Fuel Pump??

[Eric Wettschreck]

My wifes rig (Which I'd like to put some bullet holes through) is a 2000 Bravada. Yesterday, she was driving and it ran fine. Then she said it started losing power. She pulled over and it would idle, kinda, but if she tried to step on the accelerator, it would die. Then it died and wouldn't start.

I towed it home and in the garage, I hit it with a shot of ether. It kind of wanted to start then. Otherwise, it turns over, but nothing more.

I'm thinking her fuel pump just died, and I have a fun (Insert sarcastic remark here) ahead of me. Any one have other ideas??

[Surface Tension]

First you'll test to see if it is the fuel pump.

Can you hear the fuel pump start up when you turn the key to acc.

You should be able to hear it for a few seconds before it turns off.

Can't hear it, start checking fuses and relays. Cross your fingers. Then look around the tank for broken wire. Might as well test for voltage while your down there.

I wish they still put drain plugs on gas tanks, siphoning is impossible. Hopefully your tank isn't full.

Weather should be nice Saturday, we'll know where you'll be, not a good view from there either. Good Luck.

PS: this job is rated 10 on the PBR scale.

[CadCruzer]

I would Change the fuel filter first. Alot easier and cheeper than a new fuel pump.

[Eric Wettschreck]

Frank,

I can't hear the pump. Fuses are good. It's tough to get in there with a volt meter to test for voltage as, I'm sure you know this, everything is conviently located on the top of the tank.

Tanks only about 1/4 full so I'm lucky in that regard.

No, the view isn't pretty. I've dropped a couple of tanks before, and if I remember correctly, I didn't have a very good time.

Filters fine.

10+ on the PBR scale I'm thinkin.

[Shack]

 Originally Posted By: boilerguy

I towed it home and in the garage, I hit it with a shot of ether. It kind of wanted to start then. Otherwise, it turns over, but nothing more.

boiler,

When you say this, did it start and run fine? Did it start and run poor? Any popping or miss fire when started? Did you spray the ether steady and then eng. ran fine during this time?

Could be fuel pump, but I would not rule out ign. (coil, timing belt or other things).

I would do like Surface said. If you have a hard time hearing pump run, remove gas cap and listen down filler neck. It might be worth running down to parts store and buying a fuel pressure tester kit. They are cheap ($19.00 to $30.00 bucks) and come in handy in the future for a lot of things.

I would do an initial key on and check pressure test. Then do a cranking over test while watching gauge for about 10-20 seconds and see how long the fuel pressure holds. I do not know the exact range for PSI, but I think it should be around 30-40 psi. If it fails to produce pressure or hold pressure, the pump is junk. If it all appears to be ok, it is not the pump.

[Shack]

Sorry, it took me awhile to write that post.

Another question I have is did your wife noticed any popping noises before it died. This would not rule out a fule pump if she did. I have had lean concerns cause popping/back fire noises in the past.

[muc33]

Yeah, I got to witness the roadside statue. I offered the Mrs. a ride back to work, but she already had one lined up with a guy in a badge!!!! They can speed and not get in trouble. Hopefully they let her hit the lights and sirens.

I have no clue what to tell you as to fix, other than, PBR YOU ASAP! Don't let your scalp get red over this!

[Macgyver55]

You should have a pressure testing port on the fuel rail where you can check the pressure. I usually just push the schrader valve for a quick check, and if there is pressure, put a gauge on it, if not the pump isn't working. If it tries to run with a shot of starting fluid like you said, unfortunately, in all likelyhood it is probably the pump. You can try having the wife turn on the key while you give the tank a few thumps with a rubber mallet. It may start the pump running, but my bet is your Saturday is shot!

There was also a problem with connectors getting hot and burning the terminals on pickups and SUVs but I don't recall if the Bravadas were affected by it. Either way you'll be changing the module.

[Eric Wettschreck]

No popping, spitting, or backfiring when it died. It has spark. I'll rule out the timing belt real quick as it turns over evenly. Not the uneven or high squeal I've heard in the past when timing chains/belts have broken.

When I hit it with ether I just gave it a quick hit, and the motor fired. I didn't keep trying after that as I'm not a big fan of ether.

Macgyver, you say either way I'll be replacing the module. Um, module??? By module do you mean fuel pump assembly???

Chad, the Mrs said you offered her a ride. Thanks.

[Shack]

Ya, boiler, most likely it is a fuel pump. If a belt jumps a tooth, it can cause something close to what happened. I just questioned it. I hate when the straight and narrow obvious repair is done and the next day a poster goes "well, bought the part and installed. Did not fix it, what next"

The fuel pump/sending unit is called a module and show be replaced at same time (I hate when the sedning unit fails shortly after a repair). You replace just the pump side and leave the sending unit.

Here is an image of a module (pump and sending unit)..

Mc brought up the best rule of testing for a fuel pump, bang on the tank. I most times will start, but not run long after. But if the pump is running, it is most likey weak.

Good luck dude.

P.S.,

Even in the aftermarket relm they are around 300 bones. Never cheap is it

[Jeremy airjer W]

Fuel pressure has to be at least 56 psi with the poppet style injectors that the 4.3 has. If it is 55 psi it will not start. A fuel pressure gauge is needed to accurate determine if the pump is bad. The fuel pressure schrader valve is located on the driver side by the firewall, by the distributor.

