98 blazer fuel pump problems

[spree]

Sometimes I don't hear fuel pump and it won't start, I reach under blazer and hit fuel tank and it starts right up, been going on for about 2 years now. Could it be a bad fuel pump or just a bad ground...always starts when I hit the tank??

[MT-2500]

Originally Posted by spree

Sometimes I don't hear fuel pump and it won't start, I reach under blazer and hit fuel tank and it starts right up, been going on for about 2 years now. Could it be a bad fuel pump or just a bad ground...always starts when I hit the tank??

Could be either or a bad connection or wiring or fuel pump relay.

When no start or no fuel pump check for good 12 volts to fuel pump on gray fuel pump feed wire.

Post back on that

How is the fuel pump rressure readings?

[MT-2500]

Usually taping bottom of tank to get fuel pump to run is a sign of bad fuel pump motor.

[spree]

I've took it to several different places and it doesn't do it their...they say they can't find anything wrong, didn't start once and had it towed and when it got their it started, they also said they can't find anything wrong...sometimes it will go 6 months before doing it again. When it does it it has no pressure and no buzzing from the pump...i reach under and hit the tank with my fist and it starts right up. Starting to get me worried, can't trust it when my wife wants to drive it, so it's been all mine.

[Schrade]

Originally Posted by MT-2500

Usually taping bottom of tank to get fuel pump to run is a sign of bad fuel pump motor.

For 2 years?

If 2 months, I'd agree. But after 2 years, I say wiring problem...

[spree]

It doesn't happen very often, but happened to me twice yesterday. Someone said you can remove the back seat, pull back the carpet, remove a trap door and fuel pump is right their...anyone heard of that?

[MT-2500]

Originally Posted by spree

It doesn't happen very often, but happened to me twice yesterday. Someone said you can remove the back seat, pull back the carpet, remove a trap door and fuel pump is right their...anyone heard of that?

Not on a blazer.
You need to do some proper testing when it does it.

When it no run check for 12 volt power on gray wire at fuel pump relay.
I have had some hard to find the problem that I tie in a test light bulb on the gray wire.

If power there check wiring back to fuel pump and check all grounds and wiring connections good.
If no power there check relay and wiring to relay.

[CraigZerch]

Check the wiring before you do anything else.

[Schrade]

Originally Posted by spree

It doesn't happen very often, but happened to me twice yesterday. Someone said you can remove the back seat, pull back the carpet, remove a trap door and fuel pump is right their...anyone heard of that?

Close, but not quite... It's closer to this:

It doesn't happen very often, but happened to me twice yesterday. Someone said you can remove the back seat, pull back the carpet, make a trap door and fuel pump is right their...anyone heard of that?

If you do it that way, and I would have, if I'd known how much a pain it was, the I suggest NOT welding the cutout back in, rather using a larger piece of metal, and using sheet metal screws.

Something about sparks and gas vapors bothers me UH HUH. I don't know how to play a harp either.

[spree]

Originally Posted by spree

Sometimes I don't hear fuel pump and it won't start, I reach under blazer and hit fuel tank and it starts right up, been going on for about 2 years now. Could it be a bad fuel pump or just a bad ground...always starts when I hit the tank??

My luck finally ran out, had to change the fuel pump, man i never want to do that again. Doe's anyone know what the middle fuel line to the pump does?

[old_master]

I hope you installed an AC Delco or Delphi pump. If you installed an aftermarket pump, you'll be in there again anywhere from tomorrow to a few months from now, if you're lucky!

3/8" line is the pressure line to the injector. 5/16" line is the return line from the fuel pressure regulator. The return line empties into the well that the fuel pump is in inside the module, that's what keeps the pump cool. The 1/4" line is fuel for vapor for the EVAP system. The vapor line has a different style connector from the fuel lines. You can just pinch it together to remove the line from the module.

[spree]

Originally Posted by old_master

I hope you installed an AC Delco or Delphi pump. If you installed an aftermarket pump, you'll be in there again anywhere from tomorrow to a few months from now, if you're lucky!

3/8" line is the pressure line to the injector. 5/16" line is the return line from the fuel pressure regulator. The return line empties into the well that the fuel pump is in inside the module, that's what keeps the pump cool. The 1/4" line is fuel for vapor for the EVAP system. The vapor line has a different style connector from the fuel lines. You can just pinch it together to remove the line from the module.

The 1/4 " line does not snap on the pump like the old one did, I feel it will come loose when I hit a bump (will this be a problem? and what kind of problem will it be?) ( when I pull it off and start, nothing comes out or goe's in)I can cut the hose off and put on a regular fuel line. ( Should I do this?) The pump came from Auto Zone with 1 year warranty. Everything seems to be working good, although I haven't driving it yet. I guess we'll find out this week how it works.
I just looked looked, it is a Airtex pump ($200 cheaper then AC Delco) hope it works good, but at least I know how to take it out.

What my question is : what happens if the middle line (1/4" with the different connector) comes off while driving???

[old_master]

The vapor line clicks when it's fully connected, some of them you can feel and not hear the click. As long as you can't pull it straight off, it should be ok. Cross your fingers with the Airtex pump. I've had them fail before the vehicle even left the shop, (multiple times). The three main problems with aftermarket pumps are: They're noisy. The maximum output is too low, and the check valve doesn't seal as well as it should. Maximum output spec is 108psi, aftermarket pumps are closer to 90psi... not good. The check valve needs to keep pressure in the lines after the pump shuts off. If it doesn't, leakdown becomes excessive which causes extended cranking to start the engine. The guarantee is nice, but it looks bad to my customers when the part fails so quickly. Explaining why we used a cheap quality pump is bad enough, but doing the job the second time, for free, is what really hurts We only install AC Delco pumps, sure they are more expensive, but to me, and my customers, they're worth it.

[spree]

Originally Posted by old_master

The vapor line clicks when it's fully connected, some of them you can feel and not hear the click. As long as you can't pull it straight off, it should be ok. Cross your fingers with the Airtex pump. I've had them fail before the vehicle even left the shop, (multiple times). The three main problems with aftermarket pumps are: They're noisy. The maximum output is too low, and the check valve doesn't seal as well as it should. Maximum output spec is 108psi, aftermarket pumps are closer to 90psi... not good. The check valve needs to keep pressure in the lines after the pump shuts off. If it doesn't, leakdown becomes excessive which causes extended cranking to start the engine. The guarantee is nice, but it looks bad to my customers when the part fails so quickly. Explaining why we used a cheap quality pump is bad enough, but doing the job the second time, for free, is what really hurts We only install AC Delco pumps, sure they are more expensive, but to me, and my customers, they're worth it.

I can pull the vapor line off, I can feel it click on but it comes off easy, too easy, I have a feeling it will come un-clicked I guess you could say. The pump has a different hum then the original but it started up on half of a crank. Always had good luck with Auto Zone parts, I hope they don't fail me this time, but I have no choice, I will be driving it starting tomorrow. I will keep you informed on how everything went. Thanks for the advise.

[spree]

Originally Posted by spree

I can pull the vapor line off, I can feel it click on but it comes off easy, too easy, I have a feeling it will come un-clicked I guess you could say. The pump has a different hum then the original but it started up on half of a crank. Always had good luck with Auto Zone parts, I hope they don't fail me this time, but I have no choice, I will be driving it starting tomorrow. I will keep you informed on how everything went. Thanks for the advise.

So far starting on 1/2 a crank and running good, only been 1 day though. It's been warm here and I've been riding the bike. Will get more of a chance to test it out soon. Will keep you informed on Airtex pump.