of gas in it from a jerry can brought by a friend (hey, it had worked once...) before giving up and having it towed to the shop where the fuel pump was finally actually diagnosed. They had to drop the tank to replace it, and remarked that it was completely slam-full for... some reason. :icon_goofygrin:

I managed to act shocked for a second before fessing up to what I'd done.

Ok, I gotta confession too make lol! I never let the truck get below a quarter tank by the gas gauge. Well this go round it was sitting at a hair above empty... Only added 5 gallons in case they have to drop the tank if it was the fuel pump... Well, no misfire, no tach jumping around ect... Basically the thing was like bone dry on fuel! My wife had the grin of the devil and said "humm, it is your Blazer, I just took it from you because I like the heated seats"... I just shook my head and smiled :) Those of you married out there know exactly what I am talking about lol!!! What are ya gonna do :)

Rule # 1 Happy wife happy life
RULE # 2 Sometimes being a hermit is a plus.
Rule # 3 If you do not agree you have never been married.


Edit = order change