The wiring loom that runs along the driverside inside frame rail is where the wiring for the pump is. There is plenty of access to this loom between the tank and the fuel filter. You are looking for a grey wire if there is more than one you want to probe the bigger one. DO NOT STAB THESE OR ANY WIRES ON A VEHICLE WITH A TEST LIGHT, THIS WILL CAUSE THE PROBED WIRES TO CORRODE, FAIL, AND CAUSE FUTURE PROBLEMS! I have used J-R Jumpers (bed of nails) to check wiring for years with no wiring issues as a result of using them. Off the soap box, There should be 12 volts for a couple of seconds when you turn the key. There should be 12 volts anytime the engine is cranking or running.

It is especially important to check power before condemning the fuel pump! The last step is to whack the tank with a hammer while somebody cranks the engine over. If it starts replace the pump!!

I have never replaced a fuel filter to solve a crank no start issue. However I have humored plenty of customers who wished to have this done before any diagnostics where preformed. With that said If the fuel pump is replaced the fuel filter should also be replaced at the same time, no ifs, ands, or buts!

The 4.3 has a Timing Chain not a Timing Belt!

The last thought is there are two options for removing the fuel lines from the fuel pump mudule. Both will require fuel line quick disconnect tools. The first method is to break off the plastic fittings that are part of the module with the fuel lines still attached, then remove the fuel lines with the tool. The other is to specifically use these quick connect tools.

They can be found at just about any parts store. With the tank lowered down a little these can be wedged into the fuel line fittings and they will release without breaking anything. Most of the guys at the shop break them. I have not had to using these tools.

If you do drop the tank there is a vacuum hose on the front of the tank that should be removed before the tank is lowered to prevent the nipple on the plastic evap outlet from breaking off. (a little personal experience there)

Good luck Boilerguy, and may the PBR flow like honey!

[Eric Wettschreck]

Thanks for the tech info guys. Appreciate it.

[Scott K]

Boilerguy, I emailed you a step by step incase you need it. Good luck!

By the way, there is a tsb stating fuel pressure spec is 60-66, not 55-60. tsb # 01-06-04-057

[Jeremy airjer W]

BG one more thing. I think shack or mcgyver already mentioned it but make sure you check the connector at the fuel pump/mudule. If any of the terminals are not shiny and look black or melted (four terminals) replace the connector while you have the tank out.

Next weekend I think you should tackle the intake gasket!

[Eric Wettschreck]

 Originally Posted By: airjer

Next weekend I think you should tackle the intake gasket!

Dude, next weekend I'd rather go fishing. The weekend after that, I hope this rig is sold.

[Jeremy airjer W]

[harvey lee]

I replaced my pump on the pick up last year and its not a easy job but can be done. The hardest part for me was getting under the truck and removing the tank. With a hoist much easier. Get the truck up as high as you can and still be safe. The ring that holds the pump in the tank will more than likely be full of sand and dirt. Clean it out and then tap it with a punch or screwdriver to loosen the retaining ring and then you are good to go. Have a few PBR's and put the tank back in place.

Also, be careful disconnecting the lines so you dont break one. They will bend a little.

[Eric Wettschreck]

Well fellas, this is going to be a drag.

I tested all the fuses and relay. I even switched out the horn and fuel pump relay as they are the same. No go. I depressed the schrader valve and just a little gas came spitting out. Definately not under pressure at all, let alone 66 psi. Turn the key to on, no sound from the back. Crank it over and spit it with a shot of ether, she fires right up. Soooooooooo, new pump and filter here we come.

I just got back from the parts store. You'd think these puppies are gold plated for the cost of them. However, the local parts store guys are still remembering that they totally screwed up a block I had them machine so they gave me a break. Still, pump module and filter, plus an oil filter and air filter for my 68 fury came to $360. Ouch.

Yous guys know how I'll be spending my weekend. Laying on the ground dropping a tank with numerous PBR breaks.

Thanks again for the tech tips fellas. Airjer, I would have broken the vacuum nipple for sure and would have been swearing up a storm about the fuel lines if you didn't let me know ahead of time.

[Shack]

Thanks Air for correcting the timing belt thing . I can honestly say I have work on a Bravada.

Tom,

Way to tackle it on your own. I get what the PBR stands for now . For me it would be about 6 Bl's . I have a hoist and a tranny jack .

You guys crack me up.

[Jim Almquist]

Poor Boy's Refreshments ?

[DTro]

Good Luck Eric

It reminds me of a story of a 83 Firebird Trans AM I had. One day it just died.

I could no longer hear the fuel pump running. Checked fuses/relays.

Bought parts, dropped the tank (pump is inside tank). Also dropped every four letter word in the book a hundred times over while dropping the tank(did all this work myself at 17 yrs old).

Finally got the old pump out, replaced it......nothing. I was so frusterated I just brought it in to the nearest dealer.

They found a broken wire along the fuel line near the front tire.

Live and Learn I say.......

[Eric Wettschreck]

Done. Not the first tank I've dropped, not the worst one either. 7 PBR's and I had it going last night. This leaves today open to get workin on my boat, and a bunch of PBR's.

Appreciate all the tech tips fellas. Jer, that's the first time I"ve ever seen hose clamps like that. Weird that they don't leak. I surely would have broken the plastic vacuum nipple as there's no way I would have seen that line until it was too late.

The wiring harness's wern't toasty at all, but the new module came with new ones so I soldiered the new ones in, anyway. Seemed like the right thing to do.

[Jeremy airjer W]

 Quote:

The wiring harness's wern't toasty at all, but the new module came with new ones so I soldiered the new ones in, anyway. Seemed like the right thing to do.

Never a bad choice!